Main report: Bioenergy - a Sustainable and Reliable Energy Source

Main report: Bioenergy - a Sustainable and Reliable Energy Source
This report was jointly prepared
for IEA Bioenergy by the Energy
Research Centre of the Netherlands
(ECN), E4tech, Chalmers University
of Technology, and the Copernicus
Institute of the University of
Utrecht. The purpose of the report
was to produce an authoritative
review of the entire bioenergy sector
aimed at policy and investment
decision makers. The brief to the
contractors was to provide a global
perspective of the potential for
bioenergy, the main opportunities
for deployment in the short and
medium term and the principal
issues and challenges facing the
development of the sector.
Bioenergy – a Sustainable
and Reliable Energy Source
MAIN REPORT
IEA Bioenergy
IEA BIOENERGY: ExCo: 2009:06
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BIOENERGY – A SUSTAINABLE AND RELIABLE ENERGY SOURCE
A review of status and prospects
Lead authors: Ausilio Bauen (E4tech); Göran Berndes (Chalmers University of Technology);
Martin Junginger (Copernicus Institute of the University of Utrecht); Marc Londo (ECN) and François Vuille (E4tech)
Contributing authors: Robert Ball (E4tech); Tjasa Bole (ECN); Claire Chudziak (E4tech);
André Faaij (Copernicus Institute of the University of Utrecht) and Hamid Mozaffarian (ECN)
KEY MESSAGES
Bioenergy is already making a substantial contribution to meeting global energy demand. This contribution can
be expanded very significantly in the future, providing greenhouse gas savings and other environmental benefits,
as well as contributing to energy security, improving trade balances, providing opportunities for social and
economic development in rural communities, and improving the management of resources and wastes.
Bioenergy could sustainably contribute between a quarter and a third of global primary energy supply in 2050.
It is the only renewable source that can replace fossil fuels in all energy markets – in the production of heat,
electricity, and fuels for transport.
Many bioenergy routes can be used to convert a range of raw biomass feedstocks into a final energy product.
Technologies for producing heat and power from biomass are already well-developed and fully commercialised, as
are 1st generation routes to biofuels for transport. A wide range of additional conversion technologies are under
development, offering prospects of improved efficiencies, lower costs and improved environmental performance.
However, expansion of bioenergy also poses some challenges. The potential competition for land and for raw
material with other biomass uses must be carefully managed. The productivity of food and biomass feedstocks
needs to be increased by improved agricultural practices. Bioenergy must become increasingly competitive
with other energy sources. Logistics and infrastructure issues must be addressed, and there is need for further
technological innovation leading to more efficient and cleaner conversion of a more diverse range of feedstocks.
Further work on these issues is essential so that policies can focus on encouraging sustainable routes and provide
confidence to policy makers and the public at large.
Disclaimer: Whilst the information in this publication is derived from reliable sources and reasonable care has been taken
in the compilation, IEA Bioenergy and the authors of the publication cannot make any representation or warranty, express
or implied, regarding the verity, accuracy, adequacy or completeness of the information contained herein. IEA Bioenergy and
the authors do not accept any liability towards the readers and users of the publication for any inaccuracy, error, or omission,
regardless of the cause, or any damages resulting there from. In no event shall IEA Bioenergy or the authors have any
liability for lost profits and/or indirect, special, punitive, or consequential damages.
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TABLE OF CONTENTS
KEY MESSAGES
2
EXECUTIVE SUMMARY
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Introduction
Biomass Resources
Biomass Conversion Technologies
Bioenergy Markets
Interactions with Other Markets
Bioenergy and Policy Objectives
Lessons for the Future
A Sensible Way Forward
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CHAPTER 1: INTRODUCTION
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1.1 Objectives and Scope of the Report
1.2 Structure of the Report
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CHAPTER 2: BIOMASS RESOURCES AND POTENTIALS
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2.1 Overview of Biomass Feedstocks and Global Technical Potentials
2.1.1 Technical biomass potential
2.1.2 Key factors influencing technical biomass potential
2.1.3 Biomass potential taking into account several sustainability constraints
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2.2 Regional and Short-term Biomass Utilisation Scenarios
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2.3 Environmental and Other Aspects of Energy Crop Production
2.3.1 Water availability and competition
2.3.2 Environmental functions of bioenergy production
2.3.3 Biodiversity
2.3.4 The agricultural sector, crop improvements and GMOs
2.3.5 Climate change impacts
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2.4 Biomass Supply Chains and Logistics
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2.5 Key Messages for Decision Makers
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CHAPTER 3: BIOENERGY ROUTES AND CONVERSION TECHNOLOGIES
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3.1 Biomass – A Unique Renewable Resource
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3.2 Characteristics of Bioenergy Routes
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3.3 Biomass Pre-treatment and Upgrading Technologies
3.3.1 Pelletisation
3.3.2 Pyrolysis and hydrothermal upgrading
3.3.3 Torrefaction
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3.4 Biomass for Heat Applications
3.4.1 Combustion
3.4.2 Gasification
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3.5 Biomass for Power and CHP Applications
3.5.1 Biomass combustion
3.5.2 Co-firing
3.5.3 Gasification
3.5.4 Anaerobic digestion
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3.6 Biofuels for Transport Applications
3.6.1 Definitions and development status
3.6.2 1st generation biofuels
3.6.3 2nd generation biofuels
3.6.4 3rd generation biofuels
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3.7 Biorefineries
3.7.1 Concept and definition
3.7.2 Development status and prospects
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3.8 Key Messages for Decision Makers
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CHAPTER 4: BIOMASS TRADE AND BIOENERGY MARKETS
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4.1 Bioenergy Markets and Opportunities
4.1.1 Biomass-to-heat
4.1.2 Biomass-to-power and CHP
4.1.3 Biomass-to-biofuels
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4.2 Trade in Biomass Energy Carriers
4.2.1 Main commodities traded and trading routes
4.2.2 Current and future trade volumes
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4.3 Bioenergy and Commodity Markets
4.3.1 Introduction
4.3.2 Bioenergy and agro-forestry – relationships between competing sectors
4.3.3 Price impact estimates
4.3.4 Policy implications
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4.4 Barriers to Deployment and Market Risks
4.4.1 Supply side risks and barriers
4.4.2 Technology risks and barriers
4.4.3 Market risks and barriers
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4.5 Key Messages for Decision Makers
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CHAPTER 5: BIOENERGY AND POLICY OBJECTIVES
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5.1 Introduction
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5.2 The Role of Bioenergy in the Stationary and Transport Energy Systems
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5.3 Bioenergy and Climate Change Mitigation
5.3.1 Conclusions from lifecycle assessments and well-to-wheel analyses
5.3.2 Impact of direct and indirect land use change on greenhouse gas emissions
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5.4 Bioenergy and Energy Security
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5.5 Other Environmental and Socio-economic Aspects
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5.6 Key Messages for Decision Makers
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CHAPTER 6: MAKING POLICY FOR BIOENERGY DEPLOYMENT
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6.1 Introduction
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6.2 Common Lessons for Bioenergy Policy Making
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6.3 Bioenergy Technology Support Instruments for Different Development Stages
6.3.1 Policies related to the RD&D phase
6.3.2 Policies related to early markets
6.3.3 Policies related to mass markets
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6.4 Key Characteristics of Bioenergy Policies by Sector
6.4.1 Heat
6.4.2 Power generation
6.4.3 Biofuels
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6.5 Other Policy Domains Relevant for Bioenergy
6.5.1 Agricultural policies
6.5.2 Forestry policies
6.5.3 Land use planning policies
6.5.4 Trade policies
6.5.5 Environmental policies
6.5.6 Communication with the public and education of relevant professional groups
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6.6 Sustainability Policies and Certification
6.6.1 Sustainability principles relating to bioenergy
6.6.2 Key characteristics of bioenergy certification systems
6.6.3 Addressing indirect effects
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6.7 Support for Bioenergy Policy
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6.8 Key Messages for Decision Makers
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REFERENCES
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ANNEX 1: UNITS AND CONVERSION FACTORS
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Annex 1.1 Energy Conversion Factors
Annex 1.2 Metric System Prefixes
Annex 1.3 Currency Conversion Approach Adopted in this Report
ANNEX 2 : BIOMASS RESOURCES AND POTENTIALS
Annex 2.1 Overview of the Long-term Global Technical Potential of Bioenergy Supply
Annex 2.2 Biomass Yields of Food and Lignocellulosic Crops
Annex 2.3 Overview of Regional Biomass Production Scenario Studies
ANNEX 3: BIOENERGY ROUTES AND CONVERSION TECHNOLOGIES
Annex
Annex
Annex
Annex
Annex
Annex
Annex
Annex
Annex
Annex
3.1 Biomass Upgrading Technologies
3.2 Biomass-to-Heat Technologies
3.3 Biomass Combustion-to-Power Technologies
3.4 Co-firing Technologies
3.5 Biomass Gasification Technologies
3.6 Anaerobic Digestion Technologies
3.7 Feedstock Yields for Sugar and Starch Crops used for Bioethanol Production
3.8 Production Costs for Different Biofuels
3.9 Renewable Diesel by Hydrogenation
3.10 Conversion Pathway of Lignocellulosic Material into Bioethanol
ANNEX 4: BIOMASS TRADE AND BIOENERGY MARKETS
Annex 4.1 Overview of Bioenergy Flows into Final Applications
ANNEX 5: BIOENERGY AND POLICY OBJECTIVES
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Annex 5.1 Bioenergy, Land Use and GHG Emissions
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ANNEX 6: MAKING POLICIES FOR BIOENERGY DEPLOYMENT
Annex 6.1 Key Characteristics of Several Biomass Sustainability Certification Initiatives
Annex 6.2 Key Issues in Certification System Implementation
Annex 6.3 Overview of Intergovernmental Platforms for Exchange on Renewables and Bioenergy
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ANNEX 7: GLOSSARY OF TERMS AND ACRONYMS
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ACKNOWLEDGEMENTS
108
5
EXECUTIVE SUMMARY
INTRODUCTION
10% of global annual primary energy consumption. This is
mostly traditional biomass used for cooking and heating.
See Figure 1.
The supply of sustainable energy is one of the main
challenges that mankind will face over the coming decades,
particularly because of the need to address climate change.
Biomass can make a substantial contribution to supplying
future energy demand in a sustainable way. It is presently
the largest global contributor of renewable energy, and has
significant potential to expand in the production of heat,
electricity, and fuels for transport. Further deployment of
bioenergy, if carefully managed, could provide:
• an even larger contribution to global primary energy
supply;
• significant reductions in greenhouse gas emissions, and
potentially other environmental benefits;
• improvements in energy security and trade balances, by
substituting imported fossil fuels with domestic biomass;
• opportunities for economic and social development in rural
communities; and
• scope for using wastes and residues, reducing waste
disposal problems, and making better use of resources.
There is significant potential to expand biomass use by
tapping the large volumes of unused residues and wastes.
The use of conventional crops for energy use can also be
expanded, with careful consideration of land availability
and food demand. In the medium term, lignocellulosic crops
(both herbaceous and woody) could be produced on marginal,
degraded and surplus agricultural lands and provide the bulk
of the biomass resource. In the longer term, aquatic biomass
(algae) could also make a significant contribution.
Based on this diverse range of feedstocks, the technical
potential for biomass is estimated in the literature to
be possibly as high as 1500 EJ/yr by 2050, although
most biomass supply scenarios that take into account
sustainability constraints, indicate an annual potential of
between 200 and 500 EJ/yr (excluding aquatic biomass).
Forestry and agricultural residues and other organic wastes
(including municipal solid waste) would provide between
50 and 150 EJ/year, while the remainder would come
from energy crops, surplus forest growth, and increased
agricultural productivity. See Figure 2.
This review provides an overview of the potential for
bioenergy and the challenges associated with its increased
deployment. It discusses opportunities and risks in relation
to resources, technologies, practices, markets and policy. The
aim is to provide insights into the opportunities and required
actions for the development of a sustainable bioenergy
industry.
Projected world primary energy demand by 2050 is expected
to be in the range of 600 to 1000 EJ (compared to about
500 EJ in 2008). Scenarios looking at the penetration of
different low carbon energy sources indicate that future
demand for bioenergy could be up to 250 EJ/yr. This
projected demand falls well within the sustainable supply
potential estimate, so it is reasonable to assume that biomass
could sustainably contribute between a quarter and a third
of the future global energy mix. See Figure 2. Whatever
is actually realised will depend on the cost competitiveness
of bioenergy and on future policy frameworks, such as
greenhouse gas emission reduction targets.
BIOMASS RESOURCES
At present, forestry, agricultural and municipal residues,
and wastes are the main feedstocks for the generation of
electricity and heat from biomass. In addition, a very small
share of sugar, grain, and vegetable oil crops are used
as feedstocks for the production of liquid biofuels. Today,
biomass supplies some 50 EJ1 globally, which represents
Figure 1. Share of bioenergy in the world primary energy mix. Source: based on IEA, 2006; and IPCC, 2007.
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EJ = 1018 Joules (J) = 1015 kilojoules (kJ) = 24 million tonnes of oil equivalent (Mtoe).
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Figure 2. Technical and sustainable biomass supply potentials and expected demand for biomass (primary energy) based on global energy
models and expected total world primary energy demand in 2050. Current world biomass use and primary energy demand are shown for
comparative purposes. Adapted from Dornburg et al. (2008) based on several review studies.
Other factors that may affect biomass potential include
the impact of biotechnology, such as genetically modified
organisms, water availability, and the effects of climate
change on productivity.
Growth in the use of biomass resources in the mid-term
period to 2030 will depend on many demand and supply
side factors. Strong renewable energy targets being set at
regional and national level (e.g. the European Renewable
Energy Directive) are likely to lead to a significant increase
in demand. This demand is likely to be met through increased
use of residues and wastes, sugar, starch and oil crops, and
increasingly, lignocellulosic crops. The contribution of energy
crops depends on the choice of crop and planting rates,
which are influenced by productivity increases in agriculture,
environmental constraints, water availability and logistical
constraints. Under favourable conditions substantial growth
is possible over the next 20 years. However, estimates of the
potential increase in production do vary widely. For example,
the biomass potential from residues and energy crops in the
EU to 2030 is estimated to range between 4.4 and 24 EJ.
The uptake of biomass depends on several factors:
• biomass production costs – US$4/GJ is often regarded as
an upper limit if bioenergy is to be widely deployed today
in all sectors;
• logistics – as with all agricultural commodities, energy
crops and residues all require appropriate supply chain
infrastructure;
• resource and environmental issues – biomass feedstock
production can have both positive and negative effects on
the environment (water availability and quality, soil quality
and biodiversity). These will result in regulations restricting
or incentivising particular practices (e.g. environmental
regulations, sustainability standards, etc.).
The long-term potential for energy crops depends largely on:
• land availability, which depends on food sector development
(growth in food demand, population diet, and increased
crop productivity) and factors limiting access to land, such
as water and nature protection;
• the choice of energy crops, which defines the biomass yield
levels that can be obtained on the available land.
Drivers for increased bioenergy use (e.g. policy targets for
renewables) can lead to increased demand for biomass,
leading to competition for land currently used for food
production, and possibly (indirectly) causing sensitive areas
to be taken into production. This will require intervention
7
by policy makers, in the form of regulation of bioenergy
chains and/or regulation of land use, to ensure sustainable
demand and production. Development of appropriate policy
requires an understanding of the complex issues involved and
international cooperation on measures to promote global
sustainable biomass production systems and practices.
To achieve the bioenergy potential targets in the longer
term, government policies, and industrial efforts need to be
directed at increasing biomass yield levels and modernising
agriculture in regions such as Africa, the Far East and
Latin America, directly increasing global food production
and thus the resources available for biomass. This can be
achieved by technology development, and by the diffusion of
best sustainable agricultural practices. The sustainable use
of residues and wastes for bioenergy, which present limited
or zero environmental risks, needs to be encouraged and
promoted globally.
BIOMASS CONVERSION
TECHNOLOGIES
Ethanol pilot plant based on corn fibre and other cellulosic
material, New Energy Company of Indiana, USA.
(Courtesy DOE/NREL and W. Gretz)
There are many bioenergy routes which can be used to
convert raw biomass feedstock into a final energy product
(see Figure 3). Several conversion technologies have been
developed that are adapted to the different physical nature
and chemical composition of the feedstock, and to the energy
service required (heat, power, transport fuel). Upgrading
technologies for biomass feedstocks (e.g. pelletisation,
torrefaction, and pyrolysis) are being developed to convert
bulky raw biomass into denser and more practical energy
carriers for more efficient transport, storage and convenient
use in subsequent conversion processes.
and is often cost-competitive with fossil fuel alternatives.
Technologies range from rudimentary stoves to sophisticated
modern appliances. For a more energy efficient use of the
biomass resource, modern, large-scale heat applications are
often combined with electricity production in combined heat
and power (CHP) systems.
Different technologies exist or are being developed to
produce electricity from biomass. Co-combustion (also
called co-firing) in coal-based power plants is the most costeffective use of biomass for power generation. Dedicated
The production of heat by the direct combustion of biomass
is the leading bioenergy application throughout the world,
Figure 3: Schematic view of the wide variety of bioenergy routes. Source: E4tech, 2009.
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Figure 4. Development status of the main technologies to upgrade biomass and/or to convert it into heat and/or power. Source: E4tech, 2009.
that rely on non-food biomass (e.g. lignocellulosic feedstocks
such as organic wastes, forestry residues, high yielding woody
or grass energy crops and algae). The use of these feedstocks
for 2nd generation biofuel production would significantly
decrease the potential pressure on land use, improve
greenhouse gas emission reductions when compared to some
1st generation biofuels, and result in lower environmental
and social risk. 2nd generation technologies, mainly using
lignocellulosic feedstocks for the production of ethanol,
synthetic diesel and aviation fuels, are still immature and
need further development and investment to demonstrate
reliable operation at commercial scale and to achieve cost
reductions through scale-up and replication. The current level
of activity in the area indicates that these routes are likely to
become commercial over the next decade. Future generations
of biofuels, such as oils produced from algae, are at the
applied R&D stage, and require considerable development
before they can become competitive contributors to the
energy markets. See Figure 5.
biomass combustion plants, including MSW combustion
plants, are also in successful commercial operation, and many
are industrial or district heating CHP facilities. For sludges,
liquids and wet organic materials, anaerobic digestion is
currently the best-suited option for producing electricity
and/or heat from biomass, although its economic case relies
heavily on the availability of low cost feedstock. All these
technologies are well established and commercially available.
There are few examples of commercial gasification plants,
and the deployment of this technology is affected by its
complexity and cost. In the longer term, if reliable and
cost-effective operation can be more widely demonstrated,
gasification promises greater efficiency, better economics at
both small and large-scale and lower emissions compared
with other biomass-based power generation options. Other
technologies (such as Organic Rankine Cycle and Stirling
engines) are currently in the demonstration stage and
could prove economically viable in a range of small-scale
applications, especially for CHP. See Figure 4.
In the transport sector, 1st generation biofuels are widely
deployed in several countries – mainly bioethanol from
starch and sugar crops and biodiesel from oil crops and
residual oils and fats. Production costs of current biofuels
vary significantly depending on the feedstock used (and their
volatile prices), and on the scale of the plant. The potential
for further deploying these 1st generation technologies is
high, subject to sustainable land use criteria being met.
Further development of bioenergy technologies is needed
mainly to improve the efficiency, reliability and sustainability
of bioenergy chains. In the heat sector, improvement would
lead to cleaner, more reliable systems linked to higher quality
fuel supplies. In the electricity sector, the development of
smaller and more cost-effective electricity or CHP systems
could better match local resource availability. In the
transport sector, improvements could lead to higher quality
and more sustainable biofuels.
1st generation biofuels face both social and environmental
challenges, largely because they use food crops which could
lead to food price increases and possibly indirect land use
change. While such risks can be mitigated by regulation
and sustainability assurance and certification, technology
development is also advancing for next generation processes
Ultimately, bioenergy production may increasingly occur in
biorefineries where transport biofuels, power, heat, chemicals
and other marketable products could all be co-produced from
a mix of biomass feedstocks. The link between producing
energy and other materials deserves further attention
technically and commercially.
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Figure 5. Development status of the main technologies to produce biofuels for transport from biomass. Source: E4tech, 2009.
BIOENERGY MARKETS
The predominant use of biomass today consists of fuel wood
used in non-commercial applications, in simple inefficient
stoves for domestic heating and cooking in developing
countries, where biomass contributes some 22% to the
total primary energy mix. This traditional use of biomass
is expected to grow with increasing world population, but
there is significant scope to improve its efficiency and
environmental performance, and thereby help reduce biomass
consumption and related impacts. See Figure 6.
In industrialised countries, the total contribution of modern
biomass is on average only about 3% of total primary
energy, and consists mostly of heat-only and heat and power
applications. Many countries have targets to significantly
increase biomass use, as it is seen as a key contributor to
meeting energy and environmental policy objectives. Current
markets, growing as a result of attractive economics, mostly
involve domestic heat supply (e.g. pellet boilers), large-scale
industrial and community CHP generation (particularly
Figure 6: Share of the biomass sources in the primary bioenergy mix. Source: based on data from IPCC, 2007.
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Figure 7: Main international biomass for energy trade routes. Intra-European trade is not displayed for clarity. Source: Junginger and Faaij, 2008.
and mitigated to enable stronger sustained growth of the
bioenergy sector. These include:
where low cost feedstocks from forest residues, bagasse,
MSW etc. are available), and co-firing in large coal-based
power plants. The deployment of dedicated electricity
plants has been mainly confined to low cost feedstocks
in relatively small-scale applications, such as the use of
biogas and landfill gas from waste treatment. Globally, the
use of biomass in heat and industrial energy applications
is expected to double by 2050 under business-as-usual
scenarios, while electricity production from biomass is
projected to increase, from its current share of 1.3% in total
power production to 2.4 - 3.3% by 2030 (corresponding to a
5 - 6% average annual growth rate).
• Security of the feedstock supply. This is susceptible to the
inherent volatility of biological production (due to weather
and seasonal variations), which can lead to significant
variations in feedstock supply quantity, quality and price.
Risk mitigation strategies already common in food and
energy markets include having a larger, more fluid, global
biomass sector and the creation of buffer stocks.
• Economies of scale and logistics. Many commercially
available technologies suffer from poor economics at a
small-scale, but conversely larger scales require improved
and more complex feedstock supply logistics. Efforts are
required to develop technologies at appropriate scales
and with appropriate supply chains to meet different
application requirements.
Transport biofuels are currently the fastest growing bioenergy
sector, receiving a lot of public attention. However, today
they represent only 1.5% of total road transport fuel
consumption and only 2% of total bioenergy. They are,
however, expected to play an increasing role in meeting
the demand for road transport fuel, with 2nd generation
biofuels increasing in importance over the next two decades.
Even under business-as-usual scenarios, biofuel production
is expected to increase by a factor of 10 to 20 relative to
current levels by 2030 (corresponding to a 6 - 8% average
annual growth rate).
• Competition. Bioenergy technologies compete with other
renewable and non-renewable energy sources, and may
compete for feedstock with other sectors such as food,
chemicals and materials. Also, the development of 2nd
generation biofuel technologies could lead to competition
for biomass resources between bioenergy applications, and
potentially with other industry sectors. Support needs to be
directed at developing cost-effective bioenergy routes and
at deploying larger quantities of biomass feedstocks from
sustainable sources.
Global trade in biomass feedstocks (e.g. wood chips,
vegetable oils and agricultural residues) and processed
bioenergy carriers (e.g. ethanol, biodiesel, wood pellets) is
growing rapidly. Present estimates indicate that bioenergy
trade is modest – around 1 EJ (about 2% of current
bioenergy use). In the longer term, much larger quantities
of these products might be traded internationally, with
Latin America and Sub-Saharan Africa as potential net
exporters and North America, Europe and Asia foreseen as
net importers. Trade will be an important component of the
sustained growth of the bioenergy sector. See Figure 7.
• Public and NGO acceptance. This is a major risk factor
facing alternative energy sources and bioenergy in
particular. The public needs to be informed and confident
that bioenergy is environmentally and socially beneficial
and does not result in significant negative environmental
and social trade-offs.
The quest for a sustainable energy system will require more
bioenergy than the growth projected under the business-asusual scenarios. A number of biomass supply chain issues
and market risks and barriers will need to be addressed
However, the industry is confident such challenges can be
met as similar challenges have been addressed in other
sectors and appropriate technologies and practices are being
developed and deployed.
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INTERACTIONS WITH OTHER
MARKETS
remain the only option for decarbonising aviation transport,
a sector for which it will be difficult to find an alternative to
liquid fuels.
Developments in the bioenergy sector can influence markets
for agricultural products (e.g. food and feed products, straw)
and forest products (e.g. paper, board). However, this impact
is not straightforward due to:
• other factors, such as biomass yield variations and fossil
fuel price volatilities influencing markets just as much or
more than biomass;
• other policy domains, including forestry, agriculture,
environment, transport, health and trade, also having
influence on bioenergy policies; and
• a lack of transparency in many product and commodity
markets, especially in forest products, making it difficult
to assess the impact of bioenergy development.
Land suitable for producing biomass for energy can also be
used for the creation of biospheric carbon sinks. Several
factors determine the relative attractiveness of these
two options, in particular land productivity, including
co-products, and fossil fuel replacement efficiency. Also,
possible direct and indirect emissions from converting land
to another use can substantially reduce the climate benefit
of both bioenergy and carbon sink projects, and need to be
taken into careful consideration. A further influencing factor
is the time scale that is used for the evaluation of the carbon
reduction potential: a short time scale tends to favour the
sink option, while a longer time scale offers larger savings
as biomass production is not limited by saturation but can
repeatedly (from harvest to harvest) deliver greenhouse gas
emission reductions by substituting for fossil fuels. Mature
forests that have ceased to serve as carbon sinks can in
principle be managed in a conventional manner to produce
timber and other forest products, offering a relatively low
GHG reduction per hectare. Alternatively, they could be
converted to higher yielding energy plantations (or to food
production) but this would involve the release of at least part
of the carbon store created.
While all forms of bioenergy interrelate with agriculture
and/or forest markets through their feedstock demand, the
impact of 1st generation liquid biofuels on food prices has
been a topic of strong debate in recent years. Although
different studies reveal a wide variety of opinions on the
magnitude of these impacts, most model-based demand
scenarios indicate a relatively limited risk of biofuels
significantly affecting the price of food crops. In general,
markets can work to dampen these effects.
The use of domestic biomass resources can make a
contribution to energy security, depending on which energy
source it is replacing. Biomass imports from widely
distributed international sources generally also contribute
to the diversification of the energy mix. However, supply
security can be affected by natural variations in biomass
outputs and by supply-demand imbalances in the food and
forest product sectors, potentially leading to shortages.
Markets will need access to monetary and physical resources,
and will need to function efficiently and transparently in
order to counteract the pressure of increasing demand. There
is therefore an important role for policy in providing support
to an increasingly efficient industry, for example in terms
of yields, use of residues and wastes, and land use, while
providing regulation to avoid negative impacts associated
with the exploitation of physical resources. This requires
active coordination between energy, agriculture and forestry,
trade and environmental policies.
The production of bioenergy can also result in other (positive
and negative) environmental and socio-economic effects.
Most of the environmental effects are linked to biomass
feedstock production, many of which can be mitigated
through best practices and appropriate regulation. Technical
solutions are available for mitigating most environmental
impacts from bioenergy conversion facilities, and their
BIOENERGY AND POLICY
OBJECTIVES
Bioenergy can significantly increase its existing contribution
to policy objectives, such as CO2 emission reductions
and energy security, as well as to social and economic
development objectives.
Appreciating where bioenergy can have the greatest impact
on GHG emissions reduction relies on both an understanding
of the emissions resulting from different bioenergy routes
and the importance of bioenergy in reducing emissions in
a particular sector. Bioenergy chains can perform very
differently with regard to GHG emissions. Substituting
biomass for fossil fuels in heat and electricity generation is
generally less costly and provides larger emission reductions
per unit of biomass than substituting biomass for gasoline or
diesel used for transport. However, the stationary bioenergy
sector can rely on a range of different low carbon options
while biofuels are the primary option for decarbonising road
transport until all-electric and/or hydrogen fuel cell powered
vehicles become widely deployed, which is unlikely to be
the case for some decades. In the long-term, biofuels might
Tyseley Waste-to-Energy plant, Birmingham, UK. Built in 1996, the
28 MW plant with a 2-stream incinerator has a combined capacity of
over 350,000 tonnes per year of municipal solid waste and a fifteen
year Non-Fossil Fuel Obligation Contract. An award winning lighting
system illuminates the plant at night.
12
Biomass contributes 12% of total energy consumption in Denmark and straw from agriculture is an important element. Consumption of
biomass for energy production is now 100 PJ/year which is two-thirds of the total technical potential of domestic biomass resources. (Courtesy
J. Bunger, Denmark).
or regional characteristics and strengths, e.g. in terms of
existing or potential biomass feedstocks available, specific
features of the industrial and energy sector, and the
infrastructure and trade context.
use is largely a question of appropriate environmental
regulations and their enforcement. The use of organic waste
and agricultural/forestry residues, and of lignocellulosic crops
that could be grown on a wider spectrum of land types, may
mitigate land and water demand and reduce competition
with food.
• Policies should take into account the development stage
of a specific bioenergy technology, and provide incentives
consistent with the barriers that an option is facing.
Factors such as technology maturity, characteristics of
incumbent technologies, and price volatilities all need to
be taken into consideration. In each development stage,
there may be a specific trade-off between incentives being
technology-neutral and closely relating to the policy
drivers, and on the other hand creating a sufficiently
protected environment for technologies to evolve and
mature.
Feedstock production systems can also provide several
benefits. For instance, forest residue harvesting improves
forest site conditions for planting, thinning generally
improves the growth and productivity of the remaining stand,
and removal of biomass from over-dense stands can reduce
the risk of wildfire. In agriculture, biomass can be cultivated
in so-called multifunctional plantations that – through
well chosen locations, design, management, and system
integration – offer extra environmental services that, in turn,
create added value for the systems.
• There are two classes of currently preferred policy
instruments for bio-electricity and renewable electricity in
general. These are technology-specific feed-in tariffs and
more generic incentives such as renewable energy quotas
and tax differentiation between bioenergy and fossil-based
energy. Each approach has its pros and cons, with neither
being clearly more effective.
Policy around bioenergy needs to be designed so that it is
consistent with meeting environmental and social objectives.
Bioenergy needs to be regulated so that environmental and
social issues are taken into consideration, environmental
services provided by bioenergy systems are recognised and
valued, and it contributes to rural development objectives.
• Access to markets is a critical factor for almost all
bioenergy technologies so that policies need to pay
attention to grid access, and standardisation of feedstocks
and biofuels.
LESSONS FOR THE FUTURE
As the deployment of many bioenergy options depends on
government support, at least in the short and medium term,
the design and implementation of appropriate policies and
support mechanisms is vital, and defensible, particularly
given the associated environmental benefits and existing
government support for fossil fuels. These policies should also
ensure that bioenergy contributes to economic, environmental
and social goals. Experience over the last couple of decades
has taught us the following.
• As all bioenergy options depend on feedstock availability,
a policy strategy for bioenergy should pay attention to the
sectors that will provide the biomass. For the agricultural
and forestry sectors, this includes consideration of
aspects such as productivity improvement, availability
of agricultural and forest land, and access to and
extractability of primary residues. For other feedstocks,
such as residues from wood processing and municipal
solid waste, important aspects are mobilisation and
responsible use.
• A policy initiative for bioenergy is most effective when it is
part of a long-term vision that builds on specific national
13
the development and implementation of sustainability
assurance schemes;
- incentivising biofuels based on their potential greenhouse
gas benefits;
- considering potential impacts of biomass demand for
energy applications on commodity markets and on
indirect land use change; and
- defining growth rates that result in feedstock demands
that the sector can cope with on a sustainable basis.
• A long-term successful bioenergy strategy needs to take
into account sustainability issues. Policies and standards
safeguarding biomass sustainability are currently in rapid
development. Due to the complexity of the sustainability
issue, future policy making and the development of
standards will need to focus on integrated approaches, in
which the complex interactions with aspects such as land
use, agriculture and forestry, and social development are
taken into account.
• Development of new and improved biomass conversion
technologies will be essential for widespread deployment
and long-term success. Public and private funding needs
to be devoted to research, development and deployment as
follows:
- for liquid biofuels – advanced technologies that allow for
a broader feedstock base using non-food crops with fewer
(direct and indirect) environmental and social risks, and
higher greenhouse gas benefits;
- for power and heat production – more efficient advanced
technologies, such as gasification and advanced steam
cycles, and technologies with improved economics at
a smaller scale to allow for more distributed use of
biomass; and
- for novel biomass – upgrading technologies and multiproduct biorefineries, which could contribute to the
deployment and overall cost-competitiveness of bioenergy.
• Long-term continuity and predictability of policy support
is also important. This does not mean that all policies need
to be long-term but policies conducive to the growth of a
sector should have a duration that is clearly stated and in
line with meeting certain objectives, such as cost reduction
to competitive levels with conventional technologies.
• The successful development of bioenergy does not only
depend on specific policies which provide incentives for
its uptake, but on the broader energy and environment
legal and planning framework. This requires coordination
amongst policies and other government actions, as well as
working with industry and other stakeholders to establish
a framework conducive to investment in bioenergy.
A SENSIBLE WAY FORWARD
• As the availability of residues and wastes will limit
bioenergy deployment in the long-term, policies stimulating
increased productivity in agriculture and forestry, and
public and private efforts aimed at development of novel
energy crops, such as perennial lignocellulosic crops, and
other forms of biomass, such as algae, are essential for a
sustained growth of the bioenergy industry. These efforts
need to be integrated with sustainable land use policies
which also consider making efficient and environmentally
sound use of marginal and degraded lands.
Climate change and energy security are problems for which
solutions need to be developed and implemented urgently.
The scale of the challenge is such that it will require
contributions from disparate sources of energy. Bioenergy
already contributes significantly to addressing these problems
and can contribute much further through existing and
new conversion technologies and feedstocks. Furthermore,
bioenergy can contribute to other environmental and social
objectives, such as waste treatment and rural development.
However, policy makers and the public at large will need to
be comfortable that this expansion is sustainable.
Bioenergy can result in many external benefits but also
entails risks. A development and deployment strategy needs
to be based on careful consideration of the strengths and
weaknesses, as well as the opportunities and threats that
characterise it.
• Current bioenergy routes that generate heat and electricity
from the sustainable use of residues and wastes should be
strongly stimulated. These rely on commercial technologies,
lead to a better use of raw materials, and result in clear
GHG savings and possibly other emission reductions
compared to fossil fuels. The development of infrastructure
and logistics, quality standards and trading platforms will
be crucial to growth and may require policy support.
• Further increasing the deployment of bioenergy, and in
particular of biofuels for transport in the short-term,
should be pursued by:
- paying specific attention to sustainability issues directly
related to the biomass-to-energy production chain,
and avoiding or mitigating negative impacts through
14
CHAPTER 1: INTRODUCTION
Biomass consists of any organic matter of vegetable or
animal origin. It is available in many forms and from many
different sources e.g. forestry products (biomass from
logging and silvicultural treatments, process residues such as
sawdust and black liquor, etc.); agricultural products (crops,
harvest residues, food processing waste, animal dung, etc.);
and municipal and other waste (waste wood, sewage sludge,
organic components of municipal solid waste, etc).
triggered a renewed interest in biomass for the production
of heat, electricity, and transport fuels. Many countries
have introduced policies to support bioenergy, not least
as a means of diversifying their agricultural sectors. This
has been accompanied by significant developments in
conversion processes, with several cleaner, more efficient
technologies at the research, development, and demonstration
stage, and others already introduced into the market. The
biomass resource base is potentially large, and so are
the opportunities for its increased use in different energy
segments in industrialised and developing countries.
Biomass energy is solar energy stored in the chemical bonds
of carbon and hydrogen chains as a result of photosynthesis
or the metabolic activity of organisms. Biomass can be
referred to as nature’s solar battery reflecting its ability to
store energy until required, which makes it more predictable
and responsive than the sun or wind.
Bioenergy has become increasingly diversified in terms of
final uses, and also in terms of resources. While biomass in
the past was very much limited to woody feedstock, today's
bioenergy landscape includes virtually all of the biomass
types available, ranging from food industry residues (waste
cooking oil, tallow) to energy crops such as corn, sugar-cane,
and Miscanthus. New conversion technologies are being
developed to account for the varied physical nature and
chemical composition of the feedstocks available, as well as
the energy service required. There is also growing interest
and research in the production of chemicals from biomass,
possibly in conjunction with the production of energy.
The multi-functional role of biomass, in terms of both the
products and services it might provide, offers an opportunity
to generate value beyond energy products.
Biomass is the oldest fuel used by mankind and has been its
main source of energy for cooking and keeping warm from
the dawn of civilisation to the industrial revolution. However,
over the last century its use has been supplanted by higher
energy density, easier to handle and cheaper fossil fuels such
as coal and oil.
Today, biomass (mainly wood) contributes some 10% to the
world primary energy mix, and is still by far the most widely
used renewable energy source (Figure 1-1). While bioenergy
represents a mere 3% of primary energy in industrialised
countries, it accounts for 22% of the energy mix in
developing countries, where it contributes largely to domestic
heating and cooking, mostly in simple inefficient stoves.
As a result the bioenergy sector has witnessed significant
growth in recent years, in particular in relation to biofuels
for the road transport sector, which have grown considerably
faster than heat and electricity uses (IEA 2008a). While
the development of the bioenergy industry remains very
Over the last three decades, issues of energy security,
increasing prices of fossil fuels, and global warming have
Figure 1-1. Share of bioenergy in the world primary energy mix. Source: based on IEA, 2006; and IPCC, 2007.
15
1.1 Objectives and Scope of the Report
dependent on regional policies, it is becoming increasingly
globalised as a result of an emerging global trade in biomass
products such as pellets and bioethanol.
This report provides a concise review on resource, technical,
economic, environmental, social and policy aspects of
bioenergy. It discusses the future potential for bioenergy
and the main opportunities for deployment in the short
and medium term. It also discusses the principal risks and
challenges associated with the development of bioenergy, and
how they may constrain its use. Its aim is to assist policy
and other decision makers with information that is conducive
to exploiting the opportunities and mitigating the risks
associated with bioenergy, and which may help secure the
sustainable development of the sector.
As bioenergy grows out of its niche position and becomes
increasingly mainstream, its environmental and social
performance has come under greater scrutiny. Public
scepticism about the potential greenhouse gas savings
biofuels might achieve has increased, alongside concerns
about their broader environmental and social impacts. These
issues have been further exacerbated by the potential indirect
impacts of bioenergy use, i.e. the potential negative impacts
of displacing biomass from other uses (such as food, feed,
pulp and paper, etc.) and having to find substitutes for
those uses.
1.2 Structure of the Report
To date, bioenergy is a very small part of the agricultural
and energy sectors (about 3% of primary energy in OECD
countries, and on average far less than 1% of agricultural
land is used for energy crops), so while there may be some
hotspots for environmental and social concern, its global
implications should not be major at this stage. However,
the development of a sustainable bioenergy industry will
necessitate a better understanding of the risks posed by
this growing sector and the development of practices and
policies that minimise any environmental and social risks
and maximise the multi-functional benefits that biomass
can provide. The debate around bioenergy has often proved
emotional in recent years. There is a need for this debate
to become more informed by sound scientific evidence. This
also means that more consistent approaches to assessing the
impacts and opportunities of bioenergy are required.
This review is structured along the value chain of bioenergy:
• Chapter 2 describes the availability and cost of feedstock
as well as the environmental and social issues associated
with their production.
• Chapter 3 reviews current and future technology pathways
(R&D status and deployment horizon, preferred scale,
feedstock, conversion efficiency, reliability and lifetime,
cost, etc.).
• Chapter 4 provides an assessment of the global bioenergy
market and biomass trade potential, and discusses
deployment issues.
• Chapter 5 discusses the role of bioenergy in meeting policy
objectives such as climate change mitigation, energy
security and other environmental and socio-economic
objectives.
• Chapter 6 reviews the different support mechanisms and
regulatory frameworks affecting the bioenergy value chain,
and discusses lessons relevant to bioenergy policy making.
While bioenergy needs to address environmental and
social issues, it also faces other challenges relating to
competition both with other energy sources and for biomass
resources, market, and logistics issues associated with
procuring increasing volumes of biomass, and the need for
technological innovation for more efficient conversion of a
more diverse range of feedstocks. The potential opportunities
for bioenergy may be big, and its contribution to many of
society’s objectives (e.g. energy security, climate change
mitigation, etc.) may be important, but numerous challenges
need to be addressed for its untapped potential to be used in
a sustainable way.
Each Chapter is complemented by a set of annexes that
provides additional reference materials and more
in-depth discussion on specific key topics.
In Finland, the goal is to double the use of renewable energy sources by 2025 and thus contribute over one-third of total energy consumption.
This increase will come almost entirely from bioenergy with forest residues being a significant component. The image above shows the
Timberjack Slash Bundler manufacturing ‘compacted residue logs’ after final harvest. (Courtesy Dr Arto Timperi, Timberjack and J Tustin)
16
CHAPTER 2: BIOMASS RESOURCES AND POTENTIALS
Key questions addressed in this Chapter:
1. What are the most important current and future biomass feedstocks?
2. What are the main factors determining the long-term biomass potential for energy?
3. How significant could the contribution of biomass be to the global energy mix by 2050?
4. What logistical constraints do biomass supply chains have to tackle?
5. What are the potential implications of large-scale biomass production and use?
2.1 Overview of Biomass Feedstocks
and Global Technical Potentials
Energy crops are potentially the largest supply source.
However, it is difficult to narrow down the potential estimate
for this category since it mainly depends on two parameters
that are very uncertain:2
• land availability, which depends on food sector
development (food demand growth and productivity
development in agriculture), demand for other agricultural
and forestry commodities (e.g. timber) and factors
constraining access to land, such as nature protection; and
• the biomass yield levels that can be achieved on the
available land.
Information about the long-term primary biomass potential
is essential to understand the prospective role of bioenergy
in the global energy mix. In the past fifteen years, a large
number of studies have assessed the longer term (20502100) biomass supply potential for different regions, and
globally. Since these studies used different approaches to
consider determining factors – such as demand for food, soil
and water constraints, biodiversity and nature preservation
requirements, and a variety of other sustainability issues –
they come to diverging conclusions regarding the biomass
supply, ranging from roughly the current level of production
(about 50 EJ) to levels above the current world primary
energy consumption (about 500 EJ).
In the category ‘energy crop production on surplus
agricultural land’, the type of crop produced on this land
has a large impact on the bioenergy potential. Typical
examples of current cultivated crop use are confined to
biofuels for transport, e.g. sugar-cane for ethanol production
in Brazil, corn for ethanol production in the USA and
various oil crops (rapeseed, sunflower, soy and oil palm)
for biodiesel production. In the longer term, there is a
common expectation that lignocellulosic crops will also be
used, including both perennial herbaceous crops such as
switchgrass and Miscanthus, and woody crops that can be
either:
• coppice systems utilising tree crops such as willow, poplar
and Eucalyptus species grown in multi-year rotations (3 to
6 years); or
• fast growing single stem plantations utilising species such
as hybrid poplar and Eucalyptus, grown in short rotations
(6 to 12 years).
When assessing the biomass potential, one must distinguish
between the technical potential, which is the unconstrained
production potential limited only by the technology used and
the natural circumstances, and the sustainable potential,
which further considers a range of environmental and social
constraints in order to guarantee sustainable feedstock
production.
2.1.1 Technical biomass potential
When assessing global biomass potential, several key
influencing factors prove uncertain. For this reason,
assessments of the global technical potential cover almost
three orders of magnitude, as shown in Table 2-1 which
provides a synthesis of existing studies. This table presents
the biomass categories most commonly considered in
assessments. Currently most bioenergy feedstocks comprise:
• wood and agricultural wastes and residues (for heat and
power production); and
• conventional food crops (for biofuel production).
Several lignocellulosic crops can be grown in less favourable
soils and climatic conditions, so that large land areas could
become available for these types of crops. The production
of biofuels for transport can not however, take advantage of
the favourable performance of lignocellulosic crops because
the technologies for converting such feedstocks into biofuels
have yet to become commercially available. Lignocellulosic
feedstocks are therefore currently used for heat and power
(see Chapter 3).
Agricultural and wood-based residues and wastes form
the vast majority of currently used biomass (IEA 2008b).
Their long-term potential is mainly dependent on future
developments in agricultural and forestry production,
including the demand for the products of which they are the
by-product.
Even though conventional food crops for transport biofuels
often produce high yields, the bioenergy output per hectare
is commonly lower than expected with lignocellulosic crops3.
2 The expectations about future availability of forest wood and of residues from agriculture and forestry also vary substantially among the studies.
3 A notable exception is sugar-cane, which can achieve high ethanol yields per hectare.
17
Table 2-1. Overview of the global technical potential of land-based biomass supply (primary energy) over the long-term for a number of
categories (comprehensive version in Annex 2-1). For comparison, current global primary energy consumption is ca. 500 EJ.
Biomass category
Definition
Technical
bioenergy
potential year
2050 (EJ/yr)
Energy crop production Biomass that can be produced on future surplus agricultural land not required
on surplus agricultural for food, fodder or other agricultural or forestry commodities production. Two
land
types of energy crops can be distinguished:
1) conventional energy crops, normally used to produce food and animal feed
(e.g. maize, sugar-beet, sugar-cane, rapeseed, oil palm, soybeans)
2) Lignocellulosic energy crops, composed of cellulose, hemicelluloses and lignin
(e.g. poplar, willow, eucalyptus, miscanthus, switchgrass).
0 – 700
Energy crop production Biomass that can be produced on deforested or otherwise degraded or marginal
on marginal lands
land that is still suitable for (for example) reforestation.
<604 – 110
Residues from
agriculture
Residues associated with food production and processing, both primary (e.g.
cereal straw from harvesting) and secondary (e.g. rice husks from rice milling).
15 – 70
Forest residues
Residues associated with wood production and processing, both primary (e.g.
branches and twigs from logging) and secondary (sawdust and bark from the
wood processing industry). In general, increased level of forest management,
e.g. silvicultural thinning improving forest stands, makes it possible to utilise
a larger part of the forest growth, which is well above the present level of
biomass extraction in many countries.
30 – 150
Dung
Biomass from animal manure
Organic wastes
Biomass associated with materials use, e.g. waste wood (producers),
municipal solid waste
5 – 55
Total
5 – >504
<60 – >1100
could be cultivated in colonies in the open sea. Potentials for
algae have not been studied as extensively as the land-based
biomass resources indicated in Table 2-1, but they could
reach up to several hundreds of EJ for microalgae and up to
several thousands of EJ for macroalgae (Florentinus et al.,
2008). All types of algae however, have relatively low dry
matter content, so their applicability as a biomass feedstock
is not straightforward. Other potential introduction barriers,
such as logistical issues for offshore cultivation, have not yet
been fully explored. Therefore, it is still difficult to assess the
sustainability and economic competitiveness of algae options,
and we have not taken them into detailed account in this
review.
One reason is that a smaller share of the aboveground
growth of food crops is used as bioenergy feedstock compared
to lignocellulosic crops, where most of the growth can be
used. Another reason is that the lignocellulosic crops are
often perennials and several species are grown in multi-year
rotations, and they can therefore benefit from longer growing
seasons. When considering the net energy output (i.e. energy
output minus energy inputs in production) the difference
becomes larger, since the lignocellulosic crops generally
require fewer agronomic inputs per hectare (see also Annex
2.2 and Chapter 5).
In addition to the feedstocks mentioned above, by-products
are often obtained when conventional food crops are used. For
instance, straw can be used as animal fodder or as a fuel, and
processing by-products (e.g. dry distillers grain with solubles
(DDGS) from starch fermentation) can be used for animal feed
or chemicals production. This use of by-products improves the
situation with regard to land use since it substitutes for other
production that would have claimed land elsewhere.
2.1.2 Key factors influencing technical biomass
potential
Although assessments have not succeeded in providing narrow,
distinct estimates of the biomass potential, they do indicate
the most influential parameters that affect this potential,
which enables strategies to improve the prospects of the longer
term bioenergy supply to be formulated. The most important
influencing factors are:
• Land availability for biomass production is particularly
impacted by agricultural productivity, and the level of
modernisation of agriculture that can be achieved globally,
particularly in developing countries5. There is room for
considerably higher land use efficiencies that can, in
Relatively recently, algae have gained attention as a source of
biomass for energy. This term can relate to both microalgae
and macroalgae (or seaweed). Microalgae can be cultivated
most cost-effectively in open ponds on land, and in offshore
reservoirs (Florentinus et al., 2008). Potentially, they contain
substantial concentrations of vegetable oil. Macroalgae
4 For an explanation of the ‘>’ and ‘<’ signs see Annex 2-1
5 The expectations about future availability of forest wood and of residues from agriculture and forestry also vary substantially among the studies.
18
Figure 2-1. Illustration of the impact of different scenarios for agricultural productivity improvement on total technical bioenergy production
potential in 2050, all other assumptions remaining equal (Smeets 2008). The two upper scenarios were not taken into account in the review of
Table 2-1, as they were considered too optimistic in their assumptions. All numbers in EJ.
• In a much less optimistic scenario for bioenergy – where
agricultural productivity would remain at its current
levels, population growth would continue at high rates
and (biomass) trade and technology exchange would be
severely limited – no land would then be available and only
municipal solid waste (MSW) and some agricultural and
forestry residues might be used. Such a scenario would
leave the supply potential in the order of magnitude of the
present level of biomass use, i.e. about 50 EJ.
principle, more than compensate for the growing demand
for food. For example, while average corn yields in
industrialised countries such as the USA can reach up to
10 tonnes per hectare, in many developing countries with
subsistence farming, average corn yields typically only
achieve 1-3 tonnes per hectare.
• Under different assumptions for the level of improvements
in agricultural technology, water supply and efficiency in
use (rain-fed/irrigated), improvements in feed conversion
efficiencies6 in animal husbandry, and the animal
production system used (pastoral, mixed, landless), a
wide range of potentially available surplus agricultural
land can be projected. For example, Smeets (2008)
estimated that 0.7-3.5 billion hectares of surplus
agricultural land could potentially become available for
bioenergy by 2050, with especially large areas in subSaharan Africa and Latin America7. If the suitable part
of this land was used for lignocellulosic crops, in addition
to residues and forestry growth not required in the forest
industry, technically over 1500 EJ could be produced (see
Figure 2-1). This is even more than the upper limit of
the review material presented in Table 2-1. Such a high
level of bioenergy production would likely have negative
environmental effects such as water stress in some regions,
loss of biodiversity as well as possibly negative socioeconomic consequences, and should thus be considered
unrealistic.
2.1.3 Biomass potential taking into account
several sustainability constraints
More moderate scenarios, taking into account a number
of uncertainties and sustainability constraints can be
summarised in the following three main categories of
biomass:8
1. Residues from forestry and agriculture and organic
waste, including MSW9. In total, this category represents
between 50 and 150 EJ/year, with a mean estimate of
around 100 EJ/yr. This part of the potential biomass
supply is relatively certain, although consumption changes
(including diet) and competing applications may push the
net availability for energy applications to the lower end of
the range.
6 For an explanation of the ‘>’ and ‘<’ signs see Annex 2-1.
7 A notable exception is sugar-cane, which can achieve high ethanol yields per hectare.
8 Based on a recent analysis by Dornburg et al. (2008).
9 The annual per capita generation of MSW varies from <100 kg in developing countries to >700 kg in industrialised countries, and is closely
correlated with the gross domestic product (GDP) of a country.
19
2. Surplus forestry. In addition to forestry residues a
further 60-100 EJ/yr of surplus forest growth could
be available. The availability of this biomass category
depends on the degree of restrictions set by sustainable
forest management principles (which vary). These include
requirements for protecting biodiversity and maintaining
provision of various ecosystem services.
a large area, which excludes current nature protection
areas, where water scarcity provides limitations and
soil degradation is more severe (additional potential
indicated as ‘no exclusion’ in Figure 2-2).
• Faster development of agricultural technology could add
some 140 EJ/yr to the above values.
In summary, under the assumptions listed above, the
three categories added together lead to a sustainable
biomass supply potential of up to 500 EJ (see Figure
2-2). Under less favourable circumstances, if residues and
surplus forestry supplies remain modest and crops only
deliver feedstock from surplus existing agricultural lands
without additional learning in agricultural practices, the
biomass potential may remain in the order of 200 EJ.
This wide range (200-500 EJ) illustrates that there is still
considerable uncertainty about the potential availability of
sustainable biomass.
3. Biomass produced via cropping systems.
• A more conservative estimate of energy crop production
on possible surplus good quality agricultural and pasture
lands, accounting for water scarcity, land degradation
and new land claims for nature reserves amounts to
an estimated 120 EJ/yr (potential indicated as ‘with
exclusion of areas’ in Figure 2-2).
• The potential contribution of water-scarce, marginal
and degraded lands for energy crop production, could
amount to an additional 70 EJ/yr. This would comprise
Figure 2-2. Technical biomass supply potentials, sustainable biomass potential, expected demand for biomass (primary energy) based on global
energy models and expected total world primary energy demand in 2050. Current world biomass use and primary energy demand are shown for
comparative purposes. Adapted from Dornburg et al., (2008) based on several review studies.
20
How much of the biomass supply potential could actually be
realised will depend principally on the demand for bioenergy.
Different energy models estimating how energy demand
could be met cost-efficiently under different GHG emissions
constraints, estimate that in 2050 between 50 and 250 EJ/
yr of biomass would be used in the primary energy mix10
(see Section 4.1 for a more elaborate discussion on market
opportunities for bioenergy in different sectors).
Biomass production costs. A key factor taken into account
in almost all these studies is biomass production costs.
Typically costs of US$3-4/GJ for primary biomass are
seen as a threshold to compete with fossil fuel prices.
Higher fossil fuel prices (especially gasoline) and policy
incentives in favour of bioenergy can substantially enlarge
the economically viable potential in the various studies (e.g.
from 4 to 5.6 EJ in the EEA (2007) study).
Indicatively, the increasing cost of biomass feedstocks
more often limits the biomass use rather than a shortage of
technical potential. However, this does not imply that resource
availability is never a limiting factor. Especially in world
regions with high biomass demand and low technical potential,
this can be the case. Also, up until 2100, energy models
develop in contrasting ways – from bioenergy staying below
50 EJ/year to, in the highest case, reaching about 475 EJ/
year by 2100 (IPCC 2001). In these cases, feedstock and land
availability clearly are important limiting factors. For further
details on the models compared, see Dornburg et al. (2008).
Environmental constraints. Environmental restrictions
can be considered in different ways. In the EEA (2007)
study, a 30% share of 'environmentally orientated' farming
is required, while the Refuel study (de Wit and Faaij,
2008) assumes strong agricultural efficiency increases
and distributes the agricultural land that is consequently
released between bioenergy production and land for nature
conservation areas. See also Section 2.3.
At the same time, scenario analyses predict a global primary
energy use of about 600-1040 EJ/yr in 2050. Thus, up to
2050, biomass has the potential to meet a substantial share –
between a quarter and a third – of the world energy demand.
2.2 Regional and Short-term Biomass
Utilisation Scenarios
While the potential contribution of biomass could be substantial
in the longer term, the question remains how much of this
potential could be realised within the next two decades. As a
complement to Figure 2-1, Table 2.2 shows selected studies
that present how biomass feedstock production may develop in
the short-to-medium term in different world regions and major
countries, taking economic, environmental and other criteria
into account (see Annex 2.3 for a short introduction of each
study and more details on the study assumptions).
Choice of crops. As shown in Annex 2.3, the projected
primary biomass potentials and land requirements can
vary substantially, and also depend on the choice of crops
(sugar/starch, oil or lignocellulosic). All studies investigated
assume that 1st generation food crops are likely to
substantially contribute to the overall biomass production
until 2030. In the studies for Europe and the USA, a mix of
conventional and lignocellulosic crops is assumed, while in
the ORNL study (Kline et al., 2008), almost all energy crops
are conventional crops, requiring more land per EJ (e.g.
for Latin American, about 70 out of 123 million hectares
are used for soy cultivation). The choice of feedstock will
also largely be determined by the commercial availability of
advanced conversion technologies (see Chapter 3).
Logistical constraints. Finally, only one of the studies in
Table 2-2 (Parker et al., 2008) takes spatially explicit
logistical constraints into account (see also Section 2.4).
The share that can be reached efficiently by existing
infrastructure can in some cases reduce the technical
potential significantly.
Table 2-2. Overview and short description of regional biomass production scenario studies. For additional assumptions, see Annex 2.3.
Region
Study / author
Time frame
Land use for energy
crops (million hectare)
Primary biomass
potential Energy crops
+ residues (EJ)#
Europe
Refuel / de Wit &
Faaij (2008)
2030
66 arable land
(+24 pasture)
12-15 + 9
EEA (2007)
2030
25
3.4-5.0 + 1
USA (18 western
states only)
Parker et al., (2008)
2015
20
2.1 + 0.8
Latin America
Kline et al., (2008)
2017
121
19.7 + 4.7
China & India
Kline et al., (2008)
2017
86
13.2 + 3.7
Australia
CEC (2008)
2020
ca. 0.05
0.003 + 0.15
# When comparing these potentials to the ones presented in Table 2-1, it should be kept in mind that the values presented here are a) only for
specific geographical regions, b) for a shorter time horizon, c) taking economic, environmental and other additional criteria into account, and d)
based on different assumptions for energy crop use, yields, etc.
10 In the IPCC-SRES main scenarios, biomass consumption in 2050 for energy varies between 50-120 EJ. However, these scenarios show the
development mainly in the absence of ambitious climate policies. Given the additional requirement of low-carbon energy supply, these estimates can be
considered as low compared to those that can be expected in a world striving for low stabilisation targets. This notion is strengthened by considering
the recent debate in Nature where Pielke et al. (2008) argue that the reference scenarios used by the IPCC's fourth assessment report (AR4) – SRES –
seriously underestimates the technological challenge associated with stabilising greenhouse-gas concentrations.
21
2.3.1 Water availability and competition
In summary, these studies show that with increased use of
forestry and agricultural residues the utilisation of biomass
can already be strongly increased over current levels. The
short to medium term energy crop potential depends strongly
on productivity increases that can be achieved in food
production and on environmental constraints that will restrict
energy crop cultivation on different land types. Achieving
high yields will generally require that lignocellulosic crops
rather than food crops are cultivated, though this will depend
on the region and crop suitability. In the European scenarios
with substantial dedicated lignocellulosic energy crops, the
Refuel study shows that a substantial part of the long-term
European technical potential (18-59 EJ as shown in Annex
2.3) may be realised by 2030, also considering economic
and environmental criteria (but not explicitly considering
logistics). Further considerations affecting dedicated biomass
production are discussed in the following Section.
Water is a critical resource for both food and biomass
production and is in short supply in many regions. Largescale expansion of energy crop production could lead to a
large increase in evapotranspiration, potentially as large as
the present evapotranspiration from global cropland. In some
countries this could exacerbate an already stressed water
situation. Outcomes for water depend on which biomass
production systems are established and where.
Under strategies that focus on biofuels for transport and
mainly lead to increased cultivation of conventional food
crops, increasing global water use will resemble that
driven by increasing food sector demand. Note that the
geographical pattern may be different though, since the
demand for crops for biofuels may vary geographically due
to the increasing demand in the food sector. A shift to relying
primarily on lignocellulosic feedstocks changes the situation
in relation to water.
2.3 Environmental and Other Aspects
of Energy Crop Production
Firstly, to the extent that bioenergy is based on the
utilisation of residues and biomass on processing by-products
within the food and forestry sectors, water use would not
increase significantly due to increasing bioenergy. The
water that is used to produce the food and conventional
forest products is the same water that will also produce the
residues and by-products potentially available for bioenergy.
When assessing biomass production potentials, it is
important to acknowledge the complex linkages between
the large-scale production and use of biomass for energy
and materials, food production, energy use, water use,
biodiversity and climate change. In Figure 2-3 this
complexity is highlighted by showing some key relationships
and assumptions. No single study or model has yet been able
to describe these intricate relationships adequately. As stated
in Section 2.1, it is to a certain extent possible to quantify
the limitations for food requirements, water constraints, and
nature reserves on the available biomass potential. For other
factors, such as the use of GMO’s or climate change, this is
not currently possible.
Secondly, a number of dedicated bioenergy crops are drought
tolerant and relatively water efficient crops that are grown
under multi-year rotations.12 By adopting such crops
farmers may better cope with a change in precipitation
patterns and increased rates of evapotranspiration due to
higher temperatures. If a larger fraction of the rainfall can
be harnessed and consumed in plant production, a boost
in productivity and total production can be accomplished
without necessarily increasing the withdrawal of freshwater
from rivers, lakes, and aquifers.
The environmental impacts of conventional crop production
have been researched in far greater detail than those
of lignocellulosic crop production. However, in general
lignocellulosic crops can be expected to cause fewer and
lower impacts associated with agronomic inputs since
they require less fertiliser and agro chemicals, and are
perennial. In addition, bioenergy crop production can have
positive impacts, for example, it can help to improve the soil
structure and fertility of degraded lands.
However, without proper planning at the hydrological
catchment level, an increased allocation of freshwater flows
to plant transpiration may lead to lowered groundwater
levels, aggravate river depletion, and reduce downstream
water availability. To assess the impact of land and water use
and management, an integrated basin analysis is required;
however, this is rarely done today. The impact of energy
crops on changes in hydrology needs to be researched in
order to advance our understanding of how the changes in
water and land management will affect downstream users
and ecosystems. In many cases such impacts can be positive.
For example, local water harvesting and run-off collection
upstream may reduce erosion and sedimentation loads in
downstream rivers, while building resilience in the upstream
farming communities.
On the other hand, the conversion of areas with sparse
vegetation to high-yielding lignocellulosic plantations
may lead to substantial reductions in downstream water
availability, which may lead to deteriorating conditions in
water scarce areas. The environmental impacts depend on
local conditions, with the reference land use (i.e. the land use
replaced by energy crops) being a crucial parameter.
A number of critical aspects affecting the prospects for
biomass production are discussed in more detail below.11
11 Note that in addition to the aspects described here, several other issues are described elsewhere in this report, such as the greenhouse gas (GHG)
emissions due to use of fossil fuels in the production, transportation and use of bioenergy carriers, direct and indirect land use changes (see Section 5.3) and
socio-economic aspects (see Section 4.3.3 and 5.5). Possible assurance mechanisms to safeguard sustainable biomass production are included in Chapter 6.
12 As a drawback, these crops often however also have lower yields.
22
Figure 2-3. Overview of key relationships relevant to assessment of bioenergy potentials (Dornburg et al., 2008). Indirect land use issues and
social issues are not displayed (see Chapter 5).
2.3.2 Environmental functions of bioenergy
production
multifunctional plantations that – through well chosen
location, design, management, and system integration – offer
extra environmental services that, in turn, create added
value for the systems.
Much attention is presently directed to the possible negative
consequences of land use change, such as biodiversity losses,
greenhouse gas emissions, and degradation of soils and
water bodies, referring to well-documented effects of forest
conversion and cropland expansion to uncultivated areas.
However, the production of biomass for energy can generate
additional benefits.
Many such plantations provide water-related services, such
as vegetation filters for the treatment of nutrient bearing
water such as wastewater from households, collected
runoff water from farmlands and leachate from landfills.
Plantations can also be located in the landscape and
managed to capture the nutrients in passing runoff water.
Sewage sludge from treatment plants can also be used as
fertiliser in vegetation filters. Plantations can be sited and
managed to limit wind and water erosion, and will reduce
the volume of sediment and nutrients transported into river
systems. They may reduce shallow land slides and local ‘flash
floods’.
For instance, forest residue harvesting also has
environmental or silvicultural benefits. It improves forest site
conditions for replanting. Stump harvesting (as practised
in Nordic Countries) reduces risk of devastating root rot
attack on subsequent stands. Thinning generally improves
the growth and productivity of the remaining stand. Removal
of biomass from over dense stands can reduce wildfire
risk. In agriculture, biomass can be cultivated in so-called
23
grasses. New biotechnological routes to produce both nongenetically modified (non-GM) and GM plants are possible.
Contrary to annual crops, perennial crops can help reduce
soil erosion, for example perennial grasses are used by the
USA Conservation Reserve Programme to minimise soil
erosion. Besides the onsite benefits of reduced soil losses,
there are also offsite benefits such as reduced sediment load
in reservoirs, rivers, and irrigation channels.
GM energy crop species may be more acceptable to the
public than GM food crops, but there are still concerns
about the potential environmental impacts of such plants,
including gene flow from non-native to native plant
relatives. As a result, non-GM biotechnologies may remain
particularly attractive. On the other hand, GMO food
crops have already been widely accepted in many non-EU
countries. Finally, it is important to note that, especially
for restoration of degraded soils, bioenergy crops must
be optimised not maximised, as low input systems involve
limited nutrients and chemical inputs.
Perennial crops can also improve nutrient flows through
the formation of an extensive root system that adds to the
organic matter content of the soil and facilitates nutrient
retention. Nutrient flow is a key issue for forest and
agricultural production systems. When ploughed under
or left on the field/forest, primary residues may recycle
valuable nutrients to the soil and help prevent erosion, thus
only a share may be available for extraction. Prevention
of soil organic matter depletion and nutrient depletion is
important to maintain site productivity for future crops.
2.3.5 Climate change impacts
Climate change is likely to change rainfall patterns while
water transpiration and evaporation will be increased by
rising temperatures. The net effect of this is not easy to
predict, and large variations can be expected in different
regions of the world. Semi-arid and arid areas are
particularly likely to be confronted with reduced water
availability and problems in many river basins may be
expected to increase. Generally, the negative effects of
climate change will outweigh the benefits for freshwater
systems, thereby adversely influencing water availability in
many regions and hence irrigation potentials.
2.3.3 Biodiversity
Although assessments of biomass potential commonly
exclude nature conservation areas as not being available for
biomass production, in the real world biodiversity impacts
may still arise. In the short-term, impacts from existing
agricultural and forest land for bioenergy are dominant.
For example, the use of biomass from natural forests could
reduce the quantity or quality of natural vegetation and
availability of dead wood, and consequently biodiversity.
Finally, biomass may pose environmental risks, but also
environmental benefits if properly managed. Reaping
the GHG abatement potential of biomass will involve
understanding the risks and mitigating them, but also
accepting some trade-offs in exchange for long-term
benefits.
In the longer term, the pressure to convert natural
ecosystems to energy crop cultivation could become very
important. Expansion of intensive farming may have an
impact on biodiversity through the release of nutrients and
chemicals which can lead to changes in species composition
in the surrounding ecosystems. Arable monocultures are
commonly worse than mixed cropping systems and perennial
crops in this respect and can have additional negative effects
on biodiversity, e.g. animal-human conflicts.
2.4 Biomass Supply Chains and
Logistics
Biodiversity loss may also occur indirectly, such as
when productive land use displaced by energy crops is
re-established by converting natural ecosystems into
croplands or pastures elsewhere.
As was shown in the previous sections, biomass potentials
are influenced by the development of the agricultural sector
and various sustainability constraints. Additional constraints
linked to the collection and distribution of dedicated energy
crops and agricultural and forestry residues may further
affect the realisable potential. These include:
• Equipment constraints. Collection methods may vary
greatly between developed and developing countries, but
also by region in developing countries. Mechanisation
of the harvesting process and integration of residue
collection may greatly influence the efficiency, but may
also require significant investments.
• Current harvesting methods and practices. Often
agricultural residues are burnt before the harvest
(e.g. sugar-cane tops and leaves, to facilitate manual
harvesting), burnt after harvest, or ploughed back into
the field in order to improve soil quality or suppress the
growth of weeds.
• Physical constraints. Steep slopes, wet soils, small size of
fields and low-quality infrastructure can make the cropped
area inaccessible to mechanical harvesters or may cause
harvesting to be more inefficient. Specialised equipment
may partially help overcome these constraints.
2.3.4 The agricultural sector, crop improvements
and GMOs
Sound agricultural methods (agroforestry, precision farming,
biological pest control, etc.) exist that can achieve major
increases in productivity with neutral or even positive
environmental impacts. However, such practices must
be secured by sufficient knowledge, funds, and human
capacity, which are often not present, especially in many
developing countries. Other barriers to the sustainable
production of biomass crops are the lack of social capital,
land rights, market access and market power for small-scale
landholders.
Dedicated energy crops have not been subject to the same
breeding efforts as the major food crops. Selection of
suitable crop species and genotypes for given locations to
match specific soil types and climate is possible, but is
at an early stage of development for some energy crops,
and traditional plant breeding, selection and hybridisation
techniques are slow, particularly in woody crops but also in
24
Figure 2-4. Typical cost structures in different countries for wood chips from whole trees, thinnings and forest residues delivered to a plant. Data
from Alakangas and Virkkunen (2007), Bradley (2007), Energidata et al., (2005), Leinonen (2004), Leinonen (2007) and Mizaraite et al., (2007).
Transport distances vary between different studies, typically between 50-100 kilometres.
• The economics of biomass conversion plants generally
become more favourable with increasing scale. Feedstock
costs on the other hand typically rise as required feedstock
volumes increase, due to longer transport distances.
Typically, a trade-off between these two factors determines
the economic optimal plant size. Advanced pre-treatment
technologies such as further densification (briquetting or
pelletising) or thermochemical treatment (such as pyrolysis
or torrefaction) can further increase the energy density,
which makes long transport distances more economical, and
thus may allow larger plant sizes (see also Section 3.3).
• Seasonal availability and storability also impact feedstock
supply for biomass conversion plants. For example, the
harvesting season of sugar-cane is typically 6-7 months in
a year, which limits the operational hours per year. In some
cases, this may require storage of biomass (e.g. bagasse)
for several months. The storability of biomass can also be
problematic. Straw, for example, has a relatively short
harvesting period, but its use is year long and storage is
an important problem. As another example, sugar-cane
cannot be stored for more than 24 hours due to decreasing
sugar content, so storage of the final product (ethanol)
is preferred. In general, storage of biomass feedstocks is
problematic if moisture contents are high (e.g. >20%), as
this generally increases the rate of dry matter loss and the
risk of self-ignition. Advanced pre-treatment options can
partially solve these issues. For more information, see the
IEA Good Practice Guidelines (IEA, 2007c).
• In terms of both costs and energy requirements,
transportation by boat is far superior to train or truck. The
combination of high density biomass energy carriers (such
as wood pellets or ethanol) and transport in large sea-going
vessels has enabled the advent of intercontinental biomass
These factors also influence the economics of biomass supply
chains. The logistics associated with conventional food crops
(such as sugar-cane, corn, rapeseed, and palm oil) and
forestry products (such as round wood and pulp chips) are well
established and cost-efficient. Experience with these crops
can to some extent be applied to the new bioenergy crops,
e.g. perennial grasses or fast-growing trees. However, for
most field residues, the development of cost-efficient supply
chains is a major challenge. The collection, pre-transport
processing (such as chipping or baling) and transportation of
woody and agricultural residues can add significantly to the
overall feedstock costs, as can be seen in Figure 2-4 for woody
biomass.
Also, cost structures are highly dependent on the available
infrastructure and current harvesting practices, e.g. whether
whole trees are skidded to the roadside, so residues are
available at the roadside, or trees are cut to length in the
forest and residues therefore need to be forwarded. Improving
woody residue supply chains by reducing costs is an ongoing
process, with much experience gained in Scandinavia over the
last three decades. Over time, different production chains have
been developed and deployed for the market to handle various
raw and refined woody biomass fuels.
In general, when considering the logistics for large-scale
bioenergy conversion plants, one has to take into account the
following factors:
• Biomass has a low energy density, especially compared to
fossil fuels, and often a high moisture content (up to 55%).
Increasing the energy density by chipping, baling, bundling
etc, and reducing the water content is crucial, to reduce
transportation costs and improve the physical properties.
25
between 200 and 500 EJ/year by the year 2050. Residues
from forestry and agriculture, and organic waste (including
MSW) represent between 50 and 150 EJ/year of this
potential, with the remainder from surplus forest growth and
energy crops. The biomass potential could be greater if algae
prove to be successful.
supply chains, and has to a large extent decoupled the
production of electricity or biofuels from the geographical
resource. For example, energy plants in Europe have
been utilising wood pellets and other agricultural residues
from North America, South America and Southeast
Asia transported by ocean vessel (Marchal et al., 2004;
Ryckmans et al., 2006, see also Section 4.2). Low density
biomass energy carriers such as chips and bales are often
transported by truck and maximum economic transport
distances are typically limited to 100km.
• Finally, the optimal biomass supply chain also strongly
depends on the quality requirements and required annual
feedstock of the end-user.
Estimates of world energy demand by 2050 range between
600-1000 EJ/year, and indicate that bioenergy could
contribute up to 250 EJ/year, in competition with other
sources. Thus, the projected biomass supply should be able to
meet this projected demand and potentially contribute between
a quarter and a third of the global energy mix.
4. What logistical constraints do biomass supply chains have
to tackle?
2.5 Key Messages for Decision Makers
The critical issues in biomass logistics are:
• The specific properties of biomass: low energy density, often
requiring drying and densification; and seasonal availability
and problematic storage requiring further pre-treatment.
• Factors limiting the supply: availability and appropriateness
of mechanised equipment; and inadequate infrastructure to
access conversion facilities and markets.
1. What are the most important current and future biomass
feedstocks?
The most widely used feedstocks for the production of heat
and electricity from biomass at present are forestry and
agricultural residues and various organic wastes. Conventional
sugar, grain, and vegetable oil crops are used for liquid
biofuels production. In the longer term lignocellulosic crops
(both perennial herbaceous and woody) could provide the bulk
of the resource. Algae have high potential for the longer term,
but are a relatively unexplored feedstock at the present stage
of their development.
The main solutions to these issues are the development of
advanced densification and other pre-treatment technologies,
diversifying procurement geographically and in terms of
biomass types, and the optimisation of fuel supply chains from
field to plant gate (including the development of specialised
harvesting and handling equipment), leading to lowest
delivered costs. These developments are crucial to the future
deployment of large-scale biomass conversion plants and
international bioenergy trade.
2. What are the main factors determining the long-term
biomass potential for energy?
The availability of forestry and agricultural wastes and
residues is mainly determined by future developments in
agricultural and forestry production, including demand for
the products of which they are a by-product. The main factors
determining future bioenergy crop availability are:
• modernisation and technology development in agriculture,
including productivity increases and technology exchange
(directly influencing global food production and thus the
amount of available land for biomass feedstock production);
• the biomass yield levels that can be obtained on the
available land and the choice of crop;
• the efficiency of feedstock logistics;
• the sustainability constraints imposed on bioenergy crop
production; and
• population growth, and resulting food and feed demand.
5. What are the potential implications of large-scale biomass
production and use?
It is important to note that the impacts of large-scale energy
crop production on environmental and socio-economic aspects
can be both positive and negative, and are highly dependent on
the specific situation and location of a project. In many cases,
there may be tensions between economic, environmental, and
social aspects. Potentially important positive implications of
large-scale biomass production might include:
• reduction of greenhouse gas emissions and other pollutants;
• improved energy security for developed as well as developing
countries;
• improvements in waste management and resource efficiency;
and
• provision of environmental and socio-economic functions,
e.g. soil restoration, vegetation filters, reduction of wildfire
risk, rural diversification and development.
Other key factors determining the supply of bioenergy crops
and other biomass in the coming decades will continue to
be the costs of production or collection, the availability of
suitable infrastructure, competing fossil fuel costs, and the
levels of policy incentives in support of bioenergy. Finally, the
potential development of aquatic species i.e. algae is a key
factor. Depending on how these constraints are taken into
account, various scenarios for North America and Europe
show that moderate to substantial parts of the long-term
technical potentials may be realised by 2030.
Risks or negative impacts from large-scale biomass production
mainly relate to:
• environmental impacts, e.g. on water availability and
quality, soil quality, biodiversity, net greenhouse gas
emissions from land use change;
• competition for land and biomass with food and other
products, and with other ecosystems; and
• social impacts related to, for example, land rights.
3. How significant could the contribution of biomass be to the
global energy mix by 2050?
Moderate biomass potential scenarios, taking into account
sustainability constraints, indicate an annual potential of
Best practice and appropriate regulation should be used to
maximise benefits and minimise negative impacts.
26
CHAPTER 3: BIOENERGY ROUTES AND CONVERSION TECHNOLOGIES
Key questions addressed in this Chapter:
1. How does bioenergy differ from other renewable alternatives?
2. What are the bioenergy options to produce heat, power and transport biofuels from biomass and
how do they compare in terms of development status?
3. What are the limitations of using biofuels for the transport sector?
4. What are the issues associated with 1st generation biofuels and to what extent can 2nd generation
biofuels address these?
5. What is holding back 2nd generation biofuels from becoming commercial?
6. What are the main priorities for further development and improvement of the conversion
technologies, and how would these assist deployment?
3.1 Biomass – A Unique Renewable
Resource
3.2 Characteristics of Bioenergy Routes
A bioenergy chain, or route, consists of a series of conversion
steps by which a raw biomass feedstock is transformed into a
final energy product (heat, electricity, or transport biofuel).
There are many potential bioenergy chains as a result of
the wide range of raw biomass feedstocks (wood, grass, oil,
starch, fat, etc.) and the variety of possible end-uses. An
overview of bioenergy routes is given in Figure 3-1.
In many ways biomass is a unique renewable resource.
• It can be stored and transported relatively easily in
contrast to renewable options such as wind and solar,
which create intermittent electrical power that requires
immediate consumption and a connection to the grid.
• It has a cost. With the exception of waste and residues,
the cost of biomass often represents a significant share
(usually of the order 50-90%) of the production cost
of bioenergy. This makes the economics of bioenergy
fundamentally different from that of other renewable
energy options that mostly rely on free resources (e.g.
wind, sunlight, geothermal heat, wave, etc.).
• One or more conversion steps are needed to transform raw
biomass into consumable bioenergy products and services.
As it grows, plant biomass captures solar energy and
converts it (through photosynthesis) to chemical energy
stored in the chemical bonds of its molecular constituents.
This chemical energy can be either directly released as
heat via combustion (and subsequently transformed into
power via an engine or turbine) or converted into a variety
of marketable intermediate chemical and energy products.
The latter biomass-derived energy products can be solid
(chips, pellets, charcoal, etc.), liquid (biodiesel, bioethanol,
etc.) or gaseous (biogas, synthesis gas, hydrogen,
etc.) that, in turn, can be used in a variety of energy
applications including use as transport fuels.
• Finally, biomass is a resource that is extremely varied in
nature, which is again unlike all other renewable energy
resources (e.g. the sunlight spectrum is the same all
around the world). This requires specific technologies to
be developed for each case, as explained in the following
section.
Different conversion technologies have been developed that
are adapted to the different physical natures and chemical
compositions of feedstocks, as well as to the energy service
required (heat, electricity, transport fuel). While some
routes are straightforward (e.g. direct combustion of forest
wood for heat production), others necessitate several pretreatment, upgrading and conversion steps, such as those
required for the production of liquid fuels that can be used in
an internal combustion engine.
Three main classes of conversion routes can be identified:
• Thermochemical conversion, by which biomass undergoes
chemical degradation induced by high temperature. The
four thermochemical routes are combustion, gasification,
pyrolysis, and torrefaction which differ mainly in their
temperature ranges, heating rate and amount of oxygen
present in the reaction.
• Physicochemical conversion is used to produce liquid
fuels (biodiesel or vegetable oil) from oil crop (rapeseed,
soybean, Jatropha, etc.) by oil extraction possibly followed
by a transesterification process.
• Biological routes use living micro-organisms (enzymes,
bacteria) to degrade the feedstock and produce liquid
and gaseous fuels. Biological routes are numerous, key
mechanisms being fermentation from sugar (sugar-cane,
sugar-beet, etc.), starch (corn/maize, wheat, etc.) and
lignocellulosic (grass, wood, etc.) feedstock, anaerobic
digestion (mostly from wet biomass), and the more recent
bio-photochemical routes (e.g. hydrogen production using
algae), which require the action of sunlight.
27
Figure 3-1: Synthetic view of the wide variety of bioenergy routes. Source: E4tech (2008).
A brief description of the main characteristics of the
different conversion technologies is provided below, and a
more in-depth description of these various bioenergy routes is
available in Annex 3.
Every bioenergy conversion chain generates co-products, in
addition to a principal energy product. Co-products may add
substantial economic value to the overall process. Examples
include animal feed, food additives, specialty chemicals,
charcoal, and fertilisers. Further discussion on this topic is
provided in the section on biorefineries (Section 3.7).
The preferred bioenergy route will depend on many
considerations, including technology readiness, feedstock type
and volumes available, as well as the energy service required.
Different actors may have different objectives and hence
favour varying technologies. Whilst project developers will be
interested in maximising financial return, governments will
be addressing additional considerations such as carbon saving
potential, energy security, and nationwide economic return.
3.3 Biomass Pre-treatment and
Upgrading Technologies
Although it has the great advantage of being a renewable
source of energy, biomass has a number of disadvantages when
compared with fossil fuels. It has a lower energy density (up
to five times lower per unit volume) and is more variable in
its physical nature, making handling, transport and storage
more complex and more expensive than for fossil fuels. Also,
the chemical composition and moisture content of biomass
feedstocks may vary considerably, which may require pretreatment in order to meet the requirements for quality and
homogeneity of many conversion technologies.
For these reasons, biomass pre-treatment (or upgrading)
techniques are used that convert raw biomass into easier to
handle, denser and more homogeneous (solid or liquid) fuels,
in order to reduce supply chain cost and increase the efficiency
and reliability of downstream processes. Increasing the
energy density of biomass may be attractive if it is necessary
to decouple bioenergy production from its point of use, due
to the increasing cost of transport. The main upgrading
technologies used to increase the energy density of the biomass
are, in order of development status: pelletisation, pyrolysis,
torrefaction, and hydrothermal upgrading (see Figure 3-2).
See Annex 3.1 for a more detailed description of these
technologies.
3.3.1 Pelletisation
Pellets, which are simply made by compressing comminuted
small particles of solid biomass, have become a common fuel
in developed countries, both in households (in the increasingly
popular pellet boilers) and industry. The adoption of quality
standards is contributing to a rise in the use of pellets and
their international trade. Pellets hold promise for supplying
large volumes of standardised solid fuel, in particular for
heating applications where they already represent a cost
competitive alternative to fossil fuels such as heating oil and
gas (EuBioNet2 2007).
However, pellets tend to absorb moisture during transport
and storage, which can significantly reduce their net calorific
value. This calls for various mitigation measures along the
supply chain, including quality control. Today, pellets are
mostly produced from sawdust, a co-product of sawmills,
which may be a limiting factor in terms of the volume of
pellets that can be easily introduced into the market.
28
3.3.2 Pyrolysis and hydrothermal upgrading
demonstration units have been realised (e.g. in Finland and
Canada), and both economic and technical issues around
quality, consistency and long-term stability of the bio-oil,
which tends to degrade over time, remain to be addressed.
Pyrolysis is the controlled thermal decomposition of biomass
occurring at around 500°C in the absence of oxygen
(anaerobic environment) that produces a liquid bio-oil,
a mixture of gas (syngas) and charcoal (biochar). There
are two main types of pyrolysis processes: fast and slow.
These are characterised by different residence times in the
pyrolysis reactor, and lead to different proportions of the
liquid, gas, and solid fractions. While slow pyrolysis favours
the production of bio-char, which can be substituted in any
applications using coal, fast pyrolysis is given more attention
as it maximises the production of bio-oil.
3.3.3 Torrefaction
Torrefaction is a high-efficiency thermal process occurring
at 200-300°C by which biomass (usually wood) is chemically
upgraded into a dry product that resembles coal in
appearance. Torrefied biomass has a high energy density
and is hydrophobic, which means it can be transported
over long distances and stored outside without absorbing
any significant amount of water, hence without reducing
its calorific value. Torrefied biomass can also be pelletised
to further reduce its handling and transportation costs.
Torrefied pellets are expected to be even more cost
competitive than traditional pellets.
Bio-oil should be cheaper to handle, store and transport
compared to raw solid biomass. Also, the energy density
(per unit volume) of bio-oil is higher than that of pellets or
torrefied biomass, which gives it a competitive advantage in
terms of transport cost. Potentially, bio-oil could be upgraded
and used as a transport fuel, providing an efficient route
to fuels that could be closely integrated with a petroleum
infrastructure (see Section 3.6.3).
The homogeneous and coal-like properties of torrified
biomass make it an interesting feedstock in terms of
compatibility with a range of conversion technologies.
Torrefaction technology is currently at the demonstration
stage, but could become commercially available in the near
future. This would facilitate access to remote resources, such
as residues from forest products industries and forests in
remote regions.
Bio-oils can also be produced by liquefaction in the presence
of water, and possibly additional solvents (e.g. methanol),
at high pressure (120-200 atmospheres) and relatively
mild temperatures (300-400ºC). This process is known as
hydrothermal upgrading (HTU). One attractive feature of this
process is that wet biomass can be used directly and that the
bio-oil is less soluble in water in contrast to the bio-oil from
fast pyrolysis.
3.4 Biomass for Heat Applications
The production of heat from biomass is the traditional energy
use of biomass. Biomass-to-heat systems are all commercial
(see Figure 3-2) and mostly cost-competitive, although the
economic case will be context specific and depends on the
cost of fossil alternatives.
However, in spite of these advantages and although
considerable experience has been gained over recent decades,
in particular for fast pyrolysis, these technologies are still
at the demonstration stage. Only a few successful pyrolysis
Figure 3-2. Development status of the main upgrading technologies (green), biomass-to-heat technologies (red) and biomass-to-power
and CHP technologies (blue).
29
3.4.1 Combustion
Industrial systems. An increasing number of boilers in the
0.5-10 MWth range are found in industries that consume large
amounts of heat and have large volumes of biomass residues
at their disposal. The industrial sector is potentially a large
market for biomass heating, but it requires tailored solutions
that meet the technical requirements of different industries,
e.g. in terms of heating temperatures and flue gas quality.
The burning of biomass for heat is the oldest and most
common way of converting solid biomass to energy. Because
combustion is a straightforward and well understood process,
there is a wide range of existing commercial technologies
tailored to the characteristics of the biomass and the scale of
the application (see Annex 3.2 for a more detailed description
of the biomass-fuelled heating systems).
3.4.2 Gasification
Domestic systems. The direct burning of woody feedstock
has been used since the dawn of civilisation and is still by
far the biomass conversion technology making the largest
contribution to global energy supply (see Annex 4.1). Although
modern units, such as increasingly popular pellet boilers, have
an efficiency as high as 90%, the vast majority of domestic
biomass devices in use are low efficiency (5-30%) traditional
cooking stoves found mostly in developing countries (IEA
2008b). The potential for expanding biomass heating in
industrialised countries and improving the use of biomass for
heating in developing countries is considerable.
The use of gasifiers for direct heat application is mainly
confined to emerging countries, while gasification for the
production of higher value energy products (e.g. electricity and
transport fuel) is of greater importance to developed countries
(see Section 3.5.3). Hundreds of smaller size biomass gasifiers
(10-500 kWth) are for example, being deployed mainly
for intermittently operating thermal applications in China,
India and South East Asia with viable pay-backs. However,
reliability and maintenance of these units for continuous
operation seems be an issue (see Annex 3.5 for further
details).
District heating and cooling. Although it is a proven
technology, the economic case for biomass-based district
heating depends on a number of complex technoeconomic
parameters. Today, biomass-based district heating provides a
significant share of the heating requirements in some countries
(e.g. northern European countries). Although an economic
case can be made for appropriately-scaled district heating
networks, the high cost of new heat distribution networks and
the difficulty of guaranteeing high overall efficiency are key
issues hindering further deployment. Interest in district cooling
systems (especially in combination with heat and electricity
production, i.e. tri-generation) is on the rise. This could
provide an efficient way of providing cooling services and
improve the economic viability of biomass schemes through
enhanced utilisation of plant and infrastructure.
3.5 Biomass for Power and CHP
Applications
There are a multitude of feedstock and conversion technology
combinations to produce power and combined heat and
power (CHP), albeit at different stages of development and
deployment. Figure 3-2 shows the development status of
different routes that are explained further in this section.
The economic case of a bioenergy option for power and
CHP depends not only on the actual technology (capital and
operating costs, conversion efficiency, process reliability,
economies of scale, etc.), but also crucially on the locally
prevailing context for both biomass supply (quality, type,
Figure 3-3. Capital cost for available biomass-fuelled technologies for power (blue bars) and CHP (orange bars). Sources: E4tech based on
IEA (2007a, 2007b, 2008c, 2008e), Obernberger and Biedermann (2005), IEE (2007), and van Tilburg (2006, 2008).
30
Figure 3-4. Production cost for available biomass-fuelled technologies to power (blue bars) and CHP (red bars). For the sake of making
comparison possible, the production costs have been calculated based on the capital costs given in Figure 3-3 and on the following assumptions
for each of the technologies considered: (1) Plant lifetime = 20 years, (2) Discount rate = 10%, (3) Heat value=5US$/GJ (for CHP
applications only), (4) Biomass cost=3 US$/GJ.
availability and cost) and final energy demand (cost of
alternative energy production, heat demand and value,
grid accessibility, support policies, etc.). Figure 3-3 and
Figure 3-4 compare the capital cost and production cost
for the main conversion technologies available for power
and CHP applications. The wide range of costs found for
most technologies indicates both that economies of scale are
important (e.g. for steam turbines) and that most of these
technologies are still in their demonstration stage (Stirling
Engine, BIG/CC and Organic Rankine Cycle).
at the larger scale (30-100 MWe) when using low cost
feedstocks available in large volumes such as agricultural
residues (e.g. bagasse), or wood residues and black liquor from
the pulp and paper industry. However, a growing number of
viable smaller scale plants (5-10 MWe) using other type of
residues (wood, straw, etc.) are found throughout Europe and
North America.
MSW waste-to-energy plants. Municipal solid waste
(MSW) is a highly heterogeneous and usually heavily
contaminated feedstock, which calls for robust technologies
and rigorous controls over emissions, leading to relatively
high costs associated with waste-to-energy facilities. Different
technologies are available, and the choice usually depends on
the degree of separation of the different MSW fractions. The
generally uncompetitive cost at which electricity is generated
means that, in the absence of an appropriate waste hierarchy
and associated incentives, MSW remains a largely unexploited
energy resource despite its significant potential in most
countries.
The advantages and disadvantages of each combustion-topower technology are described in the following sections and
in more detail in Annex 3.3.
3.5.1 Biomass combustion
Biomass-based power plants. The heat produced by direct
biomass combustion in a boiler can be used to generate
electricity via a steam turbine or engine. The electrical
efficiency of the steam cycle is lower than that of alternative
technologies such as gasification-based pathways (see below),
but it is currently the cheapest and most reliable route to
produce power from biomass in stand alone applications.
Biomass-based cogeneration (CHP) plants. The principal
means to significantly increase the overall efficiency of a
power plant (and hence its competitiveness) is to find an
economic application for its waste heat. Combined heat and
power (CHP) plants, also called cogeneration plants, have
typical overall (thermal + electric) efficiencies in the range of
80-90%, provided a good match can be found between heat
production and demand (IEA 2008c). This is commonly the
case, for example, in the sugar-cane industry.
In a fragmented biomass supply market, the cost of
purchasing large quantities of biomass may increase sharply
as the distance to suppliers (and thereby logistical cost)
increases. In this context, the importance of economies of
scale for steam-cycle plants has meant that dedicated biomass
power plants have generally only proven commercially viable
31
conversion into liquid biofuels). Thus gasification technology
could suit several possible applications in various market
segments.
Co-generation has been shown to reduce the cost of power
production by 40-60% for stand-alone plants in the range of
1-30 MWe. However, for domestic and commercial heating
applications, the scale of biomass CHP plants is often
limited by the total local heat demand and by its seasonal
variation, which can significantly affect economic returns
unless absorption cooling is also considered (tri-generation).
In combination with a power-generation device, gasification
can offer higher overall conversion efficiencies compared
to combustion-based routes. This is particularly true for
small-scale plants (<5-10 MWe) where relatively simple
gasification systems could be coupled with gas engines, and
where steam-based systems are disadvantaged by significant
diseconomies of scale. At larger scales (>30 MWe),
gasification based systems are coupled with combined gas
and steam turbines, again providing efficiency advantages
compared to combustion. However, such plants require more
skilled operation compared to combustion plants, and their
efficiency and reliability still need to be fully established.
Although several projects based on advanced concepts such
as the Biomass Integrated Gasification Combined Cycle
(BIG/CC) are in the pipeline in northern Europe, USA,
Japan, and India, it is not yet clear what the future holds for
large-scale biomass gasification for power generation.
Distributed cogeneration units. In the lower capacity
range, the Stirling Engine (10-100 kWe) and the Organic
Rankine Cycle (ORC) (50-2000 kWe) are promising
technologies for distributed cogeneration. Currently at the
demonstration stage, improvements are still needed, in
particular concerning conversion efficiency, reliability, and
cost. Developments in these technologies are, however, not
focussing primarily on biomass-fuelled units, although some
efforts in this direction have been made in Europe (Germany,
Austria, the Netherlands, and Switzerland).
3.5.2 Co-firing
The co-combustion of liquid and solid biomass materials
with fossil fuels in thermal processes for heat and power
production can be relevant to all scales of operation.
Biomass co-firing activities have expanded rapidly in recent
years, particularly in Northern Europe, and the most popular
approach has involved the direct co-firing of solid biomass
with coal in existing large power station boilers. This has
proved to be the most cost-effective and most efficient largescale means of converting biomass to electricity and, where
relevant, district heating. This is because this approach
capitalises on the existing infrastructure of the coal plant
and thus requires only minor investment in the biomass
pre-treatment and feed-in systems. It also profits from the
comparatively higher conversion efficiencies of these coal
plants.
Gasification can also co-produce a range of end-products,
such as heat and electricity, together with liquid fuels and
possibly other products in biorefineries. Such advanced
concepts are currently being investigated in research and
pilot plants. (See Annex 3.5 for further details).
3.5.4 Anaerobic digestion
Anaerobic digestion is the biological degradation of biomass
in oxygen-free conditions. The main product of anaerobic
digestion is biogas, a methane-rich gas. Biogas can either be
burnt in power generation devices for on-site (co)generation,
or upgraded to natural gas standards for injection into the
natural gas network as biomethane or for use directly as
gaseous biofuel in gas engine-based captive fleets such as
buses.
However, in spite of the great progress achieved in co-firing
over the past decade, biomass properties pose several
challenges to coal plants that may affect their operation and
lifetime, in particular when a feedstock other than wood is
used. This generally limits the amount of biomass that can
be co-fired. The alternative option of indirect and parallel
co-firing is designed to avoid these issues, but is much more
expensive than direct co-firing (see Annex 3.4 for further
details on co-firing technologies).
Anaerobic digestion can biodegrade virtually all biomass
that animals can digest (essentially any biomass excluding
woody materials). It is particularly suited to wet feedstocks
such as animal manure, sewage sludge from waste water
treatment plants, wet agricultural residues and the organic
fraction of MSW. Anaerobic digestion also occurs naturally
underground in landfills and produces landfill gases which
can be collected for use in energy applications.
Carbon capture and storage (CCS) from fossil-fuelled power
plant flue gases is being considered as a measure to reduce
greenhouse gas emissions. In this context, CCS can also be
applied to co-firing plants, which would enable the capture of
carbon from biomass (biotic CCS), resulting in a net negative
carbon emission or carbon sink associated with biomass
combustion.
Anaerobic digestion is a well established commercial
technology, although its economic case relies heavily on the
availability of very cheap or free feedstock such as sewage
sludge, manure and some agricultural residues. Today, China
is by far the biggest biogas producer in the world, with
around 18 million farm households using biogas and about
3,500 medium to large-scale digester units (DEFRA 2007).
In Europe, specific support mechanisms have resulted in
Germany being the leader in this technology, with farm-based
units totalling a combined 550 MWe installed capacity in
2006 (i.e. similar to that of a coal power plant). In order
to increase productivity, decentralised farm-size units are
increasingly relying on supplementary feedstock such as
agricultural residues or crops. Sewage sludge digestion
and use of landfill gas are both effectively supported by
waste disposal fees, which means that these are globally
3.5.3 Gasification
Gasification is a thermo-chemical process in which
biomass is transformed into fuel gas, a mixture of several
combustible gases. It has two key advantages over direct
combustion. First, gasification is a highly versatile process as
virtually any biomass feedstock can be converted to fuel gas
with high efficiency. Second, fuel gas can be used directly for
heat or power applications or upgraded to syngas for biofuel
production (see Figure 3-1 as well as Section 3.6.3 for
32
• 3rd generation biofuels (also called advanced biofuels)
generally include biofuel production routes which are at
the earlier stages of research and development or are
significantly further from commercialisation (e.g. biofuels
from algae, hydrogen from biomass).
the most common forms of anaerobic digestion generating
energy at present (led by UK, Italy, and Spain). In contrast,
deployment of biogas technology in the USA suffers from a
reputation for poor reliability (EPA 2008).
The key co-product of anaerobic digestion is a nutrient-rich
digestate, which can be used as a fertiliser. However, when
using contaminated feedstock, contaminants may end up in
the digestate, making it unsuitable for this and difficult to
dispose of. Biomass pre-treatment and separation processes
to remove these contaminants can help to avoid this,
although these are processes which still need to be proven at
larger commercial scale. (See Annex 3.6 for more details).
The goal for 2nd and 3rd generation technologies is therefore to
produce sustainable, low cost biofuels from a broad range of
resources that do not compete with food production and that
have significantly lower GHG emissions than 1st generation
biofuels. An overview of the development status of the different
bioenergy routes to biofuels is given in Figure 3-5.
3.6.2 1st generation biofuels
Bioethanol from sugar and starch crops. The biological
fermentation process used to produce ethanol from sugars
extracted from sugar and starch crops is technically
mature and commercially available. However, technical
improvements can still be made to commercial ethanol
production routes, e.g. improved enzymes to convert starch
to sugars (hydrolysis), improved bacteria (fermentation),
water separation methods, process and plant optimisation,
and greater value-added co-products (e.g. development of
biorefineries – see Section 3.7).
3.6 Biofuels for Transport Applications
3.6.1 Definitions and development status
Biofuels are commonly separated into different ‘generations’
according to their level of development and the feedstocks
they use, though there is no universally agreed definition.
Generally:
• 1st generation biofuels include mature technologies for
the production of bioethanol from sugar and starch crops,
biodiesel and renewable diesel from oil crops and animal
fats, and biomethane from the anaerobic digestion of wet
biomass.
• 2nd generation biofuels encompass a broad range of novel
biofuels based on new feedstocks. These include:
- Bioethanol and biodiesel produced from conventional
technologies but based on novel starch, oil and sugar
crops such as Jatropha, cassava or Miscanthus;
- A range of conventional and novel biofuels (e.g. ethanol,
butanol, syndiesel) produced from lignocellulosic
materials (i.e. fibrous biomass such as straw, wood,
and grass). These routes are based on biochemical and
thermochemical technologies still at the demonstration
stage.
Production costs vary significantly depending on the
feedstock used and scale of the plant. The trend has been
towards larger plants, with new plants generally of capacity
greater than 200 million litres per year. Ethanol can be
produced from Brazilian sugar-cane at less than US$0.31/l,
whereas the production cost of ethanol from corn in the
USA in close to US$0.75/l and that from wheat in the UK is
about US$0.87/l (see Figure 3-6 and Annex 3.7 and Annex
3.8 for yield and production cost figures). Feedstock costs
account for approximately half of the cost of sugar-cane
ethanol production, and for significantly more in the case of
the other 1st generation bioethanol production pathways, such
as corn ethanol.
Figure 3-5. Development status of the main technologies to produce liquid and gaseous biofuels.
33
Figure 3-6. Indicative production costs of 1st generation bioethanol and biodiesel from different crops and from animal fat in the main
producing regions in 2007. Source: E4tech (2008).
Biodiesel and renewable diesel from oil crops, waste oils
and fats. There are various routes to produce diesel-type
fuels from biomass (see Table 3-1). Transesterification and
hydrogenation are technically mature and commercially
available 1st generation technologies that produce biodiesel
from vegetable oil and animal fats. Transesterification, a
relatively straightforward catalytic process, is the dominant
of the two technologies. So far there has been limited
deployment of hydrogenation technology, a process resembling
oil refining, although it produces a renewable diesel of superior
quality (with higher blending potential) to that obtained via
transesterification. This is a result of limited interest so far
from oil companies and refineries in becoming involved in
biofuels production, and the reluctance of the sector due to
potential technical risks associated with the degradation
of hydrogenation catalysts. However, continued interest in
vegetable oils and animal fats as feedstocks could lead to
greater deployment of hydrogenation. A description of the
hydrogenation route is given in Annex 3.9.
As in the case of bioethanol, production costs of biodiesel vary
significantly depending on the feedstock used and scale of the
plant, and the trend has also been towards larger plants exceeding
200 million litres per year. Production costs range roughly from
$0.50/l to $1.60/l, depending on whether waste feedstock or
vegetable oil is used (see Figure 3-6 or Annex 3.7 and Annex
3.8 for yield and production cost figures). Production costs are
dominated by feedstock cost in the case of vegetable oils.
Biomethane. As an alternative to combusting biogas to generate
electricity (see Section 3.5.4), biogas can also be upgraded to
biomethane and injected into the natural gas network for use
in gas-powered vehicles. This route is experiencing significant
deployment and development (see Section 4.1.3).
Table 3-1. Characterisation of routes to diesel-type biofuels.
Common
name
Full name
Biodiesel
FAME or FAEE
biodiesel (fatty
acid methyl / ethyl
ester)
Renewable
diesel
Hydrotreated
biodiesel
Green diesel Synthetic diesel
or syndiesel
Biofuel
generation
Conversion Route
Product characterisation
Biomass used
1st
Transesterification of
vegetable oils and animal
fats
FAME biodiesel has lower
energy content than fossil
diesel and has blending
limits in some applications
Rapeseed, palm,
tallow, soybean,
etc
1st
Hydrogenation of vegetable Similar to fossil diesel
oils or animal fats
Same as FAME
biodiesel.
2nd
Gasification of biomass
followed by Fischer
Tropsch (FT) synthesis
Lignocellulosic
biomass e.g.
wood.
34
Similar to fossil diesel
A number of known systems (e.g. membranes, absorption
washers (water, glycole, amines, NaOH, etc) or pressure
swing adsorption) are being improved to fulfil modern
environmental standards and consume less process electricity.
New systems such as cryogenic upgrading, in which the
separated CO2 can also be used in a pure form, are currently
at the demonstration stage. Cost reduction and process
simplification of this technology is still required.
municipal solid waste (MSW). Ethanol is produced by first
breaking down the cellulose and hemicellulose into sugars,
which can then be fermented using a mature 1st generation
process. Lignocellulosic materials are more complex to break
down than starch, and therefore require more advanced pretreatment and conversion processes than those used in the
production of 1st generation ethanol (see Annex 3.10 for more
technical details on this conversion pathway).
Challenges for 1st generation biofuels. 1st generation biofuels
face several challenges:
• Economic case. The profitability of biofuels is heavily
dependent on the prices of both fossil oil and the
commodity feedstocks used, both of which tend to fluctuate
considerably, as well as on policy support.
• Social issues. The feedstocks used are generally also used
for food, leading to increased competition as both biofuel
and food demands continue to rise (see also Section 4.3).
• Environmental issues. The greenhouse gas benefits over
conventional fossil fuels vary widely depending on the
feedstock and process used (and can even be negative
in certain cases – see also Section 5.3). Efforts need
to be dedicated to developing more efficient processes,
improving the greenhouse gas balance of biofuel chains,
and extending the range of feedstocks that can be used, in
particular residues and wastes.
• Market and infrastructure. The deployment of biomethanefuelled vehicles suffers from the limited uptake of gas
vehicles and related infrastructure.
• End-use issues. One advantage of biofuels is that they
increase the so-called oxygenate levels of gasoline and
diesel, thereby improving the combustion of the fuel.
However, there are technical limits to the level at which
bioethanol and biodiesel can be blended with gasoline and
diesel for use in conventional cars. In most countries, car
warranties generally limit biofuel blends with fossil fuels
to between 5% and 10%. Going beyond 10% blend would
require some changes to engine components and design.
There are many routes to produce 2nd generation bioethanol,
lignocellulosic ethanol being at the most advanced stage
of development and deployment despite still being at the
demonstration stage. Although some of the individual stages
involved in the process are already commercial (e.g. dilute acid
pre-treatment, fermentation and distillation), technological
advances are still needed in several process steps (e.g.
enzymatic hydrolysis, fermentation of C5 sugars) in order to
achieve the cost savings necessary to make lignocellulosic
ethanol a competitive alternative. Most lignocellulosic ethanol
R&D is currently taking place in the USA, but there is interest
in Northern Europe (with its large forestry resources), and in
Brazil (with its extensive 1st generation ethanol production
from sugar-cane and associated availability of bagasse which
could be used as a feedstock). Significant progress is being
made in RD&D, and it is likely that commercial scale plants
will be deployed over the next decade. See Figure 3-7 for
estimated cost projections of 2nd generation bioethanol.
Biomass-to-Liquids (BTL). Using thermochemical conversion
processes, a wide variety of biomass feedstocks can be
converted into a range of liquid and gaseous transport fuels,
such as synthetic diesel and gasoline, methanol, ethanol,
dimethylether (DME), methane, and hydrogen.
Gasification-based routes. Combining gasification with the
catalytic upgrading of the syngas to a liquid fuel (using, for
example, the Fischer Tropsch process) has the potential to
produce a range of synthetic biofuels (synfuels) with low GHG
intensity. These routes are particularly attractive and have
therefore been given considerable attention both in Europe and
North America.
In Brazil, ethanol is already blended in conventional vehicles
up to 25% by volume and most new cars sold are flex-fuel
vehicles which can function on any blend up to 85% or
100% ethanol depending on climate. These flex-fuel cars are
now widely available in many countries. As far as biodiesel
is concerned, blends of up to 30% have been used in fleet
vehicles, and in some regions (e.g. Germany) vehicles that
can be fuelled with 100% biodiesel used to be available on
the market.
Both biomass gasification and the Fischer Tropsch process
involve mature technologies, already used at commercial
scale. However, there is very limited experience in integrating
biomass gasification with downstream processes for the
production of liquid or gaseous transport fuels. Also, each
individual system is generally designed to work on a particular
feedstock with narrow physical and chemical property ranges.
Further R&D is needed to determine and optimise plant
configurations that will be technically and economically
viable based on a variety of feedstocks. Technologies are in
the demonstration stage in Germany for the production of
methanol from gasified mixed feedstock and for the production
of green diesel (also known as syndiesel, see Table 3-1) from
forest residue and waste wood (NNFCC 2007). Demonstration
plants for ethanol production via gasification are being built
in the USA. Successful demonstration could lead to the
deployment of commercial scale plants over the next decade.
Advanced biofuels with properties closer to gasoline and
diesel, such as syndiesel or renewable diesel, could be blended
at much higher levels, or used in conventional vehicles to
completely displace fossil fuels. These fuels can also be
potentially more easily integrated in existing transport and
distribution infrastructure.
3.6.3 2nd generation biofuels
Bioethanol from lignocellulosic feedstocks. Ethanol can
be produced from lignocellulosic biomass; that is from
any organic matter that contains a combination of lignin,
cellulose and hemicelluloses. This includes agricultural wastes
(e.g. straw), forestry products and wastes, energy crops
(e.g. Miscanthus, poplar) and the biological component of
However, a key uncertainty for BTL is whether it will be
possible to procure enough sustainable biomass to feed a
plant at the scale needed for economic viability. With current
35
security), and the future cost of competing fuels. The GHG
emissions reduction potential of 2nd generation biofuels is high,
and generally better than most 1st generation biofuel routes.
Further investment in 2nd generation biofuels is likely to rely
on the recognition of their relative merits compared to other
fuels and on the mitigation of technical risk by demonstration
of reliable operation at scale. The availability of comparatively
low-cost and sustainable feedstocks in significant quantity will
also be key to their deployment (IEA 2008d).
technologies, it is expected that economic BTL plants will
need to be very large (requiring around a million tonnes of
dry biomass a year). Therefore the challenge is whether this
process can be made to work technically and economically at
a smaller scale, which would enable distributed production
of synfuel, due to reduced feedstock procurement needs and
reduced transport costs.
Pyrolysis-based routes. Pyrolysis technology (see Section
3.3.2) could be applied at small-scale (e.g. around 50 kt/
yr biomass input) near to the feedstock source, followed by
pyrolysis oil transport, or at a larger scale at a centralised
location (possibly at around 150 kt/yr input or larger).
Pyrolysis oils produced from current pyrolysis processes
cannot be directly integrated into a conventional oil refinery,
and would require upgrading to lower acidity and water
content. This could be done at the point of pyrolysis, or after
transport of the pyrolysis oil to a refinery. The upgraded
pyrolysis oil could then be incorporated into an existing
refinery process, such as hydrocracking or FCC (fluid
catalytic cracking), producing conventional refinery products
such as diesel or gasoline. Upgrading processes could also
be developed that enable use of the pyrolysis oil directly in a
diesel blend.
3.6.4 3rd generation biofuels
Biofuels from algae. Algae can be separated into two distinct
groups: macroalgae and microalgae.
• Macroalgae (e.g. seaweed) are currently harvested mainly
for non-energy purposes such as food, vitamins, and
pharmaceuticals. They could potentially also be used as
a source of biomass for heat and power, for example via
anaerobic digestion to produce biomethane. Liquid biofuels
could also be produced, for example via fermentation of
sugars and starch to ethanol, via hydrothermal upgrading
to an oil, or via gasification of dry biomass to a number of
fuels (e.g. hydrogen).
Macroalgae are still at an early stage of development with
critical issues and controversial debate on the potential
biomass yield. In some highly controlled environments,
high yields were obtained (up to 45 dry tonnes/ha/yr),
however, at costs excluding scale-up and commercialisation
(EPOBIO 2007).
Pyrolysis technology is currently at the demonstration stage
and technologies for upgrading the bio-oil to transport fuels
are at the applied R&D and pilot stage. Main challenges
concern the production of stable bio-oils (see Annex 3-1)
and the development of cost effective catalytic upgrading
processes.
• Microalgae are microscopic photosynthetic organisms (e.g.
diatoms, green algae, golden algae, blue-green algae), that
produce chemicals and substances that can be harvested
to produce a variety of useful products. Although many
conversion routes are possible with microalgae, their
high concentration of lipids, which can be extracted and
esterified to produce a biodiesel, seems to be the most
promising route for bioenergy.
Challenges for 2nd generation biofuels. Significant cost
reductions are necessary if 2nd generation technologies are
to compete with conventional fossil fuels and 1st generation
biofuels. However, the cost reductions needed depend on the
level of support such technologies would receive based on their
GHG savings potential and other potential benefits (e.g. energy
Figure 3-7. Cost projections for lignocellulosic ethanol and BTL diesel. Source: IEA (2008c) and see also IEA (2008d) for data figures.
36
These routes vary in terms of commercial maturity and in
the number of different conversion steps required. However,
the one thing common to all of them is that they are not
economically viable at present or even in the near future.
Furthermore, the use of hydrogen as a transport fuel will
require the deployment of hydrogen vehicles and a related
fuelling infrastructure. Alternatively, biomethane and
bioethanol, for which fuelling stations are already being
deployed, could be used as hydrogen carriers and converted
to hydrogen on board the vehicle using reformers, though this
leads to significant additional vehicle complexity and cost.
There has been a great deal of interest in microalgal
biofuels due to their potentially very high oil yields per
hectare. High yielding microalgae species have been
quoted as having the potential to yield up to 20 times
more oil per unit of land area devoted to their production
than conventional crops such as oil palm (Christi 2007),
although more realistic projections may be in the range of
6-10 times (Carbon Trust 2008).
Other reasons why microalgae are appealing is that some
of the nutrients they require can be found in waste water,
potentially enabling microalgae to be used for the dual
purpose of cleaning waste water and producing biofuel
feedstock. Microalgal production systems may also be
linked to waste CO2 streams, as this has been shown to
improve the growth rate of the algae. Last but not least,
they can be grown on non productive land.
3.7 Biorefineries
3.7.1 Concept and definition
One of the challenges for many bioenergy routes is their poor
competitiveness compared with fossil energy. An option for
making them more cost-competitive is to co-produce other
high value products from the same feedstocks in biorefineries.
Biorefineries are largely at the conceptual stage, with
potentially interesting new products and routes still being
identified. Even a clear definition of biorefineries is still
lacking, and different definitions are being used depending
on the type of activity and stakeholders involved. Within
the framework of IEA Bioenergy Task 42 on biorefineries
the following general biorefinery definition is being used:
A biorefinery is the processing of biomass into a spectrum
of marketable products and energy. This implies that
biorefineries:
• are a cluster of facilities, processes, and industries;
• are sustainable: maximising economics, minimising
environmental impacts, replacing fossil fuel, while taking
socio-economic aspects into account;
• contain different processing steps: upstream processing,
transformation, fractionation, thermochemical and/or
biochemical conversion, extraction, separation,
downstream processing;
• can use any biomass feedstock: crops, organic residues,
agroresidues, forest residues, wood, aquatic biomass;
• produce more than one product, each with an existing (or
shortly expected) market of acceptable volumes and prices;
• can provide both intermediate and final products, i.e. food,
feed, chemicals, and materials; and
• can co-produce energy as fuels, power, and/or heat.
The key challenge is to sustain microalgae populations
over long periods, with both high productivity and high
oil yields. Two types of cultivation systems are being
investigated: open pond and photo-bioreactor. The latter
is a closed system, which provides a highly controlled
growing environment without infection by foreign species,
but is obviously a much more costly approach.
There are still many technical challenges that need to be
overcome before algae can be commercially grown for fuel
production, and very large cost reductions must be achieved,
which may prove to be a major challenge. As a result, the
potential of microalgae to also produce high value co-products
is likely to play an important role in improving the economics
of biofuel production.
Liquid-phase catalytic processing of biomass-derived
compounds. Sugars and other carbohydrates extracted
from various biomass components can be biochemically
or catalytically converted into hydrocarbons (e.g.
hydroxymethylfurfural (HMF) or its derivates). These can
serve as substitutes for the petroleum-based building blocks
used for the production of fuels, plastics and fine chemicals
(NSF 2008). These routes are potentially interesting, as they
could produce high energy density liquid fuels, with potentially
high yields via a limited number of chemical reactions, from a
potentially wide range of biomass feedstocks. There has been
much recent development activity, largely at the applied R&D
stage, on these routes both in universities and companies, and
in particular start-up companies.
3.7.2 Development status and prospects
Some current biomass-based industries such as biofuels
plants, pulp and paper mills and food processing plants could
be considered to be the ‘1st generation’ of biorefineries.
Renewable materials like polylactic acid derived from corn
starch are increasingly becoming commercially viable and
could form an important part of future biorefineries.
Hydrogen from biomass. Hydrogen can be used to power
vehicles, in fuel cells or dedicated internal combustion
engines. Many expect hydrogen to play an important role in
decarbonising the transport sector in the long-term, as it can
be derived from many renewable sources including biomass
and water. There are several different routes for the conversion
of biomass to hydrogen. These include:
• biological routes, such as fermentation of biomass to
hydrogen or anaerobic digestion with methane reforming;
• thermal routes, such as gasification followed by upgrading
and reforming of syngas, aqueous phase reforming of
biomass-derived solutions, and reforming of bio-oils; and
• photosynthetic routes, such as direct hydrogen production by
photosynthetic organisms.
New concepts of biorefineries are looking at extracting a much
broader range of materials and chemicals from the rich variety
of biomass building blocks (see Figure 3-8) for a schematic
illustration of two biorefinery types.
The deployment of new biorefinery concepts, based largely on
lignocellulosic feedstocks, will need to rely on the technical
maturity of a range of processes to produce materials,
chemicals, and energy. Considerable development work is
37
Press Juice
‘biochemical’
‘biotech./physical’
Proteins,
Soluble Sugars
Grain
Starch line,
sugar
Raw Material
Flour (Meal)
Fuels,
Chemicals,
Polymers and
Materials
‘biotech/chemical’
‘physical/chemical’
Residues
Green
Biomass
technical press
Biogas
Cogeneration
Heat and Power
(CHP)
Hydrogen
Feed, Fuels,
Chemicals,
Polymers and
Materials
Whole Crop
Cereals
- Dry Mill -
‘physical/chemical’
Residues
Cogeneration
Heat and Power,
Extractives
Residues
Press Cake
‘hydrothermal’
‘enzymatic’
‘thermal chemical’
Cellulose
Lignocellulose
Straw
‘biotech./chemical’
Lignocellulose
Raw material
Figure 3-8. Illustrative scheme of a Green Biorefinery (left) and a whole crop biorefinery (right). Source: Kamm et. al. (2006).
efficiency, logistics, and emissions advantages in the longer
term if reliable and cost effective operation can be confirmed.
Many other novel concepts to produce advanced biofuels (e.g.
hydrogen from algae) are at an earlier stage of development.
underway and new biorefinery concepts are expected to be
commercially deployed by 2020. The mix of market and
government support for green materials and chemicals and for
bioenergy will be an important factor in determining the type
and rate of deployment of biorefineries.
3. What are the limitations of using biofuels in the
transport sector?
There are technical limits to the level at which bioethanol
and biodiesel can be blended with gasoline and diesel for use
in conventional car engines (usually up to 5-10%). However,
flex-fuel cars, which can be refuelled with any ethanol blend
up to 85-100% ethanol, are now widely available in many
countries. Also, dedicated vehicles are available on the
market that can be fuelled with biodiesel blends, typically a
30% blend, or 100% biodiesel. Advanced biofuels such as
syndiesel or renewable diesel could be blended at much higher
levels, or used in conventional vehicles to completely displace
fossil fuels. These fuels can potentially also be more easily
integrated in existing transport and distribution infrastructure.
3.8 Key Messages for Decision Makers
1. How does bioenergy differ from other renewable
alternatives?
In contrast with other renewable energy options, biomass can
generate carbon-based fuels, of a composition potentially very
similar to that of fossil fuels, the basis for much of present-day
energy technology. Furthermore, biomass is a form of stored
solar energy which helps overcome the intermittency of the
latter. This makes biomass very suitable for use in both heat
and power generation, particularly in the transport sector
where it is currently the principal renewable alternative to
gasoline and diesel. However, biomass feedstock comes at a
cost, unlike other renewable energy resources such as wind,
hydro, geothermal, wave, and sunlight that are free ‘fuels’.
4. What are the issues associated with 1st generation biofuels
and to what extent can 2nd generation biofuels address these?
1st generation biofuels face both social and environmental
challenges. Being mostly based on food and feed crops,
1st generation bioethanol and biodiesel may have a direct
impact on the price of food commodities. Also, depending
on the agricultural practices and possible changes in land
use, these biofuels may have very limited (or even negative)
GHG reduction potential, and may result in other adverse
environmental impacts, such as biodiversity loss. While such
risks can be mitigated through regulation and sustainability
assurance, technology development is also hard at work
to develop next generation processes that rely on non-food
biomass (wastes, residues, high yielding woody or grass energy
crops or algae) that do not have an impact on land use or
decrease the pressure on land use from biofuel production.
These routes will have significantly lower GHG emissions than
fossil fuels.
2. What are the bioenergy options to produce heat, power and
transport biofuels from biomass and how do they compare in
terms of development status?
A multitude of technologies exist, or are being developed,
to convert diverse biomass feedstocks to a wide range of
solid, liquid and gaseous fuels, and to heat and electricity.
Routes based on direct biomass combustion (to produce heat
and/or power), anaerobic digestion (including landfill gas),
and 1st generation biofuels processes are mature and
commercially available.
More advanced options based on thermo- or biochemical
processes are being developed and range between the research
and demonstration stage. These include relatively welldeveloped technologies such as 2nd generation ethanol (i.e.
lignocellulosic ethanol) and gasification-based power and
biofuels. Gasification for power and CHP may offer scale,
38
5. What is holding back 2nd generation biofuels from
becoming commercial?
2nd generation technologies are not yet mature. Further
developments are needed in order to reduce their production
cost and demonstrate their reliability at substantial scale.
Further investments are thus needed which will rely on the
recognition of the relative merits of 2nd generation biofuels
in terms of GHG reduction potential and, where appropriate,
their ability to mitigate some of the impacts, e.g. on food
markets, associated with 1st generation feedstocks.
6. What are the main priorities for further development and
improvement of the conversion technologies, and how would
these assist deployment?
Further development of bioenergy technologies is needed
mainly to improve the efficiency, reliability, and sustainability
of current bioenergy chains. The priorities for further
development, however, depend on the sector. In the heat
sector, improvement is needed to achieve cleaner more reliable
systems linked to quality fuel supply. In the electricity sector,
the development of smaller and more cost-effective electricity
or CHP systems could better match resource availability. In
the transport fuel sector, biofuels of improved quality and
sustainability are needed.
39
CHAPTER 4: BIOMASS TRADE AND BIOENERGY MARKETS
Key questions addressed in this Chapter:
1. What is the market status and prospects for bioenergy in different market segments?
2. What are the main biomass feedstocks and products traded?
3. What are the current and potential trade volumes?
4. Does long distance transport of biomass use more energy than that embodied in the biomass itself?
5. Which commodity markets are going to be affected by an increasing use of bioenergy?
6. What is the impact of biofuels on the recent increase in food commodity prices?
7. What measures can be taken to minimise the impacts of bioenergy development on commodity markets?
8. What is hindering market penetration of bioenergy?
4.1 Bioenergy Markets and
Opportunities
the bioenergy mix, of which 30% is in the form of dedicated
energy crops and the rest as by-products (dung, straw,
bagasse, etc.). This means that dedicated energy crops
currently only contribute 0.27% of the world energy mix.
Municipal solid wastes and landfill gas currently contribute
3% of the bioenergy mix, but have a large untapped
potential.
Today, biomass provides about 10% (~50 EJ) of the world’s
primary energy supplies (IEA 2008b). This share varies
widely, however, between developing and industrialised
regions. While bioenergy covers an average 22% of the
primary energy consumption in developing countries, and
can reach over 90% in rural countries such as Nepal (IEA
2008e), the total contribution of biomass to the primary
energy mix is on average only about 3.4% in the OECD,
although many of these economies have set targets to
significantly increase this share.
The IEA has established two scenarios for the future of the
global primary energy consumption, which are based on
different assumptions regarding the level of government
intervention to 2030. While the reference scenario assumes
that no new government policies are introduced during the
projection period, the alternative scenario includes a set
of policy measures addressing climate change and energy
security issues (IEA 2006). In both these scenarios, the
volume of bioenergy is expected to grow at an average rate
Of the 50 EJ of bioenergy supplied worldwide, close to
90% is of woody origin, with fuelwood by far the largest
contributor (Figure 4-1). Agriculture contributes 10% to
Figure 4-1. Share of the biomass sources in the primary bioenergy mix. Source: based on data from IPCC (2007).
40
Figure 4-2: Biomass end-use in 2030 and 2050 under various scenarios. Source: IEA (2008c).
of 1.3-1.4% per annum to 2030. Out to 2050, the volume
of biomass used for energy purposes is projected to reach
between 90 and 150 EJ (2100-3600 Mtoe) depending on the
scenario considered (Figure 4-2), and could thus contribute
up to 23% to the total world primary energy supply (IEA
2008b). The future share of bioenergy in the global energy
mix, as well as the market share of the different bioenergy
technologies within this mix, will depend on a number of
context-dependent driving forces. These aspects are discussed
in the following sections, while Annex 4.1 provides details of
the current biomass flow into final energy applications.
In developed countries, biomass heating faces strong
competition with natural gas and coal, which are convenient
and widely available options. Biomass heating is particularly
well developed in countries with good resource availability
and where district heating systems are already in place
e.g. Northern Europe. Sweden is the leader with biomass
contributing close to 50% of its large-scale heat production,
followed by Austria (24%), Finland (17%), Denmark (14%)
and Norway (10%). On average 5% of large-scale heat is
provided by biomass in the USA and 7% in the IEA member
countries (IEA 2007b).
4.1.1 Biomass-to-heat
Prospects. In a ‘business as usual’ scenario, the demand for
traditional biomass will grow from 34 EJ today to 36 EJ in
2030 due to population growth, with over 2.7 billion people
relying on traditional cooking. This increase could however
be largely offset by an increase in energy efficiency resulting
from the introduction of efficient, modern stoves. Traditional
biomass consumption could be globally reduced by up to 70%
by 2050 in the event of fast market penetration of modern
stoves and a large shift from traditional biomass to, for
example, LPG (see Figure 4-2). Such a shift would further
contribute to reducing the health issues related to toxic
emissions from traditional stoves and alleviate unsustainable
biomass harvesting, while generating a potential US$1.5
billion per year retrofit market for modern stoves to 2015
(IEA 2006).
Status. In spite of the versatile end-use potential of biomass,
heat is by far the largest market segment for bioenergy. Of
the 50 EJ of biomass supplied to the global primary energy
mix in 2006 (IEA 2008b), an estimated 39 EJ (i.e. 87%) is
burnt in traditional stoves for domestic heating and cooking
primarily in developing countries (IEA 2008e). In 2005, an
estimated 570 million wood or charcoal cooking stoves were
in use worldwide, as well as some 21 million household-scale
biogas digesters for cooking and lighting, mostly in China
and India (REN 21 2006). In the developing world, handpicked fuelwood is a free source of energy in rural areas,
which makes it the cheapest option, irrespective of the poor
efficiency of traditional stoves.
In industrialised countries, modern solid biomass
technologies are in many cases cost competitive with
conventional fossil-based options, in particular in the
building sector (see Figure 4-3). For decades heating with
wood has been considered as a poor, dirty, and inconvenient
technology in industrialised countries. However, the advent
of user friendly, efficient, and clean pellet boilers is now
contributing to the increased acceptance and popularity of
biomass-based heating in households.
In OECD countries the volume of biomass for residential heat
is expected to grow by 40-90% to reach 3.2-4.3 EJ in 2030
(IEA 2006), mostly due to the growing market for modern
boilers and stoves.
The global use of biomass and waste in the industrial sector
is expected to increase slowly, in line with increased energy
demand, by between 1.9% and 2.2% annually to reach close
to 13 EJ by 2030. However, while this increase will be in
41
Figure 4-3: Cost breakdown and ranges (excluding VAT) in 2005 for a selection of renewable heating and cooling technologies compared with
the reference energy price range (shaded horizontal bar) for gas, fuel oil and electricity heat energy carriers for the domestic (top of range bar)
and industrial (bottom) sectors. Source: IEA (2007b).
In the EU, 55 TWh of electricity from biomass were produced
in 2004 (roughly the annual consumption of Switzerland),
mostly from wood residues and MSW. Finland is leading
the way with 12% of its power consumption produced from
biomass and wastes. In the United States some 85% of total
wood process wastes (excluding forest residues) are used for
power generation.
both developed and developing countries, an annual drop of
0.6-1% over this period is expected in transition economies
(IEA 2006).
4.1.2 Biomass-to-power and CHP
Status. In 2006 biomass-based power and heat plants
consumed a feedstock volume equivalent to 3.5 EJ, which
represents a mere 7% of the global biomass used for energy
purposes (IEA 2008b). Consumption in the OECD countries
accounted for 82% of this volume, with Europe and North
America leading with close to 1.3 EJ each.
A proliferation of smaller-scale biomass-to-power or CHP
projects throughout developed countries and emerging
economies have been recorded in recent years. China, Brazil,
Latin America, Thailand, and India are turning increasingly
to biomass power plants alongside other renewable resources
(IEA 2007a).
Worldwide, the installed capacity for biomass-based power
generation was about 45 GW in 2006 (IEA 2008b), with an
estimated electricity production of some 239 TWh (roughly
the annual total power consumption of Spain). This power
production occurs mostly in:
• co-firing plants for those countries with coal plants;
• combustion-based CHP plants for countries that possess
district heating systems (Nordic countries in Europe), large
pulp and paper or food industries (e.g. Brazil, USA);
• MSW incineration plants, although a large potential is still
untapped;
• stand-alone power plants where large amounts of residues
are available (e.g. sugar-cane bagasse in Brazil); and
• anaerobic digestion units (e.g. in Germany) and landfill
gas units (e.g. in the UK), as a result of increasingly strict
environmental regulations on waste disposal and landfills
at EU level.
Biomass-based cogeneration of heat and power accounted for
some US$5.2 billion global asset financing in 2008, which
is about 9% of the $60 billion invested in renewable energy
capacity worldwide in 2007 (NEF 2008). However, whilst
the global renewable energy sector increased by 45% in
2006, biomass-to-power has seen the slowest growth with a
mere 5.5% recorded. This can be explained by the increasing
scarcity of cheap and easily accessible biomass feedstock, as
well as by the poor economics of biomass-to-power plants at
small-scale (this encourages large-scale projects, but these are
slower to develop).
Prospects. According to most energy scenarios (IEA 2006),
global electricity production from biomass is projected to
42
In the longer term, biomass integrated gasification gas
turbines (BIG/GT) and combined cycles (BIG/CC) are
promising technologies that could offer greater prospects
for relatively large-scale power generation from dedicated
biomass plants, thanks to their high overall efficiency.
Again, the deployment horizons for these gasification-based
technologies are difficult to predict, as significant cost
reduction, as well as improvement of efficiency and reliability
at larger scale are still required.
increase from its current 1.3% share (231 TWh/year) to
2.4-3.3% by 2030 (~800-1000 TWh/year), corresponding
to a 5-6% average annual growth rate. In absolute terms,
the net increase would thus be about four times the current
production, with a significant contribution to CO2 emissions
reduction. In spite of this rapid growth, this still represents
a relatively small contribution from biomass compared with
its technical potential. The main opportunities in the short to
medium term are as follows:
• Co-firing remains a promising cost-efficient option for
producing power from biomass, particularly due to the
flexibility it offers to the power producers who can select
the cheapest fuel on a day-to-day basis.
• It is estimated that the biogas production from farm-size
and larger-scale biogas-to-power units will grow 55% in
the EU by 2010 (EurObserv'ER 2007, 2008a). A boom
in biogas is also expected in the USA, China, and India.
MSW could potentially be a significant feedstock for
biogas, but its use depends on linking energy and waste
policies. Currently, there is limited industry interest in
most regions in energy or fuel production.
• The economic case for stand-alone combustion-based
biomass plants is more strongly dependent on local policy
and regulatory conditions, but can offer interesting
opportunities where biomass feedstock is available at an
affordable cost.
Long-distance transportation reduces the economic and
environmental attractiveness of biomass, which has resulted
in greater interest in energy densification techniques. While
pelletisation is the only densification technique commercially
available, it might lose market share to torrefaction and
pyrolysis, which offer comparable advantages (see Section
3.3), in particular for large-scale power generation.
Remote forestry companies (e.g. in Siberia) are envisaging
torrefaction as potentially the most cost-effective way of
transporting their fuelwood to very distant sale points in the
near term (PC 2008). The advent of pyrolysis will depend
on its ability to solve remaining technical and economic
challenges, and sound market projections are thus not yet
available for this technology.
4.1.3 Biomass-to-biofuels
Status. Biofuels are a fast growing bioenergy sector. Although
Brazil has been producing bioethanol from sugar-cane since
the late 1970s, it is only in the last decade that biofuel
production has acquired global production significance.
In the medium term, the commercialisation of smallscale gasification could be of significant importance in
the deployment of decentralised biomass power and CHP
systems. However, it is currently unclear as to when
this technology will become commercial. Similarly, the
commercialisation of Stirling and ORC Engines could
also enhance the prospects of small-scale biomass power
and CHP generation, although the prime movers in these
emerging technologies are not expected to focus on biomassfuelled systems.
However, biofuels today represent only about 1.5% of the
total road transport fuel consumption (IEA 2008b), and only
account for some 2% in the final bioenergy mix (in energy
terms) (IPCC 2007). Nearly 80% of the global supply of
biofuels is bioethanol from Brazil (from sugar-cane) and the
USA (from corn/maize), where plants with capacities up to
Figure 4-4: Major biofuel producers in 2007 (in billion litres). Source: Estimates based on Lichts (2007) and national sources.
43
transport, as the alternatives mentioned have little prospects
in these segments (IEA 2008a).
more than 500 million litres per year are found (NNFCC
2007). China and India also produce significant quantities,
mostly of ethanol (Figure 4-4). Bioethanol production has
grown significantly, almost doubling in the period 2000
to 2005.
The growth of the biofuels industry will depend very much
on its environmental and social sustainability. Recently, both
the direct and indirect environmental and social effects of
biofuels have come under increasing scrutiny (RFA 2008).
Sustained government support is likely to depend very much
upon understanding and mitigating any undesired impacts,
such as emissions from indirect land use change or impacts
on food prices.
Global biodiesel production has also grown significantly,
almost tripling between 2000 and 2005 (IEA 2006). Most
production is based in Europe (Figure 4-4), with companies in
Germany and Austria having established themselves as leading
technology providers.
Bioethanol is used as a gasoline substitute, and is generally
blended with gasoline to different extents depending on fuel
and vehicle specifications. In Brazil alone, neat ethanol is
sold for use in vehicles, in addition to gasoline and ethanol
blends. In the USA, strong growth in ethanol output can
largely be attributed to tax incentives and rising demand for
ethanol as a gasoline-blending component (IEA 2006). In
Brazil, demand for ethanol dropped due to falling oil prices
in the 1980s, but it has recently experienced a resurgence as
a result of falling production costs, higher oil prices and the
introduction of flex-fuel vehicles that allow switching between
ethanol and conventional gasoline.
Biodiesel is used as a diesel substitute, and is generally
blended up to 5% with diesel, mainly as a result of
limitations imposed by fuel and vehicle specifications.
Higher biodiesel fuel blends are only used in the case of
fleet vehicles (e.g. trucks and buses). The bulk of biofuel
produced in the EU is biodiesel, which accounts for 87% of
the global biodiesel supply (with Germany and France the
largest European producers), as a result of past support for
domestic biofuel production. However, total global production
of biodiesel remains small compared with that of ethanol,
amounting to approximately 4.1 Mtoe in 2006 (IEA 2008b).
While 2nd generation biofuels based on lignocellulosic
feedstocks promise access to a greater resource and greater
GHG reduction potential than current ethanol and biodiesel
production from sugar, starch and oil crops, these routes are
still a decade or two away from contributing a significant
proportion of the world’s liquid fuels (IEA 2008d). New
biofuel technologies could also allow biofuels to penetrate
other transport fuel markets such as aviation fuel (e.g.
production of kerosene from Fischer Tropsch routes).
Biogas upgrading to biomethane is undergoing a dramatic
development, as a result of the worldwide exponential
increase of natural gas vehicles (NGV). There were nine
million units in 2007 compared with four million in 2004.
Although somewhat optimistic, forecasts for NGV fleets in
2030 range between 100 and 200 million vehicles (IANGV
2008). The EU target for renewable energy used in road
transport is 10% by 2020, a significant share of which could
come from biomethane. Sweden, with a fleet of 15,000
natural gas vehicles has already reached a share of 55%
biomethane in natural gas for transport, and Switzerland has
reached ~35 %. Germany and Austria are both aiming for
20% by 2020 (IANGV 2008).
4.2 Trade in Biomass Energy Carriers
Prospects. Demand for road transport fuels is expected to
continue to increase significantly in the coming decades,
especially in developing countries. Biofuels are expected
to play an increasing role in meeting this demand, with a
projected average production growth rate of 6-8% per year,
reaching a 5% share of road transport fuel in 2030 (IEA
2008b). This implies a cumulative investment in biorefineries
of between $160bn and $225bn in order to meet demand in
the period 2005-2030 (IEA 2006).The biggest increase in
biofuels consumption is expected to take place in the United
States, in Europe, in China and in Brazil (IEA 2008b).
International bioenergy trade has developed rapidly over the
past decade. Domestic biomass resources that are readily
available in industrialised countries are often already exploited
and the mobilisation of additional domestic resources often
faces barriers such as lack of sufficient supply infrastructures
or high production costs. In this context, bioenergy imports
often represent a cost-effective alternative to diversify the
energy mix, reduce CO2 emissions and/or meet specific
bioenergy or general renewable energy targets.
Energy security and climate change policy are the main
drivers for the expansion of biofuel use. Agricultural policy
has also been – and continues to be – an important driver.
Oil and other commodity prices also have a strong influence
on biofuels markets. Oil price increases make 1st generation
biofuels increasingly cost competitive, although this effect
may be counterbalanced by increases in agricultural
commodity prices. Additionally, the prospects for biofuels
depend on developments in competing low-carbon and oilreducing technologies for transport, such as vehicle efficiency
improvement and electric vehicles in the medium term and
fuel cell vehicles in the longer term. In the longer run, a
remaining market for biofuels will be aviation and heavy duty
Many developing countries have a large technical potential
for agricultural and forest residues and dedicated biomass
production. Given the lower costs for land and labour in
these countries, biomass production costs are often much
lower than in industrialised countries, but the domestic
demand is commonly not sufficient to realise the potentials.
For these countries, bioenergy exports offer an opportunity
for income generation and employment creation. In this
regard, the development of international markets for biomass
may become an essential component towards the realisation
of these potentials. The main current commodities traded
and trade routes are presented below.
44
4.2.1 Main commodities traded and trading routes
largest bioethanol producers and consumers, covering
almost 90% of the 40 million m3 produced globally in 2006.
Estimates13 indicate that bioethanol trade has steadily
grown from about 3 million m3 in 2000 to 6 million m3 in
2005. Presuming that the rise in recent years was mostly
due to increasing fuel ethanol trade, about 10% of the fuel
ethanol consumed in 2005 was imported. The world’s largest
exporter by far is Brazil (48% of the total traded volume
in 2005), followed by the USA (6%) and France (6%). As
indicated in Figure 4-5, Brazil’s major export markets for
fuel ethanol are the USA, Japan and the EU.
Wood pellets are among the most successfully traded biomass
commodities, due to the techno-economic advantages they
offer compared to other solid biomass fuels (see Section
3.3.1). These attractive properties have caused the demand
for wood pellets to soar over the last years. A rough estimate
indicates that between 2004 and 2006, traded wood pellet
volumes have increased by about 50%. Most wood pellet
production (and consumption) is currently taking place in
Europe. It is estimated that in 2006 between 6-7 million
tonnes of wood pellets were produced globally, with 3-4
million in Europe and two million in Canada and the USA.
Estimating the size of global pellet trade is challenging, as
there are currently no official statistics available for this
immature and fast developing market. Intra-European trade
(including refined wood fuels and briquettes) amounted to
about 30 PJ in 2004 (approximately 1.7 million tonnes) and
the major flows are from east to west, i.e. from Finland, the
Baltic countries and eastern European countries to the rest
of Scandinavia, the UK and the Benelux (Ryckmans et al.,
2006). About 35% of all wood pellets produced in Europe
are traded across a border. Turning to inter-continental
trade, Canada is the largest pellet exporter followed by the
USA (see Figure 4-5).
Based on forecasts for gasoline consumption, it is estimated
that ethanol demand would reach 272 million m3 by 2030
(from 33 million m3 in 2005) if targets/mandates for fuel
ethanol use around the world are maintained and reached.
This volume corresponds to about 10% of the estimated
global demand for gasoline in 2030 (against less than 1%
today). An estimated 24-46 million m3 could potentially be
traded internationally in 2030 (Walter et al., 2007). Brazil
alone could supply this volume, but other (mostly developing)
countries have the potential to also become large-scale
producers and exporters.
Other internationally traded biomass products include:
Wood chips, which are mainly traded as raw material for
wood pulp production, with lower quality fractions utilised for
energy applications despite their low bulk density and usually
high moisture content.
Further trade developments will depend on both government
support measures (e.g. feed-in tariffs for co-firing wood
pellets or pellet stove investment subsidies) and fossil fuel
prices. Expectations are that demand for wood pellets will
increase most strongly in Western Europe in the coming
decades. Global production is estimated to reach 12 million
tonnes by 2012, of which at least one third may be traded
internationally.
Waste wood, which is mainly traded within Europe, e.g.
between the Netherlands, Germany, and Sweden. This trade
is driven by the introduction of a landfill ban on combustible
materials in a number of EU countries, as well as by varying
subsidies and combustion capacities across Europe.
Bioethanol is a commodity which has been produced and
traded globally in large volumes for decades. The bioethanol
market is well-developed, as is its infrastructure and logistics
in many countries. The USA and Brazil are the world’s
Round wood, which indirectly contributes to bioenergy trade.
For example, a significant share of Finnish bioenergy is based
Figure 4-5. Main international biomass for energy trade routes. Intra-European trade is not displayed for clarity (Junginger and Faaij 2008).
13 Data on traded ethanol volumes destined as transportation fuel are imprecise due to various potential uses of ethanol (fuel, industrial or for beverage
use) and also because of the lack of proper codes for biofuels in the Harmonized System Commodity Description and Coding System.
45
on imported round wood. A fraction of the roundwood ends
up in energy production (e.g. utilisation of saw dust or black
liquor).
trade (e.g. roundwood of which elements such as bark, saw
dust, and black liquor are later used for energy). However,
the traded volumes of commodities such as wood pellets,
bioethanol, and biodiesel for energy use are increasing
rapidly. While reliable statistics are not available, it is
estimated that since 2006, directly traded volumes are
larger than those traded indirectly – on an energy basis
Various agricultural residues, including, for example, palm
kernel expeller and shells (residues from palm oil production)
exported to, amongst others, the UK, the Netherlands,
and Italy. Many other residues are reported to be traded
internationally, mainly for co-firing in coal power plants, such
as rice and wheat husks, olive press cakes and cocoa and
peanut shells.
Table 4-1. An estimate of the scope of international trade of biomass
and biofuels in 2006 (tall oil, ETBE and various waste streams
excluded). Source: adapted from Heinimö and Junginger (2009).
Palm oil, soy bean oil and other vegetable oils, oil seeds
and biodiesel, are increasingly traded on a global scale in
response to increasing demand for biodiesel in the EU and
many other world regions. These commodities are already
traded on a large-scale for food and feed purposes. As liquid
biofuel producers are generally reluctant to reveal the origin
of their feedstock sources, estimates of traded volumes for
energy purposes are uncertain. In 2004, an estimated 1
million tonnes (out of 23 million tonnes traded) of these
commodities were used for energy purposes (Heinimö and
Junginger 2009). There are indications that this volume has
been increasing rapidly. Main producers and exporters of
vegetable oils (and increasingly of biodiesel) are Malaysia
and Indonesia for palm oil and Argentina for soy bean oil
(see Figure 4-5).
4.2.2 Current and future trade volumes
Currently the global level of bioenergy trading is small
compared to either trade in agriculture and forestry
commodities (Heinimö and Junginger 2009) or to the global
bioenergy use of approximately 50 EJ (see Table 4-1). In
2004 most trade in bioenergy was associated with indirect
PJ
Million tonnes
Ethanol
160
6
Biodiesel
>90
>2.4
Fuelwood
40
3
Charcoal
20
0.9
Wood pellets
45
2.6
Palm oil
>60
>1.6
Direct trade
>380
>16.7
Industrial
round wood
480
50
Wood chips
and particles
150
16
Indirect trade
630
66
>1000
>83
Total
Figure 4-6. Overview of bioenergy imports/exports in IEA Bioenergy Task 40 member countries in 2004 (figures for Belgium and the UK refer to
2005). Percentages indicate the share of the traded volumes as part of the domestic primary biomass supply. Numbers should be considered as
rough estimates. Source: Junginger et al., (2008).
46
(Heinimö and Junginger 2009). Biomass imports already
contribute substantially to the overall biomass use in
developed countries, e.g. 21-43% in North-West Europe and
Scandinavia (see Figure 4-6). In the longer term, significant
amounts (up to over 100 EJ) of biomass commodities might
be traded internationally, with Latin America and SubSaharan Africa having the potential to become large net
exporters and North America, Europe and South-East Asia
large net importers (Hansson et al., 2006; Junginger et al.,
2008; see also Chapter 2).
Assessments of the future use of wood predict a more rapid
increase in use for energy than for materials applications.
The level of demand from the energy sector will depend on
three factors: bioenergy targets, the level of support the
sector receives from governments, and the competitiveness of
bioenergy options with other renewables. On the basis of the
above data, by 2020 the combined shortfall of wood supply in
Europe could reach 300 million m3 (Mantau et al., 2007). The
projected increase in the occurrence of extreme events caused
by climate change, such as wildfire, major insect epidemics,
and storm damage is expected to further increase this wood
deficit.
4.3 Bioenergy and Commodity Markets
Moreover, the forestry sector cannot respond to an increase in
demand as rapidly as the agricultural sector, simply because
forest trees have an average lifetime of several decades. Unless
more wood resources in Europe are mobilised, the predicted
deficit in wood supply will have to be compensated for by
imports or shared by all industries. This will most likely result
in higher wood prices and reduced growth rates for all the
sectors that depend on wood as their main raw material.
4.3.1 Introduction
Developments in the bioenergy sector increasingly impact on
the markets of several basic commodities. Every application
of bioenergy represents a new demand for feedstock from
the forestry and agricultural sectors. Effectively, the
bioenergy sector now competes with other industries that
use the same raw biomass materials. As a consequence,
markets for transport fuels, agricultural commodities, and
their intermediate and by-products become increasingly
interdependent.
In some countries (e.g. Sweden) the effect of the additional
demand from the bioenergy sector has already become so
strong that the paper and board industries are receiving
subsidies from the government to enable them to compete with
industries from countries that do not face such competition
for feedstock. Elsewhere, the biomass-based heat and power
generation sector is heavily dependent on government support
to ensure sufficient purchasing power to secure the necessary
feedstock volumes. Furthermore, potential suppliers of
wood tend to lack appropriate market information on the
developments in supply and demand, which makes it very
difficult to achieve a new market balance because an increase
in demand does not always lead to an increase in supply
(Ericson et al., 2008).
4.3.2 Bioenergy and agroforestry – relationships
between competing sectors
Relationship between bioenergy and forestry-based sectors.
Wood has many applications, both as the primary product
of the forestry sector (logs) and as a residue from the wood
processing industry (wood chips and sawdust). The forestry
and wood processing sectors make a complex and intertwined
system of industries and activities, in which a large number of
wood types of different qualities are processed and used in a
large variety of applications, including energy.
Furthermore, large volumes of wood are used virtually at the
point of origin, which makes it hard to make any inventory of
material flows and relative shares of the different applications.
According to UNECE/FAO, there is a lack of data regarding
volumes of wood resources mobilised both on the supply side14
and on the consumption side15, which makes any estimate of
the flows of wood residues to different applications uncertain.
Estimating trade flows of wood pellets used for co-firing
proves particularly difficult, partly because of the lack of a
clear definition of ‘trade’.
Relationship between liquid biofuel for transport and
agriculture-based sectors. In the case of liquid biofuels for
transport and other industries that use the same agricultural
raw material, the relationship is even more complex than the
example of wood. Firstly, different agricultural crops respond
to price movements on a year-to-year basis via farmers’
decisions as to which crops to cultivate. Secondly, many crops
can substitute for another in their applications, e.g. oilseeds
(soy, oil palm, rapeseed) and cereals (wheat, barley, corn,
rice). It must be noted that there are wide differences between
biofuels with respect to their impacts on consumption of
agricultural crops. These are summarised in Table 4-2.
In the EU, current use for sawn timber, pulp and paper,
wood-based panels and other products accounts for about
58% of the total wood use (820 million m3), while energy use
accounts for the remaining 42% (mainly for heat production
in private households and heat and/or power production in
industries) (Mantau et al., 2007). This relatively balanced
use of wood between industry and energy applications can be
considered representative for most developed countries. In
the developing world, most of the biomass used for energy is
collected by hand and consumed directly by households for
cooking and heating. There is limited and mostly informal
trading, therefore structured consumption data are hardly
available.
Furthermore, an increase in production of liquid biofuels
also results in an increased production of co-products and
residues that are used as inputs to other sectors. The example
of rapeseed-based biodiesel is typical. In 2005, the non-food
use of rapeseed oil overtook its food use for the first time. This
increased use of rapeseed oil for biodiesel production resulted
in the increased availability of rapeseed cake, which is used
as an animal feed. This resulted in an estimated drop of up to
40% of the price of rapeseed cake (EC 2007). Other sectors
14 In particular on woody biomass outside the forest, post consumer recovered wood and logging residues.
15 Especially on wood use for energy and on conversion factors calculating wood raw material equivalent from units of products.
47
Table 4-2. Feedstock consumption levels for different types of biofuels
Biofuel
From feedstock
Region
Current feedstock consumption level for
biofuels as a share of total feedstock production
Bioethanol
Cereals
EU
1.4%
Bioethanol
Cereals (maize)
USA
20%
Bioethanol
Cereals
World
4.5%
Bioethanol
Sugar-cane
Brazil
50%
Biodiesel
Rapeseed
EU
60%
Biodiesel
Oilseeds
World
5%
develop to reach the different targets set by countries and
world regions. Table 4-3 summarises the results of these
studies and the reasons for their limited comparability.
that feel the effect of the developing biodiesel industry are:
• the food industry facing higher prices of rapeseed oil;
• the producers of vegetable oils (who are the main
beneficiaries of increased prices for their product);
• glycerine producers facing lower prices for their product
(glycerine is the main by-product of biodiesel production and
large volumes have thus become available on the market);
and
• the cosmetics and pharmaceutical industries, that are
benefiting from availability of cheap glycerine.
Key conclusions that can be drawn from these studies are:
• The studies reviewed strongly disagree on the scale of
impact that biofuels have had or will have on the price of
agricultural commodities.
- The IMF stated that biofuels ‘at least in part’ account
for the food price increases in 2007 and 2008 (Johnson
2007)16, while the World Bank believes this share to
be around 70% for the period between 2003 and 2008
(World Bank 2008).
- Most estimates based on agro-economic models predict
that future price impacts will be in the order of a few
percent to some tens of percent at the most in the
years 2015 or 2020, when much higher production
volumes of biofuels are assumed17. Extrapolated to the
current situation, these results imply that the impact
on commodity prices of the current production level of
biofuels (2.6% of transport fuel based on energy content
in the EU in 2007 according to EurObserv’ER (2008b))
would therefore be even smaller.
- Studies that compare future scenarios with and without
biofuels (Banse et al., 2008a and Schmidhuber 2006)
estimate that, rather than increasing agricultural
commodity prices, biofuels would only slow the trend
of declining real agricultural prices in the long-term.
Furthermore, these models do not consider in detail
the biofuels-induced reductions in prices of co-products
(e.g. glycerine), which would also have to be taken into
account to estimate the net price effects on agricultural
commodities.
A similar situation occurs when bioethanol is produced from
cereals: this application is directly competing with grain
for human and animal consumption, but at the same time
increases availability of DDGS (distillers dried grains with
solubles) which is used as animal feed. Such feedback loops
can dampen the impact on cereal prices (Ericson et al.,
2008).
4.3.3 Price impact estimates
Price impact on raw material (feedstock). Agricultural prices
have always been impacted by energy prices. However, this
impact has so far been limited to effects on agricultural
inputs (e.g. fertiliser, pesticides and diesel). With rapidly
rising energy prices and the increasing role of bioenergy,
energy prices are also now directly affecting agricultural
output prices (Schmidhuber 2006).
Price changes for woody biomass are very difficult to
estimate because they are not traded on established
trading platforms. Even markets for wood pellets (the
most commonly used wood type by the stationary sector)
are currently largely bilateral and highly volatile. With
increasing oil prices, pellet prices are expected to increase,
although no meaningful statistics are currently available
regarding pellet production, trade, consumption and quality
(Junginger et al., 2008).
• The impact of biofuels on the price of agricultural
commodities is likely to grow as more countries adopt
specific biofuels targets. National biofuel policies must
therefore always take into consideration the global context
and outlook for biofuels deployment when formulating
their own targets.
There is a far more robust basis for quantitative assessment
of the impacts of liquid biofuels for transport on agricultural
commodities, as both are traded on established platforms
and allow for gathering of consistent and reliable price
data. However, very few comprehensive studies have focused
on the immediate price impact of biofuels on agricultural
commodities (FAO 2008). Most of the model-based studies
are forward-looking and estimate a situation where biofuels
• Finally, some of the studies point to spill-over effects
into markets for agricultural commodities that are not
directly consumed by the biofuel industry (or in negligible
quantities only)18. This can happen for two reasons:
- increased use of substitute crops by other sectors (e.g.
16 In a BBC radio interview on April 14, 2008, Johnson suggested biofuels causing 20-30% of the price increase (Open Europe 2008).
17 The latter are for cases where no or low productivity increases are expected and no 2nd generation biofuels are taken into account.
18 Those impacts are estimated with the cross price effect.
48
Table 4-3. Summary of studies estimating price impacts of biofuels deployment on agricultural commodities.
Source
Geographical
scope of
target
Biofuel
share
(%)
Impact on global price of feedstock
production
Bioethanol
Biodiesel
Crosscommodity price
impact19
Comments
Banse et al.,
(2008a)
World
Various
country
targets for
2020
+18% cereals
+10% sugar
Relative to no
biofuels
Schmidhuber
(2005)
World
10 mio
ton
feedstock
used for
ethanol)
+2.8% maize
+9.8% sugar
Relative to no
biofuels
IFPRI
(Rosegrant
2008)
World
2007
levels
30% price increase
for grains between
2001-2007
Relative to no
biofuels
EC (2007)
EU
10% by
2020
+ 3-6% cereal
Relative to 2006
prices
+ 8-10% rapeseed
+ 15% sunfl. seed
Rel. to 2006 prices
Dynamic model;
assuming 30%
2nd gen, and 20%
imports.
Banse et al
(2008b)
EU
10% by
2020
+6% cereals
+2% sugar
Relative to no
biofuels
+9% oilseeds
Relative to no
biofuels
General equilibrium
model; no 2nd gen
assumed.
JRC
(Edwards
2008)
EU
10% by
2020
+4% cereal
+24% veg oils
Unspec. model type;
demand for food
assumed in elastic, no
2nd gen. assumed.
Elobeid et al., USA
(2006)
20% by
2015
+58% maize
Relative to
2006 prices
Collins
(2008)
2008/09
levels
+40% maize
Relative to 2006/07
maize price level
OECD (2006) USA, Brazil,
Canada,
EU
10% by
2014
+ 60% sugar
+ 4% cereals
Relative to no
biofuels
+2% oilseeds
+20% veg oil
Rel. to no biofuels
Partial equilibrium
model; no 2nd gen.
assumed. Static,
no prod. increases,
no int. trade, no
marginal land.
IFPRI
(Msangi et
al., 2007)
20% by
2020
+25-40% corn
+40-65% sugarcane
+15-30% wheat
Relative to no
biofuels
+ 40-75% oilseeds
Relative. to no
biofuels
Partial equilibrium
model; varying 2nd
gen deployment; yield
improvements account
for.
USA
China+USA
+EU+India
+Brazil
+20% oilseeds
Relative to no
biofuels
General equilibrium
model; no 2nd gen
assumed.
+1.1%
+0.2%
+0.9%
+1.2%
sugar,
veg oils,
wheat,
rice
Partial equilibrium
model; no 2nd gen.
+ 5 soybean
+20% soy oil
+20% wheat
Partical equilibrium
models, no 2nd gen.
assumed. Price
changes through
demand elasticity.
Price elasticity
model; prices changes
through demand
elasticity.
19 Changes in the prices of agro-commodities affected by changes in prices of biofuels feedstocks.
49
Unspecified model;
price changes
expressed for every
addition 10 mio tons
of feedstock used for
biofuel production. No
2nd gen assumed.
the meat industry increasingly turns to using barley as
animal feed when wheat becomes too costly); and
- competition for land: farmers will plant more of the most
profitable crops, thus reducing the output of the existing
ones – in a situation where they cannot expand the area
of arable land.
In developing countries, where consumers tend to buy fewer
processed products and food often accounts for more than
40% of total household consumption (UNDP 1997), higher
food commodity prices are likely to increase hunger and
chronic under nourishment among landless poor, potentially
inducing political and social conflict. On the other hand,
land-owning farmers may benefit from higher food prices.
Thus the balance of distributional impacts is difficult to
assess.
Several studies also indicate other factors that will probably
have a stronger impact on current food price dynamics than
biofuels deployment:
• In the long-term, influential structural factors on the
demand side of agricultural commodities include income
and population growth, while on the supply side increase
in agricultural yields and area of agricultural land are
important (Banse et al., 2008a).
4.3.4 Policy implications
The complexity of the relationship between bioenergy and
commodity markets means that both sectors are subject to
influence from policies of various domains, not just energy,
but also trade, agricultural, environmental, and competition
policies. The possible role of governments in helping to limit
pressure on commodity markets caused by bioenergy is
discussed in the next section.
• In the short-term, sudden food price hikes are most often
caused by weather effects, or a price hike in fossil energy,
which is an important input in agricultural systems. These
fundamental factors in the price volatility of agricultural
commodities can then be exacerbated by more speculative
responses, such as the entrance of hedge funds in
agricultural commodity markets, and hoarding effects in a
nervous market. Also, export taxes introduced by exporting
countries to curb domestic inflation, lead to additional
tightness in the global market.
The role of government bioenergy support schemes. Because
most of the demand for bioenergy is government-induced, the
purchasing power of the sector relies heavily on the level of
government support. This means that government policies on
biofuels can have a direct effect on feedstock price.
The biofuels sector suffers most from high feedstock prices.
In the case of food products, markets are often highly
concentrated and the biofuel industry is thus mostly the
price-taking sector, not the price-setter. Furthermore, the
biofuels sector is particularly vulnerable to feedstock price
increases, as feedstock costs represent 60% or more of total
production costs of 1st generation biofuels (Deurwaarder
et al., 2007). If prices of biofuels do not follow increases
of feedstock price, the margins of producers get squeezed,
capacity expansion is discouraged, and, subsequently, the
impact on markets of agro-commodities is relaxed.
Impact on retail food prices. The price impact on retail food
products has to be approached from a different perspective
to the impact on raw agricultural materials. To understand
how an increase in the costs of inputs translates into price
increases, it is important to look at the price structure of
food commodities and its link to production costs.
In developed countries, the share of production costs in
retail prices of food products has been steadily decreasing,
while the shares of distribution, marketing, and margins
have been increasing over time. In Western Europe, for
example, production costs, on average, account for only 9%
of the retail price of a loaf of bread, with cereal costs only
contributing around 4% (EC 2007). Based on the estimates
of the impact of biofuels on crop prices discussed above, even
with significantly higher shares of biofuels on the market by
2020, the price of bread would increase by only a fraction
of a percentage (if all else stays equal). Animal products are
more affected by price increases since feed costs account
for between 20% and 70% of total meat production costs,
depending on the type of livestock, but on average only 25%
of the retail price of meat.20
Impacts differ strongly between policies and countries.
However, with governments switching to stronger policies
(e.g. from indicative targets to tax-based systems and
quota obligations), a less price-elastic demand for biofuels
is being created and hence the sector’s purchasing power
is increased, inducing higher price levels in situations of
scarcity. A study on the effects of the USA support system
for biofuels estimates that the removal of a tax credit
while keeping the mandate and tariff on imported ethanol
would reduce corn prices in the year of removal by around
3.5%, while removing it in the absence of the mandate and
tariffs would reduce them by 14.5% (McPhail and Babcock
2008a). Interestingly, the removal of the RFS22 mandate
would decrease corn prices in 2008/09 by only 3.9%
(McPhail and Babcock 2008b). Thus it seems that different
support policies have a different effect on the market for
feedstock. Furthermore, impacts may differ substantially
between countries, given their specific conditions in terms of,
for example, agricultural systems, cropping traditions, and
rural livelihoods. Any policy should take such considerations
into account (BEFS 2008).
Estimates of the impact of biofuels on the consumer price
index (CPI) in the USA range from 1% (USDA 2008 and
Urbanchuk 200721) to 9% (Lapp 2007). However, there
have been cases of retailers disproportionately increasing
food prices on account of increasing food production costs,
especially where they hold large shares of the retail food
market. Stimulating competition in the food retail sector can
help curtail such practices.
20 Although we can expect the situation in developing countries to be somewhat different, the higher share of agricultural inputs in retail food prices is
most likely to come from lower costs of capital and labour, rather than higher share of feedstock inputs.
21 Urbanchuk (2007) estimates that a 33% price increase in corn prices would cause a 0.3% increase in the CPI of food overall and a 0.7% increase in
the CPI of meats and eggs.
22 The Renewable Fuel Standard as part of the Energy Policy Act of 2005 mandates the use of 7.5 billion gallons of renewable fuels by 2012.
50
4.4 Barriers to Deployment and
Market Risks
Unlike transport fuel prices that are global because fuel is
a globally traded commodity, power and heat prices vary
tremendously from country to country, creating differences in
the competitiveness of biomass for power and heat between
countries. This also means that the role of governments in
supporting bioenergy can vary greatly depending on the
individual situation.
There is a wide variety of existing and potential factors
hindering the further deployment of bioenergy. These
can be classified as factors relating to supply side,
technologies,
and markets.
The role of functioning markets and of international trade. In
a completely free market, with perfect information, farmers
all over the world would respond to global increases in prices
for agricultural commodities by either bringing new land into
production, switching to different crops, or improving yields.
However, because agricultural markets are far from perfect,
price signals often do not reach farmers. Even when they do,
there are a number of barriers that prevent higher prices of
agricultural commodities being translated into increasing
agricultural output. Amongst the most significant barriers
are the export-limiting measures adopted by governments in
an effort to curb domestic inflation and protect consumers,
but which also discourage farmers who are then unable to
sell their crops at higher global market prices. To minimise
the price impact of any additional demand for agricultural
commodities, governments must ensure that all the institutions
necessary to ensure proper functioning of the agricultural
markets are in place, and abstain from any distortionary
policies that prevent market signals from being translated into
supply adjustments.
4.4.1 Supply side risks and barriers
Cultivation risks. Some essential supply side concerns,
which the bioenergy sector shares with the food and
forestry sectors, relate to the risks of biological
production. For current 1st generation biofuels, these risks
are directly related to crop production, while, for bioheat
and biopower, the risks are generally associated with
the supply of residues, mainly from the forest and wood
industry. El Nino, drought and other weather-related
impacts, fire and pests (including insects, plants diseases,
and vertebrates) affect biomass production as well as
food and fibre production and can drastically reduce
the availability of biomass feedstocks. This is true for
both dedicated energy crops and residues. The increases
in prices for major food commodities in recent years
illustrate the possible effects: adverse weather conditions
in 2006 and 2007 in some major crop producing areas
are cited as one of the major causes of this price increase.
The danger of pest and insect attacks, as well as
susceptibility to fire, is a clear disadvantage of plantations
– particularly monocultures. These risks can be reduced
through proper planning and management (including
continuously changing or rotating the genetic base in use),
but they cannot be eliminated. In general, diversity is
normally the best mechanism to minimise risk.
Residues supply for power and heat. The case of biomass used
for power generation is fundamentally different from that
of biofuels. Because most biomass-based power plants feed
on waste or residues, an increased demand will not directly
cause an increase in the production of round wood. Thus the
supply stream of wood residues can be seen as independently
determined by the demand for the main forestry product
(roundwood). For example, the supply of residues (and
therefore also of wood pellets) decreases significantly in the
case of a downturn in the housing market, due to the reduced
demand for construction wood. Government interventions
are therefore limited in their ability to influence the supply
of the raw material (sawdust). In a well functioning market,
increased pelletising capacity would be established in regions
where residues are not being utilised for energy production.
Unfortunately, the pellet market has so far not been able to
consistently pass market signals up through its value chain.
Longer term supply side concerns include uncertainties
about the effects of climate change, in that increasing
temperatures and shifting rain patterns could profoundly
change the suitability of different parts of the world for
the production of certain crops. In addition, soil, and
water degradation, for instance due to improper irrigation
practice or excessive crop residue removal, can also
severely impact the productivity of cultivations and at
worst make further production non-viable.
The importance of open and transparent trade. One of
the most important conditions for efficient allocation of a
scarce resource such as biomass amongst all its alternative
applications is an open and transparent trade system.
Agricultural commodities have long been traded on established
platforms and the increased trade in biofuels has prompted
the development of standardised contracts and other
trading instruments for them. The development of wood and
agricultural residues into global energy commodities has not
yet reached this level, with few, mostly bilateral transactions,
and consequently huge price variations and considerable price
uncertainty. It can be reasonably expected that 2nd generation
biofuels will suffer from similar problems once they reach
large-scale production levels. If bioenergy targets are to be
reached at least-cost, they must also be accompanied by efforts
to increase the efficient and transparent trading of biomass.
51
Procurement risks. The principal market needs from a
feedstock supply perspective relate to securing quantity,
quality and price (see Table 4-4). However the specific
challenges are different for different bioenergy feedstocks.
A distinction can be made between different categories:
• biomass feedstocks that are also produced for food,
fibre and other material purposes;
• dedicated biomass crops that are specific to the
bioenergy sector; and
• waste and residues.
The current production of biofuels for transport relies on
food commodity feedstocks with established markets and
logistics. These feedstocks have the advantage of being
well known by farmers who have already invested in
machinery and other facilities related to their production.
To a large extent this also applies to agricultural residues.
Table 4-4. Major challenges for plant developers in relation to
securing quantity, quality, and price of biomass feedstock.
Procurement
risk factor
Unlike dedicated crops and residues, wastes such as
municipal solid waste (MSW) and sewage sludges suffer
much less from procurement risks.
Major challenges
Quantity
• ‘Chicken and egg’ problem in joint
development of biomass supply and demand.
• Lack of fluid market in non-commodity
biomass feedstocks.
• Small supplier base.
• Lack of adequate and integrated
infrastructure.
Quality
• Biomass variability in physical
characteristics and chemical composition.
• Low density.
• Lack of infrastructure to verify quality of
supply.
Price
• Potential for variability because of limited
supply base.
• Difficulty in securing long-term contracts
(longer than 2-3 years).
4.4.2 Technology risks and barriers
Although each bioenergy technology has its own technical
challenges to overcome that depend mostly on their
development status (see Chapter 3), a number of risks and
barriers to deployment are common across the range of
technologies. The principal concerns are discussed below,
the majority of which relate to the physical properties and
chemical composition of the biomass feedstock.
Ability to handle feedstock variability. Most bioenergy
conversion technologies are not very flexible to changes in
feedstock quality and moisture content. This may impact on
both the performance and reliability of the plant, which in
turn affects its economics.
Feedstock handling. Solid biomass feedstock generally has
a low bulk density and comes in a variety of structures
and types, which makes it technically difficult to handle
and store. Reliability of the feeding systems into the boiler/
reactor is a common issue and is considered one of the main
technical challenges still to be overcome, particularly for
gasification units that operate under pressure.
Similarly, much of the solid biomass that is used for heat and
power in industrialised countries has been extracted from
forests as part of well established forest industry practices.
Extraction of new forest assortments, such as thinnings
from silvicultural activities and felling residues, will require
specially-adapted machinery, but could benefit from similar
developments within the established forest sector.
Economies of scale. Commercially available technologies,
apart from technologies for heating applications, generally
suffer from poor economics at small-scale. This is a
particular problem because of the difficulty in supplying
mainly lignocellulosic feedstocks to large plants due to
insufficient resource availability, distribution, density
and logistics. Addressing this risk will require the
commercialisation of technologies with improved economics
at small-scale and an improvement in the availability of
biomass and its supply logistics.
For conventional feedstocks, i.e. forest materials and
agricultural crops, price variability remains a risk. The
feedstock competition with the food and forestry sectors
makes the business situation more complicated, since the
feedstock prices are also influenced by the supply-demand
balances in these sectors. Apart from price competition,
the food and forestry sectors can also affect the bioenergy
supply through lobbying and other general strategic efforts to
improve their own prospects.
Co-product contamination. The solid co-product fraction
of bioenergy conversion (ash, digestate, etc.) may contain
contaminants such as heavy metals. This is particularly the
case when feedstocks such as short rotation crops, straw,
grasses and husks, as well as waste wood are used, which
usually contain higher concentrations of alkali metals
than traditional wood fuel. In the context of increasingly
strict environmental regulation, questions remain
regarding the most affordable manner for treating and
using these by-products and disposing of them in the most
environmentally sound way.
The supply side challenges are quite different for dedicated
bioenergy crops. Many of these feedstocks are largely
unproven in production and face agronomic, technical,
institutional, and, not least, cultural barriers. For many
of the lignocellulosic grasses, the technologies and
infrastructure present on farms can be used directly in their
production. Woody crops, on the other hand, require either
adapted agricultural or forestry equipment.
Biomass residues are co-products of the wood and agriculture
industries. Hence, the availability (and price) of biomass
residues is difficult to predict and secure as it is directly
affected by the variability in production from these industry
sectors, which in turn depends on both the cultivation risks
described above and the variation in the demand for these
primary products. For instance, the recent housing crisis in
the USA, resulting in fewer houses being built and hence less
timber consumed, has been interpreted as a possible cause of
the sawdust shortage in the USA pellet industry.
52
Toxic emissions. Similarly, further R&D effort for flue gas
cleansing will be required to meet increasingly stringent
limits on toxic emissions (NOx, CO, particulates, etc.). This
is particularly important for small-scale combustion units, as
they need simple and affordable solutions (IEA 2008e).
4.4.3 Market risks and barriers
Competition and competitiveness. Bioenergy faces
competition from alternative sources in all its market
segments. While bioenergy is generally cheaper than most
alternative renewable resources, it is usually not cost
competitive with conventional fossil solutions without public
support. The competitiveness of bioenergy is very much
local public resistance is more likely due to local issues
such as traffic movements, local air pollution, smells, noise,
visual impacts, etc. In general, society needs to be informed
and confident that bioenergy is environmentally and socially
beneficial and does not result in negative environmental and
social trade-offs on a global or local level.
dependent on the cost of biomass (including any transport
costs). Many local factors also affect the competitiveness
of bioenergy such as infrastructure, cost of alternatives and
regulatory aspects (e.g. grid accessibility). Some examples
where bioenergy is competitive with conventional sources
are: power generation from waste gases, certain heat
applications based on woodchips and pellets, and ethanol
production from sugar-cane.
4.5 Key Messages for Decision
Makers
Competition within the bioenergy sector. Within the
bioenergy sector, there is no competition as yet between
the commercial technologies that tend to be relatively
similar in terms of the biomass types they can use; their
regional availability; and the final product they can deliver.
However, the advent of new technologies could change this.
In particular, new technologies for the production of biofuels
from lignocellulosic feedstock could lead to competition
for biomass resources between transport fuel applications
and heat and power applications. Technological advances
in conversion technologies for biomass-fuelled heat, power,
or transport would affect the competitiveness and use
of bioenergy for those different applications, as would
advances in the competitiveness of other renewable and nonconventional fossil sources of energy.
1. What is the market status and prospects for bioenergy in
different market segments?
Bioenergy covers 10% of global primary energy
consumption, of which around 90% consists of biomass
for domestic cooking and heating in developing countries.
Traditional biomass consumption could be globally reduced
by up to 70% by 2050 by the widespread introduction of
modern efficient stoves.
Policy and regulation. A stable and supportive policy
environment is a prerequisite for the successful deployment
of biomass in different applications. Similarly, there is a
need for clarity and foresight in regulatory aspects, such as
planning regulation and emissions standards.
Electricity from biomass currently represents a mere 1.3%
of the global power production, and this share is projected
to increase to 3-5% by 2050 in most energy scenarios.
The main opportunities in the short-term are co-firing with
fossil fuels (the most cost-effective option), biogas-to-power
units and MSW combustion plants, with other dedicated
solid biomass requiring greater support for greater
deployment. Gasification-based technologies could offer
prospects in the longer term both at small- and large-scale.
Investor confidence. Supply side risks such as feedstock
availability and price, and how these are affected by
competing uses is a major source of concern for investors.
Since feedstock costs represent 50-90% of the production
costs of bioenergy, not being able to secure long-term supply
contracts casts uncertainties over the viability of projects.
The cost of feedstock is a key aspect that differentiates
bioenergy from all the other renewable resources that feed
on ‘free’ fuel such as sunlight and wind, etc.
Biofuels today represent less than 1% of the total road
transport fuel consumption but this sector is expected to
be the fastest growing bioenergy segment. A 6-8% annual
growth rate for biofuels production is expected over the
next decades. This rate will be strongly determined by what
policies are put in place, which are likely to depend in turn
on how the biofuel industry manages environmental and
social sustainability challenges, and the development rate of
other alternative fuel-vehicle technologies in transport.
2. What are the main biomass feedstocks and products
traded?
On the technology side, feedstock variability and its impact
on conversion processes also affects investors' confidence.
Furthermore, the range of feedstock and technology options
adds complexity to investment decisions, particularly
considering the absence of a critical mass of knowledgeable
investors (although this has changed somewhat in
recent years). Also, the very high cost of first-of-a-kind
demonstration plants, and the insufficient record of success
stories, tends to restrain investments.
The main biomass-based energy carriers traded today are:
• wood pellets (mainly from North America and Eastern
Europe to Northern and Western Europe);
• ethanol (mainly from Brazil to Europe and the USA); and
• vegetable oils and biodiesel (mainly from South-East Asia
and Latin America to the USA and Europe).
Many other bioenergy feedstocks are traded for energy use,
such as wood chips, waste wood and agricultural residues.
Furthermore, components of biomass commodities traded
for other purposes (e.g. round wood) end up indirectly in
energy use (e.g. bark, saw dust, and black liquor).
The interaction of biomass with other sectors, such as food
and forestry, and the policies affecting them, is also a source
of risk, placing further uncertainty on the future development
of the bioenergy sector. Finally, the fragmented nature of
policy support directed to bioenergy (focusing on feedstock
production, conversion or end-use) enhances policy risk.
3. What are the current and potential trade volumes?
Current trade volumes are estimated to be around 1 EJ (in
2006) and growing rapidly. Compared to a global biomass
use of 50 EJ and total energy demand of 500 EJ, this is
relatively small. However, in the longer term, up to several
hundred EJ of biomass commodities might be traded
internationally, with Latin America and Sub-Saharan
Public and NGO acceptance. Public and NGO acceptance is
a major risk factor for all alternative energy sources, but
bioenergy in particular. While concerns of NGOs and the
general public are usually global (social justice, impact of
land use change, deforestation and overall CO2 balance),
53
• reducing the share of fossil fuels in the total cost of crop
production;
• critically reviewing trade-distorting government
interventions (e.g. export bans); and
• facilitating the development of more transparent trading
platforms for wood products.
Africa as potential large net exporters, and North America,
Europe and South-East Asia as large net importers.
4. Does long distance transport of biomass use more energy
than that embodied in the biomass itself?
Long distance transport of biomass takes place by sea in
energy efficient bulk carriers. Especially when the biomass
is pre-treated in order to increase the energy density, energy
use due to long distance transport is very low compared to
the energy content of the material transported. Long distance
transport on land (particularly road transport) is significantly
more energy intensive; for cost reasons, most biomass
supply chains try to keep transport through these modes to a
minimum.
8. What is hindering market penetration of bioenergy?
Major risks and barriers to deployment are found all along
the bioenergy value chain and concern all final energy
products (bioheat, biopower, and biofuel for transport). On
the supply side, there are challenges in relation to securing
quantity, quality, and price of biomass feedstock irrespective
of the origin of the feedstock (energy crops, wastes, or
residues). There are also technology challenges related to
the varied physical properties and chemical composition of
the biomass feedstock, and challenges associated with the
poor economics of current power and biofuel technologies at
small-scales.
5. Which commodity markets are going to be affected by an
increasing use of bioenergy?
Increasing use of biomass for energy will affect commodity
markets of agricultural and forestry products. This impact
can be direct, e.g. bioenergy and food chains competing for
the same product or same land, but can also be manifested
in indirect ways, e.g. by co-products of bioenergy chains
substituting feed crops. In general, the interactions between
bioenergy and commodity markets are complex, and the
impact may differ significantly for different bioenergy
options.
On the demand side, some of the key factors affecting
bioenergy deployment are cost-competitiveness, stability
and supportiveness of policy frameworks, and investors’
confidence in the sector and its technologies, in particular to
overcome funding challenges associated with demonstrating
the reliable operation of new technologies at commercial
scale. In the power and heat sectors, competition with other
renewable energy sources may also be an issue. Public
acceptance is another critical factor closely related to
the case for the sustainability of energy crops for biofuel
production, especially conventional starch, sugar, and oil
crops destined to biofuel production (woody biomass, wastes
and residues are less of a public concern). Public percetion
also can affect the planning approval for bioenergy facilities
at a local level.
6. What is the impact of biofuels on the recent increase in
food commodity prices?
The use of biofuels is one of many factors affecting
agricultural commodity prices. Although demand for biofuel
might have a significant impact in the future, today it is far
from being the dominant influencing factor in the case of
most agricultural commodities. In the short-term, sudden
food price hikes are mostly caused by weather effects, and
price rises in fossil energy, which is an important input to
agricultural systems. These fundamental factors affecting
price volatility of agricultural commodities can be magnified
by speculative market responses and by policy responses
such as export taxes. In the long-term, influential factors
on the demand side include population and income growth,
and resulting increases in demand for food and feed. On
the supply side, developments in agricultural yields and
agricultural land area available are important factors. If
the demand for biofuel feedstocks were to cause significant
competition for land with food and feed crops, this could
have a significant impact on food prices in the future.
7. What measures can be taken to minimise the impacts of
bioenergy development on commodity markets?
Given that the biofuels market is largely policy driven,
cautious target setting could limit disproportionate reactions
from the market and minimise the impact of bioenergy
development on commodity markets. Also, measures
are needed to coordinate bioenergy policy with forestry,
agricultural, competition, trade and environmental policies.
This comprises policies aimed at:
• increasing agricultural yields, particularly in countries
lagging in modern agricultural practices;
• creating selective incentives for biofuels produced from
agricultural and forestry residues and crops from marginal
and/or degraded land;
54
CHAPTER 5: BIOENERGY AND POLICY OBJECTIVES
Key questions addressed in this Chapter:
1. Is biomass best used to produce transport fuel or to generate heat and power?
2. If climate change mitigation in the energy sector is the objective, how can biomass be used
most cost-effectively?
3. What is the impact of greenhouse gas emissions from direct and indirect land use change on
the greenhouse gas balances of biofuels?
4. Is it better to use land for carbon sink creation than for bioenergy production?
5. Can biofuels play a role in improving energy security?
6. How can food insecurity and other socio-economic impacts be mitigated?
5.1 Introduction
areas for heating, warm water, and cooking, means that
biomethane production could be an interesting option with
large deployment potential. The build-up of a biomethane
refuelling infrastructure for the transport sector could also
rely on existing natural gas pipelines.
• There is significant potential to use surplus heat from
biomass-based power and transport fuel production in
domestic applications through heat distribution networks
where these exist. Alternatively biomass energy conversion
that requires heat input, e.g. ethanol production, could
benefit from co-siting with energy plants and industries
generating surplus heat.
Different bioenergy feedstocks and uses have different
implications in terms of, for example, energy security, ecology,
and climate. Consequently, different objectives and related
policies lead to different prioritisation of bioenergy options, as
well as biofuel chain configurations.
This chapter provides a strategic view on the relationship
between bioenergy and policy objectives, taking into
consideration the uncertainty of the longer term goals that
will define sustainable energy and transport, and the strong
influence of incumbent energy and transport infrastructures.
The development of bioenergy will also be shaped by the
presence of competing energy resources and technologies for
meeting policy goals such as energy security improvement
and climate change mitigation. As an illustration of
this, model-based energy system studies report diverging
findings on whether biomass should be used for transport or
stationary energy. How biomass is to be used is to a large
degree determined by the availability and cost of alternative
transportation options that do not rely on biomass. If hydrogen
or electric vehicles do not become technically viable or are too
expensive, the only remaining supply-side option to reduce oil
dependency and/or achieve very low emissions of CO2 is to rely
on biofuels for transport. In contrast, the stationary sector can
rely on a range of different low carbon options, and has a huge
potential for energy efficiency improvement. Thus, the focused
use of biomass for heat and power rests on the argument
that other climate friendly transport options will become
commercially available soon and make biofuels for transport
irrelevant.
5.2 The Role of Bioenergy in the
Stationary and Transport Energy Systems
The socio-economic context and the established industry,
energy, and transport systems are major – and geographically
varying – determinants of the technology response to
government policies. Technologies that can be integrated
with existing systems and do not require drastic changes
in consumer behaviour have a clear advantage. In the case
of bioenergy, examples of this are the blending strategy
for biofuels in transport and the substitution of fossil fuels
by biomass in the forest industry. Therefore, bioenergy
deployment needs to consider existing and planned energy
infrastructure, because new power plants, pipelines, etc.
will stay in operation for many decades. Some specific
illustrations:
• The large – and growing – installed capacity of coal-based
power (see Figure 5-1) makes biomass co-firing with coal an
interesting near-term option (IEA 2008b). The longer term
prospects for this option depend on whether carbon capture
and storage and/or high biomass shares in the fuel mix can
provide competitive power when stringent climate targets
are established.
• The large installed capacity of natural gas-based power
generation, and the widespread natural gas grid in domestic
Individual countries differ in their existing energy
infrastructure and the sources of energy (including bioenergy)
that they have access to. Therefore, they will probably prioritise
biomass use differently. Technology development will also
affect the use of bioenergy, and while region-specific factors
may influence energy technology development, this will largely
follow global trends. Standards, e.g. fuel standards for engines,
also influence technology development and deployment.
55
Figure 5-1. Thermal power plants in EU25 exceeding 10 MW. A 10-15% biomass share in all existing coal plants under 40 years old would
correspond to ca 900 PJ of biomass, or 90 TWh, or almost 20% of the renewable electricity generation in EU27 in 2005. Source: Kjärstad
and Johnson (2007).
5.3 Bioenergy and Climate Change
Mitigation
emissions compared with conventional fossil routes. However,
the lack of solid empirical data for some parameters, and
of a commonly agreed methodology (e.g. how by-products
are taken into account) contributes to uncertainties in the
climate impact of bioenergy chains and to the diverging
results provided by studies (see, for example, IEA 2008d).
Despite the uncertainties in the data and methodologies, some
conclusions can safely be drawn.
An essential feature of bioenergy as a climate mitigation
option is that it requires land for biomass feedstock
cultivation. Land can be used for climate change mitigation in
two principal ways:
• By increasing the land’s biospheric carbon (C) stocks (soils
and standing biomass) and thereby withdrawing CO2 from
the atmosphere23(here denoted carbon sink option).
• By supplying biomass as a substitute for fossil-based fuels
and other products and thereby reducing the emissions of
fossil CO2 to the atmosphere (here denoted bioenergy option).
Biomass-to-heat and power generally leads to larger
greenhouse gas emission reductions and biomass cascades are
better than single-product systems. Bioenergy will be most
effective for GHG mitigation when it is adopted in association
with other products i.e. by utilising biomass wastes of primary
product chains or biomass that has already served one or more
functions. When used for energy, biomass that substitutes
for fossil fuels in heat and electricity generation in general
provides larger and less costly CO2 emissions reduction per
unit of biomass than substituting biofuels for gasoline or diesel
in transport. The major reasons for this are:
• the lower conversion efficiency, compared to the fossil
alternative, when biomass is processed into biofuels and
used for transport, and
• the higher energy inputs in the production and conversion of
biomass into such fuels, when based on conventional arable
crops.
These two options are not mutually exclusive. The
establishment of bioenergy systems in themselves often leads
to (positive or negative) changes in the biospheric carbon
stocks. Both the bioenergy and the carbon sink option can
also induce indirect land use change (LUC) when they are
implemented. The possible emissions from direct and indirect
LUC can substantially influence the climate benefit of
bioenergy systems as well as carbon sink projects.
The remainder of this section provides an overview of the GHG
reduction potential of different bioenergy options, with and
without consideration of LUC effects. The option of using land
for carbon sinks is then compared to the bioenergy option.
At the same time, the stationary sector can rely on a range of
different low carbon options, while biofuels may be the major
option for climate change mitigation and energy security
improvement in the transport sector. Future fossil fuels in
the transport sector may also yield higher GHG emissions,
5.3.1 Conclusions from lifecycle assessments and
well-to-wheel analyses
In lifecycle assessments of GHG emissions, the benefits of
bioenergy are estimated in terms of the reduction of GHG
23 Reducing the present rate of deforestation and other ecosystem degradation can be regarded as a third option as it leads to a deviation from
trends in atmospheric CO2 accumulation (due to biospheric C losses) in the same way as bioenergy substituting fossil fuel use reduces the rate of
atmospheric CO2 accumulation (due to reduced fossil C emissions). Preservation of biospheric C stocks differs from bioenergy in the same way as C
sink creation: it does not require any energy system changes.
56
produced in Sweden which reduces GHG emissions by some
80% compared to gasoline. It has also been estimated that
cellulosic ethanol could achieve roughly the same emissions
reduction in the future as Brazilian sugar-cane ethanol (Farrell
et al., 2006).
and improve the case for biofuels. Transport fuels from less
conventional oil resources and coal based Fischer Tropsch
diesel both have higher lifecycle GHG emissions than the
gasoline and diesel used today.
The question whether to use biomass for transport or
stationary energy purposes may become less relevant in the
longer term, when bioenergy systems may increasingly consist
of biorefinery technologies that produce liquid/gaseous biofuels
for transport in combination with power, heat, solid biofuels,
chemicals and other products (see also Section 3.7). The
driving factors are the synergies available with the higher total
energy efficiency and resource efficiency obtained by combined
approaches, and the potential added value from producing a
range of products.
Process options such as, for example, the choice of fuel for the
conversion process, have an important influence on the final
result of GHG calculations. Recent analyses using updated
values for crop management and yields, conversion process
configuration, and by-product utilisation found emissions
reductions of roughly 50-60% for maize ethanol in USA
(Liska et al., 2009). As stated above, earlier studies showed
almost no reduction and sometimes a slight increase. The
choice of fuel for the conversion process is one major reason
for this difference. High climate benefit also requires that
nitrous oxide emissions are minimised by means of efficient
fertilisation strategies using commercial nitrogen fertiliser
produced in plants that have nitrous oxide gas cleaning.
Greenhouse gas emission reductions vary strongly between
chains but choice of methodological approach also strongly
influences the outcome of analyses. Greenhouse gas emissions
of bioenergy systems (and thus the GHG reduction potential)
vary widely with changing feedstock growing conditions and
process options, and changing calculation methodologies.
Finally, the choice of method for the allocation of impacts
between main product and by-product(s) strongly affects the
performance.
Typically, Brazilian sugar-cane ethanol achieves GHG emission
reductions of 85% whereas the GHG emissions from ethanol
made from conventionally grown maize in the USA are
reported to be slightly more or slightly less than those from
gasoline per unit of energy. Another example is wheat ethanol
Figure 5-2 exemplifies the wide range of results that can
be obtained for one bioenergy production system (wheat
ethanol in Sweden) by varying three different factors: the fuel
combusted in the conversion process, the time horizon and the
Figure 5-2. Energy balances (upper diagram) and GHG emissions (lower diagram) for wheat-based ethanol production, taking into account
various methods for considering by-product uses. System expansion refers to the assumption that the use of by-products leads to reduced
production of an alternative product with the same use. The bars designated ‘Future’ show how the systems can improve due to development in
both the feedstock production and the conversion to ethanol. Based on Börjesson (2008).
57
allocation method. The upper diagram of Figure 5-2 shows
the ratio of ethanol produced to external energy invested in
the process and the lower one presents the net GHG emissions,
including a comparison with gasoline.
Results are given for allocation by economic value, by energy
value, and ‘system expansion’ where the avoided impacts of a
substitute product that the by-product replaces are accounted
for. If by-products are utilised efficiently so as to maximise
their energy and climate benefits, the performance of the
bioenergy system improves substantially. However, economic
realities may lead to uses that contribute less to climate
benefits. Note also that the use of by-products as animal feed –
which leads to significant GHG reductions in Figure 5-2 when
by-product is assumed to replace soy protein imports in the
system expansion method – is limited by the relatively small
size of this by-product market, corresponding to a few percent
of the transport fuel demand.
than by increasing yields, but concern about the negative
impacts of expanding oil palm plantations may shift focus
to increasing plantation productivity. But, to avoid indirect
impacts, yield increases would have to outstrip increases in
demand.
• If European biofuel demand leads to pastures and
grasslands being converted to croplands for rape seed (or
other annual crops), soil C emissions from these lands
may be high. But even if biodiesel comes from rape seed
cultivated on the present cropland, rising demand for this
feedstock may lead to increasing prices, which may in
turn lead to increased palm oil production (and possibly
deforestation) for rape seed oil substitution in the food
sector. Another illustrative example is the shift from soy to
corn cultivation in response to increasing ethanol demand
in the USA, which has induced increased expansion of soy
cultivation in Brazil and other countries (Laurance 2007).
If biofuel crops are grown on previous agricultural land
which has been taken out of production, soil C losses may be
minimal. Similarly, planting short or long rotation forestry
on grasslands with limited C and ecosystem value may
result in limited C loss or possibly C gains, depending on the
planting and management techniques used. In many cases,
bioenergy initiatives could lead to a net increase in biospheric
C stores if perennial grasses or short rotation woody crops are
established on land with sparse vegetation and/or C depleted
soils on degraded and marginal lands. In this context, land
application of bio-char produced via slow pyrolysis offers an
option where the C is sequestered in a more stable form and
also improves the structure and fertility of soils (Lehman et
al., 2006; Gaunt et al., 2008).
A key message from this is that, although the same bioenergy
chain can perform very differently, most bioenergy options
can deliver significant GHG savings if high LUC emissions are
avoided.24 There is a clear potential for improvement of the
current production of ethanol and other biofuels worldwide,
leading to increased GHG savings. However, policies must be
put in place that stimulates such improvement (see Chapter 6).
5.3.2 Impact of direct and indirect land use
change on greenhouse gas emissions
Modelling studies have shown that the possible direct and
indirect emissions from converting land to an alternative
use can substantially reduce the climate benefit of bioenergy
initiatives (Leemans, et al., 1996; Fargione et al., 2008;
Searchinger et al., 2008; Gibbs et al., 2008; RFA 2008).
The promotion of biofuels for transport in recent years is
being questioned because of concerns that they may result in
a marginal or even negative contribution to greenhouse gas
emissions reduction, in part due to large CO2 emissions from
induced LUC.
The quantifications reported so far are based on model
projections of LUC. These involve a significant degree of
uncertainty, for example in relation to causal chains and the
carbon stock changes linked to LUC. The effects are complex
and difficult to quantify in relation to a specific bioenergy
project (see Figure 5-3):
• Brazilian sugar-cane plantations are primarily established on
pastures, displacing cattle ranching (Sparovek et al., 2008).
This may lead to intensified cattle production on existing
pastures or establishment of new pastures elsewhere. If a
substantial part of the pasture expansion were to take place
in the Amazon region, CO2 emissions from deforestation
would severely reduce the climate benefits of Brazilian
ethanol.
• Oil palm expansion (predominantly for food production
purposes) has caused significant deforestation in SE Asia
and large CO2 emissions, especially from peatland forests.
Historically, increased palm oil production has largely been
achieved by establishment of additional plantations rather
Despite the substantial degree of uncertainty, if the expansion
of crops for 1st generation biofuels results directly or indirectly
in the loss of permanent grasslands and forests it is likely to
have negative impacts on GHG emissions. This conclusion
clearly highlights the need for land development strategies
that reduce the risk of displacement, along with accompanying
policies reducing the pressure on ecosystems with large C
stocks. Such policies may also be preferred for reasons other
than climate change, for instance nature conservation and
biodiversity preservation (see also Chapter 6), even in the
absence of ambitious bioenergy programmes.
The question whether land should be used for biomass
production for fossil fuel substitution or for the creation of
biospheric carbon stores has been subject to substantial debate
and scientific effort.25 The lack of uniform and comprehensive
evaluation standards and varying limitations in scope for
studies (e.g. studies commonly disregard the effects of indirect
land use change) has resulted in a diverse set of studies that
are difficult to compare and whose comparison does not
provide clear answers. Also, as has been stated above, the two
principal land use options for climate change mitigation are
not mutually exclusive: bioenergy systems have carbon stocks
associated with them and forests established as carbon sinks
can deliver products for various uses, including bioenergy.
24 There are examples of bioenergy systems that are unlikely to give a positive contribution to climate change mitigation, regardless of process
configuration. The common feature is that their establishment involves conversion of carbon-rich ecosystems to bioenergy plantations. This is
further discussed in Section 5.3.2.
25 IEA Bioenergy Task 38 is one example of thematic research networks involved with these issues.
58
Figure 5-3. Illustration of how LUC emissions can influence the climate benefit of biofuels. The x-axis shows the net GHG emissions reduction
(CO2eq.) of using biofuels (excluding LUC effects), with typical performance (green bars) indicated based on biofuel output per hectare in
IEA (2008c) and GHG emissions reduction in RFA (2008). Different use of process fuel is one major explanation for the range for the sugarcane and cereal ethanol cases, for tropical biodiesel the specific crop causes the range, with palm biodiesel performing better than soybean
biodiesel. The y-axis shows the net loss of carbon in soils and vegetation when different ecosystem types are converted to bioenergy plantations:
the bars to the left of the y-axis indicate the ranges for C content in different ecosystem types (IPCC 2001; Searchinger 2008). The dashed
lines indicate how many years of biofuels production and use that is required to fully compensate for the C emissions due to land conversion to
bioenergy plantations. The dots represent specific cases reported in Fargione et al., (2008).
The relative attractiveness of the bioenergy and carbon sink
options is also dependent on the timescale that is used for
the evaluation. A short timeframe (a few decades) tends to
favour the sink option, while a longer timeframe favours the
bioenergy option. The reason is that the accumulation of
carbon in forests and soils cannot continue endlessly – the
forest eventually matures and reaches a steady state condition.
This is also the case for soils. In contrast, bioenergy can be
produced repeatedly and continue to deliver greenhouse gas
emissions reduction by substituting fossil fuels.
Ranking of land use options based on their contribution to
climate change mitigation is also complicated by the fact that
the performance of the different options is site-specific and
is determined by many parameters. Among the more critical
parameters are:
• Biomass productivity and the efficiency with which the
harvested material is used – high productivity and efficiency
in use favour the bioenergy option. Low productivity land
may be better used for carbon sinks, given that this can be
accomplished without displacing land users to other areas
where their activities lead to indirect CO2 emissions. Local
acceptance is also a prerequisite for the long-term integrity
of sink projects.
• The fossil fuel system to be displaced – the GHG emissions
reduction is for instance higher when bioenergy replaces
coal that is used with low efficiency and lower when it
replaces efficient natural gas-based electricity or gasoline/
diesel for transport.
• The initial state of the land converted to carbon sinks
or bioenergy plantations (and of land elsewhere possibly
impacted indirectly) – conversion of land with large carbon
stocks in soils and vegetation can completely negate the
climate benefit of the sink/bioenergy establishment.
The bioenergy and carbon sink options obviously differ in their
influence on the energy and transport systems. Bioenergy
promotion induces system changes as the use of biofuels for
heat, power, and transport increases. In contrast, the carbon
sink option reduces the need for system change in relation to
a given climate target since it has the same effect as shifting
to a less ambitious climate target. The lock-in character of
the sink option is one disadvantage: mature forests that have
ceased to serve as carbon sinks can in principle be managed
in a conventional manner to produce timber and other forest
products, offering a relatively low GHG reduction per hectare.
Alternatively, they could be converted to higher yielding energy
59
Furthermore, the contribution of bioenergy to improving
energy security largely depends on decoupling the bioenergy
system from oil and gas inputs. The use of coal as a fuel
for the conversion process may be less of an issue from the
perspective of energy security, but it drastically reduces the
climate benefit of biofuels. In relation to energy crops, energy
security will be improved through systems that achieve high
energy outputs per unit of land used. Figure 5-4 illustrates
these points for the Swedish case, showing the net production
of vehicular fuels, i.e. the gross biofuel yield less the amount
of vehicular fuels used for the cultivation, harvest, and
transportation of biomass to the processing plant.
plantations (or to food production) but this would involve the
release of at least part of the carbon store created. On the
other hand, carbon sinks can be viewed as a way to buy time
for the advancement of climate-friendly energy technologies
other than bioenergy. Thus, from an energy and transport
systems transformation perspective, the merits of the two
options are highly dependent on expectations about other
energy technologies.
5.4 Bioenergy and Energy Security
Biomass provides a diverse source of energy, potentially
improving energy security through the substitution of oil
and natural gas. The use of domestic bioenergy resources
would generally contribute to the diversification of the energy
mix. Biomass imports, from widely distributed international
sources, also contribute to energy diversification, especially if
lignocellulosic resources and bioenergy products derived from
them are considered. The international bioenergy market is
expected to have a wide range of net suppliers from several
world regions (see also Chapter 2) and import of bioenergy is
therefore not affected by the same geo-political concerns as
oil and natural gas imports are. There may be other problems
however.
Figure 5-4 also shows how biofuels differ in terms of
additional energy use, i.e. energy inputs other than vehicular
fuels. From the perspective of GHG emissions reduction,
an assessment of biofuel alternatives on the basis of Figure
5-4 should consider types of energy inputs required. For
example, using sugar-beet as feedstock requires relatively
more energy but also produces a large amount of net vehicular
fuel per hectare. It matters greatly how the required energy
is produced. If it is generated from biomass instead of fossil
fuels, replacing gasoline with beet ethanol leads to higher
GHG emissions reduction. If biofuel plants are located close
to activities with excess heat, ‘free’ process heat may be
utilised.26
El Nino drought and other weather-related impacts, fires
and pests can drastically reduce the availability of bioenergy
feedstocks. The increases in prices of major food commodities
in recent years illustrate these effects (for further discussion
of its causes see Section 4.3.3). Supply-demand imbalances
in the food and forestry sectors could lead to increases in
biomass prices for energy, and vice-versa.
Oil is commonly thought of as a transport fuel but in many
places in the world oil is more commonly used for space
heating and power generation than for transportation. The
transport sector currently consumes about half of the oil
used globally. Thus, biofuels may replace oil in the stationary
energy system as well (see Figure 5-1). Using biomass to
Figure 5-4. Net production of vehicular fuel per hectare per year and other non-vehicular energy inputs, for various biofuel alternatives to be
produced in Sweden. The dashed lines indicate how the alternatives compare to the energy quotient, net vehicular fuel production/other energy
input. Source: Berndes et al., (2008).
26 The heat can be considered ‘free’ if no other use is possible, and the heat therefore in the absence of the vehicular biofuels plant would not have
yielded any other utility.
60
replace oil is in general cheaper in the stationary sector and
the net oil replacement per unit of biomass is generally higher
than in the transport sector, since solid biofuels – produced
with fewer energy inputs and conversion losses than liquid
biofuels – can be used. In countries where natural gas import
dependency is a concern, the promotion of bioenergy could
also mitigate the increasing gas dependency and – where gasbased electricity is growing particularly quickly – could also
improve the security of supply for electricity. As for other
renewable options, bioenergy promotion in the stationary
energy system influences the development of stationary energy
towards a higher degree of diversity with respect to technology
and fuel choice. It also reduces the investment in fossil energy
plants that, once built, can be expected to be in operation for
several decades.
Bioenergy strategies that mainly focus on biofuels for transport
and lead to increased cultivation of conventional agricultural
crops for the production of 1st generation biofuels amplify the
risk of further expansion of agricultural land into forests and
other land with high biodiversity values, potentially causing
continued ecosystem conversion and biodiversity loss (RFA
2008, Thow and Warhurst 2007). They may also intensify
concerns about the capacity of the agricultural resource
base (soils, freshwater) to sustainably support an increasing
agricultural output, due to the well-documented degradation
of soils and water bodies that typically accompanies intensive
agricultural practices (MEA 2005; CA 2007).
Increased bioenergy use does not necessarily lead to
increased competition for food and feed crops. As has been
described in Chapter 3, there are a multitude of conversion
options that generate energy from biomass and which can
use many different feedstocks other than food/feed crops.
Under strategies that shift demand to alternative – mainly
lignocellulosic – feedstocks, bioenergy expansion could use
other sources such as agriculture and forestry residues that
would not require additional land or water, although these
could potentially cause negative effects if extraction rates
are excessive (see Chapter 2). Lignocellulosic crops could
also be grown on a wider spectrum of land types. Marginal
lands, pastures and grasslands, which are not suitable for
1st generation biofuels due to environmental and greenhouse
gas implications, could become an additional resource
for feedstock production under sustainable management
practices. The cultivation of perennial energy crops also
presents an opportunity for increasing water productivity, by
decreasing the proportion of rainfall lost through unproductive
evaporation.
On a more strategic systems level, the use of biofuels in
gasoline/diesel blends can reduce oil imports but may not
induce the kind of development that can act as a bridge to a
more radical decoupling of transport from oil. The biofuels
presently used in low-level blends – ethanol and biodiesel – are
channelled through the established oil industry infrastructure,
and are not conducive to a large-scale substitution of fossil
fuels. This would require either the development of an
infrastructure and vehicles that would accept higher quantities
of ethanol and biodiesel, or the development of fuels that
would be compatible with the existing distribution and vehicle
infrastructure in large quantities (e.g. Fischer Tropsch fuels).
The Brazilian biofuel strategy with higher-level blends has
reduced the country’s oil dependency drastically, but Brazil is
so far an isolated case. Low-level blending is more commonly
favoured due to compatibility with the existing vehicle stock.
Sweden is possibly one exception where E85 car sales are
increasing rapidly27 and an extensive network of dedicated
pumps at fuelling stations has been established. Another
example of prospective developments that might act as a
bridge to a drastic decoupling of transport from oil can be
seen in the further development of hybrid vehicles into plug-in
hybrid vehicles – a large-scale penetration of plug-in hybrids
could dramatically reduce the requirements of transport fuels
(be it gasoline/diesel or biofuels).
Marginal/degraded areas could also be considered for
lignocellulosic feedstock production. However, marginal lands
may also have alternative uses, implying that the current
land users must be involved to ensure positive local socioeconomic development. In many cases, this may require
approaches other than monoculture plantations, such as
agroforestry systems integrating bioenergy production with
food crop cultivation and cattle production. Furthermore,
biomass production on marginal/degraded land may not be
the automatic outcome of increasing biomass demand. As
bioenergy use increases and farmers adopt bioenergy crops,
they will consider developments in both the food and bioenergy
sectors when planning their operations. The economic realities
at farm level may then still lead to bioenergy crops competing
with food crops, since it is the good soils that also result in
higher yields for the bioenergy crops. Biomass plantations
may eventually be pushed to marginal/degraded land due to
increasing land costs following increased competition for prime
cropland, but this competition will probably also be reflected
in increasing food commodity prices.
5.5 Other Environmental and Socioeconomic Aspects
In addition to providing a possible strategy for addressing
the twin challenges of energy security and climate change,
the production and use of bioenergy can also result in other
(positive and negative) environmental, health and socioeconomic effects. Most of the environmental effects are
connected to feedstock production. The environmental impact
from fuel processing is usually lower (Zah 2007). Solutions
are available to mitigate the environmental impacts that
result from biofuel plants, although they may not be installed
in regions with lax environmental regulations or limited law
enforcement capacity.
Rules and regulations may dictate that certain bioenergy crops
should be produced on certain soils not suitable for food/feed
crops production (such as wastelands in India) or on lands
where the cultivation of food/feed crops causes significant
27 During the first half of 2008 E85 cars accounted for roughly 20% of new car sales. Since July 5, regulations also allow for conversion of gasoline/
diesel cars to ethanol or gas.
61
5.6 Key Messages for Decision Makers
environmental impacts (such as sloping soils susceptible
to erosion on the Loess Plateau in China). Regulations
may also prevent farmers from using more than a certain
share of their land for energy crop production (see Chapter
6). There are also many examples of how integrating
technical, ecological, and social knowledge at a local level
makes it possible to produce biomass for energy while
minimising any risks and generating additional benefits,
such as environmental services and improved productivity in
agriculture and forestry (see Chapter 2).
1. Is biomass best used to produce transport fuel or to
generate heat and power?
The use of biomass is guided by its competitiveness relative
to other options in different sectors, its fit with existing
technologies and energy infrastructure, and its contribution
to complying with energy and environmental regulations.
Given that the uptake of biomass is largely dependent
on policy incentives, the best use is likely to be one that
cost-effectively contributes to energy and environmental
policy objectives, e.g. in terms of least cost per tonne of
avoided CO2. This in turn depends on the level of energy
and environmental objectives, and how other energy
alternatives can help meet them in different sectors (e.g. new
technologies for the transport sector, and carbon capture and
storage (CCS) in power).
Rural development is commonly cited as one of the
major benefits of increased bioenergy use. This is viewed
differently in developing and industrialised countries. In
industrialised countries rural development is seen as a way
of differentiating and supporting the agricultural sector
and rural areas in general. In developing countries rural
development is seen in a broader livelihood context providing
employment, much needed income and helping to develop
the agricultural system. The link between bioenergy and food
security is predominantly a concern for developing countries
where the vulnerability to rising food prices is higher, which
may have effects beyond those parts of the population that
could directly benefit from bioenergy. Sustainability concerns
also include direct and indirect socio-economic aspects,
including land conflicts and human rights violations.
So, the best use of biomass will depend entirely on the
policy priorities and how these can be met in different
sectors. Since individual countries differ in their energy
infrastructure and the sources of energy they have access to,
each will probably prioritise and incentivise its biomass use
differently.
2. If climate change mitigation in the energy sector is the
objective, how can biomass be used most cost-effectively?
It is beyond the scope of this report to comprehensively
report on mitigating measures in agriculture and land use in
general. However, it is increasingly acknowledged that the
model that drove agricultural development in industrialised
countries and the spread of the green revolution must
be revised so that agricultural knowledge, science, and
technology effectively meet the challenges of reducing hunger
and poverty, improving rural livelihoods and facilitating
equitable and environmentally, socially, and economically
sustainable development (IAASTD 2008). In this context,
increasing bioenergy demand presents challenges but also
opportunities for promoting more sustainable land and
water uses around the world. As was described in Chapter 2,
several biofuel crops can provide important environmental
services in agricultural landscapes, such as erosion
reduction and microclimate regulation, thereby enhancing
the overall agricultural productivity. If domestic and
international investors in developing countries can effectively
engage local communities and make them partners in the
development of a biofuels industry that integrates with food
production, reaping the benefits of the inflow of technology,
infrastructure and capital for the benefit of both food and
bioenergy production, positive rural development may be
realised.
Producing heat and power are in general more cost-efficient
and land-efficient ways of using biomass to reduce
greenhouse gas emissions than producing transport fuels,
especially if coal use is replaced. However, while there are
other renewable and low carbon options for producing heat
and power, biofuels are very well placed to contribute to
the reduction of transport emissions, as there are currently
limited cost-effective abatement options available.
If other options do not mature and become more cost
effective, then this may be the best way to use biomass,
though it still may be of interest as a complement to other
transport abatement options, such as hybrid vehicles. This is
also true if there is the ambition to achieve large reductions
in GHG emissions in the short to medium term, implying a
need to tackle the transport sector.
3. What is the impact of greenhouse gas emissions from
direct and indirect land use change on the greenhouse gas
balances of biofuels?
Emissions from direct and indirect land use change can
substantially reduce the GHG benefit of biofuels that are
based on cultivated feedstock, and potentially lead to very
long greenhouse gas payback times to make up for those
emissions. The extent of the impact of land use change
depends on the land that is converted, the type of crop that
is planted, and the efficiency with which it is used. The use
of waste and residues from agriculture and forestry largely
avoids this problem, although there may be instances where
this use also leads to indirect land use change if the previous
users of the biomass are forced to shift to using cultivated
biomass.
Summing up, bioenergy can help meet environmental and
energy policy objectives but can also have highly undesirable
side effects. Policy around bioenergy needs to be designed so
that it contributes to consistent energy and environmental
policy objectives. Bioenergy also needs to be regulated so
that broader environmental and social issues are taken
into consideration and environmental services provided by
bioenergy systems should be recognised and valued. Chapter
6 discusses how these challenges can be addressed.
62
4. Is it better to use land for carbon sink creation or for
bioenergy production?
On a short timescale, carbon sinks can provide cheaper
and larger greenhouse gas reductions per hectare of land
than bioenergy production – especially if low efficiency
bioenergy use is the alternative. However, the sink option is
constrained by saturation (only a limited amount of carbon
can be stored on a hectare of land), whereas bioenergy can
be produced repeatedly, from harvest cycle to harvest cycle,
thus accumulating emissions reductions in time. Longer
timescales therefore tend to favour bioenergy production.
The impacts of the two options other than on greenhouse
gas emissions also need to be considered. Finally, these two
options are not mutually exclusive: depending on where and
how they are established and managed, bioenergy systems
are themselves net sources or sinks of carbon, and a forest
established for the purpose of sequestering carbon can be
managed to produce timber and other forest products.
5. Can biofuels play a role in improving energy security?
The use of domestic biomass resources improves energy
security. Also, biomass imports from widely distributed
international sources would generally contribute to a
diversification of the energy mix and improved energy
security. However, the effective contribution largely depends
on the extent to which the bioenergy production system is
decoupled from oil and gas inputs. The best use of biomass to
address energy security concerns will vary – some countries
may prioritise the substitution of natural gas imports while
other countries see oil import dependency as the major
concern.
6. How can food insecurity and other negative socioeconomic impacts be mitigated?
At the macro level, policies causing rapidly increasing
and price-inelastic demand for biofuel feedstocks should
be avoided, as they can result in negative impacts on food
security and other socio-economic aspects. Instead a cautious
approach to biofuels expansion is needed that mitigates
potential risks through an understanding of the elasticity
of the system and by stimulating the use of resources and
technologies that limit the impact on basic food production.
At the implementation level, companies investing in
developing countries need to effectively engage local
communities and make them partners in the development of
a biofuels industry that is integrated with food production,
thus reaping the benefits of the inflow of technology,
infrastructure, capital, and income for the benefit of both
food and bioenergy production.
63
CHAPTER 6: MAKING POLICY FOR BIOENERGY DEPLOYMENT
Key questions addressed in this Chapter:
1. Why is bioenergy dependent on policy support, and what considerations justify this support?
2. What are the ingredients for successful bioenergy policies?
3. Which policy instruments can be applied to promote and deploy bioenergy?
4. What are the main instruments that are characteristic of bioenergy policy making in the heat,
electricity, and biofuels sectors?
5. Should feed-in tariffs or quota systems be preferred?
6. How can sustainable production and use of bioenergy be guaranteed?
6.1 Introduction
make or break business opportunities. Furthermore,
their specific formulation influences the extent to which
introduced technologies contribute to the underlying policy
objectives, such as greenhouse gas emission reduction,
energy security improvement, economic development, and
overall sustainability. Strategies need to be well-designed
if bioenergy options are to be developed, introduced and
deployed. Biomass is an energy source that offers important
large-scale solutions, but can also contribute to local energy
supply. Therefore, successful deployment of bioenergy
requires not only a national policy strategy, but also energy
planning and incentives at local administrative levels (see
Table 6-1).
The external costs and benefits of energy production
options are not sufficiently reflected in energy prices, an
important reason why most bioenergy solutions are not (yet)
economically competitive with conventional fossil fuel options.
Policy support is therefore essential for almost all bioenergy
pathways. Furthermore, specific policies may be needed for
removing bioenergy introduction barriers as described in
Section 4.4.
The specific formulation of bioenergy policies can have
major consequences for bioenergy options and can
Table 6-1. Key motivations for bioenergy policy, as stated in country summaries and key policy documents. Source: GBEP (2007).
X
X
India
Mexico
X
South Africa
X
Canada
X
France
X
Germany
X
Italy
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
UK
X
X
X
X
X
X
X
X
X
X
X
Russia
EU
X
X
X
Japan
US
Cost
effectiveness
China
Technological
progress
X
Agricultural
development
X
Rural
development
Environment
Brazil
Country
Energy
security
Climate change
Objectives
X
X
X
X
X
X
X
X
X
X
X
X
64
X
A main driver behind bioenergy policies is the cost reduction
that can be achieved through market introduction of
bioenergy technologies (learning by doing), which can finally
lead to competitive cost levels. A long-term structural cost
gap may be defendable taking external benefits of bioenergy
into account. The valuation of these external benefits may
differ between countries and regions. As Chapter 5 shows
this may lead to different emphases in policy making, both
in terms of sectors supported and in the specific policy
measures applied. In this chapter, we summarise knowledge
and experience in setting up successful bioenergy policies.
6.2 Common Lessons for Bioenergy
Policy Making
On the basis of current knowledge and experience
(Menanteau et al., 2003; Sawin 2004; GBEP 2007; IEA
2007b; Junginger 2007; Lehtonen 2007; IRGC 2008; Neeft
et al., 2007), several general recommendations can be given
for sensible bioenergy policy making:
• A policy initiative for bioenergy is most effective when it
is part of a long-term vision for bioenergy. Such a vision
should be clear about its motivation (see Chapter 5).
Furthermore, the vision should identify the specific national
or regional strengths that bioenergy options could build on,
e.g. in terms of existing or potential available feedstocks,
the trade and infrastructure context, and specific features
of the industrial sector. Almost all successful bioenergy
policies were able to open up opportunities that were
already partly available in the country.
• Long-term continuity and predictability of policy
support appears to be pivotal for successful development
of bioenergy options. This implies that, from the
start, policies should take into account the specific
characteristics of the options involved (e.g. in terms of the
key factors affecting their competitiveness) and provide
sufficiently long-term measures to address them. This does
not mean that all policies need to be maintained forever,
however it improves policy predictability when the duration
of a policy regime is clearly stated in the beginning. For
further details see Section 6.4.
• Bioenergy policies should take into account the
development stages of specific bioenergy technologies,
and provide incentives consistent with the barriers that
an option is facing. The best-fit type of policy support for
early markets, be it quantity-based obligations or subsidies
reducing production costs, strongly depends on the
characteristics of the option and its market development.
Factors such as technology maturity, market transparency,
the allocation of market power and the split between
investment and variable costs need to be taken into
consideration. Further details are provided in Sections 6.3
and 6.5.
• Access to markets is critical for almost all bioenergy
technologies. For biomass-to-power, connection to the grid
is the key issue that needs to be addressed at the power
distribution network level. For biofuels, standardisation
of biofuels and of vehicles (in the case of higher blends)
is essential for reliable market access. As biofuels are
increasingly becoming a globally traded commodity (see
Section 4.2), national standards will need to converge into
internationally acknowledged ones.
65
• As all bioenergy options depend on feedstock availability,
a policy strategy for bioenergy should pay attention to
the agricultural, forestry and waste sectors from which
feedstock is expected to come. In the long-term, specific
support for productivity improvement in these sectors
will be pivotal for reconciling feedstock demand from, for
example, the food, feed, and wood processing industries
and the bioenergy sector. This is also key for the reduction
of impacts in agricultural commodity markets (see Section
4.3).
• As with any policy related to technology development or
otherwise, a policy strategy on bioenergy should meet
several standard criteria such as credibility, enforceability,
clarity, simplicity, and transparency.
• A long-term successful bioenergy strategy will also
need to take into account sustainability issues. Policies
safeguarding bioenergy sustainability are currently in rapid
development. Important issues are energy and greenhouse
gas balances, direct and indirect impacts on land use, and
other environmental, social, and economic impacts. Due
to the complexity of the sustainability issue, future policy
making on bioenergy will need to focus on integrated
approaches, in which the complex interactions with other
policy domains such as land use, agriculture and forestry,
and human development are taken into account. For
further details see Section 6.6.
• Finally, bioenergy support policies are a precondition,
but not a guarantee for the successful development
of bioenergy. Other critical factors include the legal,
administrative, technological, and cognitive framework.
Unforeseen barriers can affect the introduction of
installations, and also the set-up of feedstock supply and
reliable logistics; both essential for successful bioenergy
initiatives. As such factors are often affected by other
governmental departments, internal streamlining and
checking of policies for consistency are crucial.
6.3 Bioenergy Technology Support
Instruments for Different Development
Stages
As with any technology, several stages can be identified in
the development of bioenergy, and for each stage, specific
policy instruments apply. Figure 6-1 gives an overview of
instruments, roughly structured by development stage, based
on a wide set of reviews (Sawin 2004; van der Linden et al.,
2005; Ros et al., 2006; GBEP 2007; IEA 2007b; Neeft et
al., 2007; OECD 2008a). In the different phases, support
needs to be directed at:
• RD&D – learning by searching: invention by R&D efforts,
pilot and demonstration projects, and assessment of market
prospects.
• Early market – learning by doing: improving
competitiveness with established options, and building
practical experience.
• Mass market – deploying: incentives for further technology
and production cost reduction, broader regulation, and
policies enabling wide deployment of sustainable bioenergy
projects and products.
6.3.1 Policies related to the RD&D phase
chain – feedstock producers, energy producers, and
distributors. To create an incentive for cost reduction and
avoid structural ‘addiction’ to subsidies, the level of financial
support can be reduced over the years (albeit in a gradual
and well-planned manner). The level of support can also be
differentiated to reflect the cost of different technologies.
Costs of such policies can be carried by the government
(the taxpayer ultimately paying the cost), or they can be
redistributed among consumers by, for example, a levy on
non-renewable energy, making the policy budget revenue
neutral for the government.
• Quantity-based instruments, in the form of quota obligations
and tendering schemes. Quota obligations are minimum
shares of bioenergy imposed by governments on consumers,
suppliers, or producers, and include a penalty for noncompliance. An obligation can be combined with a system of
tradable certificates in order to improve cost-efficiency and
provide a compliance mechanism. Generally, an obligation
system does not require additional governmental spending:
costs are borne by the parties to which the obligation
applies. In the case where the obligation is placed on a
producer or a supplier, the costs are generally passed on to
the consumer. In tendering schemes, an obligation (e.g. to
produce bioenergy) is sold in an auctioning mechanism to
the bidder who offers the best price, e.g. the lowest required
subsidy level to meet the obligation.
• Measures related to market access can facilitate early
market penetration of new technologies by giving them
preferred access to markets or infrastructure (e.g. public
procurement, preferential access to the grid), or by
standardising the product. These are typically measures that
act as a prelude to early markets.
We can distinguish between two main mechanisms for taking
bioenergy options through the RD&D phase: direct or indirect
R&D funding, and measures aimed at reducing investment
risks.
• RD&D funding is a very common way for governments to
encourage technology development in its initial development
phase. This provides support for options that are considered
promising by researchers and/or market actors. Apart
from direct funding, RD&D funding can also be carried
out indirectly under Public-Private Partnership (PPP)
arrangements.
• Investment related subsidies, e.g. for the realisation of
pilot and demonstration projects, have a direct impact
on reducing the initial barrier of investment costs.
Government support can help overcome this threshold by
direct investment subsidies, soft loans, and fiscal measures
decreasing investment costs. In particular soft loans and
fiscal measures may be extended to the initial market phase
of a technology.
6.3.2 Policies related to early markets
After bioenergy options have passed the demonstration phase,
there often remains an excess cost in comparison with existing
commercial technologies. In the early market stages, a key
objective of policies is to reduce this cost gap by allowing the
technology to be introduced and by building up experience
(learning by doing). Three categories of instruments are
applied in this context:
• Measures reducing production costs, in the form of feedin tariffs, feed-in premiums, and tax exemptions. These
incentives can be targeted at different parts of the supply
Figure 6-1. Overview of policy instruments for each technology development stage. Adapted from Ros et al., (2006).
66
is common to promote bioenergy using a combination
of instruments, e.g. a quota obligation combined with a
moderate production subsidy or tax exemption.
The different support instruments categorised above have their
specific strengths and weaknesses.
• Feed-in tariffs and premiums, if well designed usually provide
more long-term certainty of support for investors, reducing
investment risks compared to quota obligations. Although
feed-in tariffs and premiums allow for technology-specific
support, thereby reducing windfall profits for low cost
technologies, there is still a need for governments to have
sufficient information on technology costs in order to set an
appropriate support level.
• An obligation entails more certainty for a government that a
target will be met, but requires sufficient players to create a
liquid certificate market. Furthermore, a generic obligation
set to, for example, renewable power generation will not
distinguish between different technologies, and will thereby
only encourage short-term low-cost technologies to enter the
market, not options that are currently expensive but have
a substantial cost reduction potential. Tradable certificate
markets are usually more complex to design than feed-in
systems, and operators have to be active in two markets;
the energy market and the certificate market. In tendering
systems, in which technology developers compete for contracts
(and corresponding support) and the most competitive bids
are awarded, it is possible to set the quantity to be achieved
and the price to be paid for this quantity. If applied properly,
tendering stimulates competition between producers and
results in cost-efficiency and price reduction. However,
the procedures for successful tendering can be complex
and therefore difficult to implement. In many countries it
6.3.3 Policies related to mass markets
After the early market entry of a new technology, structural
support may be required and should be defendable on the
basis of its positive external effects. However, sustained
support for bioenergy on a sheer production basis has its
drawbacks, as it does not guarantee that the bioenergy
options applied align best with the background motivations
for promoting it (think of a generic biofuels policy that also
provides incentives for biofuels that hardly reduce greenhouse
gas emissions). Furthermore, pursuing diverse objectives such
as energy security, climate change abatement, and economic
development by a single (bioenergy) policy is rarely efficient
(IRGC 2008). Policies can then provide incentives directly
related to the external effects, for example in the form of CO2
emission taxes or trading systems that are technology neutral.
6.4 Key Characteristics of Bioenergy
Policies by Sector
For each sector, the optimal policy mix depends on the
characteristics of specific bioenergy technologies. The current
application of different instruments by sector for G8 + 5
countries can be found in Table 6-2. This section, reviews
current experiences in heat, power and biofuels.
Table 6-2. Key motivations for bioenergy policy, as stated in country summaries and key policy documents. Source: GBEP (2007).
Brazil
E,T
China
India
Mexico
T,(E*)
(E*)
E**
France
Germany
Italy
E,H
E
E,H,T
E
E,(T)
(E),T
E**, T
T
E*,H*,T
E,H,T
Tariffs
Sustainability
criteria
n/a
Eth
E,H,T
Eth
E
As EU below
H
H
E
E
T
E,H
E
E
As EU below
E
Eth, B-D
Russia
(E,H,T)
(T)
E*,T*
E*,T
E,H,T
E,H
E
T
E**
E,H,T
E,T
E
E*,T
E*,H*,T
T
E,H,T
EU
n/a
n/a
E,H,T
USA
E,H
(E)
Japan
UK
Compulsory
grid connection
Feed-in tariffs
Grants
E,T
(E)
E*,T
Eth
T
(T)
E*,T
E*
Direct
incentives2
T
E,T
South Africa
Canada
Voluntary
targets1
Country
Binding
targets/
Mandates1
Energy Policy
(E,H,T)
As EU below
n/a
E: electricity, H: heat, T: transport, Eth: ethanol, B-D: biodiesel
*: target applies to all renewable energy sources, **: target is set at a sub-national level
(..) policy instrument still under development/awaiting approval
1 blending or market penetration
2 publicly financed incentives: tax reductions, subsidies, loan support/guarantees
67
T
As EU below
Eth
E
(T)
Eth, B-D
6.4.1 Heat 28
plants, stand-alone biomass combustion/gasification, and
anaerobic digestion). Most systems guarantee an investor
a fixed tariff level over a given number of years. In some
countries, future tariffs for new projects are also set in
advance. In contrast, quota systems have so far been less
successful in getting renewables (and bioenergy) off the
ground (van der Linden et al., 2005). It seems that an
effective quota system requires careful planning in order
to prevent its main pitfall, a lack of investment security
for producers. For tendering schemes, the critical issue is
avoidance of situations with a limited number of bidders, as
full competition is essential for this mechanism.
Although it is by far the most widespread application, the
use of small-scale biomass for heating has been generally
overlooked by policy makers. In developing countries,
policies relating to biomass for heat mostly focus on the
introduction of more efficient stoves and other appliances
with reduced emissions or local air pollutants. In developed
countries, biomass heat applications may be competitive in
some situations, depending on the alternative heating source
and the availability of relatively low cost local wood or
agricultural residues, but they will generally require some
form of support. In some countries, biomass application to
domestic heating in modern stoves has been stimulated by
investment subsidies or fiscal measures reducing investment
costs, and by standardisation of appliances in order to
improve their reliability and efficiency, and reduce their
emissions (BERR 2008).
The success of any feed-in tariff strongly depends on the
tariff being set at a sufficiently attractive level for an
investor to make a profit. In contrast to other renewable
technologies such as wind and solar, in which capital costs
dominate production costs, bioenergy projects can come with
a substantial share of variable costs in the form of feedstock
costs. This complicates the calculation of feed-in tariffs, and
makes projects vulnerable to fluctuations in feedstock prices.
Co-firing of biomass pellets in existing coal-fed power plants
is the clearest example: investment costs are relatively minor,
and the attractiveness of co-firing almost solely depends on
the costs of biomass versus those of coal (sometimes with the
addition of a CO2 tax). As large-scale power plants purchase
commodities on the global market, their costs may fluctuate
on a daily basis, and so will the financial gap between
them. A feed-in tariff may need to take such dynamics into
account, e.g. by regular adjustment or by making the subsidy
dependent on coal and pellet prices.
The majority of successful policies in biomass for heat in
recent decades have focused on more centralised applications
for heat or combined heat and power, in district heating and
industry. For these sectors, a combination of direct support
schemes with indirect incentives has been successful in
several countries. In Sweden, for example, several measures
that spurred biomass-based district heating and CHP were
implemented gradually (Junginger 2007):
• Some aiming at taxation of fossil energy use (e.g. carbon
and fossil energy taxes in 1991, an increase in carbon tax
in 2000, a tax on electricity of fossil origin for households
and services in 2004, an increase in the carbon tax level to
about €100/t CO2 in 2006), providing indirect but strong
support to biomass for heat (and power).
• Some specifically aiming at biomass-based CHP (e.g.
investment subsidies for new installations between 1997
and 2002, and a Green Electricity Certificate system from
2003).
Next to feed-in tariffs or quotas, almost all countries that
have successfully stimulated bioenergy development have
applied additional incentives relating to investment support,
such as fiscal measures or soft loans (GBEP 2007). Such
measures reduce the initial financial hurdle and reduce
private investment risks.
In particular the continuity and the complementary character
of the various measures seem to have been key factors to their
success (Junginger 2007). The existence of district heating
systems and the availability and reliability of biomass supply
chains also seem to have been critical factors in the success of
centralised biomass-to-heat and CHP.
Finally, quality and continuity of biomass supply is an
important potential barrier that policies can reduce. As heat
demand is usually of a constant nature, the stability of supply
is particularly crucial for heat applications. For example, the
UK allocated several million pounds between 2005 and 2008
to develop the supply chain and market infrastructure for wood
and straw fuels under its Bioenergy Infrastructure Scheme.
This policy specifically aims to develop the supply chain
required to harvest, store, process and supply the biomass for
CHP plants.
6.4.2 Power generation
In the power sector, feed-in tariffs have gradually become
the most popular incentive for bioenergy and for renewables
in general. Mostly, tariffs are differentiated between types of
technologies even within bioenergy (e.g. co-firing in coal-fed
Additionally, grid access for renewable power is an important
issue that needs to be addressed. This can be a particular
bottleneck for distributed, medium-scale technologies such
as biogas-to-power. Priority grid access for renewables is
applied in most countries where bioenergy technologies have
been successfully deployed (Sawin 2004).
Even when bioenergy-related policies create a favourable
climate for new initiatives, other barriers may cause policy
failure. For example, biogas-based power production
from manure and co-substrates evolved very differently in
Germany and the Netherlands, although both countries have
regions with intensive animal husbandry and both adopted
policies for this technology.
• In Germany, biogas production has increased rapidly in the
past decade, mainly due to the attractive feed-in tariffs for
this technology, including a bonus for the use of cultivated
crops, such as corn, as co-substrates29. The country now
accounts for almost 80% of total EU power generation
by co-digestion-based biogas production (Eurobserv'ER
2008a).
28 Unless mentioned otherwise, information in this sub-section derived from IEA (2007).
29 The German success was also due to a very simple pragmatic approach to digester design, which, together with good technical support, decreased
capital and ongoing costs and enabled farmers to operate plants successfully.
68
as such, but for the introduction of biofuels that best
comply with the motivations that drive biofuels policy
(Sawin 2004; Londo and Deurwaarder 2007; Lee et al.,
2008; OECD 2008a).
• Austria had a comparable feed-in tariff to Germany
resulting in an equal growth in biogas plants per capita.
However, when the high feed-in tariff reached the cap in
2006, the construction of new plants halted.
• In the same period, the Dutch renewables feed-in
premium system was also open to biogas-to-power, but in
practice manure handling regulations prevented the use
of co-substrates, thereby decreasing biogas profitability
to unattractively low levels. In 2004, the application of
co-substrates was allowed, leading to new projects being
initiated. However, the country has not caught up from
its initial slow start: In 2007 the agricultural biogas
production per capita in Germany was still about four
times higher than in the Netherlands (Eurobserv'ER
2008a). This example shows that initial policy failure can
have long-term impacts.
Additionally, two policy-related issues have appeared to be
crucial for successful implementation of biofuels: adaptation
of vehicles and fuel standardisation.
• While minor shares of ethanol and biodiesel can be blended
with their fossil equivalents without problems, use of these
biofuels as higher blends or in pure form does require
specific vehicle alterations. Policies have gradually shifted
from vehicles that could run on pure biofuel (such as
the E100 vehicles in Brazil in the 1980s and the B100
guarantees of several German car brands in the early
2000s (Neeft et al., 2007) to vehicles that run on a range
of fossil/biofuel blends, such as the ethanol flexi-fuel
vehicle. This was mainly motivated by the need to increase
the flexibility in biofuels end-use.
• Additionally, biofuels themselves need to be standardised
to ensure their reliability. Therefore, governments have
guided standard setting processes for ethanol and biodiesel
along with the introduction of policies. As a next step,
normalisation authorities of Brazil, the USA, and the EU
have started integrating their standards into a single global
standard for ethanol.
6.4.3 Biofuels
Globally, three regions have led the way in biofuels policy
until now (GBEP 2007; Neeft et al., 2007):
• Brazil, starting with the ProAlcool programme in 1975;
mainly triggered by energy security considerations,
and making use of the existing sugar-cane production
infrastructure.
• The USA, starting with the Energy Security Act in the
1980s, followed by the 1992 EPACT and the EPA Clean
Air Amendments, and developed further in the 2002 Farm
Bill; mainly triggered by energy security, air pollution
and rural support considerations, and making use of the
existing corn production infrastructure.
• The EU, member state support policies starting in the
1990s, major EU-level policies starting with the 2003
Biofuels directive; first triggered by rural support
considerations, followed by climate change and energy
security considerations, with production mainly based on
oil seeds (especially rapeseed). The renewables directive,
adopted by the European Parliament in December 2008,
recognises all these policy drivers for biofuels and contains
several criteria for biofuels sustainability (EP 2008).
Several examples show the importance of an integrated set of
incentives for a successful introduction of biofuels:
• In Brazil, Sweden and the USA, incentives for the
introduction of ethanol flexi-fuel vehicles (FFVs) have
contributed to 6.5 million of these vehicles being on the
road by 2008. However, as the introduction of E85 in
fuelling stations was not encouraged centrally in the USA,
only a limited number of stations have started providing
these fuels there (mainly in the Mid-West), and the number
of FFVs regularly running on E85 is probably modest.
In contrast, in Sweden and Brazil E85 is sold at many
stations throughout the country.
• India set out an ambitious biofuels vision in 2003,
mainly motivated by air quality considerations. However,
a specific incentive, in the form of an obligation on
fuel distributors, was only introduced in 2007. Due to
discussions on the possible competition between food and
fuels, the introduction of policies supporting domestic
biofuels production lagged behind, therefore the incentive
only spurred limited biofuels growth. In 2008, measures
to support feedstock production were introduced, including
oil crops such as Jatropha that provided a possible solution
to the food-fuel conflict in the country. With the disputes
on policy formulation and delayed attention to feedstock
availability, the period between 2003 and 2007 was
basically lost.
Although policies in these regions were developed in different
times with different motivations, there are some similarities:
• In many countries, the policy mix consists of a combination
of obligations, mostly applied to fuel suppliers, and
financial incentives, either in the form of a tax exemption
at the pump or as production and investment subsidies
to biofuel or feedstock producers (GBEP 2007; OECD
2008b). Their combination seems to be most effective:
an obligation creates demand for biofuels, while financial
incentives facilitate the development of production
capacity.
• Additionally, all three regions have supported major efforts
in RD&D. In Brazil, ProAlcool covered R&D programmes
on all parts of the supply chain (Lehtonen 2007), now the
USA and the EU are strongly supporting R&D, mostly in
2nd generation biofuels (GBEP 2007).
• Recently, new policies have been developed that provide an
incentive for biofuels on the basis of their climate merits,
and simarlarly differentiate between specific biofuels on
this basis. This is the basis of the California Low Carbon
Fuel Standard and the proposed update of the EU Fuel
Quality Directive. Generally, several studies stipulate that
biofuels policies should not strive for biofuels development
6.5 Other Policy Domains Relevant for
Bioenergy
Apart from instruments aimed at the introduction of
bioenergy technologies themselves, several other policy
domains are highly relevant to bioenergy. In this section we
focus on agricultural, forestry, trade, and environmental
policies, and communication and public support.
69
6.5.1 Agricultural policies
The link between bioenergy and agricultural policy is strong,
especially for conventional 1st generation biofuels, which
make use of food crops (OECD 2008b). Reverse effects,
i.e. the impact of biofuels policies on agricultural markets,
are discussed in Section 5.3. As agricultural markets are
strongly regulated in most OECD countries, almost all
developments in this policy domain affect the competitiveness
of biofuels. There are a wide range of policies in this area:
subsidies or intervention prices for specific crops, maximum
production quotas, or direct support to farmers (GBEP 2007;
OECD 2008a). Other known measures are direct supplyregulating schemes such as the EU’s set-aside scheme, and
the energy crop support scheme (a hectare-based subsidy)
that was operational in the EU for several years (EC 2006a).
Also the introduction of advanced bioenergy technologies that
use lignocellulosic material as feedstock will have long-term
implications for agricultural policy as increasing demand
for this type of feedstock may call for dedicated woody
or herbaceous cropping systems, and their inclusion into
agricultural policy.
An important aspect that policy needs to consider is the
productivity development in agriculture that is needed to
meet demand for food, feed, and bioenergy in the longterm, without causing conversion of natural areas to new
agricultural land. This will require a continuous increase
in agricultural yields in mainly developing countries.
Fundamentals are discussed in Sections 2.1 and 4.3. For
agricultural policy, the challenge is to support agricultural
development, by measures such as supporting investments by
farmers and enhancing technology R&D in the sector.
By increasing yield potentials, GMOs can increase both the
resource base for energy crops as well as the yields of energy
crops themselves. Future developments depend strongly on
the global policy debate on GMOs.
Spatial policies also influence bioenergy. For example, they
can regulate urbanisation so that urban sprawl does not
excessively convert agricultural land. Furthermore, nature
reserves are usually protected through spatial policies.
This is particularly relevant within the sustainability
discussion, as the conversion of nature reserves into land
for energy crops can lead to significant penalties in terms
of biodiversity and soil carbon losses.
6.5.4 Trade policies
Several aspects of trade policy also affect bioenergy. Import
and export tariffs can be applied to feedstocks as well as
end products such as liquid biofuels. Almost all OECD
countries apply import tariffs to agricultural commodities
and products (GBEP 2007). Generally, tariffs on end
products are higher than those on feedstocks, favouring
industrial processing in the importing country. Additionally,
quotas of duty-free trade may be opened to specific
exporting countries, on the basis of bilateral agreements.
As mentioned in Section 4.3, trade policy can also be
applied to exports. For example, an export tariff applied by
major feedstock producing countries protects their domestic
markets from a price hike, but reduces the incentive of
a high feedstock price for farmers in these countries
to increase their production. Several grain producers
imposed such taxes during the 2007/2008 food price
hike. Indirectly, a Russian export tariff on unprocessed
roundwood, to be gradually implemented between 2007
and 2009 (USDA 2007), will have a stimulating effect on
the availability of wood pellets from Russia, as the tariff
provides an incentive for the Russian wood processing
industry and thereby increases the availability of wood
processing residues for pellets in the country. The overall
system of trade policies and tariffs is an ongoing source of
dispute within the World Trade Organisation.
Another issue related to trade is the absence of a trading
platform for bioenergy feedstocks, and corresponding
quality standards. In particular, trade in woody materials
such as pellets could benefit significantly from the
introduction of a trading platform, as this usually makes
the market more transparent and liquid. Furthermore,
heterogeneous streams such as woody residues need
standardisation of material characteristics (Alakangas et
al., 2006).
6.5.2 Forestry policies
For the generation of heat and power, bioenergy routes
mostly use woody biomass, predominantly forestry, and
wood processing residues. Therefore policies that affect
productivity of forests and the wood-processing industry
have a direct impact on feedstock availability for bioenergy.
Measures can be directed to a wide range of objectives (EC
2006b; OECD 2008b): increasing physical productivity
(e.g. by improvement of management practices); removing
practical barriers (e.g. by improving access, or clearing
forest ownership issues); but also to other uses of forests (e.g.
biodiversity and recreational functions) that may interfere
with productivity and harvestable shares.
6.5.5 Environmental policies
Bioenergy technologies can have environmental impacts
at different stages of their production chain: in feedstock
production, conversion, end-use and in logistics. Obviously,
existing regulations are in place to address environmental
issues, for example, in agricultural production, industrial
facilities, and emissions from vehicles. However, the
introduction of new bioenergy routes often calls for
dedicated measures. In the case of new conversion
technologies, for example, the lack of experience in best
practices and achievable emission limits can be a barrier
to introduction, as local regulators would lack reference
material for an environmental permit. Guidelines from
central government can help to reduce this implementation
obstacle. Certification initiatives for safeguarding
sustainability of imported biomass and biofuels are further
discussed in Section 6.6.
6.5.3 Land use planning policies
Closely related to agricultural, forestry and environmental
policies, land use planning and spatial policies can also
strongly affect bioenergy, mainly in terms of feedstock
availability. Land evaluation and land use planning are
proven instruments for improving the physical basis of
agriculture, e.g. by improving water management and
transport infrastructure, increasing parcel size, and
identifying the most appropriate crops and cropping systems.
Comparable approaches can be used to improve prospects in
forestry.
70
6.5.6 Communication with the public and
education of relevant professional groups
• Impacts on economic development: Bioenergy chains
should contribute to local prosperity.
• Impacts on welfare: Bioenergy chains should contribute
towards social well-being for employees involved and for
the local population.
Communication about bioenergy is essential to build public
support (IEA 2007b). Furthermore, information and education
should be directed to professional groups that need to get
acquainted with different bioenergy technologies. This applies,
for example, to technical personnel who need to obtain the
skills for correct installation of domestic biomass-based
heating systems.
These principles need to be converted into criteria and
indicators, against which bioenergy can be measured. Fullchain lifecycle approaches provide the framework to perform
such assessments.
6.6.2 Key characteristics of bioenergy certification
systems
6.6 Sustainability Policies and
Certification30
Spurred by increasing concerns about undesired impacts of
the rapid introduction of bioenergy, several platforms are
currently developing certification systems. Some initiatives
come from governments with obligations on bioenergy
uptake, e.g. the UK system for its Renewable Transport
Fuel Obligation (RTFO), the Dutch ‘Cramer Criteria’ for its
national biofuels and biomass-to-power schemes, and the EU
efforts related to the Renewable Energy Directive. Others
are initiated by private parties, in an effort to implement
their social responsibility on a voluntary basis. Examples
are the biomass labels introduced by power producers Essent
and Electrabel, and the efforts made by several roundtable
groups, such as the roundtables for sustainable palm oil
(RSPO), for responsible soy (RTRS), and for sustainable
biofuels (RSB). All of these initiatives differ in the specific
sustainability issues they try to address, and in their practical
elaboration. A key challenge is the GHG calculation.
A detailed table with the key characteristics of several
initiatives can be found in Annex 6-1.
With the rapid development of bioenergy, attention to its
potentially negative impacts is also increasing (see FAO
2008). For example, production of biomass energy crops
and excessive removal of biomass residues from forest and
agricultural systems for energy production can result in
negative ecological impacts, changing land use patterns, socioeconomic impacts, and GHG emissions. With considerable
further increase in bioenergy expected, sustainability of
bioenergy is becoming a key concern and is currently being
considered as a possible requirement for market access.
Defining sustainability criteria and setting standards are
logical strategies to help ensure that biofuels are produced
in a sustainable manner. Sustainability has environmental,
social, and economic dimensions, and in all parts of the
bioenergy chain, safeguarding sustainability is complex and
multi-dimensional. Currently, much discussion is focussing
on sustainability safeguarding mechanisms, particularly
certification. Certification is the process whereby an
independent third party assesses the quality of management in
relation to a set of predetermined requirements (standards). In
this section we describe the most common principles or criteria
that have been proposed for the safeguarding of sustainability,
currently proposed mechanisms to meet these principles,
implementation strategies, and key implementation issues.
From principles to criteria and indicators. After defining
the general principles, the next step is their translation
into concrete criteria and measurable indicators. For some
principles, translation into indicators is relatively easy,
and most certification initiatives propose comparable
methodologies. However, some other principles are difficult
to translate into measurable quantities. Generally, there is
also a clear trade-off between obtaining perfect information
and practical limitations in data gathering: an ideal set of
indicators may require data gathering efforts that significantly
increase the costs of bioenergy or their feedstocks.
6.6.1 Sustainability principles relating to
bioenergy
Sustainability is a multi-dimensional concept. In the context of
sustainable bioenergy, several initiatives aiming at bioenergy
certification (see Annex 6-1) have been elaborated into a set of
key principles. These are commonly:
• Greenhouse gas balance: Bioenergy chains should reduce
greenhouse gas emissions compared to their fossil reference.
This also includes emissions of soil carbon induced by land
use changes.
• Energy balance: Bioenergy chains should generate
more energy than that needed for feedstock production,
conversion, and logistics.
• Biodiversity impacts: Bioenergy chains should not negatively
affect biodiversity.
• Impacts on production of food: Bioenergy chains should
not endanger the supply of biomass for food, materials, and
other applications.
• Other environmental impacts: Bioenergy chains should not
lead to negative impacts on soil, water, and air quality.
Level of implementation. Certification schemes can be
implemented on several levels in the bioenergy supply chain.
They can cover the impacts of the entire supply chain,
including feedstock production, conversion, end-use, and
logistics. Other initiatives, however, focus on the feedstock
production step. This is particularly related to schemes that
are inspired by the impacts of increasing biomass trade.
Accounting mechanisms (chain of custody). Obviously, a
certification system requires a mechanism to account for the
bioenergy produced under the scheme. Generally, three types of
accounting can be distinguished:
• ‘Track and trace sourcing’: A flow of information
accompanies the physical flow of biomass along the supply
chain. Most ‘fair trade’ products have a track and trace
system.
30 Unless specified otherwise, this section is based on van Dam et al. (2008) and Marchal et al. (2008).
71
argument against too rapid introduction of bioenergy
options that strongly depend on cultivated crops, where the
bioenergy application directly competes with food production.
In looking to develop more sophisticated approaches that
address this issue, two options are currently being explored:
• Within a certification system: indirect effects may be taken
into account by applying a ‘risk adder’ to, for example,
chain-based calculations on greenhouse gas emissions
(Fritsche 2008). In such an approach, a first-order
estimation is made of potential leakage effects, which are
then added to the production chain.
• Additional to a certification system: Measuring leakage
effects is complex and can only be done on national or even
international levels. They require macro-level monitoring
of changes in land use and changes in markets (Eickhout et
al., 2008). In an ideal case, observed leakage effects in the
recent past would lead to an additional penalty on specific
biomass feedstocks or on specific producing regions. In
addition, a bioenergy policy might be connected to an
integrated policy vision on land use, in which energy crop
production is stimulated with due regard to considerations
of food security, biodiversity and the other sustainability
criteria mentioned above. However, as indirect effects can
occur globally, they can hardly be controlled on a national
level.
• ‘Book and claim’: A certified producer of biomass receives
a quantity of certificates, which are traded independently
from the physical flows of biomass. Renewable power
certificates work this way.
• An intermediate system of ‘mass balancing’, in which the
biomass is traceable to the source but can be blended
along the supply chain. The FSC certification system for
construction wood works this way, and the EU renewable
energy directive also opts for this mechanism.
The strength of the first approach is that the sustainability
characteristic is bound with the specific batch of biomass.
But it comes with an additional administrative burden and
it complicates trade. As biomass trade flows become more
complex and intermingled, a book and claim system may be
more robust and cost-effective. There is no clear tendency
in current certification initiatives as to which mechanism
is preferred. Any type of accounting is accompanied by a
verification mechanism, often under the responsibility of an
independent verifier or ‘clearing house’.
Implementation issues. A sustainability scheme in bioenergy
faces several implementation issues. Largely, these issues are
consistent with problems that earlier certification systems
have experienced. At least, a sustainability scheme can
therefore (at least partly) build further on experiences in
existing schemes (e.g. FSC wood, fair trade food products,
and organic products). Key issues are summarised in Annex
6.2.
Conversely, there are also arguments against both approaches.
For instance, their compatibility within the WTO is unclear
and probably problematic. Also, price and volume effects are
spread throughout the world and among several commodities.
It is therefore difficult to monitor all possible effects.
6.6.3 Addressing indirect effects
Certification is a powerful instrument for checking the
impacts of bioenergy that can directly be attributed to a
specific production chain. However, bioenergy also has
indirect, or ‘leakage’ impacts. Mostly, they are related
to indirect changes in land use (see Section 5.3.2). For
example: an existing palm oil plantation is rerouting its
production from food to biofuels markets. As an indirect
result, a new palm oil plantation is founded in tropical
rain forest in another region, leading to deforestation and
loss of soil carbon. Alternatively, new palm oil plantations
are established on land already in use for agriculture (e.g.
coconut plantations), which in turn triggers establishment
of new coconut plantations in tropical rain forests. Impacts
on global food prices and on regional economic development
and welfare may also take place via such indirect routes.
Such indirect effects may have unsustainable impacts
such as deforestation, loss of soil carbon and greenhouse
gas emissions, without them being directly attributable
to a specific bioenergy production chain. Therefore, it is
difficult to assess such impacts by chain-based approaches.
Essentially, nationally or even globally induced land use
changes need to be taken into account. This can only be
achieved if an integral land use planning vision and strategy
are established for entire regions.
6.7 Support for Bioenergy Policy
Several platforms exist to exchange local and regional
experiences and best practices in policy making. Some of
these are functioning within broader international bodies,
such as the IEA and its Bioenergy Agreement, others are
dedicated fora, such as the Global Bioenergy Partnership
(GBEP), Renewable Energy Network for the 21st century
(REN21), and the Renewable Energy and Energy Efficiency
Partnership (REEEP). These platforms are open to national
and regional/local governments and chiefly aim to accelerate
learning processes. Often, exchange of experiences and best
practices is facilitated by websites, databases of literature
and policy measures in place, and by organising workshops
on specific topics. A concise overview of key networks and
their contact details can be found in Annex 6.3.
6.8 Key Messages for Decision Makers
1. Why is bioenergy dependent on policy support, and what
considerations justify this support?
Several bioenergy routes have been commercial for decades.
However others deserve policy support as their technologies
still need development before they become competitive.
Also, the external benefits of bioenergy (e.g. greenhouse gas
emission reduction, reduction of fossil energy dependence)
are not appropriately reflected in the market, justifying
policy intervention.
Although several studies indicate that indirect effects can
truly break the greenhouse gas emission profile of almost
any bioenergy feedstock (Eickhout et al., 2008; Searchinger
et al., 2008), it is also clear that methods to assess these
effects are still poorly developed, and outcomes strongly
depend on specific assumptions. In the context of policy
making, indirect effects are currently put forward as an
72
2. What are the ingredients for successful bioenergy policies?
Consideration of national strengths in biomass supply and of
the characteristics of the energy system, a stable long-term
framework, differentiation based on technology development
status, and attention to sustainable feedstock supply, are key
ingredients of a successful bioenergy policy.
3. Which policy instruments can be applied to promote and
deploy bioenergy?
A wide range of policy instruments can be applied to spur
bioenergy growth, from R&D support and investment grants
to quota obligations and feed-in tariffs, and more technology
neutral instruments that reward the performance towards,
for example, a greenhouse gas emission reduction objective.
The appropriate instrument depends on the development
stage of the technologies considered. In each development
stage, there may be a specific trade-off between incentives
being technology-neutral and closely relating to the policy
drivers, and on the other hand creating a sufficiently protected
environment for technologies to evolve and mature.
4. What are the main instruments that are characteristic of
bioenergy policy making in the heat, electricity, and biofuels
sectors?
A multitude of policy instruments and combinations thereof
are applied worldwide. Feed-in tariffs seem to be the most
popular instrument in the power generation sector, while
biofuels are often stimulated with quota obligations and
fuel tax reductions. In both sectors, additional measures are
often applied, such as investment subsidies (or soft loans)
for conversion installations or enhanced capital allowances.
Bioenergy policies for heat mostly focus on purchase subsidies
on appliances and incentives for bio-CHP.
5. Should feed-in tariffs or quota systems be preferred?
Both feed-in tariffs and quota systems can function or fail.
Feed-in tariffs have the advantage of creating a relatively
stable investment climate, but do not contain a direct
incentive for cost reduction. Theoretically quota systems are
better suited to achieve least-cost solutions, however their
introduction has proven to provide little stimulus to biomass
electricity production whereas the quota applies broadly to
renewable electricity generation. Ultimately, the effect of
an instrument largely depends on its judicious design and
implementation. Combinations of instruments can often be
used to compensate for their individual weaknesses.
6. How can sustainable production and use of bioenergy be
guaranteed?
At the bioenergy production chain level, sustainability can be
safeguarded by certification mechanisms, which are currently
under development. Indirect effects, such as impacts on
commodity prices and indirect land use change are more
difficult to deal with, and will need appropriate regulation
of bioenergy chains, bioenergy markets (e.g. levels of quotas
and incentives) and land use. In the short-term, it is crucial
that these macro impacts are being monitored, analysed and
reported.
73
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79
ANNEX 1: UNITS AND CONVERSION FACTORS
Annex 1.1: Energy Conversion Factors
GJ
To:
Gcal
Quad (= 1015 BTU)
GWh
Mtoe
0.239
9.479 x 10-10
2.778 x 10-4
2.4 x 10-8
10-9
10-3
Multiply by
From:
GJ
1
Gcal
4.184
1
Quad
1.055 x 109
2.52 x 108
1
2.931 x 105
25
GWh
3.6 x 103
860
3.412 x 10-6
1
8.6 x 10-5
Mtoe
107
4.2 x
1x
3.968 x
107
4x
1.163 x
10–2
11.6 x
1 x 10-7
103
1
Annex 1.2: Metric System Prefixes
Factor
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
in full digits
*
*
*
*
*
*
*
*
*
*
1024
1021
1018
1015
1012
109
106
103
102
101
1 000
1 000
1 000
1 000
1 000
1 000
1 000
1 000
100
10
*
*
*
*
*
*
*
*
*
*
10-1
10-2
10-3
10-6
10-9
10-12
10-15
10-18
10-21
10-24
0,1
0,01
0,001
0,000
0,000
0,000
0,000
0,000
0,000
0,000
000
000
000
000
000
000
000
001
000
000
000
000
000
000
000
000
000
000
000
000
001
000
000
000
000
000
000
000
000
000
000
001
000
000
000
000
000 000 000 000
000 000 000
000 000
000
001
000 001
000 000 001
000 000 000 001
in words: one…
SI prefix
Mtoe
septillion
sextillion
quintillion
quadrillion
trillion
billion
million
thousand
hundred
ten
one
tenth
hundredth
thousandth
millionth
billionth
trillionth
quadrillionth
quintillionth
sextillionth
septillionth
yottazettaexapetateragigamegakilohectodeca-
Y
Z
E
P
T
G
M
k
h
da
decicentimillimicronanopicofemtoattozeptoyocto-
d
c
m
µ
n
p
f
a
z
y
Annex 1.3: Currency Conversion Approach Adopted in this Report
For this review, financial data have been used that were expressed in different currencies, US Dollars (US$), UK pounds
(UK£) and EU Euros (EU€), and from different years. In order to translate all of this data into the chosen reference year
(US$ 2005), the following conversion was carried out:
• First, the UK£ and EU€ currencies were inflated or deflated to 2005 levels, using a domestic output price index (in
national currency) for total industry, excluding construction and energy, obtained from Eurostat (www.europa.eu/eurostat)
• Second, UK£ (2005) and EU€ (2005) currencies were converted to US$ using the 2005 year-average exchange rate, which
were 1.8189 US$/UK£ (www.bankofengland.co.uk) and 1.2441 US$/EU€ (www.dnb.nl), respectively.
These two steps are summarised in the following conversion table:
Year of source data
2000
2001
2002
2003
2004
2005
2006
2007
2008
1 EU€(year) =
US$(2005)
1.331
1.308
1.302
1.292
1.267
1.244
1.210
1.172
1.132
1 UK£(year) =
US$(2005)
1.940
1.938
1.938
1.914
1.869
1.819
1.770
1.715
1.658
80
ANNEX 2: BIOMASS RESOURCES AND POTENTIALS
Annex 2.1: Overview of the Long-term Global Technical Potential of Bioenergy Supply
An overview of the global potential of bioenergy supply over the long-term for a number of categories and the main preconditions and assumptions determining these potentials.[1]
Biomass
category
Definition
Main assumptions and remarks
Energy crop
production
on surplus
agricultural
land
Biomass that can be produced on
future surplus agricultural land, after
the demand for food and fodder is
satisfied. Two types of energy crops
can be distinguished:
1) conventional energy crops,
normally used to produce food and
animal feed (e.g. maize, sugar-beet,
sugar-cane, rapeseed, oil palm,
soybeans)
2) Lignocellulosic energy crops,
composed of cellulose, hemicelluloses
and lignin (e.g. poplar, willow,
eucalyptus, miscanthus, switchgrass).
Biomass that can be produced on
deforested or otherwise degraded or
marginal land that is still suitable
for, e.g. reforestation
Residues associated with food
production and processing, both
primary (e.g. cereals straw from
harvesting) and secondary (e.g. rice
husks from rice milling)
Potential land surplus: 0–4 billion ha (Most
studies find 1-2 billion ha). A large surplus
requires intensive agricultural production systems
(i.e. modernisation of all aspects). When this is not
feasible, the bioenergy potential could be reduced
to zero. On average higher yields are likely
because of better soil quality: 8-12 dry tonne ha-1
yr-1are assumed. See also Table 3-2.
Low – 700
On a global scale a maximum of 1.7 Gha could
be used. Low productivity of 2–5 dry tonne ha-1
yr-1. The supply could be low or zero due to poor
economics or competition with food production.
Potential depends on yield/product ratios and
the total agricultural land area as well as type
of production system. Extensive production
systems require re-use of residues for maintaining
soil fertility. Intensive systems allow for higher
utilisation rates of residues.
The sustainable energy potential of the world’s
forests is unclear. Part of the considered potential
stems from natural forest (reserves). Low value:
figure for sustainable forest management.
High value: technical potential. Figures include
processing residues.
Low estimate based on global current use.
High estimate: technical potential. Utilisation
(collection) over longer term is uncertain.[3]
Estimate on basis of literature values. Strongly
dependent on economic development, consumption
and the use of bio-materials. Figures include the
organic fraction of MSW (typically >= 50% of the
entire energy content) and waste wood. Higher values
possible by more intensive use of bio-materials.
Most pessimistic scenario: no land available
for energy farming; utilisation of residues only.
Most optimistic scenario: intensive agriculture
concentrated on the better quality soils.
<60 – 150
Energy crop
production
on marginal
lands
Residues
from
agriculture
Forest
residues
Dung
Organic
wastes
Residues associated with wood
production and processing, both
primary (e.g. branches and twigs
from logging) and secondary
(sawdust and bark from the wood
processing industry)
Biomass from animal manure
Biomass associated with materials
use, e.g. waste wood (producers),
municipal solid waste
Total
Potential bioenergy
supply up to 2050
(EJ yr -1)[2]
15 – 70
30 – 150
5 – 55
5 – >50[4]
<50 – >1000
[1] The overview is based on Berndes et al., (2003), Smeets et al., (2007) and Hoogwijk et al., (2005).
[2] A lower limit of zero implies that potential availability could be zero, e.g. if global agriculture is not modernised and additional land is needed to
meet the world’s food demand.
[3] Note that traditional use of dung as fuel should be discouraged. The dung potentials shown here mainly stem from intensive agriculture, which offers
opportunities for fermentation and production of biogas.
[4] The energy supply of bio-materials ending up as waste can vary between 20-55 EJ (or 1100-2900 Mt dry matter) per year. This range excludes
cascading and does not take into account the time delay between production of the material and ‘release’ as (organic) waste.
81
Annex 2.2: Biomass Yields of Food and Lignocellulosic Crops
Indicative biomass yields and possible subsequent transportation fuel production per hectare per year. Starch and sugar crops
require conversion via fermentation to ethanol and oil crops to biodiesel via esterification (commercial technology at present).
The woody and grass crops require either hydrolysis technology followed by ethanol or gasification to syngas to produce
synthetic fuel (both not yet commercial conversion routes, see also Chapter 4).
Crop
Crop yield
(fresh tonne/ha/yr)
Net Energy yield in fuel
(GJ/ha/ yr) [3]
By-products
5.1
~ 15
Straw
Corn
9.2
19- 37
Stover, straw, DDGS
Sugar-beet
58.5
Sugar-beet pulp
Sugar-cane
73.1
~ 111
84-152
Bagasse, tops and leaves
Conventional energy crops [1]
Wheat
Soy beans
2.7
12-13
Glycerine, seed cake
Palm oil (fresh fruit bunches)
19.2
~ 140
Palm kernel shells,
PFAD, glycerine
Rape seed
2.9
28
Glycerine, seed cake
Jatropha seeds
4-7
~ 40
Seed cake
Woody crops, e.g. poplar, willow,
Eucalyptus
10 – 15
90-110
Perennial herbaceous crops, e.g.
Miscanthus, switchgrass, reed canary
grass
10 – 30
140 – 230
3–6
18-28
Lignocellulosic energy crops [2]
Prairie grasses (low-input system,
degraded lands)
[1] Yields are generally based on current average agricultural practices in industrialised countries. Numbers are based on a 5 year average (2002-2006)
yields, for wheat, sugar-beet and rape seed based on average EU-27, for corn and soy beans on USA, for sugar-cane on Brazil (all FAOSTAT, 2008);
for palm oil on average yield 2005-2007 Malaysia (MPOB, 2008), for Jatropha based on a literature review by Jongschaap et al., (2007).
[2] Yields based on Sims et. al. (2006), EEA (2007), Berndes (2001) Tilman et al., (2006) and Smeets (2008).
[3] The net energy yield is obtained by taking into account the gross energy yield per hectare, and subtracting all energy inputs during the production
process. Sources: Sims et al., (2006) for wheat, corn, sugar-beet and rape seed, Smeets et al., (2008) for sugar-cane, Donato and Huerga (2007) for
soy, Wicke et al., (2008) for palm oil, Berndes (2001) & Fischer et al., (2007) for lignocellulosic energy crops, Tilman et al., (2006) for corn and
prairie grasses. In some cases, own estimates for the net energy yield were made.
82
Annex 2.3: Overview of Regional Biomass Production Scenario Studies
Region
Study /
author
Time
frame
Europe
de Wit
& Faaij
(2008)
2030
EEA
(2007)
2030
25 Mha
3.4-5.0 EJ crops
+ 1 EJ residues
Varying mix of conventional &
lignocellulosic feedstocks over time
EU-25 (excl. Romania & Bulgaria)
Parker
et al.,
(2008)
2015
20 Mha
2.1 EJ crops
+ 0.8 EJ residues &
MSW
18 Western USA states only
Mainly corn, herbaceous crops, forest &
agricultural residues
Feedstock cost range to produce liquid
biofuels < 24 $/GJ
Perlack
et al.,
(2005)
2050
30 Mha
7.4 EJ crops
+ 10.8 EJ residues
Entire USA
Including forest & agricultural residues
(grains & perennial crops)
Latin
America
Kline
et al.,
(2008)
2017
121 Mha
19.7 EJ crops
+ 4.7 EJ residues
Argentina, Brazil, Colombia, Mexico and
CBI
Crops: sugar-cane, corn, soy bean, wheat,
palm oil and cellulosic residues
China &
India
Kline
et al.,
(2008)
2017
86 Mha
13.2 EJ crops
+ 3.7 EJ residues
Crops: sugar-cane, corn, soy bean, wheat,
palm oil and cellulosic residues
Australia
CEC
(2008)
0.07 EJ residues
Based on process residues, (mainly bagasse
and wood) and waste streams (MSW,
sewage sludge and landfill gas)
Resource assessment for solid biomass only
USA
Land use for
energy crops
Primary biomass
potential
Remarks
66 Mha arable land 12 EJ (+3 EJ) crops Potentials of highest yielding crops (grass)
(+24 Mha pasture) + 9 EJ residues
on arable (+ pasture) land and maximum
residue use
EU-27+ Switzerland, Norway & Ukraine
feedstock cost 2.9-9.3 $ / GJ
For Europe, the resource assessment of Refuel study (de
Wit & Faaij, 2008) comprises an estimation of future
arable and pasture land area requirements for food and
livestock sectors, the surplus being potentially available for
bioenergy production while accounting for agricultural land
converted to urban use and land for nature conservation
areas. Both cultivated arable land and pasture are potentially
considered as areas for growing dedicated bioenergy
crops. Land becoming available for bio-fuel production is
a result of future consumption and technological progress,
e.g. through yield increases and improved feed conversion
efficiencies. The resulting estimate can be interpreted as
the land that becomes available without compromising food
and feed production. Also explicitly taken into account is
the area reserved for nature conservation areas, complying
with the Pan European Ecological Networks. Finally,
a bottom-up costs analysis is executed, considering 13
dedicated bioenergy crops. Note that also the potential in
the Ukraine is taken into account, which contributes about
one third of the total available land in the Refuel study. In
contrast, the EEA study (2007) aims at determining the
environmentally ‘compatible’ arable land area, and uses
a fixed set of sugar, starch and lignocellulosic crops. It
also assumes that selection of these energy crops and their
management at farm level would follow environmental
best-practice (adaptation to bio-physical constraints and
ecological values of a region, appropriate crop mixes and
rotations, low use of inputs, double cropping practices etc.).
Furthermore, it is assumed that for the maintenance or
further development of 'environmentally orientated farming'
in the EU, the present share of 'environmentally orientated'
farming would need to increase to about 30% of the utilised
agricultural area in most Member States by 2030; at least
3% of present intensively used farmland should be set
aside by 2030 for nature conservation purposes; and no
conversion of permanent grassland, dehesas and olive groves
through ploughing for targeted biomass crops. Two scenarios
(with low and high fossil fuel prices) are used to model the
economic biomass potential (4-6.6 EJ).
For the USA, a study by Parker et. al. (2008) for the
Western Governors’ Association analysed the potential
contribution of biofuels for the transportation sector in the
western USA by 2015 by combining a spatially-explicit
resource inventory and assessment, models of conversion
technologies, and transportation costs into an integrated
model of biofuel supply chains. Geographic Information
System (GIS) modelling was used in conjunction with an
infrastructure system cost optimisation model to develop
biofuel supply curves using biomass feedstocks throughout
the western USA. All routes delivering fuel price between
$2.40 and $3.00 per gasoline gallon equivalence (gge) were
considered economically viable. A diverse resource base is
relied on to provide this fuel with significant contributions
83
from municipal solid waste, agricultural residue, herbaceous
energy crop, forest thinning, corn, and lipid resources. The
biofuel potential estimated in this way is significant, but
substantial uncertainties remain, including the economic
performance of the different conversion technologies and
the overall sustainability of many of the biomass resources
considered. Perlack et al., (2005) performed a study to
determine whether by 2050 the land resources of the United
States are capable of producing a sustainable supply of
biomass sufficient to displace 30% or more of the country’s
present petroleum consumption - requiring approximately 1
billion dry tonnes of biomass feedstock per year. This was
shown to be possible, using forestry and agricultural residues,
and dedicated conventional and lignocellulosic energy crops.
Major assumptions were that inaccessible forestland and all
environmentally sensitive areas were excluded, yields of corn,
wheat, and other small grains were increased by 50% until
2050, and residue recovery was enhanced.
For selected Latin American countries and China and India,
Kline et al., (2008) performed a study to develop ‘supply
curves’ for selected countries and feedstocks. Such supply
curves permit more detailed analysis of feedstock variables
when modelling future global biofuel markets. They focused
on Argentina, Brazil, Canada, China, Colombia, India,
Mexico, and the Caribbean Basin Initiative (CBI). Future
feedstocks are divided into two groups: traditional crops
that can be converted to biofuel and cellulosic materials
such as crop and forest residues. Crop feedstocks selected
for study were sugar-cane, corn, wheat, soybeans, and palm
oil. Historic production trends and the structure of average
production costs were analysed by state (or province)
to develop supply curves for each selected crop-country
combination. To estimate the amount of feedstock available
for export and or biofuel production, the total potential
production in the baseline case was reduced based on the
percentage of production used to meet domestic food, feed,
and fibre demands in the most recent year with reported
data (usually 2006). In the table above, the main results
for the baseline scenario for 2017 are presented (the study
also presents high and low scenarios, for the years 2012 and
2027).
Finally, for Australia, CEC (2008) developed a road-map
for increasing the utilisation of biomass for stationary
applications until 2020. The aim was to focus on those
resources where there is a prospect that the resource can
be matched with an appropriate technology to contribute
sustainably and economically to stationary energy supply.
Therefore, the analysis only considers solid, process-based
residues from agriculture and forestry and various waste
streams (e.g. MSW and sewage sludge). It does not include
any substantial quantities of field-based residues or energy
crops.
84
ANNEX 3: BIOENERGY ROUTES AND CONVERSION TECHNOLOGIES
Annex 3.1: Biomass Upgrading
Technologies
has a production capacity of 600,000 tonnes and exports most
of its production to Europe, China and Japan (Bioenergy Int.
2007).
There are numerous possible pre-treatment techniques ranging
from well-established mechanical techniques that consist of
simply chopping, chipping or milling the raw feedstock into
ready to use material for subsequent conversion, to less well
established thermomechanical or thermochemical upgrading
techniques that also increase the energy density of the
biomass. Pelletisation, torrefaction and pyrolysis technologies
are such examples.
Since pellets are mostly produced from sawdust, which is
a co-product of sawmilling, the volume of pellets produced
may depend on the volume of timber consumed in the wood
industry. The recent housing crisis in the USA, resulting in
fewer houses being built and hence less timber consumed,
has been interpreted as a possible cause of the sawdust
shortage. In Canada, on the other hand, large amount of wood
unsuitable for the processing industry has been available for
pelletising due to the massive destruction of the forest by the
pine beetle (Bioenergy Int. 2007).
3.1.1 Pelletisation and briquetting
Pellets are small wood-based cylinders 6-12 mm in diameter
and 10-30 mm in length. They are produced by compressing
wood sawdust through a die. The high pressure of the press
causes the temperature of the wood to increase greatly which
causes the lignin content of the wood to form a glue that binds
the pellet together as it cools.
In Europe, average production cost of wood pellets is
estimated to be in the range 50-80 Euro/tonne (EuBioNet2
2007), compared to $60-84/tonne in Canada (Urbanowski
2005, Mani et. al. 2006). Costs of switch grass pellets are
some 40% higher (Mani et. al. 2006). The competitiveness of
wood pellets with alternative fossil options differs from country
to country depending on the tax system and market price of
pellets. The latter ranged roughly from 120 to 270 Euro/
tonne in 2007 in the 17 European countries that use pellets
(Junginger et al., 2007), where the lower limit corresponds
to industrial volumes for co-firing applications, and the upper
limit is small volumes for household boilers. Market price to
the final customer was around 184 Euro/tonne in Germany
at the end of 2007 (after climbing above 250 Euro/tonne in
2006), which makes pellets much cheaper (~4 Euro cents/
kWh) than heating oil and gas (EuBioNet2 2007). There is no
apparent correlation yet between the pellet price and oil price.
Pellets have quality standards in Europe (CEN, DIN) that
guarantee a moisture content below 10% (against 20%-25%
for commercial wood chips), a uniform density and hence
calorific value irrespective of the wood used, as well as strict
physical and chemical characteristics. Pellets can be made
from virtually any type of woody feedstock, as well as from
herbaceous biomass, fruit biomass, and peat. However, the use
of such alternative feedstocks might result in pellets with ash
or contaminant contents that do not comply with the above
standards.
Pelletising is an efficient energy densification technique as
pellets typically have a bulk density of 650 kg/m3, that is some
3.3 times higher than industrial softwood chips. Moreover,
due to their very low water content, pellets also have a high
net calorific value (or lower heating value) of about 17 MJ/
kg, that is 17% higher than wood chips. This property alone
can make it economically viable for material to be pelletised
to reduce transport and storage costs. In Sweden for instance,
where pellets are primarily used to substitute for coal in large
power plants, pellets are manufactured from sawdust at the
sawmill, before being transported to the power plant where
they are milled before combustion.
Further research is still necessary to increase the stability
and resistance to abrasion of pellets, as well as to reduce the
dust emission during handling in domestic applications (IEA
2008e).
Biomass briquettes are fabricated in a similar way as pellets
and have a typical dimension of 30-100mm. Unlike pellets,
which can be used for automatically-charged stoves and
boilers, briquettes require manual charging, which makes it a
far less user-friendly fuel. Briquettes are mainly produced and
used in Southern India.
Pellets thus have the great advantage over other woody
feedstocks of being a homogeneous, dense, and easy to
handle solid fuel, which explains its increasing popularity
both at domestic and industrial scale. However, pellets are
hygroscopic, i.e. they tend to absorb moisture during transport
and storage, which can significantly reduce their net calorific
value – down to below 10 MJ/kg (PC 2008).
3.1.2 Pyrolysis
Pyrolysis is the thermal decomposition of biomass occurring in
the absence of oxygen (anaerobic environment) that produces a
solid (charcoal), a liquid (pyrolysis oil or bio-oil) and a product
gas. The respective fraction of these three co-products depends
on the operating temperature and on the residence time of
the hot vapour used in the process. Moderate temperatures
(around 500°C) and short residence time (around 1 second)
used in so-called fast pyrolysis (or flash pyrolysis) are optimal
conditions for maximising the production of the liquid fraction
(up to 75% of the output energy content).
Pellets have become a common fuel in developed countries.
Some 442 pellet producers were identified worldwide in
2007, spread throughout Europe, Russia and North America
(Bioenergy Int. 2007). Quality standards are increasingly
contributing to the development of international trade in
pellets. Canada produced close to 1.5 million tonnes of pellets
in 2007, most of which were exported to Europe, while Russia
The production of wood charcoal using slow pyrolysis
(also known as carbonisation) has been used for centuries
85
throughout the world (e.g. in traditional stoves in developing
countries, in barbecues in Western countries, as well as in
industry such as the Brazilian steel industry). However, it is
only in the last 30 years that fast pyrolysis has been given
extensive development effort because liquid fuels are generally
easier (and thus cheaper) to handle, store and transport
than solid biomass. In spite of considerable experience
gained over the last decades, fast pyrolysis is still in its
demonstration stage. Although fast pyrolysis units are used in
niche applications such as the production of food flavourings,
only a few successful demonstration units have been realised
for bioenergy (e.g. in Finland and Canada), and both
economic and technical challenges must be resolved before
commercialisation is feasible. Bio-oil could either be burnt
directly for power in CHP applications (in boilers, stationary
engines and turbines, co-firing), or upgraded to transport fuel.
production costs (excluding feedstock cost) are estimated to
be 50-100% higher than those of pelletisation or torrefaction
plants (Uslu et. al., 2008).
Fast pyrolysis has mainly been considered as a biomass
densification step before long distance transport.
Demonstration CHP plants integrating pyrolysis and gas
turbine exist, but it is as yet unclear whether this direct
combination can prove economic as it is competing with more
efficient technologies such as gasification and simply direct
combustion. Potentially interesting opportunities may be
provided by the integration of pyrolysis processes or oils in
conventional refineries or in biorefineries (see Section 3.7).
3.1.3 Torrefaction
Torrefaction is a thermal process that involves slowly heating
the biomass at 200-300°C in the absence of oxygen. This
degrades the biomass into a completely dry coal-like product
that has lost the fibrous structure of the original biomass,
hence significantly improving its grindability, as well as net
calorific value (19-23 MJ/kg) and energy density. Torrefaction
can be a highly efficient means of densification, with torrefied
products retaining some 92% of the original feedstock energy
(Uslu et. al., 2008).
The deployment of pyrolysis technology still faces technical
and economic challenges. A key challenge remains the
improvement of the quality and consistency of the pyrolysis
oil in terms of moisture content, contaminants, corrosiveness
and viscosity, as well as in terms of stability, as bio-oil tends
to degrade and separate over time. Reactor design and bio-oil
upgrading techniques can address these technical challenges
but are expensive.
Also, current bio-oil production technology is not very
selective, resulting in a bio-oil composed of more than 300
chemicals. These prove mostly incompatible with the upgrading
of bio-oil into transport biofuels, which require precise,
highly selective composition. New techniques for increasing
the control of bio-oil composition are thus required to make
this technology more attractive. Among the technological
advances needed are better characterisation of the thermal
reactions and greater understanding of how catalysts can be
incorporated into the reaction environment to produce the
preferred bio-oil compositions (NSF 2008).
There are also technical challenges relating to scale-up,
particularly concerning heat transfer which is crucial in this
technology. Several types of reactors are under investigation,
but no prevailing design has emerged yet.
The by-products of fast pyrolysis are mainly char and a
product gas, which can typically be recycled (burnt) in the
process to produce the heat necessary for the conversion
process. Alternatively, applications for the char including soil
amendment, use as combustion fuel (possibly added to the
pyrolysis oil in co-firing applications), or gasifier feedstock
have been proposed but not yet extensively studied.
In addition, torrefaction transforms hygroscopic feedstocks
into a hydrophobic material. This represents a significant
advantage over traditional dried biomass such as pellets, since
torrefied feedstock can be transported over long distances and
stored outside without absorbing any moisture, hence without
seeing its calorific value drop.
Although torrefaction is an old technique, it is not
commercially available as a means of pre-treating biomass
for biomass-to-energy production chains. Although torrefied
biomass can be produced from a wide variety of biomass
while yielding similar product properties, this upgrading
technique is mostly applied to wood. Torrefied wood can be
subsequently pelletised, which could reduce logistics cost by
as much as 50% as compared to traditional pellets, This is
expected to compensate largely for their higher production
cost (approximately 10% higher) (Bergman 2005).
Annex 3.2: Biomass-to-Heat
Technologies
The direct burning of wood and other solid biomass feedstock
for domestic heating and cooking purposes is the oldest and
most accessible energy technology used by man, and it is still
by far the largest contribution of biomass to global energy
supply today.
While bio-oil has a calorific value of about 17.5 MJ/kg, which
is comparable to that of pellets, its energy density is about
20-30 GJ/m3 – about twice that of pellets and 4-5 times
that of torrefied biomass (but still only half that of diesel oil)
(Uslu 2008). This gives pyrolysis a competitive advantage
over pelletisation and torrefaction in terms of transport cost.
However, this advantage is not sufficient to offset the higher
cost of bio-oil. Investment costs have been calculated in
the range 1900-4200 Euro/kWth for 25 MW plants, while
Depending on the socio-economic context and environmental
legislation in place, domestic biomass combustion technologies
range from very inefficient devices such as open fire places
(efficiency ranging from -10% to 10%31) or traditional
cooking stoves found primarily in developed countries
(efficiency 10-15%), through to very efficient and increasingly
31 Because of the large amount of cool outdoor air dragged inside by the combustion process (and thus removing warm air from the heated space),
open fireplaces can actually consume more energy than they produce when the outdoor temperature is low (typically below 0°C), and thus have a
negative thermal efficiency
86
rich in nitrogen and ash. Small-scale combustion units are of
special concern, as they need simple and affordable solutions.
Finally, questions remain regarding the most environmentally
sound and affordable manner for processing ash from
contaminated biomass sources in the context of increasingly
strict landfill regulations.
popular modern chip-burners, heat storing stoves and
pellet-boilers with efficiencies of up to 90% (IEA 2008e).
Advanced biomass boilers can even reach efficiencies of 105110% (define on LHV basis)32 if flue gas condensation and
humidification of combustion air is applied, or if the waste
heat is used for absorption cooling (Westermark 2006).
A range of biomass combustion systems is available for
heat production on a larger scale for industrial purposes
or district heating. Grate boilers and underfeed stokers are
the most common technologies for small- to medium-scale
applications (200 kW-20 MW) as these offer low investment
and operating costs. Fluidised bed technologies, which
became commercial in the 1970s, offer higher thermal
efficiency and lower toxic emissions (CO, NOx) than fixed bed
approaches due to better control over combustion conditions.
Fluidised bed technologies also offer the further advantage of
a greater tolerance of moisture content and type of biomass
used. However, fluidised bed technologies have higher capital
and operating costs, and require significant economies
of scale, so that only larger plants (>20-30 MW) are
economically viable. Over 300 fluidised bed installations have
been built worldwide to date (IEA 2008e).
Annex 3.3: Biomass Combustion-toPower Technologies
The heat produced by direct combustion in boilers can be
used to produce electricity in a separated steam turbine or
engine. Overall electrical efficiency is limited by the relatively
low efficiency of the steam cycle. The efficiency of electrical
generation alone typically ranges from about 10% for small
CHP plants (<1 MWe steam-engine) up to 40% (electricityonly mode) for >50 MWe steam-turbine combined with the
most advanced fluidised bed combustion technology (IEA
2008e). The rest of the energy from the combustion (60-90%
of the energy contained in the feedstock) is lost into the air
or water as waste heat.
The main way to increase the overall efficiency of a power
plant (and hence its competitiveness) significantly is to use
this heat. By making use of waste heat, combined heat and
power (CHP), or cogeneration, plants have typical overall
efficiencies in the range 80-90% provided a good match can
be found between heat production and demand (IEA 2008c).
However, recycling the waste heat has a slightly detrimental
impact on the efficiency of the power production, which is
a few percentage points lower in CHP plants than in poweronly plants.
Production costs of biomass-based heating systems vary
widely with size and fuel cost. Heat production costs in pellet
boilers in the range 5-100 kW range from 8 to 99 Euro/
GJ, with an average of 26 Euro/GJ – about competitive with
fossil resources. A mere 4-6% cost reduction is expected
through to 2030 (at a constant fuel price) by increasing
lifetime and efficiency. Combustion of wood chips for district
heating is more commonly applied than pellet burners. These
can have higher investment costs but lower fuel prices (IEA
2007b).
The economic case of district heating depends on a number
of complex technoeconomic parameters. The cost of heat
distribution networks accounts for 35-55% of the total
investment cost of district heating plants, which calls for
a high annual utilisation rate (>75%) and concentration
of customers to reach economic viability. This can prove
difficult to attain as demand is, in general, not constant
throughout the year (IEA 2008e). Moreover, thermoeconomic
optimisation of the network efficiency is necessary, by
trading-off network losses against the cost of expensive pipe
insulation (IEA DHC 2005). Although large-scale district
heating networks can prove economic, a significant number
of failures have been reported due to the complexity of
optimising these systems properly.
Further R&D on combustion technologies will focus mainly
on increasing thermal efficiency, and the need to develop
small-scale technologies that can burn biomass other than
wood (e.g. energy crops, tree residues, etc.). Also, as the
combustion process per se is associated with toxic emissions
of volatile compounds (in particular NOx and particulates),
continuous effort is needed to further reduce these harmful
emissions in order to meet increasingly stricter emission
regulations. This is particularly the case for biomass fuels
Municipal solid waste (MSW) incineration plants are
generally large in scale but corrosion problems limit the
process steam temperature and thus reduce the electrical
conversion efficiency to about 22%. New generation CHP
plant designs using MSW are, however, expected to reach
28%-30% electrical efficiency (IEA 2007a).
Economies of scale are very important. Investment cost is
about 3,500 Euro/kWe for a 5 MWe plant, but drops to
about 2,000 Euro/kWe for a 25 MWe plant. Until recently,
dedicated biomass power plants have only proved competitive
when using large quantities of free waste that had to be
disposed of, such as MSW, black liquor from the pulp and
paper industry and agriculture residues such as bagasse.
However, a growing number of viable smaller scale plants
using other type of residues (forestry, straw, etc.) are found
throughout Europe and North America. Co-generation
has been shown to reduce the cost of power production by
40-60% for stand-alone plants in the range 1-30 MWe.
However, the scale of biomass CHP plants is often limited
by the total local heat demand and by its seasonal variation,
which can significantly affect economic returns unless
absorption cooling is also considered.
32 Since energy is required to vaporise water, energy is conversely released (in the form of heat) when water vapour is condensed. Efficiencies above
100% can be achieved if the air used in the combustion is humidified prior to entering the boiler and the flue gas naturally condensed when exiting
the boiler. This condensation energy is extra energy that adds to the combustion energy of the biomass.
87
As an alternative to conventional steam plants in the range
0.5-2 MW, the Organic Rankine Cycle (ORC) engine33
can offer technical and economic advantages (e.g. lower
process temperature, low operating cost, and the potential
to use a thermal oil boiler instead of a more expensive
high temperature-proof steam boiler) (Obernberger and
Biedermann 2005). The gross efficiency of ORC engines
can reach 17%, which is slightly higher than a steam
turbine of equivalent size. However, the net efficiency can
be significantly lower due to the relatively high power
consumption of ORC units (IEA 2008e). Although ORC is
a well-proven technology (e.g. in geothermal applications),
only a few ORC plants operate on biomass at this stage (e.g.
Switzerland, Austria, the Netherlands). Work is still needed
to improve efficiency and reliability, and to reduce costs.
• the biomass is milled to a topsize around 1-5 mm and is
directly injected into the pulverised coal firing system.
These approaches to co-firing are now in full commercial
operation in over 150 installations worldwide, of which 100
are located in Northern Europe, 40 in the USA and a few in
Australia. A very large 400 MWe capacity biomass co-firing
plant is currently being built in the UK at the existing 4 GWe
Drax coal plant. Direct co-firing can thus be considered fully
commercial. The direct co-firing of a range of liquid biomass
materials (e.g. vegetable oil, tallow) in existing plants is also
practised on a commercial basis, albeit at much smaller scale
than for the solid materials.
In most cases, the biomass co-firing ratio is limited to
around 5-10% on a heat input basis, and this is controlled by
the availability of biomass and in some cases, by site-specific
plant constraints. In one or two cases, co-firing ratios of up
to 25% have been achieved.
In the lower capacity range (10 -100 kWe), the Stirling
engine is a promising technology for domestic cogeneration.
Currently at the demonstration stage (e.g. in Denmark,
Germany, UK, Switzerland, Austria, and New Zealand),
improvements are still needed, in particular to improve the
current 12-20% conversion efficiency, which could reach up
to 28% by improving process and scaling up to 150 kWe.
Developments on Stirling units operated on biomass are very
few, with some efforts under way in Germany with pellets.
Direct co-firing in large-scale modern coal plants is today
the most cost effective use of biomass for power generation.
This technology only requires minor investment to adapt
handling and feeding equipment without noticeably affecting
boiler efficiency, provided the biomass is not too wet and
has been pre-milled to a suitable size. Furthermore, electric
efficiencies for the biomass-portion range from 35% to 45%,
which is generally higher than the efficiency of biomassdedicated plants (IEA 2007a).
Feedstock handling and storage management, excessive
equipment wear, bottlenecks in the feed system, heavy metal
contamination, and wide fluctuations in fuel moisture content
into the boiler are common technical issues with biomass
combustion plants that need to be addressed. Furthermore,
biomass often contains heavy metals, the combustion of
which can cause corrosion and deposit formation on the
heat transfer surfaces, thus reducing plant efficiency and
increasing maintenance requirements.
In spite of the significant progress achieved in co-firing over
the last decade, biomass properties pose several challenges to
coal plants that may affect their operation and lifetime. Most
of the potential issues faced by co-firing are associated with
the biomass ashes which are very different from coal ashes.
Problems arise mainly at increased co-firing ratios and with
biomass materials with high ash contents. The technical risks
are mainly associated with the increased ash deposition on
surfaces in the boiler and in SCR catalysts (thus reducing
the efficiency of the system), and with the impact of flue gas
on gas cleaning equipment. The contamination of ashes by
alkaline metals is relatively well understood and, in Europe,
this has largely been recognised in performance standards
for the utilisation of ashes in the manufacture of building
products.
Annex 3.4: Co-firing Technologies
Biomass co-firing (or co-combustion) involves supplementing
existing fossil-based (mostly pulverised coal) power plants
with biomass feedstock. There are three types of biomass
co-firing:
• direct co-firing, where the biomass is combusted directly in
the existing coal furnace;
• indirect co-firing, where the biomass undergoes a
preliminary gasification conversion before the resulting
syngas is combusted in the coal furnace; and
• parallel co-firing where the biomass is combusted in a
separate boiler, with utilisation of the steam produced
within the main coal power station steam circuits.
Indirect and parallel co-firing options are designed to avoid
biomass-related contamination issues, but have proven
much more expensive than the direct co-firing approach as
additional infrastructure is needed. Parallel co-firing units
are mostly used in pulp and paper industrial power plants.
The indirect option faces issues regarding the cooling and
cleaning of the syngases.
Over the past decade, direct co-firing has been successfully
demonstrated with many technology options and with a wide
range of biomass feedstocks (wood and herbaceous biomass,
crop residues, and energy crops). In the main, direct co-firing
has been achieved in two ways:
• the raw solid biomass is pre-mixed, generally in granular,
pelletised or dust form, with the coal in the coal handling
system; or
Indirect co-firing with pre-gasification of the biomass has
now been demonstrated in both pulverised coal power plant
and in coal gasification plants (demonstration projects in e.g.
Austria, Finland, the Netherlands). The highest efficiencies
(up to 50%) and economies of scale can be obtained with
indirect co-firing in a Biomass Integrated Gasification
33 The ORC engine is similar to steam engine but works with low boiling temperature organic oil as a process fluid instead of steam.
88
Combined Cycle (BIG/CC). Although promising, more R&D
and cost reduction efforts are needed for this technology to
reach commercial status (further information on this topic
in the gasification Section below). The calorific value of the
syngas generated is an important consideration when co-firing
with coal syngas in gas turbines.
42%) (IEA 2008e). Due to their high conversion efficiencies,
these technologies offer greater CO2 emission reduction
potential than direct combustion-based approaches.
However, these pathways rely on pressurised operations which
have not yet been adequately demonstrated at large-scale
(IEA 2008c). The first pressurised (1.8 to 2.5 MPa) biomass
integrated gasification combined cycle (BIG/CC) plant running
on 100% biomass (9 MWth and 6 MWe plant based on wood
and straw) has been successfully demonstrated in Sweden
since 1995 and technical issues (process integration, tar
formation, real-time process monitoring, etc.) appear to have
been overcome. However, other projects have not succeeded
(e.g. the ARBRE project in the UK) due to inadequate support
to resolve process shakedown and system integration issues.
Several commercial scale BIG/CC projects are in the pipeline
in northern Europe, USA, Japan and India, with respective
operational start-ups ranging from 2006 to 2011.
Co-firing with pre-pyrolysis of the biomass is still in its early
stages, but could potentially become a cost-effective bioenergy
route for countries with large distances between the fossil
plants and the regions of biomass production. This route would
be competing with other densification technologies, i.e. pellets
or torrefied biomass.
Annex 3.5: Biomass Gasification
Technologies
Gasification occurs when biomass is heated under substochiometric combustion conditions. This results in the
production of a combustible gas mixture (called producer gas
or fuel gas) rich in carbon monoxide (CO) and hydrogen (H2),
which has an energy content of 5-20 MJ/Nm3 (depending
on biomass and whether gasification is conducted with air,
oxygen, or indirect heating), that is, roughly 10-45% of the
heating value of natural gas. Fuel gas can then be upgraded to
a higher quality gas mixture called syngas.
The syngas can be converted to hydrogen-rich gas or pure
hydrogen that could be electrochemically converted in fuel
cells to produce electricity. The integrated gasification fuel
cell (IGFC) technology is expected to yield high electrical
efficiencies – 50 to 55% (Watanabe and Meada 2007).
However, significantly more RD&D is needed to develop,
demonstrate, and commercialise IGFC systems in the near
future.
Gasification was originally developed in the early 19th century
to produce town gas from coal for lighting and cooking,
before it was supplanted by natural gas and electricity. Wood
gasification-based engines called gasogene were also used
to power vehicles in Europe and elsewhere during the fuel
shortage of World War II. Gasification regained interest in
the early 1980s and has undergone significant RD&D both in
Europe and North America, with several competing reactor
designs and gas cleaning processes.
Gasification is a highly versatile process. Virtually any biomass
feedstock can be converted into syngas with a very high carbon
conversion and thermal efficiency of 85-95%. Furthermore,
syngas is an intermediate product that offers a large range of
possible secondary conversion and final energy uses (see Figure
3-1 in Chapter 3). Heat application of gasification is mainly
confined to countries with emerging economies. Hundreds of
small and medium size biomass gasifiers (< 1 MWth) are, for
example, being deployed mainly for heat applications in China,
India, and South-East Asia with attractive pay-backs (IEA
Bioenergy 2007). These gasifiers are operated intermittently
and may not conform to the environmental guidelines generally
practiced in OECD countries. Their reliability and lifespan in
continuous operation may be an issue.
Raw syngas can also be cleaned of its particulates and
condensable hydrocarbons and burnt in an internal combustion
gas engine, which offers electrical efficiency in the range
22-35% (IEA 2008c), that is, slightly higher than for
steam engines used in conjunction with biomass combustion.
Demonstration CHP and co-firing plants based on this
principle are widespread in Europe and the USA in the range
1-15 MWth (IEA 2008c). Higher electrical efficiencies are
reached if the syngas is combusted in gas turbines (up to 40%
efficiency), or in gas and steam turbine combined cycles (up to
89
Instead of being directly combusted for heat and power, the
syngas can be further processed into a methane-rich gas called
substitute or synthetic natural gas (SNG), the composition
of which makes it suitable for blending in the natural gas
network, thus offering enhanced flexibility as to the final
use. Such projects are in their demonstration stage (Austria),
with the first commercial size projects under development in
Sweden and Switzerland. The syngas can also be converted
into a liquid fuel (e.g. Fischer Tropsch or FT-diesel, DME,
methanol, or mixed alcohols) using different methods
employing the proven catalytic conversion process. These
biomass-to-liquid (BTL) routes are discussed in Section 3.6.3.
Gasification of coal and oil residues has been used for decades
at industrial scale for strategic reasons (e.g. Sasol plants in
South Africa). Biomass gasification technologies struggle for
market entry due to limited plant capacities because of the
cost of collection and transportation of biomass to central
energy conversion plants. For this reason, out of the ~5.25
GWe of existing global IGCC plant capacity in 2006, only
0.15 GWe run on biomass fuel, mostly in the EU with a
negligible capacity in North America and Asia.
Further support and development of certain biomass
gasification processes is required to address and resolve
issues related to sensitivity to feedstock quality and moisture
content, reliability of feedstock feeding systems into the
reactors, gas clean-up (tar formation, process monitoring,
and tar, alkali, chloride, ammonia, etc. removal), and process
scale-up with first-of-a-kind plants (Babu 2005). Due to
inadequate opportunities to replicate commercial applications,
it is difficult to obtain performance and reliability guarantees
from many technology developers, which poses a financial risk
to investors (IEA 2007c).
going into waste-to-energy plants (combustion), while the
organic fraction undergoes anaerobic digestion.
Since process developers cannot obtain or do not provide
adequate resources for first-of-a-kind demonstration plants,
the production costs are usually 3-4 times higher than
conventional alternatives (IEA Bioenergy 2007). Under
certain site-specific situations claims have been made that
BIG/CC plants could be commercially viable, such as in
co-production mode using black liquor from the pulp and
paper industry (IEA 2007a).
The evolving lignocellulosic and other biofuel processes,
including algal fuels, do not convert the entire feedstock to
the desired products and leave behind a significant portion of
carbonaceous matter that could be effectively utilised in closely
integrated biomass gasification processes, to improve overall
process performance. It is noteworthy that for many countries,
demand for electricity may be comparable to security of
supply of transportation fuels in importance. With adequate
incentives, biomass gasification offers prospects for the market
entry of distributed power generation to meet future needs.
Whatever form biomass gasification may evolve into, it should
play a critical role in building a ‘bridge’ for sustainable energy
for the future.
Annex 3.6: Anaerobic Digestion
Technologies
Anaerobic digestion is the biological degradation of
biodegradable organic matter under exclusion of oxygen/air
conditions. The main product of anaerobic digestion is biogas,
a gas mixture of methane (the main component of natural gas)
and carbon dioxide (CO2). The biogas produced can either be
cleaned for on-site use in heat and power generation units or
be separated from the carbon dioxide, compressed and injected
into the natural gas network for use in heat or electricity
generation elsewhere or as a transport fuel.
There are two main classes of proven technologies that differ
in their process temperatures. Thermophilic digestion (5070°C) systems offer faster throughput and better pathogen
and virus reduction than mesophilic processing (25-40°C),
but require more expensive technology and a higher degree of
hands-on operation and monitoring. Thermophilic units are
thus mostly used for centralised production. Most such plants
are found in Switzerland and to a smaller extent in Sweden.
China is by far the biggest biogas producer and user in the
world, with around 18 million farm households using biogas
(about 7 million Nm3 per year) and about 3,500 medium to
large-scale digester units (about 250 million Nm3 per year)
(DEFRA 2007). In Europe, Germany is the leading country
with some 3700 units in operation corresponding to some
1270 MWe total capacity installed in 2007 (mostly small
cogeneration units running on agricultural residues) generating
8.9 TWh of electricity annually. About 50 new plants are
installed each month. This success is mostly explained by
the support provided by the feed-in tariff targeted to farmscale systems. The UK, Italy, and Spain are leading landfill
gas production, while less successful in stimulating farmbased anaerobic digestion (see production map below). The
Danish centralised AD plants are also a technical success
and are more cost-efficient than the German plants thanks
to economies of scale. In the USA, the deployment of biogas
technology suffers from a poor reputation due to a high failure
rate. As of April 2008, a mere 114 farm-scale digesters were
in operation in the USA (EPA 2008).
The economic viability of biodigesters is highly sensitive to
unit size and feedstock price. Small-scale plants are often
uneconomic, but centralised digestion may be limited because
of the distances over which manure has to be transported,
which increases both the price of feedstock and the biosecurity
issues in the case of manure handling (CCTP 2005). Also,
the rural context of farm-based biogas digestion is often
associated with difficulty in selling the surplus process heat
and high cost of grid connection in remote areas. Finally,
the anaerobic digestion process cannot easily accommodate
changes in feedstock properties and thus requires significant
technical know-how and commitment to operate effectively.
Failure rate has been very high in the past decades, with a
detrimental impact on the economic viability of these units,
due to the complexity of design and operation. German
manufacturers largely overcame this issue with simpler designs
and good technical support.
Anaerobic digestion applies to almost any biodegradable
waste materials such as grass clippings, leftover food, sewage,
animal waste, or industrial waste. Anaerobic digesters
can also be fed with specially grown energy crops to boost
biodegradable content and hence increase biogas production.
However, lignin can not be degraded by anaerobic digestion,
which makes woody biomass not suited for this conversion
route.
Both dry and wet processing are well-established technologies,
have a good track record and have been proven at a
commercial scale. Anaerobic digestion is happening both
in centralised plants (typically for the treatment of sludges
in waste water treatment plants or landfill gas recovery
facilities close to urban areas) and in small and distributed
biodigester units, usually in rural areas on farms or even
in small households where mostly manure and agricultural
wastes are being digested. Anaerobic digestion is also part of
the mechanical biological treatment of municipal solid waste
(MSW), where the waste is sorted into refuse derived fuels
Although anaerobic digestion has long been commercial,
further technology optimisation and cost reduction are still
possible that could significantly improve the economic viability
of smaller units. The main areas of need are to improve
biomass pre-treatment to reduce fermentation time, to reduce
costs and to improve reliability of two-stage technologies34, to
34 The mechanism of anaerobic digestion involves two steps: 1) hydrolysis and acetogenesis processes, which convert bio-degradable feedstock into
glucose and amino-acid, and then into fatty acids, hydrogen and acetic acid, and 2) conversion by methanogenesis of acetic acid into a product gas
rich in methane (biogas) according to the biochemical reaction CH3COOH -> CH4 + CO2. These two steps can take place in a single reactor (singlestage AD) or in two separated reactors (two-stages AD). The latter solution allows for individual optimisation of each process, thus potentially
increasing the overall system performance, but is associated with more complex process control and higher capital cost.
90
improve biogas cleansing processes (mainly of corrosive H2S)
and to increase the robustness of the thermophilic process.
Techniques to improve the biological digestion process (through
ultrasonic treatment or enzymatic reactions) are currently at
the R&D stage. These approaches could increase biogas output
by several percentage points.
The co-product of anaerobic digestion of source-separated
wastes is a nutrient-rich digestate that may contain pollutants
if the separation is not properly done. This may make this
co-product unsuitable for use as fertiliser depending on the
regulations in place. Biomass pre-treatment and separation
processes to remove these contaminants could prove cheaper
than capital intensive cleansing processes, but these processes
Source: EurObserv'ER (2007)
91
still need to be proven at a larger commercial scale. If
anaerobic digestion is part of an industrial waste process the
digestate is often aerobically polished or dried and used in a
waste-to-energy plant.
The alternative route, of microbial fuel cells, could have
interesting prospects in the longer term. The concept of
microbial fuel cells, by which the micro-organisms that digest
the biomass are selected to generate a hydrogen-rich ‘biogas’
that can in turn be used in fuel cells is still at an early stage
of development. Although feasibility has been proven, this
technology requires a lot more R&D before it could reach
demonstration stage.
Annex 3.7: Feedstock Yields for Sugar and Starch Crops Used for Bioethanol Production
Region - Biofuel
Feedstock
Yields, 2005(l/ha)
Nominal
Average
Gasoline/diesel
equivalent
Resulting yields
in 2050
(lge/ha)
Europe – ethanol
Wheat
2500
1650
0.7%
2260
Europe – ethanol
Sugar-beet
5000
3300
0.7%
4520
Europe – FAME biodiesel
Oilseed rape
1200
1080
0.7%
1480
US/Canada – ethanol
Corn
3000
1980
0.7%
2710
US/Canada – FAME
biodiesel
Soybean/oilseed
rape
800
720
0.7%
990
Sugar-cane
6800
4490
0.7%
6140
Soybean
700
630
1.0%
990
Brazil – ethanol
Brazil – FAME biodiesel
Rest of world - ethanol
Sugar-cane
5500
3630
1.0%
5680
Rest of world - ethanol
Grain
2000
1320
1.0%
2070
Rest of world - biodiesel
Oil palm
2500
2250
1.0%
3520
Rest of world - biodiesel
Soybean/oilseed
rape
1000
900
1.0%
1410
Lignocellulose
4300
2840
1.3%
5080
Biomass
3000
3000
1.3%
5360
Second generation
World - ethanol
World – Btl biodiesel
Note: FAME = Fatty acid methyl esters; lge/ha = litres gasoline equivalent per hectare; l/ha = litres per hectare; ethanol
converted to gasoline equivalent (ethanol 67% the energy content of gasoline), biodiesel converted to diesel equivalent
(biodiesel 90% the energy content of diesel, except BTL biodiesel with 100% the energy content of petroleum diesel).
Source: IEA (2008a)
Annex 3.8: Production Costs for Different Biofuels
Total cost
[$/GJ
biofuel]
Total cost
[$/I biofuel]
0.0
14.7
0.31
0.0
35.4
0.75
11.0
8.2
24.4
0.52
Biofuel
Revenue
Feedstock Producing Year Size of plant Feedstock Conversion
from
costs [$ costs (capex
country
considered
feedstock / + opex), [$/ co-products
[million I
[$/GJ
biofuel/yr] GJ biofuel] GJ biofuel]
biofuel]
Conventional
bioethanol
sugar-cane
Brazil
2008
250
7.7
7.0
corn
USA
2008
250
29.4
6.0
sugar-beet
UK
2008
250
21.6
Conventional
biodiesel
wheat
UK
2008
250
36.2
10.5
6.0
40.7
0.87
maize
France
2008
250
29.3
10.5
5.0
34.7
0.74
soybean
US
2008
220
100.6
4.2
55.6
49.2
1.63
Brazil 2008
Argentina
220
22.6
2.7
1.7
23.5
0.78
soybean oil
rapeseed
UK
2008
220
35.6
4.2
11.3
28.5
0.94
rapeseed oil
France
2008
220
40.5
2.7
1.7
41.4
1.37
Indonesia 2008
/ Malaysia
220
25.1
2.7
1.7
26.1
0.86
palm oil
tallow
UK
2008
220
13
4
2
15.3
0.51
Lignocellulosic
ethanol
cellulosic
feedstocks
UK
2015
90
14
14
0
28.0
0.60
2022
360
14
10
0
23.5
0.50
Syndiesel
cellulosic
feedstocks
UK
2015
80
12
17
0
29.5
1.01
2022
280
12
8
0
20.0
0.69
Source: E4tech (2007)
92
Annex 3.9: Renewable Diesel by
Hydrogenation
Each stage in the conversion process has potential for
improvement:
Feedstock production could benefit from current research
into crops with higher yields, lower inputs, lower lignin
content and crops that produce the enzymes that break down
lignocellulosic biomass.
The hydrogenation of vegetable oil and animal fat yields
a bio-diesel fuel that can be blended in any proportion
with petroleum-based diesel. The process involves reacting
vegetable oil or animal fats with hydrogen (typically sourced
from an oil refinery) in the presence of a catalyst. Although
at an earlier stage of development and deployment than
transesterification, hydrogenation of vegetable oils and
animal fats can still be considered a 1st generation route as it
is demonstrated at commercial scale.
Pre-treatment is currently achieved by dilute acid and
alkaline hydrolysis and, more recently, steam explosion.
Research today focuses on the development of chemical
(e.g. ionic liquids) and biological (e.g. fungal) pre-treatment
processes, which are currently at an early stage of
development. The development of microbes which can preprocess lignocellulosic material, decrystalise the cellulose
and ferment the sugars to ethanol all in a single step could
provide great cost savings.
Two main types of hydrogenation plant exist: stand-alone or
co-processing.
• Stand-alone plants include their own dedicated
hydrotreating equipment, and produce biodiesel that can
subsequently be blended with conventional diesel from oil
refineries.
• Co-processing hydrogenation plants use the hydrotreating
capacity of existing conventional oil refineries, and produce
a single, blended diesel output. This reduces the capital
costs of the hydrogenation plant, but also reduces the
refinery’s output of petroleum-based diesel.
Hydrolysis. Acid hydrolysis is a well established process and
nearing commercialisation. Enzymatic hydrolysis is at the
later stages of R&D, and is starting to be demonstrated at
larger scale.
Fermentation of C6 sugars (hexose) to produce ethanol
has reached commercialisation. C5 sugars (pentoses), on
the other hand, are more difficult to ferment, and R&D is
underway to produce organisms that will ferment them, some
nearing demonstration at large-scale.
Hydrogenation potentially enables greater feedstock
flexibility and lower production cost than transesterification.
The technology is at the demonstration stage, and currently
requires integration with an oil refinery to avoid building a
dedicated hydrogen production unit and to maintain a high
level of fuel quality. However, production costs are dominated
by feedstock costs in the case of vegetable oils.
Separation can be performed by distillation. However, since
this is very energy intensive, other novel, less energy intensive
options are being explored.
The process whereby hydrolysis enzyme production, cellulose
hydrolysis, hexose fermentation and pentose fermentation
all take place in different steps (i.e. in different bioreactors)
is called ‘separate hydrolysis and fermentation’ (SHF).
Processes exist which combine these steps are in development
to make the overall process potentially quicker and cheaper:
• Simultaneous Saccharification and Fermentation (SSF),
where cellulose hydrolysis and hexose fermentation are
combined.
• Simultaneous Saccharification and Co-fermentation
(SSCF), where cellulose hydrolysis, hexose and pentose
fermentation all take place simultaneously.
• Consolidated Bioprocessing (CBP) where all are combined
in a single reactor.
Key areas for improvement include improving understanding
of catalysts for hydrogenation. Deployment of hydrogenation
technology has been slow because of the limited interest
so far of oil companies and refineries to become involved
in biofuels production. There has also been reticence from
the sector due to potential technical risks associated with
hydrogenation catalysts degrading. However, continued
interest in vegetable oils and animal fats as feedstocks could
lead to greater deployment of hydrogenation.
Annex 3.10: Conversion Pathway of
Lignocellulosic Material into Bioethanol
The conversion of lignocellulosic materials to ethanol involves
five key processes:
1. Feedstock Production – growth and harvesting of
lignocellulosic biomass (crops/residues).
2. Pre-treatment to separate the biomass into cellulose,
hemicellulose and lignin (and partially hydrolysing the
hemicellulose).
3. Hydrolysis of the cellulose and hemicellulose to produce
sugars. This stage can be chemical, (e.g. acid hydrolysis
- a well established process) or biological (using catalytic
enzymes - cellulases, which are in development).
4. Fermentation of the sugars to produce ethanol.
5. Separation of the ethanol from co-products of
fermentation.
93
ANNEX 4: BIOMASS TRADE AND BIOENERGY MARKETS
Annex 4.1: Overview of Bioenergy Flows into Final Applications
Source: IPCC (2007)
94
ANNEX 5: BIOENERGY AND POLICY OBJECTIVES
Annex 5.1: Bioenergy, Land Use and
GHG Emissions
tilled bioenergy crop such as rapeseed on grassland is a
third example: the annual tillage of the soil could cause a
systematic decrease in the soil carbon stocks.
Direct land use emissions may result from the production of
biomass for bioenergy. These can occur from the clearing
of vegetation including forests to establish the bioenergy
crop, the application of synthetic and natural fertilisers and
the use of fossil fuels during the cultivation and harvesting
of the bioenergy crop. The emissions from the clearing of
vegetation are predominantly CO2 from the loss of biomass,
but may include CH4 and N2O emissions if the vegetation is
burnt during clearing. The use of fertilisers produces N2O
emissions.
On the other hand, bioenergy systems may also function as
carbon sinks, or conversely afforestation, reforestation and
revegetation can enhance carbon stocks in plants and soils,
while at the same time contributing to a future biomass
resource. The figure below shows two illustrative bioenergy
cases where the relative importance of fossil fuel substitution
and increases in carbon stocks differ. The diagram on the
left could represent the case where the heat and electricity
from modern biomass-fired combined heat and power plants
substitute heat from a coal-fired boiler and electricity from
a coal-fired condensing plant. The right hand diagram could
represent the case where instead the fossil alternative would
be a modern natural gas-based CHP plant. The increases in
carbon stocks could for instance result from establishment of
short rotation tree plantations on cropland historically used
for cereal production. These diagrams were produced using
the GORCAM model (see endnote in this Annex) and do not
consider possible indirect effects.
Indirect emissions come from three main sources: (i)
emissions associated with the consumption of fossil fuels
outside the project boundary during establishment and
management of the bioenergy system; (ii) emissions
associated with the production of fossil fuels, fertilisers
or other soil additives used during cultivation; and (iii)
emissions that result from the displacement of land use
activities.
It is not possible to assign a general ranking of land use
options based on their contribution to climate change
mitigation. The climate benefit of a specific option is
determined by many parameters that are site-specific
and can differ substantially depending on cultivation
practice, conversion system configuration and the energy
infrastructure context of its establishment (and the nature of
direct and possibly indirect land use change).
The first two tend to be small components of total project
emissions. The third component – emissions that result
from the displacement of the land use activities – is more
significant and both the direct and indirect emissions from
land use change are presently a major concern for scientists,
policy makers and other parties.
Land management associated with the production of biomass
may result in decreased terrestrial carbon stocks in aboveground biomass, below-ground biomass, dead wood, litter,
and soil. For example, the production of biofuels from palm
oil plantations causes large decreases in carbon stocks if
the land was deforested to enable the establishment of the
palm oil plantation. Similarly, a project that increases the
collection of dead wood in an existing forest will lead to
reduced carbon stocks if this practice depletes the carbon
pool of dead wood in the forest. The planting of an annually
Generally, the relative merits of the two principal options
bioenergy and carbon sinks are dependent on:
• Efficiency with which biomass energy can substitute for
fossil fuel energy. This efficiency is high if:
- biomass is produced and converted efficiently;
- the replaced fossil fuel would have been used with low
efficiency; and
- a carbon intensive fossil fuel is replaced.
95
As can be seen, a combination of high yielding species
and efficient use of the biomass to replace fossil fuels
makes substitution management the preferable option over
sequestration management. In the back right corner of the
diagram the benefits of substitution management exceed
those of sequestration management by almost 250 tonnes of
carbon/ha after 40 years. On the other hand, low-efficiency
biomass use, independent of growth rate, means that the land
is better used for carbon sequestration. Where biomass is used
efficiently, but growth rates are low, the relative merits of
substitution management are limited.
• Time period of consideration: the longer the timeframe
of the analysis, the more attractive biomass energy is in
comparison with carbon sequestration, because the latter is
constrained by saturation (only a limited amount of carbon
can be stored on a hectare of land), whereas bioenergy can
be produced repeatedly, from harvest cycle to harvest cycle.
• Growth rate of the site: the higher the growth rate, the
sooner the saturation constraints of carbon sequestration
will be reached.
The figure below shows the difference after 40 years between
a scenario where land is reforested with fast growing species
to produce biomass for energy (fossil fuel substitution), and
a scenario where land is reforested with the main purpose
of storing carbon (carbon sequestration). The coloured
surface (vertical axis) depicts cumulative carbon benefits of
substitution over sequestration as a function of the efficiency
of bioenergy use, and the growth rate. Positive values indicate
that management for biomass energy is the better choice.
Endnote: Material provided by IEA Bioenergy Task 38 was
one important basis for Chapter 5 as well as for this Annex.
Task 38 analyses and integrates information on bioenergy,
land use, and greenhouse gas mitigation; thereby covering all
components that constitute a biomass or bioenergy system, i.e.
from biomass production to bioenergy conversion and end-use.
More information about products and activities of Task 38 can
be found at www.ieabioenergy-task38.org.
96
ANNEX 6: MAKING POLICIES FOR BIOENERGY DEPLOYMENT
Annex 6.1: Key Characteristics of Several Biomass Sustainability Certification Initiatives
The list of initiatives and schemes described in the Table below is based on the publication by van Dam et al., (2008), updated to July 2009
for the present report. In addition, the RED and RSB schemes have been added. This list is only a selection of key initiatives.
Check list
Green Gold
Label
Type of biomass All biomass
for heat and
electricity
Status
Certification in
implementation,
also in
development
+ (included in
GGLS8)
+
Government
(BE)
All biomass
for heat and
electricity
Green
certificates
linked to
GHG / energy
criteria
+
Biodiversity
Competition
with food
+
-
-
-
+
-
+
+
Leakage
-
-
-
-
-35
-
-
+
+
+
-37
+
GHG and/or
energy balance
Electrabel
Label
All biomass
for heat and
electricity
Certification in
implementation,
also in
development
RTFO (UK)
NTA 8080
(NL)
Biomass for All biomass
biofuels
Implemented Principles
since 2008 developed,
testing phase
C&I (pilot
studies)
+
+
RSPO
RED (EU)
RSB
Palm oil
Biomass for
biofuels
Biomass for
biofuels
Principles
developed,
testing phase
C&I (pilot
studies)
+
In
Standards
development
developed;
detailed
design
through 2009.
+
+
+
-
+
-
+
+
Economic wellbeing
-36
-
-
+
Welfare / social
criteria
-
-
-
+
+
+
-
37
+
Environmental
criteria
+
+
-
+
+
+
-
37
+
Type of
system38
Track-and-trace Track-and-trace Cooperation Metastandard
Sourcing
Sourcing
with e.g.
Electrabel,
SGS
Mass balance Not yet
Track-anddetermined
trace, mass
balance or
book and claim
Organisation
Established
by company
Essent, now
open for 3rd
parties
Roundtable
with
stakeholders
in palm oil
production
Evolving
– probably
mixture of
government
and private
schemes.
Roundtable
with multistakeholder
participation
Verifier
Control Union
Stimulated by
policy
Independent
3rd party
verification
Will be
embedded
in national
policies
Not yet
determined
Relation
to national
policies
Verifier
working group
(in progress)
On voluntary
basis
Makes use
of existing
systems
Will make
Yes – metause of existing standard
systems
approach
(Plans to) make FSC, ‘Organic’
use of existing certification
systems
Track-andtrace, mass
balance or book
and claim,
currently under
consideration.
Government Administered Initiated by
Label is
by Renewable government,
provides
developed
Fuels Agency, organisational
Green
by company
structure in
a UK
Certificate
Electrabel
government process
based on
body
criteria
compliance
SGS
Independent Independent Requirements
3rd party
3rd party
not yet
verification verification determined
Required by law In regional Embedded
NTA 8080 will
policy (in
in national be coupled to
development) policy
subsidy (only)
for biomass for
heating and
electricity
Yes (e.g. FSC) See
Yes – meta- Will apply e.g.
Electrabel
standard
FSC, and GGL
approach
Not yet
determined
35 How leakage could be taken into account is currently being investigated.
36 The monitoring of living conditions in general is included.
37 The scheme only includes a reporting requirement.
38 Track-and trace implies the physical traceability of the traded biomass. Under book-and-claim, production and redemption of a certificate is separated (and the
certificates can be traded separately from the physical biomass). Similar systems exist for example for renewable electricity, where Certificates of Origin are traded.
For some of the initiatives described here, this choice has not yet been made, but the requirement to calculate GHG and energy balances makes a track-and-trace
requirement likely.
97
Annex 6.2: Key Issues in Certification
System Implementation
a risk for market power concentration. While a certification
scheme should be thorough and reliable, it should not create
a hurdle for developing industries. This can be overcome by
pairing a certification scheme with assistance and incentives,
and supporting group certification to guarantee that small
producers are not excluded. Using existing certification
systems in the development of a biomass certification system,
at least for the short-term, may also promote the involvement
of smaller stakeholders.
A sustainability scheme in bioenergy faces several
implementation issues39.
6.2.1 Criteria and indicators
Criteria and indicators have already been developed for
some principles, while others are more difficult to put into
practice. A robust strategy could be to start a system with
available indicators and develop additional ones on the way,
making use of practical experience gained in implementation.
6.2.5 Cost levels
Additional costs for certification are composed of two types:
cost related to changes in management needed to meet the
requirements, and costs related to monitoring compliance.
Usually, the first type is more substantial than the second,
but for smallholders this balance may differ.
6.2.2 Control and monitoring systems
Any successful system should be accompanied by an effective
system of accounting and sufficient mechanisms for control
and monitoring. Furthermore, such a system is complex
given the differences in production conditions over the world,
leading to different requirements for ‘sustainable’ production.
Here, experiences with other certification systems clearly
give good and bad examples. On one hand, checks such as
field visits are indispensable, but on the other, these also lead
to increased costs. Furthermore, the certifying body clearly
functions best if it is fully independent. For example, its
financial position needs to be independent of the number of
certificates issued.
6.2.6 Stakeholder involvement
6.2.3 Compliance with trade law
Certification schemes can affect international trade
and competitiveness, and are therefore subject to WTO
regulations. This particularly applies to certification
of feedstocks when applied compulsorily in the context
of governmental bioenergy policies. Trade measures
based on environmental considerations that distinguish
between identical products on the basis of their process
and production methods (PPM) may violate the WTO’s
regulations as laid down in the Technical Barriers to
Trade (TBT) Agreement. However, jurisprudence on the
exact implications of this agreement is still unclear. Two
criteria seem to come forward: a trade policy should not
systematically advantage domestic production over imports,
and measures based on environmental considerations or
conservation of exhaustible natural resources may be
allowed. Indicatively, the following can be said about the
different principles. Setting standards for greenhouse gas
emissions and other impacts on soil, water and air seem to be
feasible under WTO law. They refer to environmental issues,
and greenhouse gas emissions are one of the most important
motivations for bioenergy policy in the first place. On the
other hand, standards for economic prosperity, social welfare,
and food security are generally considered impossible under
WTO law. On the other principles, the situation is less clear
and much will depend on the specific formulation of the
policy.
Expert judgment can flag the issues, alert stakeholders to
major concerns and provide methodologies for measuring,
valuating, and monitoring the different aspects. However,
experts should not unilaterally decide which sustainability
criteria to include and how to prioritise them. To a large
extent, the judgment of local stakeholders is also crucial to
take into account the circumstances and needs in specific
situations. An adequate understanding and involvement
of primary processors and workers in the field, often the
ones controlling and monitoring the criteria, is required
for successful implementation of a biomass certification
system. Especially for developing countries, this is not easy,
as groups with relevant grassroots expertise may not be
the most influential ones, and also lack access to modern
communication channels.
6.2.7 Limitations to national legislation and
governance
Obviously, a certification system assumes producer’s
compliance with national legislation. However, in countries
with weak governmental enforcement, a certification system
may not fully rely on this legislation. Particularly in land
use planning and clarity about land owner’s rights, this may
be an issue. A certification system may create initiatives
to support national governments to improve their laws and
enforcement systems, or include additional requirements on
these issues.
Annex 6.3: Overview of
Intergovernmental Platforms for
Exchange on Renewables and Bioenergy
Several platforms exist in which policy makers can find
advice, support, and the possibility to exchange experiences
on policy making for bioenergy. The main ones are:
6.2.4 Barriers for small stakeholder entry
6.3.1 International Energy Agency (IEA)
Smallholders, often operating with limited resources
and technical skills, may lack the capacity to meet the
requirements for certification. Therefore, there is a risk that
only larger producers will apply for certification, involving
The International Energy Agency (IEA) acts as energy policy
advisor to 27 member countries in their effort to ensure
reliable, affordable and clean energy for their citizens.
Founded during the oil crisis of 1973-74, the IEA’s initial
39 Based on van Dam et al (2008).
98
Environment Agency (EEA), International Fund for
Agricultural Development (IFAD), the World Bank and
the World Business Council on Sustainable Development
(WBCSD).
role was to co-ordinate measures in times of oil supply
emergencies. As energy markets have changed, so has the
IEA. Its mandate has broadened to incorporate the ‘Three
E’s’ of balanced energy policy making: energy security,
economic development and environmental protection. Current
work focuses on climate change policies, market reform,
energy technology collaboration and outreach to the rest
of the world, especially major consumers and producers of
energy like China, India, Russia and the OPEC countries. As
an example, IEA hosts an international renewables policies
database (http://www.iea.org/textbase/pm/?mode=re).
Further info: www.globalbioenergy.org
6.3.3 Renewable Energy Network for the 21st
Century (REN21)
The Renewable Energy Network for the 21st Century
(REN21) is a global policy network that provides a forum
for international leadership on renewable energy. Its goal
is to bolster policy development for the rapid expansion of
renewable energies in developing and industrialised economies.
Open to a wide variety of dedicated stakeholders, REN21
connects governments, international institutions, nongovernmental organisations, industry associations, and other
partnerships and initiatives. Linking the energy, development,
and environment sectors, REN21 strengthens the influence of
the unique renewable energy community that came together
at the ‘Renewables 2004’ conference in Bonn. REN21 is the
network in which ideas are shared and action is encouraged to
promote renewable energy worldwide.
Associated with IEA, the IEA Bioenergy Agreement provides
an umbrella organisation and structure for a collective
effort in the field of bioenergy where national experts from
research, government and industry work together with
experts from other member countries. For policy makers and
decision makers, IEA Bioenergy provides opportunities to
gain an international perspective on progress in bioenergy; to
compile guidelines and standards; to gain new perspectives
on deployment opportunities and issues.
Geographical scope. Mainly OECD countries
Participating countries: Australia, Japan, Austria, Republic
of Korea, Belgium, Luxembourg, Canada, The Netherlands,
Czech Republic, New Zealand, Denmark, Norway, Finland,
Portugal, France, Slovak Republic, Germany, Spain, Greece,
Sweden, Hungary, Switzerland, Ireland, Turkey, Italy,
United Kingdom, United States. (Italics indicate the Member
Countries of IEA Bioenergy. Non-OECD Members who
also participate in IEA Bioenergy are Brazil, Croatia, the
European Commission, and South Africa)
Geographic Scope. Global
Participating countries: Brazil, China, Denmark, European
Community, Germany, India, Italy, Morocco, Netherlands,
South Africa, Uganda, United Arab Emirates, United
Kingdom of Great Britain and Northern Ireland, United States
of America, supported by several other research organisations,
NGO’s and intergovernmental bodies
Further info: www.ren21.net
Further info: www.iea.org; www.ieabioenergy.com
6.3.4 Renewable Energy and Energy Efficiency
Partnership (REEEP)
6.3.2 Global Bioenergy Partnership (GBEP)
The Global Bioenergy Partnership (GBEP) provides a forum
to develop effective policy frameworks to suggest rules
and tools to promote sustainable biomass and bioenergy
development, facilitate investments in bioenergy, promote
project development and implementation, and foster R&D
and commercial bioenergy activities. GBEP’s main functions
are to promote global high-level policy dialogue on bioenergy
and facilitate international cooperation, support national and
regional bioenergy policy-making and market development,
favour efficient and sustainable uses of biomass and develop
project activities in the bioenergy field, foster exchange of
information, skills and technologies through bilateral and
multilateral collaboration and facilitate bioenergy integration
into energy markets by tackling specific barriers in the
supply chain.
The mission of the Renewable Energy and Energy Efficiency
Partnership (REEEP) is to accelerate the global market for
sustainable energy by acting as an enabler, multiplier, and
catalyser of changing energy systems. The lack of long-term
and reliable policies and regulatory measures to support
renewables and energy efficiency and a corresponding lack
of finance are the principal obstacles to the development of
sustainable energy markets. The removal of market barriers
is urgently needed to achieve long-term transformation of
the energy sector, including creation of attractive investment
environments.
REEEP projects concentrate on the following themes:
• Policy and regulation: robust policies and favourable,
transparent, and stable regulatory frameworks to attract
investors and to guarantee affordable energy services to
consumers.
• Innovative finance mechanisms: new forms of financing,
risk mitigation and finance models to make small sized
renewable and energy efficient projects bankable and
economically attractive.
Geographical scope. Global
Participating countries. Brazil, Canada, China, France,
Germany, Italy, Japan, Mexico, Netherlands, Russian
Federation, Spain, Sudan, Sweden, Tanzania, United
Kingdom, United States of America, FAO, IEA, UNCTAD,
UN/DESA, UNDP, UNEP, UNIDO, UN Foundation, World
Council for Renewable Energy (WCRE) and European
Biomass Industry Association (EUBIA). Countries that
participate as observers are: Angola, Argentina, Austria,
Colombia, India, Indonesia, Israel, Kenya, Malaysia,
Morocco, Mozambique, Norway, Peru, South Africa,
Switzerland, Tunisia, European Commission, European
Geographical scope. Global
Participating countries: Australia, Spain, UK, Ireland,
Canada, EU, Germany, Austria, New Zealand, Norway, the
Netherlands, Italy
Further info: www.reeep.org
99
6.3.5 Environment and Development Network for
Africa (AFREPREN/FWD)
The key objective of the Energy, Environment and
Development Network for Africa (AFREPREN/FWD) is to
strengthen local research capacity and to harness it in the
service of energy policy making and planning. Initiated in
1987, AFREPREN/FWD is a collective regional response to
the widespread concern over the weak link between energy
research and the formulation and implementation of energy
policy in Africa. AFREPREN/FWD, brings together over 300
African energy researchers and policy makers from Africa
who have a long-term interest in energy research and the
attendant policy-making process.
Geographical scope. Africa
Participating countries: AFREPREN/FWD has initiated
policy research studies in 19 African countries namely:
Angola, Botswana, Burundi, Eritrea, Ethiopia, Kenya,
Lesotho, Malawi, Mauritius, Mozambique, Rwanda,
Seychelles, Somalia, South Africa, Sudan, Tanzania,
Uganda, Zambia and Zimbabwe. AFREPREN/FWD also
maintains close collaborative links with energy researchers
and policy makers from Côte d'Ivoire, Ghana, Nigeria, Sierra
Leone, and Senegal.
Further info: www.afrepren.org
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ANNEX 7: GLOSSARY OF TERMS AND ACRONYMS
ABREVIATIONS
DESCRIPTION
1st generation biofuels
1st generation biofuels include mature technologies for the production of bioethanol from sugar
and starch crops, biodiesel and renewable diesel from oil crops and animal fats, and biomethane
from the anaerobic digestion of wet biomass.
2nd generation biofuels
2nd generation biofuels are novel biofuels or biofuels based on novel feedstocks. They generally
use biochemical and thermochemical routes that are at the demonstration stage, and convert
lignocellulosic biomass (i.e. fibrous biomass such as straw, wood, and grass) to biofuels (e.g.
ethanol, butanol, syndiesel).
3rd generation biofuels
3rd generation biofuels generally include advanced biofuels production routes which are at the
early stage of research and development or are significantly further from commercialisation
(e.g. biofuels from algae, hydrogen from biomass).
Agricultural residues
Agricultural residues include arable crop residues (such as straw, stem, stalk, leaves, husk, shell,
peel, etc.), forest litter, grass and animal manures, slurries and bedding (e.g. poultry litter).
Anaerobic digestion
Decomposition of biological wastes by micro-organisms, usually under wet conditions, in the
absence of air (oxygen), to produce biogas.
Animal residues
Agricultural by-products originating from livestock operations. It includes among others solid
excreta of animals.
Ash
Residue obtained from the combustion of a fuel.
Bagasse
Fibre left over after the juice has been squeezed out of sugar-cane stalks. It is commonly used
as a source of heat supply in the production of bioethanol.
Bark
The outermost sheath of tree trunks, branches, and roots of woody plants. It overlays the
wood and consists of inner bark (living tissue) and outer bark (dead tissue). Bark is usually a
by-product (residue) from conventional wood processing.
BIG/CC
Biomass integrated gasification and combined cycle.
Biobutanol
Alcohol with a 4 carbon structure and the molecular formula C4H9OH produced from biomass.
Biobutanol can easily be added to conventional petrol and can be blended up to higher
concentrations than bioethanol for use in standard vehicle engines. Biobutanol can also be used as a
blended additive to diesel fuel to reduce soot emissions.
Biodiesel
Biodiesel refers to a diesel-type fuel produced by transesterification of vegetable oils or animal fats.
Biodiesel can be blended (with some restrictions on the level of blending) with conventional diesel for
use in unmodified diesel-engine vehicles. Its full name is FAME (Fatty Acid Methyl Ester) biodiesel.
Bioenergy
Renewable energy produced from the conversion of organic matter. Organic matter may either be
used directly as a fuel or processed into liquids and gases.
Bioethanol
Alcohol with a 2 carbon structure and the molecular formula C2H5OH, produced from biomass.
Bioethanol can be blended with conventional gasoline or diesel for use in petroleum-engine vehicles.
Biofuel
Fuel produced directly or indirectly from biomass. The term biofuel applies to any solid, liquid,
or gaseous fuel produced from organic (once-living) matter. The word biofuel covers a wide range
of products, some of which are commercially available today, and some of which are still in the
research and development phase.
Biogas
A combustible gas derived from decomposing biological waste under anaerobic conditions. Biogas
normally consists of 50-60% methane, 25-50% carbon dioxide, and other possible elements such as
nitrogen, hydrogen or oxygen. See also Landfill Gas.
Biomass
Organic matter available on a renewable basis. Biomass includes forest and mill residues,
agricultural crops and wastes, wood and wood wastes, animal wastes, livestock operation residues,
aquatic plants, fast-growing trees and plants, and municipal and industrial wastes.
Biomass energy
See Bioenergy above.
Biomass feed system
Electromechanical system (e.g. conveyors, pumps) to feed the biomass feedstock into the boiler of a
biomass-based plant.
Biomethanol
Simplest possible alcohol with the molecular formula CH3OH. Biomethanol can be blended into
gasoline, but the substance is more volatile than bioethanol.
Bioreactor
A bioreactor is a vessel in which a biochemical process occurs. This usually involves organisms or
biochemically active substances derived from such organisms.
101
ABREVIATIONS
DESCRIPTION
Biochar
Biochar is charcoal created by pyrolysis of biomass.
Bio-SNG
Bio Synthetic Natural Gas is syngas (produced from gasification of biomass) that has been upgraded
to meet the quality standard of natural gas. Bio-SNG is often called simply SNG.
Black liquor
Black liquor is a by-product of the kraft process during the production of paper pulp. It is an
aqueous solution of lignin residues, hemicelluloses, and the inorganic chemicals used in the process.
Briquette
Densified solid biofuel in the shape of cubiform or cylindrical units, produced by compressing
biomass. The raw material for briquettes can be biomass of various origins (e.g. woody, herbaceous,
fruit). Biofuel briquettes are usually manufactured in a piston press. The total moisture content of
the biofuel briquette is usually less than 15 % of mass.
BTL
Biomass-to-liquid is a (multi-step) process to produce liquid biofuels from biomass. The first step is
gasification, while the second step may, for example, be Fischer Tropsch.
Bulk density
Mass of a portion of a solid fuel divided by the volume of the container which is filled by that
portion under specific conditions.
By-product
A by-product, or co-product, is a substance, other than the principal product, generated as a
consequence of producing the main product. For example, a by-product of biodiesel production
is glycerine. Every bioenergy conversion chain generates co-products. These may add substantial
economic value to the overall process. Examples include animal feed, food additives, specialty
chemicals, charcoal, and fertilisers.
Calorific Value (Q)
Amount of heat released during the complete combustion of a given amount of a combustible.
Capacity
The maximum power that a machine or system can produce or carry safely. The maximum
instantaneous output of a resource under specified conditions. The capacity of energy generating
equipment is generally expressed in kilowatts (for devices) or megawatts (for plants).
Capital cost
The total investment needed to complete a project and bring it to a commercially operable status.
The cost of construction of a new plant. The expenditures for the purchase or acquisition of
existing facilities.
Catalyst
A catalyst is a substance that increases the rate of a chemical reaction, without being consumed or
produced by the reaction. Enzymes are catalysts for many biochemical reactions.
Cellulose
Polysaccharide (long chain of simple sugar molecules) with the formula (C6H10O5)n. Cellulose is the
fibrous substance which is contained in leaves, stems, and stalks of plants and trees. It is the most
abundant organic compound on earth and can be used to produce biofuels.
Cellulosic ethanol
Cellulosic ethanol is ethanol fuel produced from lignocellulosic material such as wood. Cellulosic
ethanol is chemically identical to ethanol from other sources, such as corn or sugar, and is available
in a great diversity of biomass including waste from urban, agricultural, and forestry sources.
Char
The remains of solid biomass that has been incompletely combusted, such as charcoal resulting from
wood that is incompletely burned.
Charcoal
Solid residue derived from carbonisation distillation, pyrolysis, and torrefaction of fuelwood.
Chips
Woody material cut into short, thin wafers. Chips are used as a raw material for pulping and
fibreboard or as biomass fuel.
Circulating fluidised bed
(CFB)
A type of furnace in which the emission of sulphur compounds is lowered by the addition of crushed
limestone in the fluidised bed thus obviating the need for much of the expensive stack gas clean-up
equipment. The particles are collected and recirculated, after passing through a conventional bed,
and cooled by boiler internals.
CHP
Combined Heat and Power. See cogeneration below.
CO2
Carbon dioxide.
Cogeneration
The simultaneous production of electricity and useful thermal energy from a common fuel source.
Surplus heat from an electric generating plant can be used for industrial processes, or space and
water heating purposes (topping cycle).
Combined cycle
Two or more energy generation processes in series or in parallel, configured to optimise the energy
output of the system.
Combined Heat and
Power (CHP)
See Cogeneration above.
Combined Cycle Power
Plant
The combination of a Brayton-Joule Cycle (gas turbine) and a Rankine Cycle (steam turbine) in an
electric generation plant. The waste heat from the gas turbine provides the heat energy required for
the steam cycle. This is also called combined cycle gas turbine.
Combustion (of biomass)
The transformation of biomass fuel into heat, chemicals, and gases through chemical combination of
hydrogen and carbon in the fuel with oxygen.
102
ABREVIATIONS
DESCRIPTION
Compressed Natural Gas
(CNG)
CNG is made by compressing natural gas to less than 1% of its volume at standard atmospheric
pressure. It is used in traditional gasoline internal combustion engine cars that have been converted
into bi-fuel vehicles (gasoline/CNG).
Co-product
See By-product.
Density
Ratio of mass to volume. It must always be stated whether the density refers to the density of
individual particles or to the bulk density of the material and whether the mass of water in the
material is included.
Dimethyl ether (DME)
Liquid biofuel with the molecular formula CH3OCH3. DME is produced by the dehydration of
methanol and can be used as a fuel in diesel engines, petrol engines, and gas turbines. It works
particularly well in diesel engines due to its high cetane number.
District heating
District heating is a system for distributing heat generated in a centralised location for residential
and commercial heating requirements, such as space and water heating.
Digester
An airtight vessel or enclosure in which bacteria decompose biomass in wet conditions to
produce biogas.
Discount rate
A rate used to convert future costs or benefits to their present value.
Dry basis
Condition in which the solid biofuel is free from moisture.
Dry matter
Material after removal of moisture under specific conditions.
Dry matter content
Fraction of dry matter in the total material on mass basis.
E85
Mix of 85% ethanol and 15% petrol. E85 is a common bioethanol blend used in flex-fuel vehicles.
Other blends exist such as E5 and E100. The number always refers to the percentage of ethanol
blended in the petrol.
EC
European Commission.
Effluent
The liquid or gas discharged from a process or chemical reactor, usually containing residues from
that process.
EJ
Exajoules (1EJ = 1018J). See also Joule.
Emissions
Waste substances released into the air or water. See also Effluent.
Energy crops
Crops grown specifically for their fuel value. These include food crops such as corn and sugar-cane,
and non-food crops such as poplar trees and switchgrass.
Energy density
Ratio of net energy content and bulk volume.
Engine
A device that converts the energy of a fuel into mechanical power. The combination of an engine and
an alternator converts heat from combustion (e.g. of biomass) into power.
Enzyme
A protein or protein-based molecule that speeds up chemical reactions occurring in living things.
Enzymes act as catalysts for a single reaction, converting a specific set of reactants into specific
products.
EtOH
See Bioethanol.
Ethyl-tertio-butyl-ether
(ETBE)
Organic compound with the formula C6H14O. ETBE is commonly used as an oxygenate gasoline
additive in the production of gasoline from crude oil.
EU
European Union.
Externality
A cost or benefit not accounted for in the price of goods or services. Often ‘externality’ refers to the
cost of pollution and other environmental impacts.
FAME Biodiesel
Fatty Acid Methyl Ester Biodiesel. See Biodiesel.
Feed System
See Biomass Feed System.
Feed-in tariff
Subsidy mechanism by which the regional or national electricity companies are obligated to buy the
electricity generated from renewable resources by decentralised producers at fixed prices (the feed-in
tariffs) set by the government, The higher price helps overcome the cost disadvantages of renewable
energy sources.
Feedstock
A feedstock is any biomass resource destined for conversion to energy or biofuel. For example, corn
is a feedstock for ethanol production, soybean oil may be a feedstock for biodiesel and cellulosic
biomass has the potential to be a significant feedstock source for biofuels.
Fermentation
Conversion of carbon-containing compounds by micro-organisms for production of fuels and
chemicals such as alcohols, acids or energy-rich gases. It is a biochemical reaction that breaks down
complex organic molecules (such as carbohydrates) into simpler materials (such as ethanol, carbon
dioxide, and water). Bacteria or yeasts can ferment sugars to bioethanol.
103
ABREVIATIONS
DESCRIPTION
Firewood
Cut and split oven-ready fuelwood used in household wood burning appliances such as stoves,
fireplaces and central heating systems. Firewood usually has a uniform length, typically in the range
150 mm to 500 mm.
Fischer Tropsch (FT)
Process
Catalysed chemical reaction in which syngas from gasification is converted into a liquid biofuel of
various kinds.
Flex-fuel vehicle (FFV)
Vehicles that can use either biofuels and/or petroleum interchangeably.
Fluidised-bed
combustion (FBC)
Fluidised-bed combustion is a technology that improves the chemical reactions and heat transfer of
boilers in power plants, and hence its overall efficiency, as compared to traditional fixed-beds. FBC
plants are more flexible than conventional plants because they can be fired on coal and biomass,
among other fuels. FBC also reduces the amount of sulphur emitted in the form of SOX emissions.
Fly ash
Small ash particles carried in suspension in combustion products.
Forest residues
Material not harvested or removed from logging sites in commercial hardwood and softwood stands
as well as material resulting from forest management operations such as pre-commercial thinnings
and removal of dead and dying trees.
Fossil fuel
Solid, liquid, or gaseous fuels formed in the ground after millions of years by chemical and physical
changes in plant and animal residues under high temperature and pressure. Oil, natural gas, and
coal are fossil fuels.
Fuel cell
A device that converts the energy of a fuel directly to electricity and heat, without combustion.
Fuel gas
See Producer Gas.
Fuel handling system
A system for unloading biomass feedstock from vans or trucks, transporting the feedstock to
a storage location (e.g., pile, silo), and conveying it from storage to the boiler or other energy
conversion equipment.
Fuelwood
Wood fuel where the original composition of the wood is preserved.
Furnace
An enclosed chamber or container used to burn biomass in a controlled manner to produce heat for
space or process heating.
Gas turbine
A turbine that converts the energy of hot compressed gases (produced by burning fuel in compressed
air) into mechanical power. Often fired by natural gas or fuel oil.
Gasification
A thermochemical process at elevated temperature and reducing conditions to convert a solid fuel to
a gaseous form (CO, H2, CH4, etc.), with char, water, and condensibles as minor products.
Gasifier
A device for converting solid fuel into gaseous fuel.
Gha
Gigahectares (1Gha = 109ha).
GHG
Greenhouse gas. Gases that trap the heat of the sun in the Earth's atmosphere, producing the
greenhouse effect. The two major greenhouse gases are water vapour and carbon dioxide. Other
greenhouse gases include methane, ozone, chlorofluorocarbons, and nitrous oxide.
GIS
Geographic Information System. An information system for capturing, storing, analysing, managing,
and presenting data which are spatially referenced (linked to location).
GJ
Gigajoule (1GJ = 109J).
GJe
Gigajoule electrical.
GJth
Gigajoule thermal.
GMO
Genetically Modified Organism.
Green diesel
See Syndiesel.
Greenhouse effect
The effect of certain gases in the Earth's atmosphere in trapping heat from the sun.
Grid
An electric utility company's system for distributing power.
GW
Gigawatt. A measure of electrical power equal to one billion watts (1,000,000 kW). A large coal or
nuclear power station typically has a capacity of about 1 GW.
Heating value
Amount of heat released during the complete combustion of a given amount of a combustible. See
Higher Heating Value and Lower Heating Value for more details.
Hectare (Ha)
Common metric unit of area, equal to 2.47 acres. 1 hectare equals 10,000 square meters. 100
hectares = 1 square kilometre. Abbreviated as ha.
Herbaceous biomass
Biomass from plants that has a non-woody stem and which dies back at the end of the growing season.
Higher heating value
(HHV)
Amount of heat released during the complete combustion of a given amount of a combustible
(initially at 25°C) and the cooling of the combustion products back to 25°C. Thus, the HHV includes
the latent heat of vaporisation of the water contained in the combustion products.
104
ABREVIATIONS
DESCRIPTION
Hydrocarbon
Any chemical compound containing hydrogen, oxygen, and carbon.
Hydrogen
Simplest molecule conceivable, with a molecular formula of H2. Gaseous fuel that can be produced
from fossil fuels, biomass and electricity.
Hydrogenation
Process which typically constitutes the addition of pairs of hydrogen atoms to a molecule. Biodiesel
manufactured from the hydrogenation of vegetable oil and animal fat can be blended in any
proportion with petroleum-based diesel.
Hydrolysis
Hydrolysis is a chemical reaction that releases sugars, which are normally linked together in
complex chains. In bioethanol production, hydrolysis reactions are used to break down the cellulose
and hemicellulose in the biomass.
Hydrotreated Biodiesel
See Renewable Diesel.
IEA
International Energy Agency.
Incinerator
Any device used to burn solid or liquid residues or wastes as a method of disposal. In some
incinerators, provisions are made for recovering the heat produced.
Indirect liquefaction
Conversion of biomass to a liquid fuel through a synthesis gas intermediate step.
IPCC
Intergovernmental Panel on Climate Change.
Jatropha
Jatropha curcas is a non-edible evergreen shrub found in Asia, Africa and the West Indies. Its seeds
contain a high proportion of oil which can be used for making biodiesel.
Joule
Metric unit of energy, equivalent to the work done by a force of one Newton applied over a distance
of one metre (= 1 kg.m2/s2). One joule (J) = 0.239 calories (1 calorie = 4.187 J).
kW
Kilowatt. A measure of electrical power equal to 1,000 watts. 1 kW = 3.413 Btu/hr = 1.341
horsepower. See also Watt.
kWh
Kilowatt hour. A measure of energy equivalent to the expenditure of one kilowatt for one hour. For
example, 1 kWh will light a 100-watt light bulb for 10 hours. 1 kWh = 3.413 Btu.
kWe
Kilowatt electrical. See also kW.
kWth
Kilowatt thermal. See also kW.
Kyoto Protocol
UN-led international agreement aimed at reducing GHG emissions.
Landfill gas
Biogas generated by decomposition of organic material at landfill disposal sites. Landfill gas is
approximately 50% methane. See also Biogas.
Lifecycle Assessment
(LCA)
Investigation and valuation of the environmental impacts of a given product or service caused or
necessitated by its existence. The term 'lifecycle' refers to the notion that a fair, holistic assessment
requires the assessment of raw material production, manufacture, distribution, use and disposal
including all intervening transportation steps necessary or caused by the product's existence.
Lower Heating Value
(LHV)
Amount of heat released during the complete combustion of a given amount of a combustible
(initially at 25°C) and the cooling of the combustion products down to 150°C. Thus, the LHV
excludes the latent heat of vaporisation of the water contained in the combustion products.
Lignin
Structural constituent of wood and (to a lesser extent) other plant tissues, which encrusts the cell
walls and cements the cells together.
LNG
Liquefied natural gas.
Log wood
Cut fuelwood, with most of the material having a length of 500 mm and more.
LPG
Liquefied Petroleum Gas.
MeOH
See Biomethanol.
Methane
Methane is a combustible chemical compound with the molecular formula CH4. It is the principal
component of natural gas.
Miscanthus
Miscanthus or elephant grass, is a genus of about 15 species of perennial grasses native to
subtropical and tropical regions of Africa and southern Asia. The rapid growth, low mineral content
and high biomass yield of Miscanthus makes it a favoured choice as a bioethanol feedstock.
MJ
Megajoule (1MJ = 106J). See also Joule.
Moisture content
The quantity of water contained in a material (e.g. wood) on a volumetric or mass basis.
Monoculture
The cultivation of a single species crop.
MSW
Municipal Solid Waste.
MTBE
Methyl tert-butyl ether. MTBE is used as an oxygenate additive to raise the octane number of
gasoline.
105
ABREVIATIONS
DESCRIPTION
MW
Megawatt. A measure of electrical power equal to one million watts (1,000 kW). See also Watt.
MWe
Megawatt electrical.
MWth
Megawatt thermal.
N2
Nitrogen.
N2O
Nitrous oxide or laughing gas. Powerful greenhouse gas that can be emitted from soils with
intensive (nitrogen) fertilisation.
Nitrogen Oxides (NOx)
Nitrogen oxides are a product of photochemical reactions of nitric oxide in ambient air, and are one
type of emission produced from fuel combustion.
O2
Oxygen.
Octane number
Measure of the resistance of gasoline and other fuels to detonation (engine knocking) in sparkignition internal combustion engines. The octane rating of a fuel is indicated on the pump. The
higher the number, the slower the fuel burns. Bioethanol typically adds two to three octane numbers
when blended with ordinary petroleum, making it a cost-effective octane-enhancer.
Organic compounds
Chemical compounds based on carbon chains or rings and also containing hydrogen, with or without
oxygen, nitrogen, and other elements.
Organic matter
Matter that comes from a once-living organism.
Organic Rankine Cycle
(ORC)
A Rankine Cycle is a closed circuit steam cycle to convert heat into mechanical energy in an engine.
An organic Rankine Cycle uses an organic fluid with a high molecular mass instead of steam,
allowing heat recovery from low temperature sources such as industrial waste heat, geothermal
heat, solar ponds, etc.
Particulate
A small, discrete mass of solid or liquid matter that remains individually dispersed in gas or liquid
emissions. Particulates take the form of aerosol, dust, fume, mist, smoke, or spray. Each of these
forms has different properties.
Pellet
Densified biofuel made from pulverised biomass with or without pressing aids usually with a
cylindrical form, random length typically 5 to 30 mm, and broken ends. The raw material for
biofuel pellets can be woody biomass, herbaceous biomass, fruit biomass, or biomass blends and
mixtures. They are usually manufactured using a die. The total moisture content of biofuel pellets is
usually less than 10% of mass.
Photosynthesis
Process by which chlorophyll-containing cells in green plants convert incident light to chemical
energy, capturing carbon dioxide in the form of carbohydrates.
Pilot scale
The size of a system between the small laboratory model size (bench scale) and a full-size system.
Process heat
Heat used in an industrial process rather than for space heating or other housekeeping purposes.
Producer gas
The mixture of gases produced by the gasification of organic material such as biomass at relatively
low temperatures (700-1000°C). Producer gas is composed of carbon monoxide (CO), hydrogen
(H), carbon dioxide (CO2), Nitrogen (N2) and typically a range of hydrocarbons such as methane
(CH4). Producer gas can be burned as a fuel gas in a boiler for heat or in an internal combustion
gas engine for electricity generation or combined heat and power (CHP). It can also be upgraded to
Syngas for the production of biofuels.
Pyrolysis
The thermal decomposition of biomass at high temperatures (greater than 400°F, or 200°C) in
the absence of air. The end product of pyrolysis is a mixture of solids (char), liquids (oxygenated
oils), and gases (methane, carbon monoxide and carbon dioxide) with proportions determined by
operating temperature, pressure, oxygen content, and other conditions.
Renewable diesel
Hydrotreated biodiesel produced by the hydrogenation of vegetable oils or animal fats. Its fuel
characteristics are similar to fossil diesel.
Reforming
Chemical process used in the petrochemical industry to improve the octane rating of hydrocarbons,
but is also a useful source of other chemical compounds such as aromatic compounds and hydrogen.
Steam reforming of natural gas or syngas sometimes referred to as steam methane reforming
(SMR) is the most common method of producing commercial bulk hydrogen. At high temperatures
(700 – 1100°C) and in the presence of a metal-based catalyst (nickel), steam reacts with methane
to yield carbon monoxide and hydrogen. CH4 + H2O CO + 3 H2 Additional hydrogen can be
recovered by a lower-temperature gas-shift reaction with the carbon monoxide produced.
CO + H2O CO2 + H2.
Refuse-derived fuel
(RDF)
Fuel prepared from municipal solid waste. Non-combustible materials such as rocks, glass, and
metals are removed, and the remaining combustible portion of the solid waste is chopped or
shredded. RDF facilities process typically between 100 and 3,000 tonnes of MSW per day.
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ABREVIATIONS
DESCRIPTION
Residues
By-product of agricultural cultivation (e.g. bagasse), farming activities (e.g. manure) or forestry
industry (tree thinnings).
RME
Rape methyl ester. Esterified rape-oil commonly used as biodiesel.
Sawdust
Fine particles created when sawing wood.
Short rotation crop
Woody biomass grown as a raw material and/or for its fuel value in short rotation forestry.
Sludge
Sludge is formed in the aeration basin during biological waste water treatment or biological
treatment process and separated by sedimentation. Sludges can be converted into biogas via
anaerobic digestion.
SNG
Synthetic natural gas. Gas mixture that contains varying amounts of carbon monoxide and hydrogen
generated by the gasification of a carbon-containing fuel to a gaseous product with a heating value.
Solid biofuel
Solid fuels (e.g. pellets, wood charcoal) produced directly or indirectly from biomass.
Steam turbine
A device for converting energy of high-pressure steam (produced in a boiler) into mechanical power
which can then be used to generate electricity.
Stirling engine
Closed-cycle regenerative heat engine with a gaseous working fluid. The working fluid, the gas which
pushes on the piston, is permanently contained within the engine's system.
Switchgrass
Perennial energy crop. Switchgrass is native to the USA and known for its hardiness and rapid
growth. It is often cited as a potentially abundant 2nd generation feedstock for ethanol.
Syndiesel
Synthetic diesel produced through Fischer Tropsch synthesis from lignocellulosic biomass (e.g.,
wood). Its fuel characteristics are similar to fossil diesel.
Syngas
Syngas (from the contraction of synthesis gas) is a mixture of mainly carbon monoxide (CO) and
hydrogen (H2), which is the product of high temperature steam or oxygen gasification of organic
material such as biomass. Following clean-up to remove any impurities such as tars, syngas can be
used to produce organic molecules such as synthetic natural gas (mainly CH4) or liquid biofuels such
as synthetic diesel (via Fischer Tropsch synthesis).
Synthesis gas
See Syngas.
Synthetic Diesel
See Syndiesel.
Torrefaction
Mild pre-treatment of biomass at a temperature between 200-300°C. During torrefaction of the
biomass, its properties are changed to obtain a better fuel quality for combustion and gasification
applications.
Transesterification
Process of exchanging the alkoxy group of an ester compound with another alcohol. Biodiesel
is typically manufactured from vegetable oils or animal fats by catalytically reacting these with
methanol or ethanol via transesterification.
Tri-generation
Tri-generation is the simultaneous production of mechanical power (often converted to electricity),
heat and cooling from a single heat source such as fuel.
Turbine
A machine for converting the heat energy in steam or high temperature gas into mechanical energy.
In a turbine, a high velocity flow of steam or gas passes through successive rows of radial blades
fastened to a central shaft.
VOC
Volatile organic compounds are air pollutants found, for example, in engine exhaust.
Watt
The common base unit of power in the metric system. One watt equals one joule per second, or the
power developed in a circuit by a current of one ampere flowing through a potential difference of
one volt. 1 Watt = 3.413 Btu/hr. See also Kilowatt.
Wood chips
Chipped woody biomass in the form of pieces with a defined particle size produced by mechanical
treatment with sharp tools such as knives. Wood chips have a sub-rectangular shape with a typical
length 5-50 mm and a low thickness compared to other dimensions.
Wood fuel
All types of biofuels derived directly or indirectly from trees and shrubs grown on forest and nonforest lands, from silvicultural activities (thinning, pruning, etc.), and from industrial activities
(harvesting, logging or primary and secondary forest industries).
Woody biomass
Biomass from trees, bushes and shrubs.
Yeast
Yeast is any of various single-cell fungi capable of fermenting carbohydrates. Bioethanol is produced
by fermenting sugars with yeast.
107
IEA Bioenergy
108
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