Small Wind Electric Systems A Colorado Consumer's Guide

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					Small Wind Electric Systems
               Consumer’s Guide
Small Wind Electric Systems

Cover photo: The Southwest Windpower Air 403 wind turbine is part of a stand-alone system that
provides power for a home in Westcliffe, Colorado. Warren Gretz, NREL/PIX10601.
                                                                                           Small Wind Electric Systems                                                              

  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
   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                                         

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
      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 turbine
                           resources. Wind-electric pumping                              rated in the range of 5 to 15 kW would
                           systems can be placed where the wind                          be required to make a significant
                           resource is the best and connected to                         contribution to this demand. A 1.5-kW
                           the pump motor with an electric cable.                        wind turbine will meet the needs of a
                                                                                         home requiring 300 kWh per month
                                                                                         in a location with a 14-mile-per-hour
This .1-kW .Whisper .                                                                    (6.26-meters-per-second) annual aver-
turbine .provides .                                                                      age wind speed. The manufacturer
direct .AC .power .for .
                                                                                         can provide you with the expected
the .water .pump .for .
stock .tanks .on .a .                                                                    annual energy output of the turbine
ranch .in .Wheeler, .                                                                    as a function of annual average wind
Texas .                                                                                  speed. The manufacturer 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 decide
                                                                Elliott Bayly/PIX09681

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

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

(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
                                                                               Tilt-up tower
wind turbine on a tower with the bot-                                          in the normal
tom of the rotor blades at least 30 feet                                       operating
                                                Tilt-up tower in the           position
(9 meters) above any obstacle that              lowered position for
is within 300 feet (90 meters) of the           maintenance or
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                                                              02979311m
         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 .
    wind/photovoltaic .
    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                               

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.
       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                  

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
0                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                  

Is There Enough Wind                         are generally measured at heights
on My Site?                                  about 20–33 ft (6–10 m) above ground.
Does the wind blow hard and con-             Average wind speeds increase with
sistently enough at my site to make a        height and may be 15%–25% greater
small wind turbine system economi-           at a typical wind turbine hub height
cally worthwhile? That is a key ques-        of 80 ft (24 m) than those measured
tion and not always easily answered.         at airport anemometer heights. The
The wind resource can vary signifi-          National Climatic Data Center collects
cantly over an area of just a few miles      data from airports in the United States
because of local terrain influences          and makes wind data summaries
 on the wind flow. Yet there are steps       available for purchase. Summaries
you can take that will go a long way         of wind data from almost 1000 U.S.
toward answering the above 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        A Siting Handbook for Small Wind
plains, hilltops, and ridge crests. Local
terrain features may cause the wind                                  Wind Speeds Increase with Height
resource at a specific site to differ con-
siderably from these estimates. More                      150
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
                                             Tower height, ft and the DOE                                  90
Wind Powering America Web site at
Another way to indirectly quantify                              60
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                            0
                                                                                   0          41     75    100     124
particular location. Airport wind data                                                 Increase in wind power, %
12   Small Wind Electric Systems   Small Wind Electric Systems   13
        Small Wind Electric Systems

     Flagging, .the .effect .
     of .strong .winds .on .             Flagging                               0                           I
     area .vegetation, .                                                        No                          Brushing
     can .help .determine .         Prevailing wind
                                                                                deformity                   and slight
     area .wind .speeds . .                                                                                 flagging

                                                      II                        III                         IV
                                                      Slight                    Moderate                    Complete
                                                      flagging                  flagging                    flagging

                                                      V                         VI                          VII
                                                      Partial                   Complete                    Carpeting
                                                      throwing                  throwing


                                                             Griggs-Putnam Index of Deformity
                                      Index             I         II     III      IV         V       VI       VII
                                      Wind mph        7-9        9-11   11-13   13-16       15-18   16-21    22+
                                      Speed m/s       3-4        4-5     5-6     6-7         7-8     8-9      10

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

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

                                              of highly

                                    H            flow

              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.)         12 mph (5.4 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
      Small Wind Electric Systems

     A .grid-connected .                                 Grid-connected Systems
     wind .turbine .
     can .reduce .your .
     consumption .of .                                                                   Meter
     utility-supplied .
     electricity .


                           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 gen-            turbine is probably subject to the
                           eration to offset their consumption           electrical codes that your local gov-
                           over the entire billing period, not just      ernment (city or county), or in some
                           instantaneously. This offset enables          instances your state government, has
                           customers with generating facilities          in place. The government’s principal
                           to receive retail prices for more of the      concern is with the safety 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                

If your wind turbine is connected to        of private (investor-owned) utilities,
the local utility grid so that any of the   the terms and conditions in these
power produced by your wind tur-            agreements must be reviewed and
bine is delivered to the grid, then your    approved by state regulatory
utility also has legitimate concerns        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 delivering       turbine owners to maintain liability
electricity to its power lines during a     insurance in amounts of $1 million or
power outage. Otherwise line workers        more. Utilities consider these require-
and the public, thinking that the line      ments necessary to protect them from
is “dead,” might not take normal            liability for facilities they do not own
precautions and might be hurt or            and have no control over. Others
even killed by the power from your          consider the insurance requirements
turbine. Another concern among utili-       excessive and unduly burdensome,
ties is whether the power from your         making wind energy uneconomic. In
facility synchronizes properly with         the 21 years since utilities have been
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) you may have
                                                                                                              Bergey Windpower/PIX07166

to sign a separate agreement with
each company. Usually these agree-
ments are written by the utility or
the electricity provider. In the case
   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                       

                                 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 . .
                                   PV modules


                                                                  AC or            Load
                                            Regulation and         DC


                                             Battery bank

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
0   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   

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.
   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    Phone: (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.          Phone: (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
                 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 Technology
                                                           Machynlleth, Powys
                 5285 Port Royal Rd.
                                                           SY20 9AZ, UK
                 Springfield, VA 22151
                                                           Phone: 06154-702400
                 Phone: (800) 553-6847
                 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   

Government Agencies                     Videos
U.S. Department of Energy’s Energy      An Introduction to Residential Wind
Efficiency and Renewable Energy site    Systems with Mick Sagrillo                     A 63-minute video answering
National Climatic Data Center           questions most often asked by
Federal Building, 151 Patton Avenue     homeowners as they consider
Asheville, North Carolina, 28801-5001   purchasing and installing wind power
Phone: (828) 271-4800                   systems
                                        American Wind Energy Association
                                        Phone: (202) 383-2500
U.S. Department of Commerce   
National Technical Information          Web Sites
                                        Small Wind Systems
5285 Port Royal Road
                                        Includes answers to frequently asked
Springfield, Virginia 22161
                                        questions and information on U.S.
Phone: (800) 553-6847
Non-Government Organizations            Database of State Incentives for
American Wind Energy Association        Renewable Energy
1101 14th St., NW             
12th Floor
                                        Green Power Network Net Metering
Washington, D.C. 20005
                                        Net metering programs are now avail-
Phone: (202) 383-2500
                                        able in more than 35 states.
Solar Energy International              markets
Short courses on renewable energy
                                        Small Wind “Talk” on the Web
and sustainable development
                                        AWEA’s Home Energy Systems elec-
Phone: (970) 963-8855
                                        tronic mailing list is a forum for the
                                        discussion of small-scale energy sys-
Periodicals                             tems that include wind. To subscribe,
Apples and Oranges                      send a subscription request to awea-
Mick Sagrillo                 
A comprehensive comparison of avail-    Wind Energy for Homeowners
able small wind turbines available on   This Web page covers items you
the Home Power Magazine Web site:       should consider before investing in                       a small wind energy system and
Home Power Magazine                     provides basic information about
The definitive bimonthly magazine       the systems.
for the homemade power enthusiast.
Phone: (800)707-6586                    html                       Wind Resource Assessment
   Small Wind Electric Systems

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

Incentives for Small Wind in Colorado
For a comprehensive overview of Colorado incentives for small wind projects, visit the DSIRE (Database of State
Incentives for Renewables and Efficiency) Web site at
Wind Anemometer Loan Program                                                Wind Powering America
The Governor’s Office of Energy Management and                    
Conservation (OEMC) has purchased nine anemometer
systems with matching funds from the U.S. Department
of Energy and three systems with its own funds. OEMC
has seven 20-M systems, three 30-M systems, and one
50-M system. Anemometers measure wind parameters,
which are used to determine the feasibility for wind
energy. The anemometers are rotated on an annual
basis throughout the state to qualified applicants.
Applicants are chosen based on existing statewide                           U.S. Department of Energy
wind mapping information, site owner willingness to                         Wind Energy Program
participate in the program, and likelihood of future wind         
energy utilization when appropriate. Applicants may be
required to contribute in-kind services, as needed and
necessary, during the onsite loan period. The program
provides the host with an anemometer, tower, data
logger, guidance on tower and equipment installation at
the site, and assistance with data interpretation during
the period of site monitoring. For more information,
please visit

Angela Crooks
Governor’s Office of Energy Management and
225 E. 16th Avenue
Suite 650
Denver, CO 80203
Phone: (303) 866-2309
or toll-free at (800) 632-6662
Fax: (303) 866-2930

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. Department 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-102006-2368 • December 2006
Printed with a renewable-source ink on paper containing at least 50% wastepaper, including 10% postconsumer waste.

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