Institutional - Wind Energy: Renewable Energy and the Environment - page 227

Christi, Texas, have a radar for monitoring migration of birds, and wind turbines are shut down if
they pose a threat to the birds.
Avian mortality became an issue in Altamont Pass as wind turbines killed some raptors. Transmission
line poles had caps put on them to keep the birds from using them as a perch, thereby extending their
wings between the lines and being electrocuted. Xcel Energy, a utility company, agreed to evaluate
90,000 miles of transmission lines in twelve states to fix any equipment likely to kill birds.
The two primary areas of concern are (1) possible litigation resulting from the killing of even one
bird if it is protected by the Migratory Bird Treaty Act or the Endangered Species Act, and (2) the
effect of avian mortality on populations. A number of projects [18] have been funded since 1994 to
find out the effect of rotating blades on raptors, and if there are methods to make them stand out to
birds: color, noise, etc. Another possibility is that the trust towers make natural perches, since there
are no trees in the area. One wind farm stipulated tubular towers as a precaution, and most large
turbines now have tubular towers. NWTC, NREL, has a section on avian studies [19].
Another area that experienced problems was in southern Spain [20]. Tarifa is a temporary roost-
ing area for migratory birds to and from Africa. Biologists believe the problem of avian mortality
at the site is partly due to aerodynamics as the soaring birds travel the air currents that propel them
up the ridges where the wind turbines are located. The large birds do not have the maneuverability
of the smaller birds.
From the example in Spain, it is obvious that some locations will be off limits to wind farms.
For example, a wind farm could not be located next to a wildlife refugee for an endangered species
of bird, such as the whooping crane. Even though thousands of birds are killed by communication
towers, buildings [21], hunters, and even cars, the Sierra Club and other environmental groups will
become adversaries if there is a problem. Of the hundreds of millions of birds killed annually in
the United States, how many are killed by wind turbines? After bats became a problem in West
Virginia, guidelines became available for both bird and bat impacts [22, 23]. Wildlife/wind interac-
tion publications are available from the National Wind Coordinating Collaborative—one that is a
guidance document on preconstruction utilization counts to make predictions and postconstruction
fatality studies [24].
As expected, fatality rates for birds vary by the biological characteristics of the specific wind
farm and the surrounding area. In Altamont Pass, California, raptors had the highest fatality rates.
Outside of California, studies at twelve wind projects have estimated fatality rates from 0.63/tur-
bine/year to over 10/turbine/year at a fragmented mountain forest site in Tennessee. Bat fatality
rates are estimated from a low of 1.5/turbine/year for most of the United States to a high of 46/
turbine/year in the eastern United States [25].
There will be land areas that are excluded because of environmental considerations, national and
state parks, wetlands, and some wildlife refugees. Environmental impact statements will have to
be done as the Environmental Protection Agency has jurisdiction over many aspects of proposed
location of a wind farm. In addition, some states and even counties have regulations concerning the
environment, which will have to be met before a wind turbine or a wind farm can be installed. First,
check with local officials before you install your wind turbine.
The National Wind Coordinating Collaborative (NWCC) members are from utilities, state leg-
islatures, state utility commissions, consumer advocacy offices, wind equipment suppliers and
developers, green power marketers, environmental organizations, and state and federal agencies.
Permitting publications are available from NWCC [24].
The issues of regulatory framework, environment, and impact analysis and mitigation are cov-
ered in the AWEA Siting Handbook [26]. The information is for projects of 5 MW and greater; how-
ever, it is still useful for smaller projects. Early in the siting process, the developer should conduct
a critical analysis of the environmental issues; required permits, licenses, and regulatory approvals;
threatened or endangered species or habitat; avian and bat species; identification of wetlands and
other protected areas; and location of known archeological and historical resources. A constraints
map is a useful tool for depicting environmental and land use constraints.