Micro-Hydropower Systems - A Buyer`s Guide
Micro-
Hydropower
Systems
A Buyer’s Guide
ACKNOWLEDGMENTS
Text prepared by the Hydraulic Energy Program, Renewable
Energy Technology Program, CANMET Energy Technology Centre
(CETC) in cooperation with the Renewable and Electrical Energy
Division (REED), Electricity Resources Branch, Natural Resources
Canada (NRCan). Review and input from NRCan’s Office of
Energy Efficiency, Energy Systems & Design Inc., Homestead
Hydro Systems, Morehead Valley Hydro Inc., Thompson and
Howe Energy Systems Inc., Josée Bonhomme, Robert Clark,
Scott Davis and Stephen Graham.
Micro-Hydropower Systems: A Buyer’s Guide
This guide is distributed for information purposes only and does not necessarily
reflect the views of the Government of Canada or constitute an endorsement of
any commercial product or person. Neither Canada nor its ministers, officers,
employees or agents make any warranty with respect to this guide or assumes
any liability arising from this guide.
© Her Majesty the Queen in Right of Canada, 2004
Cat. No. M144-29/2004E
ISBN 0-662-35880-5
Aussi disponible en français sous le titre :
Microsystèmes hydroélectriques : Guide de l’acheteur
CONTENTS
About This Guide
1.0
What Is Micro-Hydropower?
1.1
1.2
1.3
2.0
4.0
7.0
8.0
26
Battery-Based Systems ........................................................................................................................................ 26
AC-Direct Systems ................................................................................................................................................ 28
Grid-Connected Systems ................................................................................................................................ 30
31
Initial Costs .............................................................................................................................................................. 31
Annual Costs ............................................................................................................................................................ 32
Evaluating a System ............................................................................................................................................ 32
...........................................................................................................................................................................
.......................................................................................
34
Expert Assistance .................................................................................................................................................. 34
Selecting a Supplier ............................................................................................................................................ 34
Safety and Protection ........................................................................................................................................ 34
Installing, Operating and Maintaining a System
7.1
7.2
7.3
........................................
...............................................................................................................................................
Buying a Micro-Hydropower System
6.1
6.2
6.3
7
17
Civil Works Components ................................................................................................................................ 17
Powerhouse Components .............................................................................................................................. 20
Drive Systems .......................................................................................................................................................... 23
Electronic Load Controllers .......................................................................................................................... 24
Transmission/Distribution Network ........................................................................................................ 25
Economics
5.1
5.2
5.3
6.0
...........................................................................................................................
How to Measure Potential Power and Energy .................................................................................... 7
How Small a System? .......................................................................................................................................... 10
Assessing Power and Energy Requirements ...................................................................................... 10
Managing Energy Demand ............................................................................................................................ 12
Feasibility Study .................................................................................................................................................... 13
Sizing the System .................................................................................................................................................. 14
Environmental Issues and Approvals .................................................................................................... 15
Choosing a System
4.1
4.2
4.3
5.0
....................................................................................................................
Basic Components of a Micro-Hydropower System
3.1
3.2
3.3
3.4
3.5
2
3
Why Micro-Hydropower? .................................................................................................................................. 4
How to Identify a Potential Site .................................................................................................................. 5
Is Micro-Hydropower for You? ...................................................................................................................... 5
How to Plan for a System
2.1
2.2
2.3
2.4
2.5
2.6
2.7
3.0
..........................................................................................................................................................................
36
Construction and Installation .................................................................................................................... 36
Commissioning and Testing ........................................................................................................................ 36
Operation and Maintenance ........................................................................................................................ 37
Further Information
..............................................
38
Appendix A Determining Head and Flow Rate ............................................................................................ 39
Appendix B Sample Data Sheet ................................................................................................................................ 44
Appendix C Typical Household Appliance Loads ........................................................................................ 45
Appendix D Costing Estimate Worksheet ........................................................................................................ 47
Glossary of Terms and Abbreviations ...................................................................................................................... 48
Bibliography .............................................................................................................................................................................. 50
Useful Web Sites ...................................................................................................................................................................... 51
Reader Survey ............................................................................................................................................................................ 53
...........................................................................................................................................
1
MICRO-HYDROPOWER ENERGY SYSTEMS
ABOUT THIS GUIDE
Micro-hydropower systems are receiving increasing interest from homeowners and others
who have property that is not served by the electrical grid. This buyer’s guide will help you
decide if micro-hydropower is a viable option for you. It will:
• introduce you to the basics of how a micro-hydropower system works
• offer pointers on how to assess how much energy and power you need
• introduce you to the principal components of a micro-hydropower system
• outline how to determine if a micro-hydropower system makes economic sense
for your circumstances
• offer some practical examples of micro-hydropower systems
This guide is not an instruction manual on how to install a micro-hydropower system;
it may not provide complete information on whether a micro-hydropower system is right
for your circumstances. Rather, it is a helpful introduction when considering micro-hydro
systems for remote off-grid residential homes, cottages, ranches, lodges, camps, parks, small
communities and First Nations communities that are not connected to an electrical grid.
Micro-hydropower systems can be complicated, are site-specific, require expertise to set
up and need some degree of maintenance. You will need a qualified person to determine
the feasibility of the system and its design and set-up. Before your final decision, consult
government agencies and your local utility to ensure that your proposed installation meets
required electrical codes, building regulations and site regulations.
2
A BUYER’S GUIDE
1.0 What Is Micro-Hydropower?
Flowing and falling water have potential energy.
Hydropower comes from converting energy in
flowing water by means of a water wheel or through
a turbine into useful mechanical power. This power
is converted into electricity using an electric generator or is used directly to run milling machines.
Most people in North America understand hydropower as involving big dams and large-scale
generating facilities. Small-scale hydropower
systems, however, are receiving a great deal of
public interest as a promising, renewable source
of electrical power for homes, parks and remote
communities.
Hydropower technology has been with us for more
than a century. Many early mills, mines and towns
in Canada built some form of power generation
from small hydropower systems in the late 19th
and early 20th centuries.
Micro-hydropower systems are relatively small
power sources that are appropriate in most cases
for individual users or groups of users who are
independent of the electricity supply grid. Hydropower systems are classified as large, medium, small,
mini and micro according to their installed power
generation capacity. Electrical power is measured
in watts (W), kilowatts (kW) or megawatts (MW).
A micro-hydropower system is generally classified
as having a generating capacity of less than 100 kW.
Systems that have an installation capacity of
between 100 kW and 1000 kW (1.0 MW) are
referred to as mini-hydro. Small hydro is defined
as having a capacity of more than 1.0 MW and up
to 10 MW, although in Canada small-hydro can
be defined by provincial and territorial utilities as
having a capacity of less than 30 MW or 50 MW.
Micro-hydro systems have the following components:
• a water turbine that converts the energy of flowing
or falling water into mechanical energy that drives
a generator, which generates electrical power – this
is the heart of a micro-hydropower system
• a control mechanism to provide stable electrical
power
• electrical transmission lines to deliver the power
to its destination
Depending on the site, the following may be
needed to develop a micro-hydropower system
(see Figure 2):
• an intake or weir to divert stream flow from
the water course
• a canal/pipeline to carry the water flow to the
forebay from the intake
• a forebay tank and trash rack to filter debris and
prevent it from being drawn into the turbine at
the penstock pipe intake
• a penstock pipe to convey the water to the
powerhouse
• a powerhouse, in which the turbine and
generator convert the power of the water into
electricity
Figure 1. A waterwheel in action
• a tailrace through which the water is released
back to the river or stream
3
MICRO-HYDROPOWER ENERGY SYSTEMS
LEGEND
A – Intake/weir
B – Canal/pipeline
C – Forebay tank
D – Penstock pipe
E – Powerhouse
F – Tailrace
G – Transmission
line
A
B
C
D
G
E
F
Figure 2. Principal components of a micro-hydropower system
Many micro-hydropower systems operate “run of
river,” which means that neither a large dam or
water storage reservoir is built nor is land flooded.
Only a fraction of the available stream flow at a
given time is used to generate power, and this has
little environmental impact. The amount of energy
that can be captured depends on the amount of
water flowing per second (the flow rate) and the
height from which the water falls (the head).
1.1 Why Micro-Hydropower?
Depending on individual circumstances, many
people find that they need to develop their own
source of electrical power. Canada has thousands
of rivers, streams and springs that could be used to
generate electricity to meet the energy requirements
for off-grid rural residents, cottage owners, small
communities, camp sites, parks and remote lodges.
Other renewable energy sources, such as solar and
wind, can be used to produce electrical power. The
choice of energy source depends on several factors,
including availability, economics and energy and
power requirements. Micro-hydropower systems
offer a stable, inflation-proof, economical and
renewable source of electricity that uses proven
and available technologies. These technologies
4
can produce as little as 100 W of electricity at
low cost and at very competitive rates, and appropriately designed and implemented systems can
provide inexpensive energy for many years.
Without hydropower and other renewable energy
sources, fossil fuel alone would have to meet our
electricity needs. Diesel and gasoline generators are
currently cheaper to buy, but the increasing cost of
fuel oil and maintenance has made them expensive
to operate. There is also the effect of their long-term
environmental impact. Small and micro-hydropower
installations have, historically, been cheap to run
but expensive to build. This is now changing, with
smaller, lighter and more efficient higher-speed
turbine equipment, the lower cost of electronic
speed- and load-control systems, and inexpensive
plastic penstock pipes. Capital investments of
hydropower systems are still higher than investing
in diesel equipment of comparable capacity, but
their long life, low operating costs and emerging
renewable energy incentives make such systems an
attractive investment for many applications.
There can be several reasons for wanting to build
a micro-hydropower system. You may simply wish
to generate electricity to fulfil your basic needs
for lighting, electronic devices, computers, small
appliances, tools, washing machines, dryers,
A BUYER’S GUIDE
refrigerators, freezers, hot water, space heating
or cooking. Over the long term, it may be more
economical for you to invest in your own system
rather than pay your local electricity utility for the
energy you need, especially if you face a significant
connection charge. Other reasons may be that you
are interested in helping to protect the environment
by avoiding the use of fossil fuels or that you wish
to be independent of the power grid.
This guide has been prepared specifically for people
who are considering off-grid power generation.
Applying micro-hydropower technology in remote
locations where electricity is provided by diesel
generators offers an opportunity to replace a
conventional fuel with a renewable energy source.
If you have a stream flowing through or near your
property and wonder if you could use a hydroelectric system to power your home and/or sell
electricity to your neighbours, this guide is for you.
It has been demonstrated that water power can
produce many times more power and energy than
several other sources for the same capital investment. A micro-hydropower system is a non-depleting
and non-polluting energy source that has provided
reliable power in the past and is one of the most
promising renewable energy sources for the future.
1.2 How to Identify a Potential Site
The best geographical areas for micro-hydropower
systems are those where there are steep rivers,
streams, creeks or springs flowing year-round,
such as in hilly areas with high year-round
rainfall. There is micro-hydropower potential in
almost all of Canada’s provinces and territories,
although most potential is in British Columbia,
Newfoundland and Labrador, Ontario and Quebec.
To assess the suitability of a site for a microhydropower system, a pre-feasibility study should
be made. This involves surveying the site to
determine the water-flow rate and the head
through which the water can fall. Methodologies
for measuring water-flow rate and making head
measurements are outlined in Section 2 and
Appendix A. The best place to start is your
nearest stream, or you can refer to topographical
maps and hydrological records of the area you
are considering. If you are new to the area, local
residents are the best source of information on
the nature of the stream, flow variations during
the year and any abnormal flows in the past. This
will give an overall picture of annual river flow
fluctuations over the seasons. If possible, flow data
should be gathered over a period of at least one
full year, although two to five years is ideal. Your
local utility may also have an inventory listing
of potential micro-hydropower sites in your area.
A site survey is carried out for promising sites
in order to gather information that is detailed
enough to make power calculations and start
design work.
1.3 Is Micro-Hydropower for You?
You may have wondered whether the stream
flowing through or near your property can be used
to generate electrical power using a hydropower
system to power your home. Is a micro-hydropower
system feasible for you? Many factors will determine
the viability of such a system:
• local, provincial/territorial and federal legal
restrictions on the development of the hydroelectric site and the use of the water
Figure 3. A typical micro-hydropower weir in
Cherry Creek, British Columbia
• the amount of power available from the stream
and its ability to meet energy and power
requirements
• the availability of turbines and generators of
the type or capacity required
• the cost of developing the site and operating
the system
5
MICRO-HYDROPOWER ENERGY SYSTEMS
Before deciding to build a micro-hydropower system
or any other kind of electricity-generating system, it
is wise to carefully evaluate all alternatives. Those
available will depend on your situation and why
you are interested in hydropower. In general, people
who are interested in such systems fall into one of
two categories:
• They may have a site that has good hydro
potential and want to develop it for their own
power requirements in an area where there is
presently no electrical service.
• They may want to generate their own power
instead of buying power from an electrical utility,
or they may wish to sell the power to the local utility.
In the case where there is no electrical service, you
will need to compare the cost of extending the
existing electrical grid to your home or area with
the cost of generating power locally. If there are
only one or two homes that are quite a distance
from the grid, it may be worthwhile to consider
local generation. The cost of connecting to the grid
depends on the distance involved; an electrical
utility could charge between $10,000 and $50,000
or more per kilometre of transmission line required
to extend the lines to connect to your home. It pays
to get a quote from your local utility before deciding.
The potentially high cost of connecting to the grid
is one of the reasons that most stand-alone power
supply systems are installed in rural areas. There
will also be ongoing electricity charges if you
connect to the grid.
If you wish to be independent of the power grid,
check the price that you will have to pay for electrical power and the approximate cost of developing
a micro-hydropower system. Compare the rate of
return on your investment with investing in other
kinds of generating systems, or consider investing
elsewhere.
If there is no electrical service in your area, the principal alternative to developing a micro-hydropower
system is usually to build some other kind of generating system. Your choice of technology will depend
on many factors, including the long-term cost of
generating electricity using each technology and
appropriate consideration of their respective social
and environmental costs and benefits.
If planned and designed properly, a micro-hydropower
system has many advantages over most conventional means of electricity generation. Some of the
most important advantages are as follows:
• The energy to run hydropower systems is almost
free once they are built, even though they usually
cost more to build than systems that generate
electricity using fossil fuel or natural gas.
• Hydropower systems are inflation-proof because
the cost of using the water in the river and stream
is not likely to increase, and the cost of fuel for
other systems could increase over the years.
• Hydropower systems last 20 to 30 years – longer
than most other kinds of generating systems.
• Smaller projects such as micro-hydro systems
can be built relatively quickly.
• As a renewable resource, a micro-hydropower
system does not depend on oil, coal or other
fossil fuel in order to operate. It promotes selfsufficiency because its development occurs
on a much smaller scale, and most adverse
environmental and social effects of large
energy development projects are eliminated.
• There is no need for long transmission lines
because output is consumed near the source.
• Under favourable circumstances, microhydropower is one of the most cost-effective
forms of renewable energy.
There are other important factors you should
address when deciding if a micro-hydropower
system would work at a specific site:
• the potential for hydropower at the site
• your requirements for energy and power
• environmental impact and approvals
• equipment options
• costs and economics
Keep in mind that each micro-hydropower
system’s cost, approvals, layout and other factors
are site-specific and unique in each case.
Figure 4. A small stream suitable for a microhydropower system
6
A BUYER’S GUIDE
2.0 How to Plan for a System
If you are thinking seriously about installing a
micro-hydropower system, you will want to plan a
system that is sure to meet your energy and power
needs. There are also various planning stages that
you will need to consider. Once these initial steps
are completed, you can begin preliminary system
design. Many factors contribute to a successful
micro-hydropower system.
2.1 How to Measure Potential Power
and Energy
The first step is to determine the hydro potential
of water flowing from the river or stream. You will
need to know the flow rate of the water and the
head through which the water can fall, as defined
in the following:
• The flow rate is the quantity of water flowing
past a point at a given time. Typical units used
for flow rate are cubic metres per second (m3/s),
litres per second (lps), gallons per minute (gpm)
and cubic feet per minute (cfm).
• The head is the vertical height in metres (m)
or feet (ft.) from the level where the water enters
the intake pipe (penstock) to the level where the
water leaves the turbine housing (see Figure 5).
See Appendix A for ways to measure the head and
stream flow rate.
Forebay
Powerhouse
Head
Turbine
Figure 5. Head of a micro-hydropower system
Power Calculation
The amount of power available from a microhydropower system is directly related to the flow
rate, head and the force of gravity. Once you have
determined the usable flow rate (the amount of
flow you can divert for power generation) and
the available head for your particular site, you
can calculate the amount of electrical power you
can expect to generate. This is calculated using
the following equation:
Pth = Q H g
Pth
Q
H
g
=
=
=
=
Theoretical power output in kW
Usable flow rate in m3/s
Gross head in m
Gravitational constant (9.8 m/s2)
Example 1
A site has a head of 10 m (33 ft.) with flow of
0.3 m3/s (636 cfm or 4755 gpm); therefore, the
potential power output is given by Q H g
(0.3 10 9.8), which is 29.4 kW.
This is only the theoretical available power,
assuming that 100 percent of the power available
in the water can be usefully converted. Efficiency
of the system also needs to be taken into account.
Energy is always lost when converted from one
form to another, and all of the equipment used to
convert the power available in the flowing water to
electrical power is less than 100 percent efficient. To
calculate the most realistic power output from your
site, you must take into account the friction losses
in the penstock pipes and the efficiency of the
turbine and generator.
When determining the head, you will need to
consider gross head and net head. Gross head
is the vertical distance between the top of the
penstock that conveys the water under pressure
and the point where the water discharges from
the turbine. Net head is the available head
after subtracting the head loss due to friction
in the penstock from the total (gross) head
(net head = gross head – losses in the penstock).
Small water turbines rarely have efficiencies better
than 80 percent. Potential power will also be lost
in the penstock pipe that carries the water to the
turbine because of frictional losses. Through careful
design, however, this loss can be reduced to a
small percentage; normally, the losses can be kept
to 5 to 10 percent. Typically, overall efficiencies for
electrical generation systems can vary from 50 to
7
MICRO-HYDROPOWER ENERGY SYSTEMS
70 percent, with higher overall efficiencies occurring in high-head systems. Generally, overall efficiencies are also lower for smaller systems. As
a rule, the “water to wire” efficiency factor for
small systems (for example, up to 10 kW) could
be taken as approximately 50 percent; for larger
systems (larger than 10 kW) the efficiency factor
is generally from 60 to 70 percent. Therefore, to
determine a realistic power output, the theoretical
power must be multiplied by an efficiency factor
of 0.5 to 0.7, depending on the capacity and type
of system.
Example 2
A turbine generator set to operate at a head of
10 m (33 ft.) with flow of 0.3 m3/s (636 cfm) will
deliver approximately 15 kW of electricity. This is
given by P = Q (0.3) H (10) g (9.8) e (0.5) =
14.7 kW, assuming an overall system efficiency
of 50 percent.
These calculations will give you an idea of how
much power you can obtain from your water
resource. Table 1 shows how much electrical
power you can expect with various heads and
water-flow rates.
P=Q H g e
e = efficiency factor (0.5 to 0.7)
Power output (in watts) = Q (lps) H (m) g e
Table 1. Typical Power Output (in Watts) With Various Head and Water-Flow Rates
Flow Rate
(lps)
Head
(m)
8
(ft.) (gpm )
5
10
15
20
40
60
80
100
150
200
79
159
238
317
634
951
1 268
1 585
2 378
3 170
1
3
25
49
74
98
196
294
392
490
735
980
2
7
49
98
147
196
392
588
784
980
1 470
1 960
4
13
98
196
294
392
784
1 176
1 568
1 960
2 940
3 920
8
26
196
392
588
784
1 568
2 352
3 136
3 920
5 880
7 840
10
33
245
490
735
980
1 960
2 940
3 920
4 900
7 350
9 800
15
49
368
735
1 103 1 470
2 940
4 410
5 880
7 350
13 230
17 640
20
66
490
980
1 470 1 960
3 920
5 880
7 840
9 800
17 640
23 520
30
98
735
1 470
2 205 2 940
5 880
8 820
14 112
17 640
26 460
35 280
40
131
980
1 960
2 940
3 920
7 840
14 112
18 816
23 520
35 280
47 040
60
197
1 470 2 940
4 410 5 880
14 112
21 168
28 224
35 280
52 920
70 560
80
262
1 960
5 880
7 840
18 816
28 224
37 632
47 040
70 560
94 080
90
295
2 205 4 410
6 615 8 820
21 168
31 752
42 336
52 920
79 380
105 840
100
328
2 450 4 900
7 350 9 800
23 520
35 280
47 040
58 800
88 200
117 600
3 920
A BUYER’S GUIDE
Flow Duration Curve and
Energy Calculations
As an owner/developer of a potential hydro site,
you may wonder how much power your site will
produce. A more exact question is how much
energy it will produce – it is energy in kilowatt
hours (kWh) that we buy from or sell to the
electricity supplier. Energy is a measure of the
length of time we have used or produced a given
amount of power. For example, if you use 1 kW
(1000 W) of electricity for one hour, you have
used 1 kWh of electrical energy. A site on
a stream or river that has a highly variable flow
(i.e., a wide range of flows with many highs
and lows) may not produce as much energy as
a river that has a smaller range of flows but that
is more consistent on average. A hydrologist or
professional consultant can produce a flow
duration curve (FDC) for a river or stream by
ordering the recorded water flows from maximum
to minimum flow (as shown in Figures 6a and 6b).
This is a way to show the probability in graph form
of how many days in a year a particular flow will be
exceeded. (The area below the curve is a measure of
the energy potential of the river or stream.)
Figure 6a. Flow duration curve for river with a high
flow for a short time
The FDC is used to assess the expected availability
of flow over time and the power and energy at a
site and to decide on the “design flow” in order to
select the turbine. Decisions can also be made on
how large a generating unit should be. If a system
is to be independent of any other energy or utility
backup, the design flow should be the flow that is
available 95 percent of the time or more. Therefore,
a stand-alone system such as a micro-hydropower
system should be designed according to the flow
that is available year-round; this is usually the flow
during the dry season. It is possible that some
streams could dry up completely at that time.
Remember that for any water source, be it a river,
stream or creek, there will be a difference in flow
between winter and summer, and this will affect
the power output produced by a micro-hydropower
system. Flow in the stream changes continually
(sometimes daily) if precipitation has occurred;
however, some generalizations can be made. In
southern Ontario, rivers and streams are at their
highest levels in early spring and are at their
lowest levels in late summer. In northern Ontario
and Quebec, smaller rivers and streams are usually
at their lowest levels in mid-winter and at their
Figure 6b. Flow duration curve for river with more
steady flow
9
MICRO-HYDROPOWER ENERGY SYSTEMS
highest in spring. British Columbia and
Newfoundland and Labrador generally have low
flows in late winter and high flows in the spring,
except for the south coast of British Columbia,
which has low flows in summer and high flows
in winter. These variations must be considered
in the estimated total energy generation expected
from a site.
Ideally, minimum flow over the year should be
taken to calculate the design flow to ensure that
power is available year-round. Normally, only
a fraction of the available flow in the stream is
used for power generation. Therefore, FDC is less
important as the size of system decreases. If the
system’s generating capacity is less than 10 kW
or so, FDC may not be relevant at all.
2.2 How Small a System?
It is important to note that there is a head and
a flow rate below which there is presently no
economic advantage in trying to obtain electrical
power. These minimum heads and flow rates are
difficult to specify because a combination of high
values of one with low values of the other can give
some useful power. For practical purposes, however,
any head less than 1 m (3 ft.) is probably going to
be uneconomical to develop. Similarly, 0.60 lps
(10 gpm) can be considered the lower limit for
the flow rate.
The following examples illustrate how different
flow rates and heads of two sites generate similar
amounts of energy:
In assessing the feasibility of developing a microhydropower system, you should carefully examine
your power and energy requirements. The power
you need is the instantaneous intensity of electricity
required to power the appliances you use; this is
measured in kilowatts. The more appliances that
are used at the same time, the more power required.
Energy is a measure of the length of time you have
used a given amount of power. It depends on the
power required by the appliances and on how long
and how often you use them. Electrical energy is
measured in kilowatt hours. You need to know the
electrical power and energy requirement for lighting,
heating, cooking and other uses for your home or
lodge. Does the micro-hydropower system potential
meet your power and energy needs? How large a
system do you really require? Power requirements
are not easy to assess correctly.
One way to determine electrical energy needs is
to look at your current electricity bills, which will
indicate the number of kilowatt hours that you use
per month. If you are currently using a fuel-based
generator for your electricity needs, record the
amount of fuel the generator used in one month
and how long the generator operated over the
same period. Keep in mind that your electricity
consumption will vary depending on the season.
Therefore, you will need to calculate the total
energy requirement (in kWh) for the whole year.
To estimate how much electricity you need:
• A flow rate of 0.6 lps (10 gpm) at 35 m (100 ft.)
of head will generate 100 W of useful power.
• List all your electrical appliances and lights
and note when and how long they are used.
• A flow rate of 20 lps (317 gpm) at 1 m (3 ft.)
of head will also deliver about 100 W of useful
power.
• Note the power that each appliance consumes.
An appliance’s power rating is usually written
on the back of the appliance and is measured
in watts or kilowatts. The EnerGuide label found
on new appliances such as refrigerators, washing
machines and dishwashers also provides energy
consumption ratings (in kWh per month or year).
Both of these systems would produce enough
energy to light a 100-W light bulb continuously,
equivalent to about 72 kWh of energy per month.
If a site has more head, less water flow is required.
The more head and flow there is, the more potential
power can be generated. It is helpful to discuss
your situation with people who already have a
micro-hydropower system and to visit these sites
if possible. You can also contact manufacturers and
suppliers for further information (see “Useful Web
Sites” on page 51).
10
2.3 Assessing Power and Energy
Requirements
• Record the number of hours each appliance is
used in a typical day.
• For each appliance, multiply the power rating in
watts by the number of hours used each day to
obtain the number of watt hours (or kWh) that
the appliance uses per day.
A BUYER’S GUIDE
• Energy-use patterns change with the seasons
(e.g., lighting is generally used more in winter).
• Add up the watt hours for all your appliances.
This total is an estimate of your electrical energy
consumption per day. Then you can calculate
how much energy you would need per month.
Although Canada’s EnerGuide label lets you compare the energy consumption of various appliances,
the ENERGY STAR® symbol – displayed alone or as
part of the EnerGuide label (see Figure 7) – helps
you identify those that are the most energy efficient
in their class.
Another way to determine your electrical energy
needs is to add up typical household appliance
loads and calculate the total energy used by a
typical household per month (see Table 2 and
Appendix C).
It is important to work out your total energy
consumption and peak power consumption because
a situation may arise in which the system could
meet one need but not the other. Compare your
power needs with what is available from your water
resource (calculate using the head and flow rate).
If your monthly energy requirements are greater
than the micro-hydropower system can generate in
a month, see where you can reduce consumption
so that it at least matches the available energy.
Figure 7. EnerGuide label with ENERGY STAR® symbol
To estimate your peak power requirement, add
the wattage rating of all appliances that might be
used simultaneously. Peak power is the maximum
amount of electricity that will be needed at any
given moment, and this requirement normally
occurs when most of the largest appliances
are running at the same time. In many microhydropower systems, the peak power demand is
more likely to define the design capacity of the
turbine rather than the system energy requirements.
When analysing and optimizing a micro-hydropower
system, remember that conservation is the most
powerful factor – ask yourself if you can make some
adjustments in how and when you use electricity.
11
MICRO-HYDROPOWER ENERGY SYSTEMS
By lowering your peak demand, you can decrease
the design capacity requirement of your system
and significantly reduce its initial cost. You may
have to adapt to new patterns and habits in order
to use energy more efficiently. Remember, saving
energy is always cheaper than producing more power.
Figure 8. Load variation and effect of load
management. Adapted from Micro-Hydro Power:
Energy from Ontario Streams.
electrical demand if the river or stream has sufficient
flow over the drier months of the year. There will be
downtime to maintain the system. By using basic
energy conservation practices such as using energyefficient appliances, you will consume much less
energy. This can easily cut your use of electricity in
half to 400 kWh per month (5000 kWh per
year). Studies on energy-use patterns in offgrid houses have found that the average
energy reduction is about 44 percent compared with houses that are supplied by the
grid, and this is achieved through energy
conservation.
Many household appliances use a small
amount of power when in standby mode
(e.g., televisions, cordless phones, computer
monitors). These loads, commonly known
as “phantom” loads or standby power, can
easily add up to 100 W of continuous power.
It is best to unplug these devices as often as
possible when not in use to help reduce total
electrical energy demand. The use of energyefficient appliances and the elimination of
phantom loads are much more critical with
small, battery-based micro-hydropower systems.
Load Management
2.4 Managing Energy Demand
How much electricity is enough? For an average
house that draws electricity from the grid, typical
energy consumption is about 800 kWh per month
(approximately 10 000 kWh per year). This does
not include electricity used for space heating and
cooling and for cooking. If this were included,
electricity usage would be much higher. Electrical
load varies throughout the day (see Figure 8). If you
look at a typical residential pattern of peak load of
electricity use in a home supplied by a local grid,
you will see that it occurs primarily between 4:00 p.m.
and 8:00 p.m., while the least-demand period is
between midnight and 6:00 a.m. There is a large
variation in power demand during these periods.
Average power consumption (demand) is the
number of kilowatt hours used over a given period;
an average power demand for a day can be calculated by dividing the total energy consumption
by the total number of hours in a day (i.e., 24).
Micro-hydropower systems can generally meet
12
Peak electricity demand can be reduced by applying
energy efficiency and load-management techniques
and by choosing energy sources other than electricity for energy-intensive activities such as heating
and cooking. Studies of energy consumption in
residential homes have shown that, on average,
about 50 percent of home energy use is for space
heating, 30 percent for water heating, 5 percent
for lighting and 15 percent for appliances. You
can gain significant benefits simply by thinking
carefully about when you use various appliances.
For example, do not use your washing machine
at the same time that you are ironing; both are
energy-intensive activities.
Various devices are available off-the-shelf that can
be used for load-management applications in a
micro-hydropower system and that will improve
energy use and reduce peak demand. Some may
come with an electronic load controller. Load
controllers (see Figure 9) with load-management
features have been performing effectively in off-grid
larger micro-hydropower systems in Canada for
many years.
A BUYER’S GUIDE
These controllers allow you to manage your peak
demand load by using the energy available from the
system to its maximum. Typically, these management systems allow you to connect at least twice
the amount of load than the capacity of the microhydropower system. (See Section 3.4 for information on electronic load controllers.)
Figure 9. Basic set-up of load-management controller
in a micro-hydropower system
For example, non-essential loads such as domestic
hot water tanks, baseboard heaters and any other
loads that could be automatically interrupted
without causing inconvenience to the consumer
can be controlled by a load-management controller.
It will turn off some or all of these loads when the
micro-hydropower system is becoming overloaded
and automatically turn them back on when the
system has surplus power. The apparent capacity
of a 10-kW plant can become 20 kW with load
management.
There are also devices such as distributed intelligent
load controllers (DILCs), which are fitted directly in
appliances such as refrigerators, battery chargers,
water heaters or space heaters to distribute the
loads around the system. These devices sense
the frequency and the voltage of the system and
switch the loads accordingly, without the risk of
overloading the system. The load-management
system should be part of the micro-hydropower
system design. It is important to keep these energysaving strategies in mind when considering the size
of your micro-hydropower system.
2.5 Feasibility Study
A pre-feasibility study is carried out to determine
whether the site is worth further investigation.
This study could involve visiting a site to measure
head and flow rate, or it could simply be a map
study. If the site looks promising, the next step is
to carry out a full-scale, detailed feasibility study.
Information collected by this study should be of the
highest quality and should be accurate enough to
permit a full technical design of the project without
a further visit. A feasibility study includes a site
survey and investigation, a hydrological assessment,
an environmental assessment, the project design,
a detailed cost estimate and the final report. The
depth of study will depend largely on the size and
complexity of the system. For a small system such
as a battery-based system, the feasibility study can
be less rigorous than for a larger system.
Carrying out a feasibility study is highly technical.
Unless you have a strong background and experience in the area, it is best left to professional
consultants or energy experts. Such expertise may
be expensive, but the project could become much
more expensive without professional help. If a
consultant prevents only one serious mistake in
the project, that person will have earned his or
her fee many times over. If you are going to call
a consultant or manufacturer, make sure that you
have at least a rough estimate of the head (vertical
drop), length of pipe needed for the head and an
approximate flow rate of your micro-hydropower
site. These are the first things that you will be asked.
The feasibility study should answer as many of
the following questions as possible:
• How much head is available?
• How long does the canal/pipeline have to be
in order to reach the head?
• What are the minimum and maximum flow
rates, and when do these occur?
• How much power can be generated with the
available flow rates?
• Who owns the land?
• Where are the nearest electricity power lines?
• What would the environmental effects of
installing a micro-hydropower system be?
• What is the approval process to install the
micro-hydropower system?
13
MICRO-HYDROPOWER ENERGY SYSTEMS
• What financial incentives are available that
encourage renewable energy, and how can you
apply for them?
• How much will it cost to develop the microhydropower system?
Finding answers to as many questions as possible
will enable you to identify any major problems
before you invest a lot of time and money in
the project.
During the feasibility study, all relevant technical and non-technical information needs to be
collected. This includes the location of the intake,
forebay tank and powerhouse; the length of the
diversion canal/pipeline; the penstock; and the
transmission/distribution network. The feasibility
report should contain detailed technical information. Design of the system includes civil works, the
penstock, generating equipment and an estimate
for the total cost of the system. It is helpful to keep
in mind that the cost per kilowatt increases for
low-head systems, low-flow systems and for systems
where a great deal of civil works components need
to be constructed.
2.6 Sizing the System
The most important question in planning a microhydropower system is how much energy can be
expected from the site and whether or not the site
will produce enough power to meet your energy
needs. For a stand-alone micro-hydropower system,
it must be large enough to meet peak power
consumption if you are to be energy-independent.
In order to determine the size of the system you
need, two types of energy estimates should be
evaluated: peak demand and total energy
consumption.
One way to determine the size of the generating
system is to design it to meet the peak power
consumption and to divert excess power at offpeak times, using an electronic load controller,
into the ballast loads. The other option is to size
the generator to meet or slightly exceed the average
power consumption and use battery storage and
an inverter to meet peak power consumption.
However, if the site potential is so small that its
power output cannot meet consumption peaks, you
may have no alternative but to use storage batteries.
14
Remember that the site’s available head and flow
rate are the major factors that limit the size of the
installation, and economics dictate the size of the
development of any hydropower site.
If the site has a flow of less than 1 lps or head that
is a less than 1 m, it may be best to consider an
alternative power source because it may not be able
to provide you with sufficient power. However, if
you have a site with sufficient flow and head, you
have the option of investing in a system that will
supply your entire electrical power requirement and
may be able to meet your peak demand. If there are
other residential homes or lodges near your site that
need electricity, you may consider sizing the system
to take into account the option of selling surplus
power. If you are a lodge owner, it may be very
attractive to use electrical power to meet as many
of your energy needs as possible and reduce your
dependency on fossil-fuel-based generators.
For a typical residential home in a town or city,
the total energy requirement is approximately
10 000 kWh per year. For an off-grid home, it could
be much lower because people who live off-grid
tend to conserve energy. In theory, you could
supply all your electrical energy needs for lighting
and appliances with a battery-based system of less
than 1 kW, which will generate 8760 kWh of energy
per year, assuming a 100 percent capacity factor.
If the water-heating load were also included, the
energy requirement would easily exceed 13 000 kWh
per year. A 2-kW system may meet your needs,
provided that the peak load will not be more than
2 kW. Assuming a capacity factor of 70 percent, this
will produce approximately 12 260 kWh of energy
per year. If you do not wish to include battery
storage, you may need a system in the range of 3 to
5 kW. There are systems that generate 200 to 400 W,
which, when coupled with good inverters, are
found to be satisfactory for many off-grid residents.
However, you still need to have a good loadmanagement system to ensure that peak demand
is kept below the maximum generation capacity
of the system (see Case Study 1 in Section 4.1).
For a small community and for lodges, depending
on the number of cabins and energy needs, you
may plan for a larger system that has a capacity
range of 15 to 30 kW. A well-designed system has
the potential to entirely replace the need for a
A BUYER’S GUIDE
fuel-based system for electrical generation. Even if
it does not replace the use of propane for cooking
and heating, burning propane for heat is much
more effective than using it to run a generator.
The cost of a micro-hydropower system is largely
related to the peak demand it supplies. Therefore,
it is important to reduce your peak electricity
requirement to keep your system costs down.
However, if the output power potential of your site
is greater than the demand, you may have surplus
power for other uses, such as space heating or
selling power to your neighbours. You may choose
to build a smaller system to meet only your needs;
at sites where it is possible to produce more than
sufficient power, this will obviously be an important
decision. Determining appropriate sizing requires
substantial effort. The engineering and hydrology
studies will determine the range of feasible options.
It bears repeating that saving energy is always
cheaper than producing more power.
2.7 Environmental Issues
and Approvals
Water is a Crown-owned resource in Canada,
and provincial and territorial ministries of natural
resources manage its use. A water licence must be
obtained from the provincial/territorial authority
before the water can be used, even for non-consumptive uses such as a micro-hydropower system.
Figure 10. Intake of micro-hydropower system in
Seaton Creek, British Columbia (photo courtesy of
Homestead Hydro Systems)
It is illegal to take surface water from a stream
without first obtaining a water licence or other
approval. It is not an offence to use unrecorded
water for domestic needs, mineral prospecting or
firefighting. Unrecorded water is water in a stream
that is neither licensed nor reserved for other
purposes but that is conserved for environmental
reasons such as fish habitat and aquatic requirements.
Before you invest time and money in a hydropower
system, find out if any regulatory issues need to
be resolved. There can be institutional and legal
considerations when installing a micro-hydropower
system, and your project will proceed more smoothly
if any regulatory problems are identified early on. It
can take some time to obtain permits and licences.
First, contact your provincial or territorial government offices that deal with land and water in order
to determine what local permits are needed for your
area. The appropriate ministry of natural resources
can indicate what is required and guide you on how
to conduct the assessment and/or proceed with the
submission. The assessment will depend on the
nature and scale of your proposed project, and in
some cases it can be as brief as two or three pages.
All local permits or requirements must be satisfied
before a federal hydropower licence will be issued,
if required.
Permits and approvals that you will need when
constructing a micro-hydropower system include
environmental approvals (provincial/territorial
and federal), an agreement regarding the use of
water (provincial/territorial), an operating agreement (provincial/territorial), land lease agreements
(provincial/territorial), permits for the use of
navigable waters (federal) and building permits
(provincial/territorial). Under the Canadian
Environmental Assessment Act, an environmental
impact assessment is required if the project receives
federal funding or if it involves federal land and
is considered by the approving agency to have a
potentially significant environmental impact. It is
unlikely, however, that you will need any federal
permits for the capacity of systems covered in
this guide. Installing a generating facility on the
developer’s property should present few problems.
The water licence is issued on a first-come, firstserved basis, and the amount of water you can
divert for power generation is regulated at the
time of issuing the licence. There may be conditions;
for example, it may be required that 10 percent of
15
MICRO-HYDROPOWER ENERGY SYSTEMS
mean annual discharge be flowing in the stream or
river at all times. Fisheries and Oceans Canada has
an interest in fish and fish habitats where there is
cross-border migration such as with salmon.
Applications can take one to two or even three
years to process. Owners can begin work on a
system while waiting for a licence only when the
system will be used solely for domestic purposes.
Water-power projects require a water licence under
the Canada Water Act.
In British Columbia, for example, Land and Water
British Columbia Inc. is the one-stop access point
for all of that province’s government requirements
for use of land and water. Approval under British
Columbia’s Land Act is required for any project
component situated on Crown land, including the
powerhouse, roads and transmission lines. Land and
Water British Columbia Inc. reviews water-power
projects of less than 50-MW capacity in British
Columbia. Note that each province and territory
has its own legislation.
Water licences for hydropower projects are generally
issued for three categories: residential, commercial
and general. The residential category applies to
projects that have a capacity of 25 kW or less (in
British Columbia), where the power is used to meet
the household requirement of the licensee. The
commercial category applies where the power is
sold to immediate family members, employees or
tenants of the licensee and the project capacity
does not exceed 499 kW, or where the project supplies power to an industrial facility in which the
licensee has an interest of more than 50 percent.
16
The general category applies to projects where
the capacity exceeds the licensee’s household and
commercial needs and includes projects that sell
energy to the provincial/territorial power grid.
Annual water rental fees for hydro projects depend
on the category of the power use (residential,
commercial or general), the capacity of the system
and the actual annual energy output of the system.
Another permit will be required from your local
electrical safety authority in order to install the
generator, control panels and all other electrical
equipment, and these must comply with the
Canadian Electrical Code. All electrical equipment
must be approved and certified by CSA International.
The lead time for the construction of a micro-hydro
project from the time of the original enquiry is
about one to two years. Approval for small systems,
especially using existing pipes, can be much faster.
You may decide to follow up on everything yourself
but, depending on the situation, it might be helpful
to hire a professional consultant to speed up the
process. The approval process is important: it is a
search for an acceptable approach that gives the
optimum use of a stretch of river or stream. We
all want to protect the environment and to make
the best use of our natural resources. For more
information, contact your nearest provincial
or territorial regional offices of the appropriate
ministry that deals with land and water related
to water-power projects. You can also visit their
Web sites.
A BUYER’S GUIDE
3.0 Basic Components of a
Micro-Hydropower System
Basic components of a typical micro-hydro system
are as follows:
Headworks
Headworks consist of the weir (see Figure 11), the
water intake and protection works at the intake to
safely divert water to the headrace canal. At some
sites you may be able to install the penstock directly
in the intake, with no need for a canal.
• civil works components (headwork, intake, gravel
trap with spillway, headrace canal, forebay and
desilting basin, penstock pipe, powerhouse and
tailrace)
• powerhouse components (turbines, generators,
drive systems and controllers)
• transmission/distribution network
3.1 Civil Works Components
Civil works structures control the water that runs
through a micro-hydropower system, and conveyances are a large part of the project work. It is
important that civil structures are located in
suitable sites and designed for optimum performance and stability. Other factors should be
considered in order to reduce cost and ensure a
reliable system, including the use of appropriate
technology, the best use of local materials and local
labour, selection of cost-effective and environmentally friendly structures, landslide-area treatment
and drainage-area treatment.
Figure 12. Intake for a 2-kW micro-hydropower
system (photo courtesy of Homestead Hydro Systems)
Intake
The intake (see Figure 12) conveys the required flow
of water from the source stream and diverts it into
the headrace of the micro-hydropower system. It is
designed and located precisely to ensure that the
full design-flow rate goes to the turbine. Because
many micro-hydropower systems are run-of-river
systems, a low-head dam or weir could be used to
hold back the water in order to provide a steadier
flow of water, depending on the site.
Gravel Trap With Spillway
Figure 11. An intake weir for a 7-kW system (photo
courtesy of Thompson and Howe Energy Systems Inc.)
The gravel trap and screen are constructed close
to the intake in order to prevent debris, gravel and
sand from getting into the penstock. Gravel traps
often have a mechanism to divert excess water back
to the river and to flush sediments back to the river
downstream of the intake. The spillway is designed
to handle floodwater and protects the intake during
heavy floods.
17
MICRO-HYDROPOWER ENERGY SYSTEMS
Headrace Canal
The headrace canal carries the design flow from
the intake to the forebay. Generally, the canal runs
parallel to the river at an ever-increasing difference
in elevation, which gives the micro-hydropower
system its head. The canal cross section and alignment should be designed for optimum performance
and economy in order to reduce losses due to leakage. You could use an open channel or pipeline to
transport the water into the forebay.
Forebay and Desilting Basin
The desilting basin is designed to settle suspended
silt and flush the basin. The forebay tank connects
the channel and the penstock. The tank allows fine
silt particles to settle before the water enters the
penstock. A fine trash rack is used to cover the
intake of the penstock to prevent debris and ice
from entering and damaging the turbine and valves.
Figure 13. Wooden screen for a 24-kW microhydropower system (photo courtesy of Thompson and
Howe Energy Systems Inc.)
Penstock Pipe
The penstock pipe transports water under pressure
from the forebay tank to the turbine, where the
potential energy of the water is converted into
kinetic energy in order to rotate the turbine.
18
The penstock is often the most expensive item
in the project budget – as much as 40 percent is
not uncommon in high-head installations. It is
therefore worthwhile to optimize its design in
order to minimize its cost. The choice of size and
type of penstock depends on several factors that
are explained briefly in this section. Basically, the
trade-off is between head loss and capital cost.
Head loss due to friction in the penstock pipe
depends principally on the velocity of the water,
the roughness of the pipe wall and the length and
diameter of the pipe. The losses decrease substantially with increased pipe diameter. Conversely,
pipe costs increase steeply with diameter. Therefore,
a compromise between cost and performance is
required. The design philosophy is to first identify
available pipe options, select a target head loss of
5 to 10 percent or less of the gross head, and keep
the length as short as possible. Several options for
sizes and types of materials may need to be calculated and evaluated in order to find a suitable
penstock pipe. A smaller penstock may save on
capital costs, but the extra head loss may account
for lost energy and revenue from generated electricity (if you are selling the power). In smaller
systems, the allowable head loss can be as much
as 33 percent. This is particularly relevant to developers who combine domestic water supply and
penstock in the same pipe.
Several factors should be considered when deciding
which material to use for a particular penstock:
design pressure, the roughness of the pipe’s interior
surface, method of joining, weight and ease of
installation, accessibility to the site, design life
and maintenance, weather conditions, availability,
relative cost and likelihood of structural damage.
The pressure rating of the penstock is critical
because the pipe wall must be thick enough to
withstand the maximum water pressure; otherwise
there will be a risk of bursting. The pressure of the
water in the penstock depends on the head; the
higher the head, the higher the pressure. Pressure
ratings are normally given in bar units or PSI;
10.2 m of head will exert a pressure of 1 bar, or
14.5 PSI. The penstock becomes more expensive
as the pressure rating increases.
A BUYER’S GUIDE
Figure 14. High-density polyethylene (HDPE)
penstock being buried in a steep hill (photo courtesy
of Thompson and Howe Energy Systems Inc.)
Figure 15. Double 10-cm (4-in.) HDPE penstock
pipe for an 8-kW system
The most commonly used materials for a penstock
are HDPE, uPVC and mild steel because of their
suitability, availability and affordability. Layout of
the penstock pipelines depends on their material,
the nature of the terrain and environmental considerations; they are generally surface-mounted or
buried underground. Special attention is necessary
where a penstock is installed in a very cold environment; protection from ice and frost must be
considered. In severe frost areas, penstocks should
always be buried below the frost line. Where
freezing is not a concern, the penstock may be left
above ground. However, it is generally preferable
to bury the penstock to provide protection from
expansion, animals and falling trees. Because of
changes in the ambient temperature, the length
of the penstock pipe may be subjected to expansion
and contraction. Expansion joints are used to compensate for maximum possible changes in length.
19
MICRO-HYDROPOWER ENERGY SYSTEMS
Powerhouse and Tailrace
The powerhouse (see Figure 16) is a building that
houses the turbine, generator and controller units.
Although the powerhouse can be a simple structure,
its foundation must be solid. The tailrace is a
channel that allows the water to flow back to the
stream after it has passed through the turbine.
connected by means of gears or belts and pulleys,
depending on the speed required for the generator
(see Section 3.3 for information on drive systems).
The choice of turbine depends mainly on the
head and the design flow for the proposed microhydropower installation. The selection also depends
on the desired running speed of the generator.
Other considerations such as whether the turbine
is expected to produce power under part-flow
conditions also play an important role in choosing
a turbine. Part-flow is where the water flow is less
than the design flow. All turbines tend to run most
efficiently at a particular combination of speed, head
and flow. In order to suit a variety of head and flow
conditions, turbines are broadly divided into four
groups (high, medium, low and ultra-low head)
and into two categories (impulse and reaction).
Pelton and Turgo turbines are the most commonly
used impulse-type turbines in micro-hydropower
systems in Canada. These turbines are simple to
manufacture, are relatively cheap and have good
efficiency and reliability. To adjust for variations
in stream flow, water flow to these turbines is easily
controlled by changing nozzle sizes or by using
adjustable nozzles. Pelton turbines are used for
sites that have low flows and high heads.
Figure 16. Powerhouse for an 8-kW system (photo
courtesy of Thompson and Howe Energy Systems Inc.)
3.2 Powerhouse Components
Turbines
A turbine unit consists of a runner connected to
a shaft that converts the potential energy in falling
water into mechanical or shaft power. The turbine
is connected either directly to the generator or is
20
Most small reaction turbines are not easy to
adjust to accommodate for variable water flow,
and those that are adjustable are expensive because
of these units’ variable guide vanes and blades. An
advantage of reaction turbines is that they can use
a site’s full available head. This is possible because
the draft tube used with the turbine recovers some
of the pressure head after the water exits the turbine.
Some of this type of turbine are now being manufactured that can generate power at head as low
as 1 m (3 ft.).
A BUYER’S GUIDE
Figure 18. Pump-as-turbine with 12-kW output
using twin 10-cm (4-in.) penstock (photo courtesy of
Thompson and Howe Energy Systems Inc.)
Water Wheels
Figure 17. A 20-cm (8-in.) pitch diameter Pelton
turbine runner (photo courtesy of Thompson and
Howe Energy Systems Inc.)
Pump-as-Turbine
For a number of years there has been wide interest
in reverse-engineered conventional pumps that
can be used as hydraulic turbines. The action of
a centrifugal pump operates like a water turbine
when it is run in reverse. Because the pumps are
mass-produced, they are more readily available
and less expensive than turbines. It is estimated
that the cost of a pump-as-turbine (PAT) is at
least 50 percent less or even lower than that
of a comparable turbine. However, for adequate
performance, a micro-hydropower site must have
a fairly constant head and flow because PATs have
very poor partial-flow efficiency. It is possible
to obtain full efficiency from PATs by installing
multiple units, where they can be turned on or
off depending on the availability of water in the
stream. PATs are most efficient in the range of
13 to 75 m (40 to 250 ft.) of gross head. The higher
the head, the less expensive the cost per kilowatt;
this is generally the case with all turbines.
Water wheels are the traditional means of converting useful energy from flowing and falling water
into mechanical power. Although not as efficient
as turbines, they are still a viable option for producing electricity for domestic purposes. They are
simple to control, lend themselves to do-it-yourself
projects and are aesthetically pleasing. There are
three basic types of water wheels: undershot,
breastshot and overshot. Variations are Poncelet
and pitchback types. The major disadvantage is
that they run relatively slowly and require a highratio gearbox or other means of increasing the
speed if they are to drive a generator. However,
for low power – for example, less than 5 kW and
heads less than 3 m (10 ft.) – they are worth
considering. In most parts of Canada, however,
water wheels are generally not recommended for
winter operation because it is almost impossible
to prevent freezing and ice buildup, which could
damage the wheel.
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MICRO-HYDROPOWER ENERGY SYSTEMS
Turbine Efficiency
Typical efficiency ranges of turbines and water
wheels are given in Table 5. For more precise
figures, contact turbine manufacturers. Turbines
are chosen or are sometimes tailor-made according
to site conditions. Selecting the right turbine is
one of the most important parts of designing a
micro-hydropower system, and the skills of an
engineer are needed in order to choose the most
effective turbine for a site, taking into consideration cost, variations in head, variations in flow,
the amount of sediment in the water and overall
reliability of the turbine.
Alternating current (AC) generators are also referred
to as alternators. They generate varying voltages,
which alternate above and below the zero voltage
point. It is this process that produces AC electricity.
This same principle is used in all electric generators,
from large hydro and nuclear plants to the alternator in your car, although the speed will vary
depending on the type of generator used.
There are two types of generators: synchronous and
asynchronous. Synchronous generators (see Figure 19)
are standard in electrical power generation and are
used in most power plants. Asynchronous generators
are more commonly known as induction generators.
Both of these generators are available in three-phase
or single-phase systems. System capacity, type of
load and length of the transmission/distribution
network dictate whether a single- or three-phase
generator should be used.
Induction generators are generally appropriate for
smaller systems. They have the advantage of being
rugged and cheaper than synchronous generators.
The induction generator is a standard three-phase
induction motor, wired to operate as a generator.
Capacitors are used for excitation and are popular for
smaller systems that generate less than 10 to 15 kW.
Generators
Generators convert the mechanical (rotational)
energy produced by the turbine to electrical energy;
this is the heart of any hydroelectrical power
system. The principle of generator operation is
quite simple: when a coil of wire is moved past
a magnetic field, a voltage is induced in the wire.
22
All generators must be driven at a constant speed
to generate steady power at the frequency of 60 Hz.
The number of poles in the generator determines
the speed, commonly stated in revolutions per
minute (rpm). The more pairs of poles, the slower
the speed. The 2-pole generator with a speed of
3600 rpm is too high for practical use with a microhydropower system. The 1800-rpm 4-pole generator
is the most commonly used. The cost of the generator is more or less inversely proportional to the
speed; the lower the speed, the larger the frame
size needs to be for equivalent power output. For
this reason, generators that operate at less than
1200 rpm become costly and bulky. In order to
match the speed of the generator to the low speed
of the turbine, a speed increaser such as belt and/or
gearbox might be needed.
A BUYER’S GUIDE
There are other factors to consider when selecting
a generator for your system, such as capacity of
the system, types of loads, availability of spare
parts, voltage regulation and cost. If high portions
of the loads are likely to be inductive loads, such
as motor and fluorescent lights, a synchronous
generator will be better than an induction
generator. Induction generators in stand-alone
application mode cannot supply the high-surge
power required by motor loads during start-up.
Selecting and sizing the generator is very technical,
and an energy expert should make the selection
during the feasibility study.
3.3 Drive Systems
Figure 19. A directly coupled Pelton turbine with
synchronous generator 8-kW system
Electrical power can be generated in either AC or
direct current (DC). AC has the advantage of allowing the use of common household appliances and
tools and is much more economical for transmitting
power to homes. DC current can be used in two
ways – either directly as DC or converted to AC
through the use of an inverter. The main advantage
of DC is ease of battery storage. For DC systems,
which are described in more detail in Section 4.1,
specially designed DC generators are used.
Generator Efficiency
Full-load efficiencies of synchronous generators
vary from 75 to 90 percent, depending on the
size of the generator. Larger generators are more
efficient, and three-phase generators are generally
more efficient than single-phase ones. The efficiency will be reduced by a few percentage points
when being used at part load (e.g., at 50 percent
of the load). Efficiency of induction generators
is approximately 75 percent at full load and
decreases to as low as 65 percent at part load.
Permanent magnet DC generators have efficiencies
of more than 80 percent at full load. It is crucial
to take these figures into account when selecting
a generator because the overall efficiency of the
system will be affected.
In order to generate electrical power at a stable
voltage and frequency, the drive system needs to
transmit power from the turbine to the generator
shaft in the required direction and at the required
speed. Typical drive systems in micro-hydropower
systems are as follows:
• Direct drive: A direct drive system is one in
which the turbine shaft is connected directly
to the generator shaft. Direct drive systems are
used only for cases where the shaft speed of the
generator shaft and the speed of the turbine are
compatible. The advantages of this type of system
are low maintenance, high efficiency and low cost.
• “V” or wedge belts and pulleys: This is
the most common choice for micro-hydropower
systems. Belts for this type of system are widely
available because they are used extensively in
all kinds of small industrial machinery.
• Timing belt and sprocket pulley: These
drives are common on vehicle camshaft drives
and use toothed belts and pulleys. They are
efficient and clean-running and are especially
worth considering for use in very small system
drives (less than 3 kW) where efficiency is critical.
• Gearbox: Gearboxes are suitable for use with
larger machines when belt drives would be too
cumbersome and inefficient. Gearboxes have
problems regarding specification, alignment,
maintenance and cost, and this rules them out
for micro-hydropower systems except where they
are specified as part of a turbine-generator set.
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MICRO-HYDROPOWER ENERGY SYSTEMS
An ELC is a solid-state electronic device designed
to regulate output power of a micro-hydropower
system. Maintaining a near-constant load on the
turbine generates stable voltage and frequency. The
controller compensates for variation in the main
load by automatically varying the amount of power
dissipated in a resistive load, generally known as
the ballast or dump load, in order to keep the total
load on the generator and turbine constant. Water
heaters are generally used as ballast loads. An ELC
constantly senses and regulates the generated
frequency. The frequency is directly proportional
to the speed of the turbine.
Figure 20. Single-line diagram of generator,
electronic load controller and main loads
3.4 Electronic Load Controllers
Water turbines, like petrol or diesel engines, will
vary in speed as load is applied or disconnected.
Although not a great problem with machinery that
uses direct shaft power, this speed variation will
seriously affect the frequency and voltage output
from a generator. It could damage the generator
by overloading it because of high power demand
or over-speeding under light or no-load conditions.
Traditionally, complex and costly hydraulic or
mechanical speed governors similar to larger hydro
systems have been used to regulate the water flow
into the turbine as the load demand varied. Over
the last two decades, electronic load controllers
(ELCs) have been developed that have increased
the simplicity and reliability of modern microhydropower systems.
24
Voltage control is not required for synchronous
generators because they have a built-in automatic
voltage regulator. Without an ELC, the frequency
will vary as the load changes and, under no-load
conditions, will be much higher than rated
frequency. ELCs react so fast to load changes that
speed changes are not even noticeable unless a very
large load is applied. The major benefit of ELCs is
that they have no moving parts, are reliable and are
virtually maintenance-free. The advent of ELCs has
allowed the introduction of simple and efficient
multi-jet turbines for micro-hydropower systems
that are no longer burdened by expensive hydraulic
governors.
ELCs can also be used as a load-management system
by assigning a predetermined prioritized secondary
load, such as water heating, space heating or other
loads. In this way, you can use the available power
rather than dumping it into the ballast load. It can
be used to connect loads by priority sequence and
can thus control loads that total four to five times
the actual output of the micro-hydropower system.
(See Section 2.4 for information on load management.)
A BUYER’S GUIDE
Figure 21. Electronic load
controller, 12-kW-rated, front
and inside view (photo courtesy
of Thompson and Howe Energy
Systems Inc.)
Figure 22. Induction generator controller, 3-kW
rated (photo courtesy of Homestead Hydro Systems)
There are various types of ELCs on the market
that can regulate systems from as small as 1 kW to
100 kW. The choice of the controller depends on
the type of generator you have. ELCs are suitable
for synchronous generators. If you have an induction generator, you will need an induction generator controller (IGC). IGCs work on a principle that
is similar to that used by ELCs, but an IGC monitors
the generated voltage and diverts the surplus power
to the ballast load.
Other types of controllers are being introduced to
the market that are based on similar principles that
may be suitable for your application. For example,
distributed intelligent load controllers (DILCs) distribute the electric power to various loads within
the home or the distribution system. DILCs are
fitted directly to appliances for refrigeration, space
heating or water heating in prioritized sequence.
They sense the frequency and the voltage of the
generating system and switch the loads accordingly,
without the risk of overloading the generating
system. DILCs can be used with other controllers
such as the ELC and IGC as part of the load management solution or can be used to displace those
controllers altogether.
Be aware that these controllers can cause some radio
frequency interference. These controllers are usually
supplied in weatherproof cabinets that also contain
the electrical meters, safety protection devices and
switchgear and all connections for power cables.
3.5 Transmission/Distribution Network
The most common way of transporting electricity
from the powerhouse to homes is via overhead
lines. The size and type of electric conductor cables
required depends on the amount of electrical power
to be transmitted and the length of the power line
to the home. For most micro-hydropower systems,
power lines would be single-phase systems. For
larger systems, the voltage may need to be stepped
up using a transformer or a standard three-phase
system in order to reduce transmission losses.
Depending on the environment and geographical
conditions, you may even need to consider an
underground power line, which generally costs
considerably more than overhead lines but may be
safer. All electrical works must follow national and
local electrical codes and should be undertaken
only by qualified and certified professionals.
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MICRO-HYDROPOWER ENERGY SYSTEMS
4.0 Choosing a System
The type of micro-hydropower system you
choose will depend on the capacity you need,
the anticipated power demand and the profile of
your site. A major consideration is whether the site
is a remote stand-alone or grid-connected system.
This section briefly describes the types of systems
that are available. For remote sites, there are
generally two types of micro-hydropower systems:
battery-based and AC-direct. For grid connection
only, AC-direct systems are appropriate, but there
are other issues that should be considered. More
information can be obtained from manufacturers
and suppliers.
batteries that are designed to gradually discharge
and charge 50 percent of their capacity hundreds
of times. There are many off-grid homes that use
battery-based systems, including those that use solar
and wind-power systems. The advantage of batterybased systems is that they require far less water flow
than AC-direct systems, they are usually less
expensive, and they use the maximum energy
available from your system.
4.1 Battery-Based Systems
If the micro-hydropower system is not able to
generate sufficient power to meet the peak load
requirement, batteries are used to store electricity
for use at night and/or for meeting loads during the
day. If your power requirement is for lighting and to
run some efficient appliances, battery-based systems
may be suitable. These systems use deep-cycle
Figure 23. A 1-kW rated low-head battery-based
system (photo courtesy of Energy Systems & Design)
26
Figure 24. Balance of system for a battery-based system
Several specialized companies offer their own
designs at competitive rates. Shop around until
you find a system that suits your needs and budget.
These systems are small, the turbine and generator
are usually integrated into one unit, they are easy to
install, and they have developed a good reputation
for reliability over the years. One advantage to keep
in mind is that a system that has energy stored in
batteries can also provide peak power that is many
times greater than the installed system. For example,
a 400-W system charging the battery bank can
provide peak power as high as 5 kW or more with
appropriate inverters, so it could be useful in
meeting a short-term peak load. Used batteries
should be recycled or disposed of as hazardous
waste in order to minimize environmental impacts.
A BUYER’S GUIDE
Equipment for this type of system is available in a
range of voltages of 12, 24, 36, 48, 120 or 240 DC.
The choice of generating voltage is dictated by the
capacity of the system and the distance that the
electrical power needs to be transmitted. The longer
the distance, the higher the voltage you will need in
order to reduce transmission losses. An inverter is
used to invert DC voltage into standard AC supply
voltage to power AC appliances. You can also use
DC-powered appliances that are powered directly
from the battery.
Case Study 1:
200-Watt Micro-Hydropower System
in Lillooet, British Columbia
(Information provided by Scott Davis, Yalakom
Appropriate Technology, British Columbia)
Battery-based micro-hydropower systems are
available from as small as 100 W to about 1600 W.
Table 6 lists the various types of systems available.
Water current turbines convert the kinetic energy
of moving water and can be used in rivers and
streams that have a high volume of water and that
are slow-moving. These turbines are different from
conventional hydropower turbines that harness the
potential energy available in a head difference of
the water flow.
power from 6 lps (100 gpm) of water flow. The
power is transmitted about 60 m (200 ft.) to
a 900 amp-hour deep-cycle battery bank and
2.5-kW-rated inverter. Installation took about
four days.
Micro-hydropower systems do not need to be
elaborate in order to give good service. In 1997,
the owner of a homestead west of Lillooet,
British Columbia, brought electrical power to
his household with a simple system. A couple
of hundred yards (180 m) of 2-inch (5-cm)
polyethelene pipe was unreeled in the mountain
stream that flowed near the house. Although
not all streams may be suitable for this kind of
arrangement, this particular system has resisted
months of sub-zero temperatures and has worked
well year-round over the last few years.
With a net pressure of about 15 pounds per
square inch (PSI), this system has about 10.5 m
(35 ft.) of head; a permanent magnet generator
unit generates about 200 W at 24 V of continuous
Figure 25. A 200-W micro-hydropower system
in action (photo courtesy of Scott Davis, Yalakom
Appropriate Technology, British Columbia)
27
MICRO-HYDROPOWER ENERGY SYSTEMS
This system provides the owner with a level of
power consumption that is close to the European
average of 200 to 300 kWh per month, as opposed
to the Canadian average of 850 to 1000 kWh per
month. It brings generous amounts of energy for
efficient lighting, electronics such a VCR and stereo,
numerous shop tools and an electric refrigerator
and freezer to this remote area for the first time.
By using other technologies such as wood burning
for space heating and propane for cooking, this
system provides a high level of clean, renewable
energy without extensive civil works. Required
maintenance has been limited to cleaning the
intake. This system could be replaced today for
about $7,500.
4.2 AC-Direct Systems
AC-direct systems are similar to those used by utilities to power our homes in towns and cities. A microhydropower AC-direct system does not have battery
storage, so the system is designed to supply the load
directly. This system is appropriate for grid-connected
sites and for remote stand-alone sites.
The AC-direct systems listed in Table 7 are available
off-the-shelf, are fully integrated for “water to
wire” installation and are generally much more
economical than custom-made designs. There are
larger integrated systems available for low-head
applications.
Figure 26. A double-jet Turgo induction generator
system, 5-kW rated
28
A BUYER’S GUIDE
The smallest fully integrated system available is
a 200-W unit, which can work with a head as low
as 1 m (3 ft.). Many larger units are manufactured
and assembled according to the site profile’s
requirements and the generating capacity needed.
(See Section 3.2 for descriptions of turbines.)
Case Study 2:
Remote 10-kW Micro-Hydropower
System
(Information provided by Scott Davis, Yalakom
Appropriate Technology, British Columbia)
Despite the presence of high-tension power lines
along the Lillooet River valley in southwestern
British Columbia, First Nations settlements along
this river have never been connected to the
utility grid.
Water from countless streams falls thousands
of feet from the mountains to the valley floor.
The Peters family lives on a small piece of reserve
land, about three kilometres from the village of
Skookumchuck. In the past, diesel generators met
the Peters’ electrical needs, but over the years it
proved to be expensive and difficult to operate.
There are two streams on the Peters’ property that
are well suited for a micro-hydropower system,
but it was the one that is larger and closer to the
house that the Peters’ chose. The site is steep and
rocky and has about 90 m (300 ft.) of head above
the house. Construction took place over a few
months. A small settling basin was dug beside the
creek. It took a day of an excavator’s time to dig
the penstock, and a crew installed the 275 m
(900 ft.) of 10-cm (4-in.) pipe in a few days.
The intake, thrust block and the powerhouse
also took some time to complete.
The system uses a direct-coupled Pelton turbine
that drives a 12-kW alternator. It features a
flywheel for improved surge capacity and has
an adjustable needle nozzle to provide efficient
operation at a wide range of flows. It usually
produces about 10 kW from a flow rate of 22 lps
(350 gpm). It can use much less water and still
provide good service for the two households
that are now using the power.
Figure 27. A 10-kW micro-hydropower system
in action (photo courtesy of Scott Davis, Yalakom
Appropriate Technology, British Columbia)
The system, which is governed by a Canadiandesigned electronic load controller, provides
generous amounts of electricity for lights and
appliances, and it operates a well pump that
the diesel unit could not. It provides year-round
electric-heated hot water for two households and
significant space heating in the winter. Propane
is used for cooking.
The system requires little maintenance other
than occasionally cleaning the intake and
greasing the bearings. A submerged intake with
a stainless steel screen has proven satisfactory for
several years. The system has run well since it was
commissioned in 1998. Replacing this system
today would cost about $25,000 in addition to
labour costs.
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MICRO-HYDROPOWER ENERGY SYSTEMS
4.3 Grid-Connected Systems
There is no reason you cannot install a system near
or where you already have a grid supply and obtain
electrical power from both your micro-hydropower
system and the grid. You may even be able to offset
your electric bill by supplying the surplus power
to the grid at the same time through net-metering,
also known as net-billing. If you want to sell your
power to the utility or to your neighbours, there are
a few regulations and approvals that must be met.
Net-Metering
Net-metering allows a small power producer – such
as a residence or farm with a micro-hydropower,
wind turbine or photovoltaic system – to connect
to the power grid to offset the purchase of electrical
energy from the utility with the surplus energy
generated by the on-site generating facility. Netmetering does away with the need to install costly
backup generators or batteries to supplement a
small renewable system. A single meter measures
the electricity purchased from the utility and turns
backward when the small power producer feeds
electricity into the grid. The net-meter measurement
determines the amount of electricity charged to
the user.
30
Net-metering programs are in various stages of
development in British Columbia, Alberta, Manitoba
and Ontario. Each utility has its own policy for grid
connections. For further information, contact the
customer relations office of your local utility.
Hybrid System
A hybrid system is where two or more generation
sources, such as a micro-hydropower, wind or
photovoltaic system or small petrol/diesel generator
are combined to provide electrical power. Such a
system offers several advantages over a single type
of generation and can be set up depending on your
power requirement. Because the peak operation
times for wind and solar power occur at different
times of the day and year, a hybrid system is more
capable of producing power when you need it.
Wind speeds are low in the summer when the sun
shines the brightest and longest; winds are strong
in the winter when there is less sunlight. If you also
add a micro-hydropower system, you are likely to
have a completely independent and reliable system
because it can provide backup service that is quieter,
more reliable and cheaper to operate than a diesel
generator, even if water flow dries up in the summer.
A BUYER’S GUIDE
5.0 Economics
How much will a micro-hydropower system cost?
There is no standard answer to this question because
costs depend on site conditions and on how much
work you are prepared to do yourself. In general,
with current technologies the total cost can range
from $1,500 to $2,500 per kilowatt of installed
capacity, depending on the system’s capacity and
location. For systems that are less than 5 kW in
power output, the cost per kW is approximately
$2,500 or higher because of the smaller size and
the cost of additional components such as a battery
bank and inverter.
Costs for developing a micro-hydropower system
fall into two categories: initial and annual costs.
Initial costs are those that occur at the beginning
of the project before any electricity is generated
and include costs to carry out a feasibility study,
purchase and install equipment and obtain permits.
Recurring annual costs are for operating and maintenance. Generally, micro-hydropower systems have
high initial costs but relatively low annual costs
compared with traditional fossil-fuel-based sources.
In fact, hydroelectric maintenance costs are the
lowest of all energy-producing technologies.
High-head, low-flow system costs are less than
low-head, high-flow systems because all components of low-flow systems (e.g., penstock,
turbine, intake and spillway) will be smaller. If
some part of the system already exists (e.g., a
dam or an intake), this will lower the total cost.
installation. Remember to include all costs: calculate
the intake, headrace, forebay, penstock, powerhouse
and electro-mechanical equipment, including the
turbine, the generator, controllers and the transmission/distribution network (see Appendix D).
If you do not own the land, you will have to add
the cost of buying or leasing it. If you are leasing,
this will fall under the category of annual costs.
There are also “soft” costs to consider; these,
depending on the size and complexity of the system,
can add considerably to initial costs. Soft costs
include pre-feasibility and feasibility studies, the
water licence application, obtaining land rights and
local permits, and transportation and construction.
At some sites, the equipment may need to be
transported by helicopter, which will increase costs
and could be significant for remote locations. You
should also include a small percentage of the initial
costs for contingencies or for unforeseen costs. It
is a good idea to obtain the services of an energy
expert to make these calculations for you, and costs
should be estimated at the time of the feasibility
study. For smaller systems, you could list the components and obtain a quote by calling suppliers
and checking catalogues and price lists.
The cost of a system will vary depending on
what kind of equipment is used, how much
material and equipment are needed, the cost
of civil works and other factors. If you hire a
contractor to build an intake, a long headrace
canal, powerhouse and tailrace, your cost will
be higher than doing it yourself. Each hydro
site is unique because about 75 percent of
the development cost is determined by the
location and site conditions. Only about
25 percent of the cost is relatively fixed, which
is the cost of the electro-mechanical equipment.
5.1 Initial Costs
At this stage, you should have a good idea of
the basic configuration of the kind of system
you require. The best sources of information
are manufacturers and suppliers. It is possible to
obtain a complete system price for your proposed
The estimated cost for 50-kW systems (see Table 8b)
is based on using a pump-as-turbine system; the
cost of the turbine will be much higher if a traditional turbine is used. The costs for civil works and
31
MICRO-HYDROPOWER ENERGY SYSTEMS
permits are not included. All costs given in Tables
8a and 8b are approximate. Keep in mind that each
micro-hydropower system is unique and that costs
are site-specific.
5.2 Annual Costs
Although minimal for a hydropower system,
the most important annual costs are for operation
and maintenance. These costs include labour
and materials for clearing the intake/trash rack,
equipment servicing, spare parts, and general and
transmission line maintenance. Others costs include
land leases, property taxes, water rental and general
administration. A contingency allowance should
be included to account for unforeseen annual
expenses. For a battery-based system, you should
include the cost of replacing the batteries every
5 to 10 years, depending on the quality and cycling
patterns anticipated.
32
5.3 Evaluating a System
Several things may need to be taken into account
in order to evaluate whether a micro-hydropower
system is right for you. If a site has sufficient flow
rate and head to meet your power and energy
requirements, the only other factor to consider is
whether there are alternative energy sources that
would be feasible and more economical. You may
have options such as solar, wind or diesel-powered
generators or even extending the local grid. If you
do have such options, there are various ways to
accurately compare the cost of generating energy
from alternative sources.
One indicator of the cost of your system is that
of dollars per installed kilowatt. To calculate this,
divide the total initial cost by the system’s capacity
in kilowatts. A drawback of this approach is that it
does not include operating costs and so does not
realistically compare a micro-hydro system with
A BUYER’S GUIDE
alternatives such as wind or diesel generation. A
more accurate comparative indicator is the energy
output cost in dollars per kilowatt hour. The unit
cost of energy is calculated based on energy generated by the system over its lifetime. The “fuel” for
micro-hydropower generation is almost free, and
therefore the system becomes more effective if it
runs most of the time because development costs
are the same whether 50 or 100 percent of its
potential power is used. The unit price of energy
will be quite different depending on what
percentage of potential power is generated.
Some of the commonly used financial analyses to
evaluate a system and to compare the cost of energy
from alternative sources are net present value (NPV)
and simple payback. The NPV of project investment
is the present value of future cash inflows minus
the present (discounted) value of the investment
and any future cash outflows (such as start-up and
operating costs) over its lifetime. This analysis
compares the value of money now with the value
of money in the future after taking inflation and
return into account. The NPV of a project that has
positive value is attractive.
Simple payback is a measure of the number of years
it would take to have your annual energy savings
pay for the initial and annual costs of operating the
micro-hydropower system, i.e., the length of time
required to recover the cost of your investment.
These financial analyses are complex. They may
involve issues such as the time value of money, lifecycle costing and tax savings. A thorough analysis
may not be necessary for smaller systems, but as
the system gets larger, a full financial and economic
analysis is valuable. If you need information on
how to make the analysis, consult the bibliography
at the end of this guide. Depending on the size
and cost of the system, it may be better to ask
an experienced professional to make this analysis.
The economics of a system will be significantly
influenced by its technical design, hydrology,
power and size. The value of the system is the
future benefits it can provide or the costs that can
be avoided. These costs are primarily associated
with alternatives to the micro-hydropower system.
In most cases, the alternatives will be diesel generation or connection to the local grid. In many
remote locations, diesel-generated electricity may
already be available. Therefore, the economic
analysis becomes a comparison of the capital and
operating costs of the micro-hydropower development against those associated with diesel generation
or extending the local grid. (See Section 1.3 for
other issues you may need to consider.)
In the event that your site has access to a local
electricity grid, it may be difficult to justify a
micro-hydropower system on economic terms
unless you are prepared to take a long-range view.
For some people, the idea of having a self-reliant
and self-sufficient lifestyle is appealing, regardless
of economic considerations. You should also
investigate various government programs to learn
about renewable energy sources that provide tax
exemptions for material and equipment and to
learn what financial incentives may be available.
33
MICRO-HYDROPOWER ENERGY SYSTEMS
6.0 Buying a MicroHydropower System
6.1 Expert Assistance
A micro-hydropower system is complex. Many
factors need to be considered, including the technical design, approvals and economics. You will need
to consult an energy expert to design and optimize
a system for your site. The sizing of the turbines
and penstock and selecting the type of generator is
technical and beyond the scope of this guide, but
experienced energy experts will be able to evaluate
your power requirements and the features of your
site and provide the most appropriate solution to
meet your energy requirements.
Smaller systems in the range of 5 kW or less may
not take as much design time as larger systems.
Smaller systems are available as integrated units,
and the manufacturer and supplier can provide
information to select an optimum sized penstock
pipe, turbine and generator. With this information
in hand, you may be able to construct the civil
works yourself. However, it is best to seek help
if you are uncertain about any aspect of a microhydropower system or project.
For larger systems, designing and sizing each
component is required for optimum operation
and performance. Optimum design and sizing of
civil works, the penstock, the turbine, the generator,
the transmission/distribution network and load
management is not only important for reliability;
it is just as important in economic terms because
the total cost of the system is directly affected. For
systems that are larger than 5 kW, seek the services
of an experienced energy expert who can find the
best equipment for your system design and advise
you on how to apply for approvals and permits.
6.2 Selecting a Supplier
Manufacturers and suppliers of renewable energy
systems are a source of valuable information. They
can help you evaluate a site, set up and install a
system and ensure that it works properly. If you
are contacting manufacturers about a specific site,
34
you should first find out (at least approximately)
the head, the minimum and maximum flow rates,
and the amount of power you want to generate.
Unfortunately, unlike other renewable energy
sectors in Canada, there is no national association
to address the needs of micro-hydropower users.
A supplier should have proven experience in
designing and installing the type of system you
require. Different suppliers specialize in different
types of systems. Some will supply only turbines,
and others may supply only controllers. There are
well-established small companies that offer turnkey
installations and that will provide a full range of
services from the pre-feasibility study onward. In
terms of value for money, these probably are the
best companies to deal with. You may wish to
request and review catalogues and price lists;
many catalogues also have useful information
about system design. Manufacturers’ hydroelectric
equipment in the 1- to 5-kW range may appear to
be expensive, but such equipment is likely to last
longer and work much better than homemade
systems. Many manufacturers have useful Web
sites, and other information is available through
the Internet.
Finding a local supplier or manufacturer is ideal
because it makes it easier to transport the equipment, access spare parts and get advice. Remember
to determine the price, warranty and conditions
before committing to a purchase. In other words,
shop around.
6.3 Safety and Protection
Many potential hazards can cause serious injury
or be deadly when you are installing and operating
a micro-hydropower system (e.g., falling off the
intake, being struck by the rotating shaft or electrocution). Follow the manufacturer’s safety instructions and precautions to the letter when handling
any equipment. It is all too easy to think that safety
is someone else’s responsibility. It’s not – it’s yours.
Whatever regulations and systems are in place, it
ultimately comes down to you to follow them.
A BUYER’S GUIDE
Electrical Protection
All micro-hydropower systems that generate
electricity will have some form of switchgear.
The purpose of the switchgear is to isolate the
generating unit when necessary, have control over
the electrical power flow and protect the system.
Some common switchgears are isolators, switches,
fuses and circuit breakers. Switchgears are designed
to protect against overloading and short-circuiting.
They are crucial for the safety of persons and
property and should never be neglected, even for
low-voltage systems. The generating system and
the load are also protected against over- or undervoltage and frequency. These protection systems
are also linked to automatically activate a shutdown
of the water flow into the turbine and power
generation in the event of a critical malfunction.
Lightning protection must also be installed where
power from a micro-hydropower system is transmitted from the powerhouse to a load by means
of a transmission line. The transmission line
must be protected against direct and indirect
lightning strikes.
The installation of the generator, control panels
and all other electrical equipment must comply
with the Canadian Electrical Code and should be
undertaken only by a qualified and certified person.
All electrical equipment should be grounded to
protect against electric shock due to electric leakage
or faulty wiring of the equipment. Wiring and
grounding should meet national standards and be
tested thoroughly. Ground fault interrupters, commonly used in homes, will disconnect the power if
faults such as metal parts in the equipment become
live or if there is a leakage of power to ground due
to faulty insulation. Adequate guards for the turbine
and all moving mechanical equipment must be
provided and should be checked before starting
the turbine.
35
MICRO-HYDROPOWER ENERGY SYSTEMS
7.0 Installing, Operating
and Maintaining a System
7.1 Construction and Installation
The construction phase of the project is the most
expensive. Before starting this phase, ensure that
you have finalized every detail, including the final
cost of the system, water licence, land-use approval
and other local permits.
installations. Ensure that all equipment and
materials will be delivered on time, and be aware
that the cost of labour could be more than the
cost of the materials and equipment. Performing
some of the unskilled manual labour yourself and
working with the contractor during construction
can reduce labour costs substantially and provide
invaluable experience in every aspect of the construction. After all, when construction is complete
and the system is in operation, you will be left to
maintain and operate it.
Depending on the size of the system, you may
choose to do much of the work yourself or have
the project done under contract. Construction and
installation of a micro-hydropower system requires
civil works, mechanical and electrical skills and
experience working with heavy objects. You will
need these skills to construct the intake and
headrace canal; install and align the penstock,
turbine and generator; build the powerhouse;
and put up the transmission line.
Figure 29. Burying a 20-cm (8-in.) Penstock pipe
(photo courtesy of Thomson and Howe Energy
Systems Inc.)
Figure 28. Powerhouse under construction for a 12-kW
system (photo courtesy of Thomson and Howe Energy
Systems Inc.)
The time of the year to construct the system
can influence the pace and quality of work.
From November to March, most parts of Canada
experience high rainfall and snowfall and subfreezing temperatures, which will slow down
construction. There are also fewer daylight hours
in winter. Access to remote areas may be difficult.
Planning is key to successful and inexpensive
36
If you decide to build a system yourself, smaller
battery-based systems are manageable with some
guidance from the manufacturer. For larger systems,
however, consult the experts.
7.2 Commissioning and Testing
The important final stage in installing a microhydropower system involves performance tests.
The purpose is to check the performance of each
component to ensure that it functions as it should
and to measure overall performance to verify that it
functions according to the design specification and
parameters. The commissioning process will check,
A BUYER’S GUIDE
for example, not only the amount of water flowing
from the intake but also the overload protection of
the generator. The tests include the total electrical
power generation at design flow, penstock pressure
tests, penstock losses, the turbine at rated and
over speed, voltage and frequency protection trips,
response time of the electronic load controller to
load changes and automatic safety features under
abnormal conditions, such as short-circuit and
emergency shutdowns. All components must be
fully tested. To ensure that safety protection devices
are set correctly, the tests may need to be repeated
several times.
7.3 Operation and Maintenance
Operation and maintenance of micro-hydropower
systems generally takes little time. It may be
necessary, in extreme cases, to check the system
daily to make sure that the intake is not becoming
clogged and that the system is in good working
order. Weekly or monthly inspection is much more
common. Depending on the design of the system,
you may also need to adjust the intake valve, nozzle
or guide vane occasionally to match the water flow
into the turbine with the amount of power you are
using or to conserve the amount of water you have
in the stream, especially in the dry season. More
extensive maintenance, such as greasing the
machinery and bearings, tightening of belts and
checking the water level in the batteries for batterybased systems should be done every month.
It may also be necessary to clean out silt, weeds and
so forth in the civil works and to repair any leaks or
deterioration. This is usually done about once a year
or as often as needed. The manufacturer normally
provides detailed information on maintenance
procedures and when they should be carried out.
If possible, you should take the opportunity to
become properly trained during the installation of
the project. It is good practice and cost-effective to
practise preventive maintenance rather than wait
for the system to fail. A well-maintained microhydropower system can provide an uninterrupted
power supply for many years.
Figure 30. Equipment inside a powerhouse (photo
courtesy of Thomson and Howe Energy Systems Inc.)
The commissioning procedure becomes much
more complex as the system becomes larger in
capacity. For larger systems, commissioning should
be done in cooperation with the micro-hydropower
system expert.
Figure 31. Headwork structure and screen in
Morehead Creek, British Columbia (photo courtesy
of Thomson and Howe Energy Systems Inc.)
37
MICRO-HYDROPOWER ENERGY SYSTEMS
8.0 Further Information
Renewable and Electrical Energy Division
Electricity Resources Branch
Natural Resources Canada
580 Booth Street, 17th Floor
Ottawa ON K1A 0E4
Fax: (613) 995-0087
Web site: www.reed.nrcan.gc.ca
Renewable Energy Technologies
CANMET Energy Technology Centre – Ottawa
Natural Resources Canada
580 Booth Street, 13th Floor
Ottawa ON K1A 0E4
Fax: (613) 996-9416
Web sites:
• The CANMET Energy Technology Centre (CETC):
www.nrcan.gc.ca/es/etb
• Canadian Renewable Energy Network:
www.canren.gc.ca
• International Small-Hydro Atlas:
www.small-hydro.com
To order additional copies of this publication
or to order other free publications on renewable
energy and energy efficiency, call 1 800 387-2000
toll-free. You can also obtain a copy of this
publication by visiting Natural Resources Canada’s
Canadian Renewable Energy Network (CanRen)
Web site at www.canren.gc.ca.
38
Free Software on
Micro-Hydropower Systems
RETScreen® International is a standardized,
renewable energy project analysis software program
that will help you determine whether a microhydropower system is a good investment for you.
The software uses spreadsheets and comes with
a comprehensive user’s manual and supporting
databases to help your evaluation. You can
download the software and user manual free
of charge from the Web site at www.retscreen.net,
or call Natural Resources Canada at (450) 652-4621
or fax your request to (450) 652-5177.
Manufacturers and Suppliers
See the Canadian Renewable Energy Network Web
site at www.canren.gc.ca for a list of manufacturers
and suppliers of micro-hydropower systems.
A BUYER’S GUIDE
Appendix A
Determining Head and Flow Rate
Measuring Head
Head is the vertical distance that water falls from
the forebay or intake to the turbine. It is measured
in metres or feet. Measuring the available head is
often seen as a task for a surveyor but, for many
systems, much quicker and less costly methods
can be used for preliminary determination of head.
There are several ways to measure the available
head, including maps, the pressure-gauge method,
dumpy levels (builders’ levels) and theodolites,
sighting meters, the water-filled tube and rod
method and altimeters.
Some measurement methods are more suitable for
low-head sites but are too tedious and/or inaccurate
for high-head sites. If possible, it is wise to take
several separate measurements of the head at each
site. It is best not to leave the site before analysing
the results because any mistakes will be easier to
check on-site. The head must be measured accurately because it is one of the most important considerations in the hydropower system’s design and
costing. The proposed location of the powerhouse
and penstock intake structure should be used as
reference points in measuring the head. Several
methodologies for measuring head are explained
briefly in the following (adapted from Micro-Hydro
Design Manual: A Guide to Small-Scale Water Power
Schemes).
Maps
Detailed topographic maps are useful for locating
potential sites and for obtaining a rough estimate
of head levels at the proposed intake, tailrace water
levels, the length of the pipelines, the size of the
drainage area and the origin and destination of the
stream. However, maps may not always be available
or entirely reliable. For high head sites with more
than 100 m (330 ft.) of head, 1:50 000 maps are
useful. Smaller-scale maps are better because they
have a higher contour resolution – 10 m (about
30 ft.) is typical. Topographic maps can be obtained
from Natural Resources Canada through its Web
site at maps.nrcan.gc.ca. Provincial and territorial
ministries for natural resources, land and water or
your local forestry office may have more detailed
maps at scales of 1:10 000 or 1:20 000.
Pressure-Gauge Method
This method can be used for high heads and low
heads; the choice of pressure gauge depends on
the head to be measured. A 20-m (65-ft.) length
of transparent plastic pipe is good for measuring
sites of approximately 60 m (200 ft.) of head. It is
probably the best of the simple methods available.
In this technique, the head is measured according
to the static pressure of water. After the pressure is
measured with a gauge, it is easily converted into
the height of the head. A column of water 1 m
high exerts a pressure equal to 9.8 kilopascals,
or 1.42 pounds per square inch (PSI). If measuring
in feet, multiply the pressure in PSI by 2.31
(e.g., 100 PSI = 100 2.31 = 231 ft.).
Figure 32. Topographic map of Squamish,
British Columbia
39
MICRO-HYDROPOWER ENERGY SYSTEMS
Sighting Meters
Hand-held sighting meters, also known as inclinometers or Abney levels (see Figure 33), measure the
slope’s angle of inclination. They are accurate if
used by an experienced operator, but it is always
best to double-check the measurement. Sighting
meters are compact, and some have range finders,
which saves the trouble of measuring linear distance.
L4
4
h4
L3
3
hn = Lnsinn
2
h3
L2
1
h2
Figure 34. Measuring head using spirit level and
plank method
h1
Water-Filled Tube and Rod Method
L1
Figure 33. Measuring head using Abney-level method
Dumpy Levels and Theodolites
A dumpy level (builder’s level) is the conventional
tool used for measuring head. An experienced operator who can check the level’s calibration should
make the measurement. When using a dumpy level,
the operator takes a horizontal sight on a staff held
by a colleague and needs an unobstructed view. A
theodolite can measure vertical and horizontal angles.
A hypsometer, similar to a theodolite, is used by
field foresters to calculate tree heights and can be
adapted for measuring head. It requires an operator
and an assistant to operate a reflection device; a
clear line of sight is also needed. A hypsometer
operates on the principle of electronic measuring
of the linear distance and includes the angle of
the measurement along with the distance. It can
provide a fairly accurate measurement when used
correctly.
40
This method is suitable for low-head sites. It is
reliable, reasonably accurate and inexpensive. Two
or three separate measurements must be made in
order to ensure that the results are consistent and
reliable. Results from this method should be crosschecked against measurements made by another
method, such as the pressure-gauge method. A
carpenter’s spirit level and a straight plank of wood
can be used for steep slopes instead of a water-filled
tube and rod (see Figure 34).
Altimeters
Altimeters can be useful when undertaking highhead pre-feasibility studies. Atmospheric pressure
variations should be taken into account, and this
method is generally not recommended except to
obtain an approximate reading. The best time to
use this method is at midday, when there is the
least atmospheric variation. Conventional altimeters
are difficult to use; new, digital ones are easier.
The principle of the altimeter is that it measures
atmospheric pressure as indicated by a change in
head of mercury of 9 mm for every 100-m change
in elevation.
A BUYER’S GUIDE
Measuring Water Flow
Flow Data
Flow rate is the quantity of water available in
a stream or river and may vary widely over the
course of a day, week, month and year. In order to
adequately assess the minimum continuous power
output to be expected from the micro-hydropower
system, the minimum quantity of water available
must be determined. The purpose of a hydrology
study is to predict the variation in the flow during
the year. It is important to know the mean stream
flow and the extreme high- and low-flow rates.
Environmental and climatic factors and human
activities in the watershed determine the amount
and characteristics of stream flow on a day-to-day
and seasonal basis. Generally, unless you are
considering a storage reservoir, you should use
the lowest mean annual flow as the basis for the
system design.
There may be legal restrictions on the amount of
water you can divert from a stream at certain times
of the year; in such a case, you will have to use this
amount of available flow as the basis of the design.
The percentage of the maximum flow that may be
diverted for power generation is defined during
government approval of the water licence.
Generally, 10 percent of mean annual discharge
flow release is required in fish-bearing streams, but
this could be lowered to 5 percent of mean annual
discharge in non-fish–bearing streams. Mean annual
discharge may also be different for a coastal stream
than for a colder climate with snow and freshet
flows. Non-classified drainages may sometimes
have no flow release requirement. Most microhydropower systems may use only a fraction of
the available water flow in the stream.
Daily stream flow data for your site may be
available from the provincial water management
branch or Environment Canada (EC). However,
most micro-hydropower sites are on very small
streams or creeks that are not monitored (gauged)
by Environment Canada. Use of data from another
stream requires multiplying the flow data by the
ratio of the watershed area of your site and the
environment site. The ratio should not be greater
than 1.2 or less than 0.8.
Watershed area ungauged
(your site)
Watershed area gauged
(EC site)
daily flow (EC) = daily flow
(your site)
To delineate the watershed area of your site,
topographic maps at 1:50 000 scale and assistance
in watershed delineation are available from the
following Web sites:
• maps.nrcan.gc.ca
• www.nh.nrcs.usda.gov/technical/
WS_delineation.html
Flow-Rate Measurement Methods
There are a variety of techniques for measuring
stream flow rate; the most commonly used are
briefly explained in this section. For more
information on these methods, consult the
bibliography.
• container method
• float method
• weir method
• salt and conductivity meter method
• current meter method
Whenever possible, stream flow data should
be measured daily and recorded for at least one
year; two to three years is ideal. If not, a few
measurements should be made during the lowflow season. If you are familiar with the stream,
you might determine the low-flow season by
keeping track of water levels and making several
flow measurements for more than a week when
the water level is at its lowest point during the year.
You may also be able to gather information from
neighbours or other sources.
41
MICRO-HYDROPOWER ENERGY SYSTEMS
Container Method
For very small streams, a common method for
measuring flow is the container method. This
involves diverting the whole flow into a container
such as a bucket or barrel by damming the stream
and recording the time it takes for the container to
fill. The rate that the container fills is the flow rate,
which is calculated simply by dividing the volume
of the container by the filling time. Flows of up to
20 lps can be measured using a 200-litre container
such as an oil drum.
One way of using this principle is for the crosssectional profile of a streambed to be charted and
an average cross section established for a known
length of stream. A series of floats, perhaps pieces
of wood, are timed over this measured length of
stream. Results are averaged and a flow velocity is
obtained. This velocity must then be reduced by a
correction factor, which estimates the mean velocity
as opposed to the surface velocity. By multiplying
averaged and corrected flow velocity, the volume
flow rate is estimated. This method provides only
an approximate estimate of the flow.
Approximate correction factors to convert measured
surface velocity to mean velocity are as follows:
Concrete channel, rectangular, smooth
0.85
Large, slow, clear stream
0.75
Small, slow, clear stream
0.65
Shallow (less than 0.5 m / 1.5 ft.)
turbulent stream
0.45
Very shallow, rocky stream
0.25
Weir Method
Figure 35. Measuring water flow rate using
container method
Float Method
For larger streams where the construction of a weir
may not be practical, or for a quick estimate of the
flow, the float method is useful. The principle of all
velocity-area methods is that flow (Q) equals the
mean velocity (Vmean) multiplied by the crosssectional area (A):
Q (m3/s) = A (m2) Vmean (m/s)
42
A weir is a structure such as a low wall across
a stream. A flow measurement weir has a notch
through which all water in the stream flows. The
flow rate can be determined from a single reading
of the difference in height between the upstream
water level and the bottom of the notch. For
reliable results, the crest of the weir must be kept
sharp, and sediment must be prevented from
accumulating behind the weir.
Weirs can be timber, concrete or metal and must
always be oriented at a right angle to the stream
flow. The weir should be located at a point where
the stream is straight and free from eddies. It is
necessary to estimate the range of flows to be
measured before designing the weir in order to
ensure that the chosen size of notch will be adequate to pass the magnitude of the stream flow.
Rectangular weirs are more suitable for large flows
in the range of 1000 lps, and triangular weirs are
suitable for small flows that have wide variation.
A combination triangular/rectangular compound
weir may be incorporated into one weir to measure
higher flows; at lower flows the water goes through
the triangular notch.
A BUYER’S GUIDE
A bucket of heavily salted water is poured into the
stream. The cloud of salty water in the stream starts
to spread out while travelling downstream. At a
certain point, it will fill the width of the stream.
The cloud will have a leading part, which is weak
in salt, a middle part, which is strong in salt, and
a lagging part, which is weak. The salinity of the
water is measured with an electrical conductivity
meter. A low-flow stream will not dilute the salt
very much, so the electrical conductivity of the
cloud will be high. Therefore, low flows are indicated by high conductivity and vice versa. The flow
rate is therefore inversely proportional to the degree
of conductivity of the cloud. The slower the flow,
the longer the cloud takes to pass the probe of the
meter. Therefore, flow is also inversely proportional
to the time it takes for the cloud to travel.
Figure 36. Measuring water flow rate using weir method
Salt and Conductivity Meter Method
Using the salt and conductivity meter method,
stream flow can be measured in a very short time
and has proven easy to do, reasonably accurate
and reliable for a wide range of stream types. It
gives better results than other methods for more
turbulent streams. The main device is a conductivity meter. The calculation takes a little longer
if done manually; alternatively, calculation can be
done automatically with an integrating meter that
will provide measurement in litres per second.
It is recommended to use about 100 g of salt for
every 100 lps of flow. As with all methods, the
measurements should be made at least twice
to confirm the accuracy of the measurement.
Current Meter Method
A current meter is essentially a shaft with a
propeller or wheel of revolving cups at one end.
When submersed, the propeller rotates at the speed
of the water current. A mechanical counter records
the number of revolutions of the propeller when
placed at a desired depth (indicated by a marker
on the propeller handle). By averaging readings
taken evenly throughout a stream cross section,
an average velocity can be determined. Current
meters use a formula that relates rotational speed
of the propeller to the speed of the water current;
the formula is supplied with the meter.
Figure 37. Flow measurement using an integrating
meter (photo courtesy of Dulas Engineering Ltd.)
43
MICRO-HYDROPOWER ENERGY SYSTEMS
Appendix B
Sample Data Sheet
Project name: _____________________________________________________________________________
A. Stream Characteristics
1. Site location:
_____________________________________
2. Available flow rate:
_____________________________________ lps
3. Design flow rate:
_____________________________________ lps
4. Head gross (static):
_____________________________________ m
5. Length of penstock:
_____________________________________ m
6. Diameter of penstock:
_____________________________________ m
7. Existing intake?
Yes
No
B. Electrical Characteristics
8. Voltage required:
_____________________________________ V (AC/DC)
9. Frequency:
_____________________________________ Hz
10. Phases:
_____________________________________
11. Expected output power:
_____________________________________ kW
12. Length of transmission line: _____________________________________ m
13. Control method desired:
Automatic
Manual
List electrical needs: _____________________________________________________________
_________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
C. Contact Information
Name:__________________________________________________________________________
Address: ________________________________________________________________________
City: ___________________________________________________________________________
Province/territory:_______________________________________________________________
Postal code: ________________________ Telephone: ________________________________
Fax: _______________________________ E-mail: _____________________________________
44
A BUYER’S GUIDE
Appendix C
Typical Household Appliance Loads
Appliances
Power Rating
(W)
Average Hours
per Month
Energy Used
(kWh) per Month
Kitchen
Blender
350
3
1
Coffee maker
900
12
11
Deep fryer
1500
8
12
Dishwasher*
1300
20
26
Exhaust fan
250
30
8
1500
10
15
Food freezer (15 cu. ft.)
350
240
84
Hot plate (one burner)
1250
14
18
900
10
9
1500
10
15
Mixer
175
6
1
Range
4000
25
100
Range and oven
3500
25
90
Frost-free (17 cu. ft.)
500
300
150
Non-frost-free (11.5 cu. ft.)
300
300
90
1200
4
5
5000
28
140
Washing machine* (33 loads/month)
500
26
13
Front-loading washer*
160
26
4
1000
12
12
Family of two
3800
80
304
Family of four
3800
140
532
Air conditioner
750
74
56
Electric blanket
180
80
14
Electric heating
1000
250
250
120
6
1
Electric kettle
Microwave oven (0.5 cu. ft.)
Microwave oven (0.8 to 1.5 cu. ft.)
Refrigerator-freezer
Toaster
Laundry
Clothes dryer (35 loads/month)
Iron
Electric water heaters
Comfort and Health
Fan (portable)
* Excluding hot water requirements
45
MICRO-HYDROPOWER ENERGY SYSTEMS
Appliances
Power Rating
(W)
Hair dryer (hand-held)
Average Hours
per Month
Energy Used
(kWh) per Month
1000
5
5
Incandescent bulb (60 W)
60
120
7
Incandescent bulb (100 W)
100
90
9
Fluorescent (4 ft.)
50
240
12
Compact fluorescent lamp (24 W)
24
240
6
1000
350
350
Telephone, portable
3
720
2
Telephone answering machine
6
720
4
250
240
60
30
240
7
Laptop charger
100
240
24
Laser printer
600
60
36
Radio
5
120
1
Stereo
120
120
14
Television (colour)
100
125
13
Television (black and white)
60
120
7
Video cassette recorder
40
100
4
Block heater
600
120
72
Lawn mower
1000
10
10
⁄ -inch drill
250
4
1
Circular saw
1000
6
6
Table saw
1000
4
4
460
2
1
2
720
1
Sewing machine
100
10
1
Vacuum cleaner
800
10
8
1000
44
44
Lights
Portable electric heater
Entertainment
Computer (desktop)
Computer (laptop)
Outdoors
Workshop tools
1
4
Lathe
Other
Clock
1
2
Water pump ( ⁄ hp)
46
A BUYER’S GUIDE
Appendix D
Costing Estimate Worksheet
Initial Costs
No. of
Units
Cost per
Unit
Total Cost
($)
Civil works
Intake
Headrace canal
Forebay
Penstock pipe
Powerhouse and tailrace
Total civil works cost
Electro-mechanical equipment
Turbine and generator set
Controller
Electrical switchgear
Transmission line cables and gears
Transmission line poles
Battery bank and inverter*
Total electro-mechanical equipment
Planning and development costs
Pre-feasibility study
Feasibility study
Permit and approvals
Engineering
Transportation
Construction and installation
Contingency
Total planning and development costs
Total initial costs
Annual costs
Operation and maintenance
Spare parts
Water rental fee
Annual
Land lease
Annual
Miscellaneous
Total annual costs
* Applies only to battery-based systems
47
MICRO-HYDROPOWER ENERGY SYSTEMS
Glossary of Terms and
Abbreviations
Terms
Alternating current (AC): Electric current
that flows in one direction and then in the
reverse direction. In North America, the standard
cycle frequency is 60 Hz; in Europe it is 50 Hz.
Alternating current is used universally in power
systems because it can be transmitted and
distributed much more economically than
direct current.
Base load: The amount of electrical power that
needs to be delivered at all times and during all
seasons.
Capacitor: A dielectric device that momentarily
absorbs and stores electric energy.
Capacity: The maximum power capability of a
power-generating system. Common units used are
kilowatts or megawatts.
Capacity factor: The ratio of the energy that a
power-generating system produces to the energy
that would be produced if it were operated at full
capacity throughout a given period, usually
one year.
Compact fluorescent light (CFL): A modern
light bulb with integral ballast using a fraction
of the electricity used by a regular incandescent
light bulb.
Current: The rate of flow of electricity, measured
in amperes, or amps. Analogous to the rate of flow
of water measured in litres per second.
Direct current (DC): Electricity that flows
continuously in one direction, such as from
a battery.
48
Flow: The quantity of water being used to produce
power. This is usually measured in units of cubic
metres per second, cubic feet per minute, litres per
second or gallons per minute.
Frequency: The number of cycles through which
an alternating current passes in a second, measured
in Hertz (Hz).
Generator: A rotating machine that converts
mechanical energy into electrical energy.
Grid: A utility term for the network of wires that
distributes electricity from a variety of sources
across a large area.
Head: The difference in elevation between two
water surfaces, measured in metres or feet. Gross
head: The vertical drop between the intake of a
pipeline (penstock) and the outlet (location of
turbine). Net head: The usable head after subtracting
losses in the penstock pipe.
Hertz (Hz): Unit of frequency measurement for
AC. Equivalent to “cycles per second,” common
household utility power is normally 60 Hz in
North America.
Inverter: An electronic device used to convert
DC electricity into AC, usually with an increase
in voltage.
Joule (J): The international unit of energy. The
energy produced by a power of one watt flowing
for one second.
Kilowatt (kW): The commercial unit of electrical
power; 1000 watts.
Kilowatt hour (kWh): A measurement of energy.
One kilowatt hour is equal to one kilowatt being
used for one hour.
Load: The collective appliances and other devices
connected to a power source.
Efficiency: The ratio of the output to the input
of energy or power, expressed as a percentage.
Megawatt (MW): A measurement of power equal
to 1 million watts.
Energy: The ability to do work; the quantity
of electricity delivered over a period of time. The
electrical energy term commonly used is kilowatt
hours (kWh), which represents the power (kW)
operating over some period of time (hours);
1 kWh = 3600 kilojoules.
Net-metering: A form of buy-back agreement in
which the grid-supplied house electricity meter turns
or measures in the utility’s favour when grid electric
power is consumed by the house, and in the house
owner’s favour when the house’s own generation
exceeds its needs and electricity flows into the grid.
At the end of the payment period, when the meter
is read, the system owner pays the utility the
difference between what the house consumed
and what was supplied to the grid.
A BUYER’S GUIDE
Off-grid: Not connected to power lines;
electrical self-sufficiency.
Abbreviations
Ah
=
ampere hour
Output: The amount of power delivered by
a system.
AC
=
alternating current
CFL
=
compact fluorescent lamp
cfm
=
cubic feet per minute
DC
=
direct current
Over speed: The speed of the turbine runner
when, under design conditions, all external loads
are removed.
Peak load: The electric load at the time of
maximum demand.
DILC =
distributed intelligent load controller
Penstock: A pipe that conveys water under
pressure from the forebay to the turbine.
e
=
efficiency
EC
=
Environment Canada
Phantom loads: Appliances that draw power
24 hours a day, even when turned off. Televisions,
VCRs, microwave ovens with clocks and computers
all contain phantom loads.
ELC
=
electronic load controller
FDC
=
flow duration curve
ft.
=
foot; feet
Power: The rate of doing work, or more generally,
the rate of converting energy from one form to
another. Measured in joules/second or watts
(1 W = 1 J/s). Electrical power is measured in
kilowatts.
gpm
=
gallons per minute
H
=
gross head
h
=
net head
Hz
=
hertz
IGC
=
induction generator controller
in.
=
inch
kW
=
kilowatt
kWh
=
kilowatt hour
lps
=
litres per second
m
=
metre
Power factor: The ratio of an appliance’s actual
power in watts to the apparent power measured in
volt-amps (VA). As an example, a 400-W appliance
with a power factor of 0.8 would require a power
source of 500 VA to drive it properly. This is why
loads with poor power factors need larger-thanexpected generators to power them.
Run-of-river: Hydropower systems where water is
used at a rate no greater than that which runs down
the river.
Transformer: A device consisting of two or more
insulated coils of wire wound around a magnetic
material such as iron, used to convert one AC
voltage to another or to electrically isolate the
individual circuits.
Turbine: A device that converts kinetic energy of
flowing water to mechanical energy. Often used to
drive generators or pumps.
MAD =
mean annual discharge
P
=
power
PSI
=
pounds per square inch
Q
=
flow rate
rpm
=
revolutions per minute
V
=
voltage
W
=
watt
Voltage (V): Measure of electrical potential; the
electrical “pressure” that forces an electrical current
to flow through a closed circuit.
Watt (W): The scientific unit of electrical power;
a rate of doing work at the rate of one joule per
second. Commonly used to define the rate of
electricity consumption of an electric appliance.
49
MICRO-HYDROPOWER ENERGY SYSTEMS
Bibliography
Books
Davis, Scott. Microhydro: Clean Power from Water
(draft). British Columbia: New Society Publishers,
2003.
DCS – Technology Development and the
International Centre for Integrated Mountain
Development (ICIMOD). Manual for Survey and
Layout Design of Private Micro-Hydropower Plants.
Butwal, Nepal: DCS – Technology Development;
Kathmandu, Nepal: ICIMOD, 1999.
Fraenkel, Peter, et al. Micro-Hydro Power: A Guide for
Development Workers. London, U.K.: Intermediate
Technology Publications in association with the
Stockholm Environment Institute, 1991.
Harvey, Adam, et al. Micro-Hydro Design Manual:
A Guide to Small-Scale Water Power Schemes.
London, U.K.: Intermediate Technology
Publications, 1993.
Inversin, Allen R. Micro-Hydropower Sourcebook:
A Practical Guide to Design and Implementation in
Developing Countries. Washington, DC: National
Rural Electric Cooperative Association
International Foundation, 1986.
Newfoundland and Labrador Department of Mines
and Energy. Micro-Hydro Power in Newfoundland
and Labrador. St. John’s, 1984.
Ontario. Ministry of Energy. Micro-Hydro Power:
Energy from Ontario Streams. Toronto, 1982.
Ontario. Ministry of Energy. Streams of Power:
Developing Small Scale Hydro Systems. Toronto,
1986.
Penche, Celso. Layman’s Guidebook on How to
Develop a Small Hydro Site, 2nd edition. Brussels,
Belgium: Commission of the European
Communities, Directorate General for Energy
(DG XVII), European Small Hydropower
Association (ESHA), 1998.
BC Hydro. Handbook for Developing Micro Hydro
in British Columbia (Draft), 2002.
Canada Mortgage and Housing Corporation. Energy
Use Patterns in Off-Grid Houses, Research
Highlights – Technical Series 01-103.
Energy, Mines and Resources Canada. Efficiency and
Alternative Energy Technology Branch. Canadian
Small Hydropower Handbook: British Columbia
Region. Ottawa, 1989.
Mathews, Robert. Micro-hydro course, Appropriate
Energy Systems, British Columbia, 2000.
National Centre for Appropriate Technology.
Micro-Hydro Power: Reviewing an Old Concept.
Butte, Montana, 1979.
Natural Resources Canada. CANMET Energy
Technology Centre (CETC). RETScreen®
International, Background – Small Hydro
Project, Varennes.
Natural Resources Canada. Renewable and Electrical
Energy Division. Energy Resources Branch.
Stand-Alone Wind Energy Systems: A Buyer’s Guide.
Ottawa, 2000.
Technical Papers
Cunningham, Paul and Atkinson, Barbara. “Micro
Hydro Power in the Nineties,” Homepower, No. 44
(December 1994 / January 1995), pp. 24–29.
Intermediate Technology Development Group
(ITDG). Micro-Hydro Power (technical brief).
U.S. Department of Energy. National Renewable
Energy Laboratory. Small Hydropower Systems
(DOE/GO-102001-1173 FS217), July 2001.
U.S. Department of Energy. Office of Energy
Efficiency and Renewable Energy. Consumer
Energy Information: EREC Reference Briefs.
Is a Micro-Hydroelectric System Feasible for You?
November 2002.
Smith, Nigel. Motors as Generators for Micro-Hydro
Power. London, U.K.: Intermediate Technology
Publications, 1997.
Weaver, Christopher S. Understanding MicroHydroelectric Generation, Technical Paper No. 18.
Volunteers in Technical Assistance (VITA), 1985.
Solar Energy Society of Canada Inc. The Canadian
Renewable Energy Guide, 2nd edition. Regina,
1999.
Weaver, Christopher S. Understanding MiniHydroelectric Generation, Technical Paper No. 19.
Volunteers in Technical Assistance (VITA), 1985.
Williams, Arthur. Pumps as Turbines: A User’s Guide.
London, U.K.: Intermediate Technology
Publications, 1995.
50
Manuals
A BUYER’S GUIDE
Useful Web Sites
Organizations
BC Hydro:
www.bchydro.com/environment/greenpower/
greenpower1751.html
British Hydropower Association:
www.british-hydro.org
David Suzuki Foundation:
www.davidsuzuki.org
EnerGuide, Office of Energy Efficiency,
Natural Resources Canada:
oee.nrcan.gc.ca/energuide/home.cfm
Friends of Renewable Energy BC:
www.forebc.com
Green Empowerment:
www.greenempowerment.org/resources.htm
Intermediate Technology Development
Group (ITDG):
www.itdg.org
International Small-Hydro Atlas:
www.small-hydro.com
Micro Hydro Centre:
www.eee.ntu.ac.uk/research/microhydro
Micro-hydro Web portal:
www.microhydropower.net
MicroPower Connect:
www.micropower-connect.org
Natural Resources Canada (topographic maps):
maps.nrcan.gc.ca
Office of Energy Efficiency and Renewable Energy,
U.S. Department of Energy:
www.eren.doe.gov/consumerinfo/refbriefs/ab2.html
RETScreen® International:
www.retscreen.net
Tax incentive for businesses:
www.canren.gc.ca/app/filerepository/
General-tax_incentives.pdf
Volunteers in Technical Assistance (VITA):
www.vita.org
Companies
Asia Phoenix Resources Ltd.:
www.powerpal.com
Canadian Hydro Components Ltd.:
www.canadianhydro.com
Canyon Industries Inc.:
www.canyonindustriesinc.com
Dependable Turbines Ltd.:
www.dtlhydro.com
Dulas Engineering Ltd.: www.dulas.org.uk
Mini-Grid Systems/Econnect Ltd.:
www.mini-grid.com
Energy Alternatives:
www.energyalternatives.ca
Energy Systems & Design:
www.microhydropower.com
Evans Engineering Ltd.:
www.microhydro.com
Harris Hydroelectric:
www.harrishydro.com
IT Power: www.itpower.co.uk
Morehead Valley Hydro Inc.:
www.smallhydropower.com
Ottawa Engineering Limited:
www.ottawaengineering.com
Powerbase Automation Systems Inc.:
www.powerbase.com
Sustainable Control Systems Ltd.:
www.scs-www.com
Thomson and Howe Energy Systems Inc.:
www.smallhydropower.com/thes.html
Yalakom Appropriate Technology:
www.yalatech.com
Micro-Hydropower Systems in Action
CADDET Centre for Renewable Energy:
www.caddet-re.org
Homepower:
www.homepower.ca
Micro-hydropower course on-line:
www.energyalternatives.ca
51
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