Small Wind Electric Systems A Hawaii Consumer's Guide by pnq12387


									Small Wind Electric Systems
Small Wind Electric Systems

Cover photo: The Parker Ranch installation in Kamuela, Hawaii, is the largest hybrid project in the country, covering
almost two acres. Five Bergey 10-kW turbines provide 50 kW of wind power.
Photo credit — Powerlight Corporation/PIX13822
                                                                             Small Wind Electric Systems                                     1

  Small Wind Electric Systems
                              A U.S. Consumer’s Guide

Can I use wind energy to power my
home? This question is being asked
across the country as more people
look for affordable and reliable sourc-
es of electricity.
Small wind electric systems can make
a significant contribution to our
nation’s energy needs. Although wind
turbines large enough to provide a
significant portion of the electricity
needed by the average U.S. home gen-
erally require one acre of property or
more, approximately 21 million U.S.
homes are built on one-acre and larger

                                                                                                                                  Bergey Windpower/PIX01476
sites, and 24% of the U.S. population
lives in rural areas.
A small wind electric system will
work for you if:
• There is enough wind where you          Homeowners, ranchers, and small businesses can use wind-
                                          generated electricity to reduce their utility bills. This grid-
  live                                    connected system installed for a home in Norman, Oklahoma,
• Tall towers are allowed in your         reduces the homeowner’s utility bill by $100 per month.
  neighborhood or rural area
• You have enough space
• You can determine how much                Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
  electricity you need or want to           First, How Can I Make My Home More Energy Efficient? . . . . 2
                                            Is Wind Energy Practical for Me? . . . . . . . . . . . . . . . . . . . . . . 3
• It works for you economically.            What Size Wind Turbine Do I Need? . . . . . . . . . . . . . . . . . . . 4
The purpose of this guide is to pro-        What are the Basic Parts of a Small Wind Electric System? . . 5
vide you with the basic information         What Do Wind Systems Cost? . . . . . . . . . . . . . . . . . . . . . . . . 7
about small wind electric systems to        Where Can I Find Installation and Maintenance Support? . . . 8
help you decide if wind energy will         How Much Energy Will My System Generate? . . . . . . . . . . . . 9
work for you.                               Is There Enough Wind on My Site? . . . . . . . . . . . . . . . . . . . 11
Why Should I Choose Wind?                   How Do I Choose the Best Site for My Wind Turbine? . . . . . 14
Wind energy systems are one                 Can I Connect My System to the Utility Grid? . . . . . . . . . . . 15
of the most cost-effective home-            Can I Go “Off-Grid”? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
based renewable energy systems.             Glossary of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Depending on your wind resource, a          For More Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2   Small Wind Electric Systems

                small wind energy system can lower                      Home Energy Use
                your electricity bill by 50% to 90%,                 Based on national averages
                help you avoid the high costs of
                extending utility power lines to                          Water
                remote locations, prevent power                          heating
                interruptions, and it is nonpolluting.                    14%
                                                                                          Heating and
                How Do Wind Turbines Work?                        Lighting,                 cooling
                Wind is created by the unequal heat-              cooking,                   44%
                                                                  and other
                ing of the Earth’s surface by the sun.
                Wind turbines convert the kinetic                   33%

                energy in wind into mechanical
                power that runs a generator to
                produce clean electricity. Today’s
                turbines are versatile modular sources                                    Refrigerator 9%
                of electricity. Their blades are aero-     The largest portion of a utility bill for a typical
                dynamically designed to capture the        house is for heating and cooling.
                maximum energy from the wind. The
                wind turns the blades, which spin a        • Save money and increase
                shaft connected to a generator that          comfort by properly maintaining
                makes electricity.                           and upgrading your heating,
                                                             ventilation, and air-conditioning
                First, How Can I Make                        systems.
                My Home More Energy
                Efficient?                                 • Install double-paned, gas-filled
                                                             windows with low-emissivity
                Before choosing a wind system for
                                                             (low-e) coatings to reduce heat
                your home, you should consider
                                                             loss in cold climates and spectrally
                reducing your energy consumption by
                                                             selective coatings to reduce heat
                making your home or business more
                                                             gain in warm climates.
                energy efficient. Reducing your
                energy consumption will signifi-           • Replace your lights in high-use
                cantly lower your utility bills and will     areas with fluorescents. Replacing
                reduce the size of the home-based            25% of your lights can save about
                renewable energy system you need.            50% of your lighting energy bill.
                To achieve maximum energy effi-            • When shopping for appliances,
                ciency, you should take a whole-             look for the ENERGY STAR® label.
                building approach. View your home            ENERGY STAR® appliances have
                as an energy system with interrelated        been identified by the U.S.
                parts, all of which work synergisti-         Environmental Protection Agency
                cally to contribute to the efficiency        and U.S. Department of Energy
                of the system. From the insulation in        as being the most energy-efficient
                your home’s walls to the light bulbs         products in their classes.
                in its fixtures, there are many ways to
                                                           • For more information on how to
                make your home more efficient.
                                                             make your home energy efficient,
                • Reduce your heating and                    see Energy Savers in the For More
                  cooling needs by up to 30% by              Information section.
                  investing just a few hundred
                  dollars in proper insulation and
                  weatherization products.
                                                                 Small Wind Electric Systems                                      3

Is Wind Energy Practical                  structures permitted in residentially
for Me?                                   zoned areas, although variances are
A small wind energy system can            often obtainable. Most zoning ordi-
provide you with a practical and          nances have a height limit of 35 feet.
economical source of electricity if:      You can find out about the zoning
                                          restrictions in your area by calling
• your property has a good wind           the local building inspector, board of
  resource                                supervisors, or planning board. They
• your home or business is located on     can tell you if you will need to obtain
  at least one acre of land in a rural    a building permit and provide you
  area                                    with a list of requirements.
• your local zoning codes or              In addition to zoning issues, your
  covenants allow wind turbines           neighbors might object to a wind
                                          machine that blocks their view, or
• your average electricity bills are
                                          they might be concerned about noise.
  $150 per month or more
                                          Most zoning and aesthetic concerns
• your property is in a remote            can be addressed by supplying objec-
  location without easy access to         tive data. For example, the ambient
  utility lines                           noise level of most modern residential
• you are comfortable with long-term      wind turbines is around 52 to 55 deci-
  investments.                            bels. This means that while the sound
                                          of the wind turbine can be picked out
Zoning Issues                             of surrounding noise if a conscious
Before you invest in a wind energy        effort is made to hear it, a residential-
system, you should research poten-        sized wind turbine is no noisier than
tial obstacles. Some jurisdictions, for   your average refrigerator.
example, restrict the height of the

                                                                                                         In Clover Valley,
                                                                                                         Minnesota, this
                                                                                                         3-kW Whisper
                                                                                                         H175 turbine on a
                                                                                                         50-foot tower is
                                                                                                         connected to the
                                                                                                         utility grid to offset
                                                                                                         the farm’s utility-
                                                                                                         supplied electricity.
                                                                                      World Power Technology/PIX07168
4    Small Wind Electric Systems

                      What Size Wind Turbine                                        Turbines used in residential applica-
                      Do I Need?                                                    tions can range in size from 400 watts
                      The size of the wind turbine you need                         to 100 kW (100 kW for very large
                      depends on your application. Small                            loads), depending on the amount of
                      turbines range in size from 20 watts                          electricity you want to generate. For
                      to 100 kilowatts (kW). The smaller or                         residential applications, you should
                      “micro” (20- to 500-watt) turbines are                        establish an energy budget to help
                      used in a variety of applications such                        define the turbine size you will need.
                      as charging batteries for recreational                        Because energy efficiency is usually
                      vehicles and sailboats.                                       less expensive than energy produc-
                                                                                    tion, making your house more energy
                      One- to 10-kW turbines can be used in                         efficient first will probably be more
                      applications such as pumping water.                           cost effective and will reduce the size
                      Wind energy has been used for centu-                          of the wind turbine you need (see
                      ries to pump water and grind grain.                           How Can I Make My Home More
                      Although mechanical windmills still                           Energy Efficient?). Wind turbine
                      provide a sensible, low-cost option                           manufacturers can help you size
                      for pumping water in low-wind areas,                          your system based on your electricity
                      farmers and ranchers are finding that                         needs and the specifics of local wind
                      wind-electric pumping is a little more                        patterns.
                      versatile and they can pump twice
                      the volume for the same initial                               A typical home uses approximately
                      investment. In addition, mechanical                           10,000 kilowatt-hours (kWh) of elec-
                      windmills must be placed directly                             tricity per year (about 830 kWh per
                      above the well, which may not take                            month). Depending on the average
                      the best advantage of available wind                          wind speed in the area, a wind tur-
                      resources. Wind-electric pumping                              bine rated in the range of 5 to 15 kW
                      systems can be placed where the wind                          would be required to make a signifi-
                      resource is the best and connected to                         cant contribution to this demand. A
                      the pump motor with an electric cable.                        1.5- kW wind turbine will meet the
                                                                                    needs of a home requiring 300 kWh
                                                                                    per month in a location with a 14-
This 1-kW Whisper                                                                   mile-per-hour (6.26-meters-per-sec-
turbine provides                                                                    ond) annual average wind speed. The
direct AC power for
                                                                                    manufacturer can provide you with
the water pump for
stock tanks on a                                                                    the expected annual energy output
ranch in Wheeler,                                                                   of the turbine as a function of annual
Texas.                                                                              average wind speed. The manufac-
                                                                                    turer will also provide information on
                                                                                    the maximum wind speed at which
                                                                                    the turbine is designed to operate
                                                                                    safely. Most turbines have automatic
                                                                                    overspeed-governing systems to keep
                                                                                    the rotor from spinning out of control
                                                                                    in very high winds. This information,
                                                                                    along with your local wind speed and
                                                                                    your energy budget, will help you
                                                           Elliott Bayly/PIX09681

                                                                                    decide which size turbine will best
                                                                                    meet your electricity needs.
                                                                        Small Wind Electric Systems               5

What are the Basic Parts
of a Small Wind Electric
Home wind energy systems gener-
ally comprise a rotor, a generator or             �����������                           ����
alternator mounted on a frame, a tail             ����������

(usually), a tower, wiring, and the
“balance of system” components:
controllers, inverters, and/or batter-
ies. Through the spinning blades, the
rotor captures the kinetic energy of
the wind and converts it into rotary
motion to drive the generator.
Wind Turbine
Most turbines manufactured today
are horizontal axis upwind machines        generator from a 60-foot tower height
with two or three blades, which are        to a 100-foot tower involves a 10%
usually made of a composite material       increase in overall system cost, but it
such as fiberglass.                        can produce 29% more power.
The amount of power a turbine will         There are two basic types of tow-
produce is determined primarily by         ers: self-supporting (free standing)
the diameter of its rotor. The diameter    and guyed. Most home wind power
of the rotor defines its “swept area,”     systems use a guyed tower. Guyed
or the quantity of wind intercepted by     towers, which are the least expensive,
the turbine. The turbine’s frame is the    can consist of lattice sections, pipe, or
structure onto which the rotor, genera-    tubing (depending on the design), and
tor, and tail are attached. The tail       supporting guy wires. They are easier
keeps the turbine facing into the wind.    to install than self-supporting tow-
                                           ers. However, because the guy radius
Tower                                      must be one-half to three-quarters
Because wind speeds increase with          of the tower height, guyed towers
height, the turbine is mounted on          require enough space to accommodate
a tower. In general, the higher the        them. Although tilt-down towers are
tower, the more power the wind             more expensive, they offer the con-
system can produce. The tower also         sumer an easy way to perform
                                                                                     Tilt-down towers
raises the turbine above the air           maintenance on smaller light-weight provide easy
turbulence that can exist close to         turbines, usually 5 kW or less.           maintenance for
the ground because of obstructions                                                        turbines.
such as hills, buildings, and trees. A
                                                                  Tilt-Down Tower
general rule of thumb is to install a
wind turbine on a tower with the bot-                                           �������������
tom of the rotor blades at least 30 feet                                        ����������
                                                ���������������������           ��������
(9 meters) above any obstacle that              ��������������������
is within 300 feet (90 meters) of the           ���������������
tower. Relatively small investments in
increased tower height can yield very
high rates of return in power produc-
tion. For instance, to raise a 10-kW                                                              ���������
6        Small Wind Electric Systems

                           Tilt-down towers can also be low-         application, the balance of system
                           ered to the ground during hazard-         parts may include a controller, storage
                           ous weather such as hurricanes.           batteries, a power conditioning unit
                           Aluminum towers are prone to              (inverter), and wiring. Some wind
                           cracking and should be avoided.           turbine controllers, inverters, or other
                           Most turbine manufacturers provide        electrical devices may be stamped
                           wind energy system packages that          by a recognized testing agency, like
                           include towers.                           Underwriters Laboratories.
                           Mounting turbines on rooftops is not      Stand-Alone Systems
                           recommended. All wind turbines            Stand-alone systems (systems not
                           vibrate and transmit the vibration        connected to the utility grid) require
                            to the structure on which they are       batteries to store excess power gener-
                           mounted. This can lead to noise and       ated for use when the wind is calm.
                           structural problems with the building,    They also need a charge controller to
                           and the rooftop can cause excessive       keep the batteries from overcharging.
                           turbulence that can shorten the life of   Deep-cycle batteries, such as those
                           the turbine.                              used for golf carts, can discharge
                           Balance of System                         and recharge 80% of their capacity
                           The parts that you need in addition       hundreds of times, which makes them
                           to the turbine and the tower, or the      a good option for remote renewable
                           balance of system parts, will depend      energy systems. Automotive batteries
                           on your application. Most manufac-        are shallow-cycle batteries and should
                           turers can provide you with a system      not be used in renewable energy
                           package that includes all the parts you   systems because of their short life
                           need for your application. For exam-      in deep-cycling operations.
                           ple, the parts required for a water
                           pumping system will be much differ-
                           ent than what you need for a residen-
                           tial application. The balance of system
                           required will also depend on whether
                           the system is grid-connected, stand-
                           alone, or part of a hybrid system.
                           For a residential grid-connected

    A Bergey XL.10,
    10-kW wind
    turbine is part of
    a grid-connected
    hybrid system that
    reduces the utility
    power used by this
    home in Vermont.
                                                                                                                Trudy Forsyth, NREL/PIX09122 and PIX09123

    The balance of
    system (upper right)
    includes from left
    to right, a Trace
    inverter for the
    PV system, a
    breaker box, and a
    Powersync inverter
    for the wind system.
                                                                    Small Wind Electric Systems                              7

Small wind turbines generate direct                                                                  A Southwest
current (DC) electricity. In very small                                                              Windpower Air
                                                                                                     303, 300-watt
systems, DC appliances operate                                                                       turbine is the sole
directly off the batteries. If you want to                                                           source of electricity
use standard appliances that use con-                                                                for this remote
                                                                                                     home in northern
ventional household alternating cur-                                                                 Arizona.
rent (AC), you must install an inverter
to convert DC electricity from the
batteries to AC. Although the inverter
slightly lowers the overall efficiency
of the system, it allows the home to
be wired for AC, a definite plus with
lenders, electrical code officials, and
future homebuyers.

                                                                                         Southwest Windpower/PIX09156
For safety, batteries should be iso-
lated from living areas and electron-
ics because they contain corrosive
and explosive substances. Lead-acid
batteries also require protection from
temperature extremes.
                                             increases. Although small turbines
Grid-Connected Systems                       cost less in initial outlay, they are
In grid-connected systems, the only          proportionally more expensive. The
additional equipment required is a           cost of an installed residential wind
power conditioning unit (inverter)           energy system with an 80-foot tower,
that makes the turbine output electri-       batteries, and inverter typically
cally compatible with the utility grid.      ranges from $15,000 to $50,000 for
Usually, batteries are not needed.           a 3- to 10-kW wind turbine.
                                             Although wind energy systems
What Do Wind Systems                         involve a significant initial invest-
Cost?                                        ment, they can be competitive with
Installation costs vary greatly depend-      conventional energy sources when
ing on local zoning, permitting, and         you account for a lifetime of reduced
utility interconnection costs. A small       or avoided utility costs. The length
turbine can cost anywhere from $3,000        of the payback period—the time
to $50,000 installed, depending on           before the savings resulting from your
size, application, and service agree-        system equal the cost of the system
ments with the manufacturer. (The            itself—depends on the system you
American Wind Energy Association             choose, the wind resource on your
[AWEA] says a typical home wind              site, electricity costs in your area, and
system costs approximately $32,000           how you use your wind system. For
(10 kW); a comparable photovoltaic           example, if you live in California and
[PV] solar system would cost over            have received the 50% buydown of
$80,000.)                                    your small wind system, have net
A general rule of thumb for estimat-         metering, and an average annual
ing the cost of a residential turbine is     wind speed of 15 miles per hour
$1,000 to $5,000 per kilowatt. Wind          (mph) (6.7 meters per second [m/
energy becomes more cost effective           s]), your simple payback would be
as the size of the turbine’s rotor           approximately 6 years.
8      Small Wind Electric Systems

                                                                                           references of past customers with
                                                                                           installations similar to the one you are
                                                                                           considering. Ask the system owners
                                                                                           about performance, reliability, and
                                                                                           maintenance and repair requirements,
                                                                                           and whether the system is meeting
                                                                                           their expectations. Also, find out how
                                                                                           long the warranty lasts and what it

                                                                                           Where Can I Find
                                                                                           Installation and
                                                                                           Maintenance Support?
                                                                                           The manufacturer/dealer should be
                                                                                           able to help you install your machine.
                                                                                           Many people elect to install the
                                                                                           machines themselves. Before attempt-
                                                                                           ing to install your wind turbine, ask
                                                             Warren Gretz, NREL/PIX09615

                                                                                           yourself the following questions:
                                                                                           • Can I pour a proper cement
                                                                                           • Do I have access to a lift or a way of
                                                                                             erecting the tower safely?
    Small wind
    turbines like this  Things to Consider When                                            • Do I know the difference between
    10-kW Bergey        Purchasing a Wind Turbine                                            AC and DC wiring?
    XL.10 provide
    electricity for     Once you determine you can install                                 • Do I know enough about electricity
    home, farm, and     a wind energy system in compliance
    ranch applications.
                                                                                             to safely wire my turbine?
                     with local land use requirements, you
                     can begin pricing systems and compo-                                  • Do I know how to safely handle
                     nents. Comparatively shop for a wind                                    and install batteries?
                     system as you would any major pur-                                    If you answered no to any of the
                     chase. Obtain and review the product                                  above questions, you should probably
                     literature from several manufacturers.                                choose to have your system installed
                     As mentioned earlier, lists of manu-                                  by a system integrator or installer.
                     facturers are available from AWEA,                                    Contact the manufacturer for help
                     (see For More Information), but not                                   or call your state energy office and
                     all small turbine manufacturers are                                   local utility for a list of local system
                     members of AWEA. Check the yellow                                     installers. You can also check the yel-
                     pages for wind energy system dealers                                  low pages for wind energy system
                     in your area.                                                         service providers. A credible installer
                     Once you have narrowed the field,                                     will provide many services such as
                     research a few companies to be sure                                   permitting. Find out if the installer is a
                     they are recognized wind energy                                       licensed electrician. Ask for references
                     businesses and that parts and service                                 and check them out. You may also
                     will be available when you need them.                                 want to check with the Better Business
                     You may wish to contact the Better                                    Bureau.
                     Business Bureau to check on                                           Although small wind turbines are
                     the company’s integrity and ask for                                   very sturdy machines, they do require
                                                                                     Small Wind Electric Systems                  9

some annual maintenance. Bolts             wind speed results in a large increase
and electrical connections should be       in power. That is why a taller tower
checked and tightened if necessary.        will increase the productivity of any
The machines should be checked for         wind turbine by giving it access to
corrosion and the guy wires for            higher wind speeds as shown in the
proper tension. In addition, you           Wind Speeds Increase with Height
should check for and replace any           graph. The formula for calculating
worn leading edge tape on the blades,      the power from a wind turbine is:
if appropriate. After 10 years, the                          Power = k Cp 1/2 ρ A V3
blades or bearings may need to be
replaced, but with proper installation     Where:
and maintenance, the machine should        P = Power output, kilowatts
last up to 20 years or longer.             Cp = Maximum power coefficient,
If you do not have the expertise to             ranging from 0.25 to 0.45,
maintain the machine, your installer            dimension less (theoretical
                                                maximum = 0.59)
may provide a service and mainte-
nance program.                             ρ = Air density, lb/ft3
                                           A = Rotor swept area, ft2 or
How Much Energy Will My                        π D2/4 (D is the rotor
System Generate?                               diameter in ft, π = 3.1416)
Most U.S. manufacturers rate their         V = Wind speed, mph
turbines by the amount of power they       k = 0.000133 A constant to yield
can safely produce at a particular             power in kilowatts. (Multiplying
wind speed, usually chosen between             the above kilowatt answer by
24 mph (10.5 m/s) and 36 mph (16 m/            1.340 converts it to horse-
s). The following formula                      power [i.e., 1 kW = 1.340
illustrates factors that are important         horsepower]).
to the performance of a wind turbine.      The rotor swept area, A, is important
Notice that the wind speed, V, has an      because the rotor is the part of the
exponent of 3 applied to it. This          turbine that captures the wind energy.
means that even a small increase in

                             Relative Size of Small Wind Turbines

                                            Swept area, m2

                    6                                        20
Rotor Diameter, m

                    5                                        10
                    4                                        0
                        4m                                        1        2        3        4       5                    6   7
                                                                                  Rotor Diameter, m

                                                                      Source: Paul Gipe, Wind Energy Basics
10                Small Wind Electric Systems

                          Air Density Change with Elevation                       height of the tower that you plan to
             10,000                                                               use, and the frequency distribution of
                 9,000                                                            the wind–an estimate of the number
                 8,000                                                            of hours that the wind will blow at
                 7,000                                                            each speed during an average year.
 Elevation, ft

                 6,000                                                            They should also adjust this calcula-
                 5,000                                                            tion for the elevation of your site.
                 4,000                                                            Contact a wind turbine manufacturer
                 3,000                                                            or dealer for assistance with this
                 2,000                                                            calculation.

                 1,000                                                            To get a preliminary estimate of the
                     70     75       80      85      90       95    100
                                                                                  performance of a particular wind tur-
                          Density change compared to sea level, %                 bine, use the formula below.
                                                                                           AEO = 0.01328 D2 V3
                                 So, the larger the rotor, the more               Where:
                                 energy it can capture. The air density,          AEO = Annual energy output,
                                 ρ, changes slightly with air tempera-                kWh/year
                                 ture and with elevation. The ratings
                                                                                  D = Rotor diameter, feet
                                 for wind turbines are based on
                                 standard conditions of 59° F (15° C)             V = Annual average wind speed,
                                 at sea level. A density correction                   mph
                                 should be made for higher elevations             The Wind Energy Payback Period
                                 as shown in the Air Density Change               Workbook found at
                                 with Elevation graph. A correction for           wind/docs/spread_sheet_Final.xls is
                                 temperature is typically not needed              a spreadsheet tool that can help you
                                 for predicting the long-term perfor-             analyze the economics of a small wind
                                                                                  electric system and decide whether
                                 mance of a wind turbine.
                                                                                  wind energy will work for you. The
                                 Although the calculation of wind                 spreadsheet can be opened using
                                 power illustrates important features             Microsoft Excel 95 software. It asks
                                 about wind turbines, the best mea-               you to provide information about how
                                 sure of wind turbine performance is              you’re going to finance the system,
                                 annual energy output. The difference             the characteristics of your site, and
                                                                                  the properties of the system you’re
                                 between power and energy is that
                                                                                  considering. It then provides you with
                                 power (kilowatts [kW]) is the rate at            a simple payback estimation in years.
                                 which electricity is consumed, while             If it takes too long to regain your capi-
                                 energy (kilowatt-hours [kWh]) is the             tal investment—the number of years
                                 quantity consumed. An estimate of                comes too close or is greater than the
                                 the annual energy output from your               life of the system—wind energy will
                                 wind turbine, kWh/year, is the best              not be practical for you.
                                 way to determine whether a particular
                                 wind turbine and tower will produce
                                 enough electricity to meet your needs.
                                 A wind turbine manufacturer can help
                                 you estimate the energy production
                                 you can expect. They will use a cal-
                                 culation based on the particular wind
                                 turbine power curve, the average
                                 annual wind speed at your site, the
                                                                                Small Wind Electric Systems                  11

Is There Enough Wind                         particular location. Airport wind data
on My Site?                                  are generally measured at heights
Does the wind blow hard and con-             about 20–33 ft (6–10 m) above ground.
sistently enough at my site to make a        Average wind speeds increase with
small wind turbine system economi-           height and may be 15%–25% greater
cally worthwhile? That is a key ques-        at a typical wind turbine hub-height
tion and not always easily answered.         of 80 ft (24 m) than those measured
The wind resource can vary signifi-          at airport anemometer heights. The
cantly over an area of just a few miles      National Climatic Data Center collects
because of local terrain influences          data from airports in the United States
 on the wind flow. Yet, there are steps      and makes wind data summaries
you can take that will go a long way         available for purchase. Summaries
towards answering the above                  of wind data from almost 1000 U.S.
question.                                    airports are also included in the Wind
                                             Energy Resource Atlas of the United
As a first step, wind resource maps          States (see For More Information).
like the one on pages 12 and 13 can
 be used to estimate the wind resource       Another useful indirect measurement
in your region. The highest average          of the wind resource is the observa-
wind speeds in the United States are         tion of an area’s vegetation. Trees,
generally found along seacoasts, on          especially conifers or evergreens, can
ridgelines, and on the Great Plains;         be permanently deformed by strong
however, many areas have wind                winds. This deformity, known as
resources strong enough to power a           “flagging,” has been used to estimate
small wind turbine economically. The         the average wind speed for an area.
wind resource estimates on this map          For more information on the use of
generally apply to terrain features that     flagging, you may want to obtain
are well exposed to the wind, such as
plains, hilltops, and ridge crests. Local                            Wind Speeds Increase with Height
terrain features may cause the wind
resource at a specific site to differ con-                ���
siderably from these estimates. More
detailed wind resource information,
including the Wind Energy Resource
Atlas of United States, published
by the U.S. Department of Energy
(DOE), can be found at the National

Wind Technology Center Web site at                              �� and the DOE
Wind Powering America Web site at                                    ��
Another way to indirectly quantify
the wind resource is to obtain average
wind speed information from a
nearby airport. However, caution
should be used because local terrain
influences and other factors may
cause the wind speed recorded at                                �
                                                                                   �          ��     ��    ���     ���
an airport to be different from your                                                   �������������������������
12   Small Wind Electric Systems   Small Wind Electric Systems   13
14       Small Wind Electric Systems

     Flagging, the effect
     of strong winds on               ��������                                �                             �
     area vegetation,                                                         ��                            ��������
     can help determine         ���������������
                                                                              ���������                     ����������
     area wind speeds.                                                                                      ��������

                                                  ��                          ���                           ��
                                                  ������                      ��������                      ��������
                                                  ��������                    ��������                      ��������

                                                  �                           ��                            ���
                                                  �������                     ��������                      ���������
                                                  ��������                    ��������


                                  �            ��������������������������������������������
                                  ������            ��        ���     ����      ���         ��      ���       ���
                                  ���������       ����       �����   ������   ������      ������   ������    ���
                                  ����������      ����       ����     ����     ����        ����     ����      ��

                            A Siting Handbook for Small Wind                  How Do I Choose the Best
                            Energy Conversion Systems (see For                Site for My Wind Turbine?
                            More Information).                                You can have varied wind resources
                            Direct monitoring by a wind resource              within the same property. In addition
                            measurement system at a site pro-                 to measuring or finding out about
                            vides the clearest picture of the avail-          the annual wind speeds, you need to
                            able resource. A good overall guide               know about the prevailing directions
                            on this subject is the Wind Resource              of the wind at your site. If you live in
                            Assessment Handbook (see For More                 complex terrain, take care in selecting
                            Information). Wind measurement                    the installation site. If you site your
                            systems are available for costs as low            wind turbine on the top of or on the
                            as $600 to $1200. This expense may or             windy side of a hill, for example, you
                            may not be hard to justify depending              will have more access to prevailing
                            on the exact nature of the proposed               winds than in a gully or on the lee-
                            small wind turbine system. The mea-               ward (sheltered) side of a hill on the
                            surement equipment must be set high               same property. In addition to geologic
                            enough to avoid turbulence created                formations, you need to consider
                            by trees, buildings, and other obstruc-           existing obstacles such as trees,
                            tions. The most useful readings are               houses, and sheds, and you need to
                            those taken at hub-height, the eleva-             plan for future obstructions such as
                            tion at the top of the tower where the            new buildings or trees that have not
                            wind turbine is going to be installed.            reached their full height. Your turbine
                            If there is a small wind turbine sys-             needs to be sited upwind of build-
                            tem in your area, you may be able to              ings and trees, and it needs to be 30
                            obtain information on the annual                  feet above anything within 300 feet.
                            output of the system and also wind                You also need enough room to raise
                            speed data if available.                          and lower the tower for maintenance,
                                                                      Small Wind Electric Systems          15

               Obstruction of the Wind by a Building
                       or Tree of Height (H)


                                    �            ����

              2H                                               20 H
                                                                                      The farther you
                                                                                      place your wind
and if your tower is guyed, you must        requires, the excess is sent or sold to   turbine from
allow room for the guy wires.               the utility.                              obstacles such
                                                                                      as buildings or
Whether the system is stand-alone           Grid-connected systems can be practi-     trees, the less
or grid-connected, you will also need       cal if the following conditions exist:    turbulence you
                                                                                      will encounter.
to take the length of the wire run          • You live in an area with average
between the turbine and the load              annual wind speed of at least
(house, batteries, water pumps, etc.)         10 mph (4.5 m/s)
into consideration. A substantial
amount of electricity can be lost as a      • Utility-supplied electricity is
result of the wire resistance—the lon-        expensive in your area (about 10 to
ger the wire run, the more electric-          15 cents per kilowatt-hour)
ity is lost. Using more or larger wire      • The utility’s requirements for
will also increase your installation          connecting your system to its grid
cost. Your wire run losses are greater        are not prohibitively expensive
when you have direct current (DC)           • There are good incentives for the
instead of alternating current (AC).          sale of excess electricity or for the
So, if you have a long wire run, it is        purchase of wind turbines.
advisable to invert DC to AC.
                                            Federal regulations (specifically, the
Can I Connect My System                     Public Utility Regulatory Policies Act
to the Utility Grid?                        of 1978, or PURPA) require utilities
Small wind energy systems can be            to connect with and purchase power
connected to the electricity distribu-      from small wind energy systems.
tion system and are called grid-            However, you should contact your
connected systems. A grid-connected         utility before connecting to their dis-
wind turbine can reduce your con-           tribution lines to address any power
sumption of utility-supplied electric-      quality and safety concerns. Your
ity for lighting, appliances, and           utility can provide you with a list of
electric heat. If the turbine cannot        requirements for connecting your sys-
deliver the amount of energy you            tem to the grid. The American Wind
need, the utility makes up the differ-      Energy Association is another good
ence. When the wind system produces         source for information on utility
more electricity than the household         interconnection requirements. The
16      Small Wind Electric Systems

     A grid-connected                                Grid-connected Systems
     wind turbine
     can reduce your
     consumption of                                                                  �����


                        following information about util-            Most of North America gets more
                        ity grid connection requirements             wind in the winter than in the sum-
                        was taken from AWEA’s Web site.              mer. For people using wind energy to
                        For more detailed information, visit         displace a large load in the summer
               or contact AWEA                like air-conditioning or irrigation
                        (see For More Information).                  water pumping, having an annual
                                                                     NEG credit allows them to produce
                        Net Metering
                                                                     NEG in the winter and be credited in
                        The concept of net metering programs         the summer.
                        is to allow the electric meters of cus-
                        tomers with generating facilities to         Safety Requirements
                        turn backwards when their generators         Whether or not your wind turbine
                        are producing more energy than the           is connected to the utility grid, the
                        customers’ demand. Net metering              installation and operation of the wind
                        allows customers to use their genera-        turbine is probably subject to the
                        tion to offset their consumption over        electrical codes that your local gov-
                        the entire billing period, not just          ernment (city or county), or in some
                        instantaneously. This offset would           instances your state government, has
                        enable customers with generating             in place. The government’s principal
                        facilities to receive retail prices for      concern is with the safety of the
                        more of the electricity they generate.       facility, so these code requirements
                        Net metering varies by state and             emphasize proper wiring and installa-
                        by utility company, depending on             tion and the use of components
                        whether net metering was legis-              that have been certified for fire and
                        lated or directed by the Public Utility      electrical safety by approved testing
                        Commission. Net metering programs            laboratories, such as Underwriters
                        all specify a way to handle the net          Laboratories. Most local electrical
                        excess generation (NEG) in terms of          codes requirements are based on
                        payment for electricity and/or length        the National Electrical Code (NEC),
                        of time allowed for NEG credit. If           which is published by the National
                        the net metering requirements define         Fire Protection Association. As of
                        NEG on a monthly basis, the consum-          1999, the latest version of the NEC did
                        er can only get credit for their excess      not have any sections specific to the
                        that month. But if the net metering          installation of wind energy facilities’
                        rules allow for annual NEG, the NEG          consequently wind energy installa-
                        credit can be carried for up to a year.      tions are governed by the generic
                                                                     provisions of the NEC.
                                                                   Small Wind Electric Systems            17

If your wind turbine is connected to        provider. In the case of private (inves-
the local utility grid so that any of the   tor-owned) utilities, the terms and
power produced by your wind tur-            conditions in these agreements must
bine is delivered to the grid, then your    be reviewed and approved by state
utility also has legitimate concerns        regulatory authorities.
about safety and power quality that
need to be addressed. The utility’s
principal concern is that your wind         Some utilities require small wind
turbine automatically stops deliver-         turbine owners to maintain liability
ing any electricity to its power lines      insurance in amounts of $1 million or
during a power outage. Otherwise            more. Utilities consider these require-
line workers and the public, thinking       ments necessary to protect them from
that the line is “dead,” might not take     liability for facilities they do not own
normal precautions and might be             and have no control over. Others
hurt or even killed by the power from       consider the insurance requirements
your turbine. Another concern among         excessive and unduly burdensome,
utilities is whether the power from         making wind energy uneconomic. In
your facility synchronizes properly         the 21 years since utilities have been
with the utility grid and it matches the    required to allow small wind systems
utility’s own power in terms of volt-       to interconnect with the grid, there
                                                                                       This grid-
age, frequency, and power quality.          has never been a liability claim, let      connected,
                                            alone a monetary award, relating to        10-kW Bergey
A few years ago, some state govern-         electrical safety.                         wind turbine
ments started developing new                                                           offsets
standardized interconnection require-       In seven states (California, Georgia,      electrical power
                                            Maryland, Nevada, Oklahoma,                consumption for
ments for small renewable energy                                                       a small business
generating facilities (including wind       Oregon, and Washington), laws              in Norman,
turbines). In most cases, the new           or regulatory authorities prohibit         Oklahoma.
requirements are based on consen-
sus-based standards and testing pro-
cedures developed by independent
third-party authorities, such as the
Institute of Electrical and Electronic
Engineers and Underwriters
Interconnection Requirements
Most utilities and other electricity
providers require you to enter into a
formal agreement with them before
you interconnect your wind turbine
with the utility grid. In states that
have retail competition for electricity
service (e.g., your utility operates
the local wires, but you have a
choice of electricity provider)
                                                                                                          Bergey Windpower/PIX07166

you may have to sign a separate
agreement with each company.
Usually these agreements are writ-
ten by the utility or the electricity
18   Small Wind Electric Systems

                 utilities from imposing any insurance                                facility. Although the basic principle
                 requirements on small wind sys-                                      is sound—utilities should not be
                 tems that qualify for “net metering.”                                held responsible for property dam-
                 In at least two other states (Idaho,                                 age or personal injury attributable
                 Virginia), regulatory authorities have                               to someone else—indemnity provi-
                 allowed utilities to impose insurance                                sions should not favor the utility but
                 requirements but have reduced the                                    should be fair to both parties. Look for
                 required coverage amounts to levels                                  language that says, “each party shall
                 consistent with conventional residen-                                indemnify the other . . .” rather than
                 tial or commercial insurance policies                                “the customer shall indemnify the
                 (e.g., $100,000 to $300,000). If your                                utility . . .”
                 insurance amounts seem excessive,
                                                                                      Customer Charges
                 you can ask for a reconsideration from
                 regulatory authorities (in the case of                               Customer charges can take a variety
                 private investor-owned utilities) or                                 of forms, including interconnection
                 the utility’s governing board (in the                                charges, metering charges, and
                 case of publicly owned utilities).                                   standby charges. You should not
                                                                                      hesitate to question any charges that
                 Indemnification                                                      seem inappropriate to you. Federal
                 An indemnity is an agreement                                         law (Public Utility Regulatory Policies
                 between two parties in which one                                     Act of 1978, or PURPA, Section 210)
                 agrees to secure the other against loss                              prohibits utilities from assessing dis-
                 or damage arising from some act or                                   criminatory charges to customers who
                 some assumed responsibility. In the                                  have their own generation facilities.
                 context of customer-owned generat-
                 ing facilities, utilities often want
                 customers to indemnify them for any
                 potential liability arising from the
                 operation of the customer’s generating

                                                                         Connecting to the Utility Grid:
                                                                         A Success Story
                                                                         This 10-kW Bergey wind turbine, installed on
                                                                         a farm in Southwestern Kansas in 1983, pro-
                                                                         duces an average 1700–1800 kilowatt-hours per
                                                                         month, reducing the user’s monthly utility bills
                                                                         by approximately 50%. The turbine cost about
                                                                         $20,000 when it was installed. Since then, the
                                                                         cost for operation and maintenance has been
                                                                         about $50 per year. The only unscheduled main-
                                                                         tenance activity over the years was repair to the
                                                                         turbine required as a result of a lightning strike.
                                                                         Insurance covered all but $500 of the $9000 cost of
                                                                         damages. The basic system parts include:
                                           Warren Gretz, NREL/PIX09634

                                                                         Bergey XL.10 wind turbine
                                                                         100-foot free-standing lattice tower
                                                                              Small Wind Electric Systems                     19

                                 Hybrid Power Systems                                                 A hybrid system
             Combine multiple sources to deliver non-intermittent electric power                      that combines a
                                                                                                      wind system with a
                                                                                                      solar and/or diesel
                                                                                                      generator can
                                                                                                      provide reliable off-
                                                                                                      grid power around
                                                                                                      the clock.


                                                                  ������           ����
                                            ��������������         ��



Can I Go “Off-Grid”?                              For the times when neither the wind
                                                  turbine nor the PV modules are pro-
Hybrid Systems
                                                  ducing, most hybrid systems provide
Hybrid wind energy systems can                    power through batteries and/or an
provide reliable off-grid power for               engine-generator powered by conven-
homes, farms, or even entire com-                 tional fuels such as diesel. If the bat-
munities (a co-housing project, for               teries run low, the engine-generator
example) that are far from the near-              can provide power and recharge
est utility lines. According to many              the batteries. Adding an engine-
renewable energy experts, a “hybrid”              generator makes the system more
system that combines wind and                     complex, but modern electronic
photovoltaic (PV) technologies offers             controllers can operate these systems
several advantages over either single             automatically. An engine-generator
system. In much of the United States,             can also reduce the size of the other
wind speeds are low in the summer                 components needed for the system.
when the sun shines brightest and                 Keep in mind that the storage capac-
longest. The wind is strong in the                ity must be large enough to supply
winter when less sunlight is available.           electrical needs during non-charging
Because the peak operating times                  periods. Battery banks are typically
for wind and PV occur at different                sized to supply the electric load for
times of the day and year, hybrid                 one to three days.
systems are more likely to produce
power when you need it. (For more                 An off-grid hybrid system may be
information on solar electric or PV               practical for you if:
systems, contact the Energy Efficiency            • You live in an area with average
and Renewable Energy Information                    annual wind speed of at least
Portal—see For More Information.)                   9 mph (4.0 m/s)
                                                  • A grid connection is not available
                                                    or can only be made through an
20   Small Wind Electric Systems

                   expensive extension. The cost of                                 • You would like to gain energy
                   running a power line to a remote                                   independence from the utility
                   site to connect with the utility grid                            • You would like to generate clean
                   can be prohibitive, ranging from                                   power.
                   $15,000 to more than $50,000 per
                   mile, depending on terrain.

                   Living Off-Grid: A Success Story
                   This home, built near Ward, Colorado (at an elevation of 9000 feet), has been
                   off-grid since it was built in 1972. When the house was built, the nearest util-
                   ity was over a mile away, and it would have cost between $60K–$70K (based
                   on 1985 rates) to connect to the utility lines. The owners decided to install a
                                                        hybrid electric system powered by wind,
                                                        solar, and a generator for a cost of about
                                                        $19,700. The parts of the system include:
                                                                              Bergey 1.5-kW wind turbine, 10-ft (3-m)
                                                                              diameter rotor, 70-ft. (21-m) tower
                                                                              Solarex PV panels, 480 watts
                                                                              24 DC battery bank, 375 ampere-hours
                                                                              Trace sine wave inverter, 120 AC, 1 phase,
                                                                              4 kW
                                                                              Onan propane-fueled generator, 6.5 kW
                                                                              rated (3 kW derated for altitude)
                                                                              Electric appliances in the home include
                                                                              television, stereo, two computers, toaster,
                                                                              blender, vacuum cleaner, and hair dryer.
                                                                              The largest electric loads are created by
                                                                              a well pump and washing machine. The
                                                                              generator runs about 20% of the time, par-
                                                                              ticularly when the washing machine
                                                                              is in use. Propane serves the other major
                                                                              loads in the home: range, refrigerator, hot
                                                   Jim Green, NREL/PIX02796

                                                                              water, and space heat. Solar collectors on
                                                                              the roof provide pre-heating for the hot
                                                                 Small Wind Electric Systems   21

Glossary of Terms                         kWh—Kilowatt-hour, a measure
Airfoil—The shape of the blade cross-     of energy equal to the use of one
section, which for most modern hori-      kilowatt in one hour.
zontal axis wind turbines is designed     MW—Megawatt, a measure of power
to enhance the lift and improve tur-      (1,000,000 watts).
bine performance.
                                          Nacelle—The body of a propeller-type
Ampere-hour—A unit for the quantity       wind turbine, containing the gearbox,
of electricity obtained by integrating    generator, blade hub, and other parts.
current flow in amperes over the time
                                          O&M costs—Operation and mainte-
in hours for its flow; used as a mea-
                                          nance costs.
sure of battery capacity.
                                          Power coefficient—The ratio of the
Anemometer—A device to measure
                                          power extracted by a wind turbine
the wind speed.
                                          to the power available in the wind
Average wind speed—The mean wind          stream.
speed over a specified period of time.
                                          Power curve—A chart showing a
Blades—The aerodynamic surface that       wind turbine’s power output across
catches the wind.                         a range of wind speeds.
Brake—Various systems used to stop        PUC—Public Utility Commission, a
the rotor from turning.                   state agency which regulates utilities.
Converter—See Inverter.                   In some areas known as Public Service
                                          Commission (PSC).
Cut-in wind speed—The wind speed
at which a wind turbine begins to         PURPA—Public Utility Regulatory
generate electricity.                     Policies Act (1978), 16 U.S.C. § 2601.18
                                          CFR §292 that refers to small
Cut-out wind speed—The wind speed         generator utility connection rules.
at which a wind turbine ceases to
generate electricity.                     Rated output capacity—The output
                                          power of a wind machine operating
Density—Mass per unit of volume.          at the rated wind speed.
Downwind—On the opposite side             Rated wind speed—The lowest wind
from the direction from which the         speed at which the rated output
wind blows.                               power of a wind turbine is produced.
Furling—A passive protection for the      Rotor—The rotating part of a wind
turbine in which the rotor folds either   turbine, including either the blades
up or around the tail vane.               and blade assembly or the rotating
Grid—The utility distribution system.     portion of a generator.
The network that connects electricity     Rotor diameter—The diameter of the
generators to electricity users.          circle swept by the rotor.
HAWT—Horizontal axis wind turbine.        Rotor speed—The revolutions per
Inverter—A device that converts direct    minute of the wind turbine rotor.
current (DC) to alternating current       Start-up wind speed—The wind speed
(AC).                                     at which a wind turbine rotor will
kW—Kilowatt, a measure of power for       begin to spin. See also Cut-in wind
electrical current (1000 watts).          speed.
22   Small Wind Electric Systems

                 Swept area—The area swept by the          Wind Energy Basics
                 turbine rotor, A = π R2, where R is the   Paul Gipe
                 radius of the rotor.                      ISBN 1-890132-07-01
                 Tip speed ratio—The speed at the tip      A comprehensive guide to modern
                 of the rotor blade as it moves through    small wind technology.
                 the air divided by the wind velocity.     American Wind Energy Association
                 This is typically a design requirement    (202) 383-2500
                 for the turbine.                
                 Turbulence—The changes in wind            Chelsea Green Publishing Company
                 speed and direction, frequently 
                 caused by obstacles.
                                                           Wind Energy Resource Atlas of the
                 Upwind—On the same side as the            United States
                 direction from which the wind is          D. Elliott et al.
                 blowing—windward.                         American Wind Energy Association
                 VAWT—Vertical axis wind turbine.          (202) 383-2500
                 Wind farm—A group of wind tur-
                 bines, often owned and maintained by
                 one company. Also known as a wind         Wind Power for Home, Farm, and
                 power plant.                              Business: Renewable Energy for the
                                                           New Millenium
                 Yaw—The movement of the tower top
                                                           Paul Gipe
                 turbine that allows the turbine to stay
                 into the wind.
                                                           Completely revised and expanded
                 For More Information                      edition of Wind Power for Home and
                 Books                                     Chelsea Green Publishing Company
                 A Siting Handbook for Small Wind
                 Energy Conversion Systems
                                                           Wind Power Workshop
                 H. Wegley, J. Ramsdell, M. Orgill and
                                                           Hugh Piggott
                 R. Drake
                                                           Provides an overview on how to
                 Report No. PNL-2521 Rev.1, 1980
                                                           design a home-built wind turbine.
                 National Technical Information
                                                           The Center for Alternative
                 5285 Port Royal Rd.
                                                           Machynlleth, Powys
                 Springfield, VA 22151
                                                           SY20 9AZ, UK
                 (800) 553-6847
                                                           Phone: 06154-702400
                 Energy Savers Tips on Saving Energy
                 and Money at Home — A consumer’s
                 guide for saving energy and reducing
                 utility bills.
                                                              Small Wind Electric Systems   23

Government Agencies                     Videos
U.S. Department of Energy’s Energy      An Introduction to Residential Wind
Efficiency and Renewable Energy         Systems with Mick Sagrillo
Information Portal                      A 63-minute video answering ques-                     tions most often asked by homeown-
National Climatic Data Center           ers as they consider purchasing and
Federal Building, 151 Patton Avenue     installing wind power systems
Asheville, North Carolina, 28801-5001   American Wind Energy Association
Phone: (828) 271-4800                   Phone: (202) 383-2500             

U.S. Department of Commerce             Web Sites
National Technical Information          Small Wind Systems
Service                                 Includes answers to frequently asked
5285 Port Royal Road                    questions and information on U.S.
Springfield, Virginia 22161             manufacturers.
(800) 553-6847                                            Database of State Incentives for
Non-Government Organizations            Renewable Energy
American Wind Energy Association
1101 14th St., NW                       Green Power Network Net Metering
12th Floor                              Net metering programs are now avail-
Washington, D.C. 20005                  able in more than 35 states.
Phone: (202) 383-2500                                     markets
Solar Energy International              Small Wind “Talk” on the Web
Short courses on renewable energy       AWEA’s Home Energy Systems elec-
and sustainable development             tronic mailing list is a forum for the
Phone: (970) 963-8855                   discussion of small-scale energy sys-                     tems that include wind. To subscribe,
                                        send a subscription request to awea-
Apples and Oranges
Mick Sagrillo                           Wind Energy for Homeowners
A comprehensive comparison of           This Web page covers items you
available small wind turbines avail-    should consider before investing
able on the Home Power Magazine         in a small wind energy system and
Web site:             provides basic information about the
Home Power Magazine           
The definitive bimonthly magazine       wind.html
for the homemade power enthusiast.
Phone: (800)707-6586                    Wind Resource Assessment                       Handbook
24   Small Wind Electric Systems

                 2002 Farm Bill — Wind                           The amount of the payments depends on
                                                                 the size of the wind installation, the pro-
                 Energy Development                              duction of electricity by that system, and
                 Provisions                                      the length of the contract period. Mainstay
                                                                 offers 3-, 5-, and 10-year purchase con-
                 Renewable Energy Systems and                    tracts. The longer contract periods provide
                 Energy Efficiency Improvements                  greater incentive payments on a $/kWh
                 Incentive Type: Low-interest loans, loan        basis. Typical payments for wind, which
                      guarantees, and grants                     are made quarterly, range from 0.2¢/kWh
                 Eligible Technologies: Renewable energy         to 1.5¢/kWh.
                      systems (energy derived from wind,
                      solar, biomass, geothermal, and hydro-     There is a $100 certification fee to get
                      gen derived from biomass or water          started with Mainstay Rewards. However,
                      using a renewable energy source) and       the fee may be paid with future green tag
                      energy efficiency improvements.            sales, and is generally waived for partici-
                 Applicable Sectors: Agriculture, rural          pants who opt for 10-year contracts.
                      small commercial                           The requirements are:
                 Amount: Varies. The grant may not exceed         1. The system must be grid-connected;
                      25% of the cost of a project, and a com-    2. Net-metering by the utility does not
                      bined grant and loan or guarantee may          restrict the system owner from selling
                      not exceed 50% of the cost of a project.       the green tags;
                 Terms: 2003 – 2007                              3. The system owner must have title to the
                 Date Enacted: 2002                                  green tags or renewable energy credits.
                 Authority: Farm Bill, Title IX, Section 9006        They cannot have been sold
                 Summary: This law allows direct financial           or transferred to any other entity;
                 assistance to farmers, ranchers, and rural       4. The system must be a new renewable,
                 small businesses for the purchase of wind           which, in most states, means pow-
                 power and other renewable energy sys-               ered up on or after 1/1/1999. See the
                 tems and for energy efficiency improve-             Mainstay Energy web site for
                 ments. This program is authorized for               exceptions;
                 funding for up to $23,000,000 per year in        5. For any systems over 10 kW, the system
                 2003-2007, totaling up to $115 million. In          generation must be metered separately.
                 determining the amount of a grant or loan,          For systems under 10 kW, separate
                 USDA shall consider the type of renewable           metering is not necessary. Payments
                 energy system, the quantity of energy likely        are made based on estimated
                 to be generated, the expected environmen-           production.
                 tal benefits, the extent to which the system    Contact:
                 is replicable, and the amount of energy         Mainstay Rewards Program
                 savings from energy efficiency improve-         Mainstay Energy
                 ments and the likely payback period.            161 E. Chicago Ave.
                 USDA Rural Development State Office             Suite 41B
                 contacts can be found at www.rurdev.            Chicago, IL 60611-2624
                     Phone: (877) 473-3682
                                                                 Fax: (312) 896-1515
                 USDA Farm Bill Web site: www.rurdev.            E-Mail:
                      Web site:
                 Green Tag Purchase Program
                 Mainstay Energy is a private company
                 offering customers who install, or have
                 installed, renewable energy systems the
                 opportunity to sell the green tags (also
                 known as renewable energy credits, or
                 RECs) associated with the energy gener-
                 ated by these systems. These green tags
                 will be brought to market as Green-e*
        or state certified
                 products. Participating customers receive
                 regular, recurring payments through the
                 Mainstay Energy Rewards Program.
Small Wind Electric Systems
For information on programs and incentives for small
wind projects in Hawaii, please visit

Maurice Kaya
                                                             U.S. Department of Energy Wind
Chief Technology Officer                                     Energy Program
Hawaii State Department of Business, Economic      
Development, and Tourism
P.O. Box 2359                                                Wind Powering America
Honolulu, HI 96804                                 
Phone: (808) 587-3812
Web site:
Art Seki
Director of Technology
Hawaiian Electric Company
P.O. Box 2750
Honolulu, HI 96840-0001
Phone: (808) 543-7987
Web site:
Curtis Framel
U.S. Department of Energy
Western Regional Office
800 Fifth Ave., Suite 3950
Seattle, WA 98104-3122
Phone: (206) 553-7841
Fax: (206) 553-2200
Web site:

A Strong Energy Portfolio for a Strong America
Energy efficiency and clean, renewable energy will mean a stronger economy, a cleaner environment, and greater energy
independence for America. Working with a wide array of state, community, industry, and university partners, the U.S. Depart-
ment of Energy’s Office of Energy Efficiency and Renewable Energy invests in a diverse portfolio of energy technologies.

Produced for the U.S. Department of Energy by the                           For more information contact:
National Renewable Energy Laboratory,                                       EERE Information Center
a DOE national laboratory                                                   1-877-EERE-INF (1-877-337-3463)
DOE/GO-102005-2075 • March 2005
Printed with a renewable-source ink on paper containing at least 50% wastepaper, including 20% postconsumer waste.

To top