Wind Energy and Wind Turbines

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Enercon E-66 wind energy converter in Egeln/Germany. The tower is 98m high and the rotor diameter is 70m. Photo: Hadhuey, CC-BY-SA-3.0, via Wikimedia Commons)

Published: November 30, 2014
Author: Justin M. Birzon
Topic Editor: Sidney Draggan

Since 1999 the United States’ installed capacity of wind-produced electricity has grown from 2,000 mW to 28,635 mW, which is enough energy to power the equivalent of more than 6.5 million homes.[1]

A functioning turbine can provide electricity directly to a building or other application as a “stand-alone,” or “off-grid” system, or it can be connected to the transmission grid.[2] Hybrid systems can combine wind, solar, and, for example, a diesel or biogas electric generator to provide holistic energy security for off-grid systems.[3]

A small wind turbine is one that generates 100 kilowatts (“kWs”)[4] or less, and is generally used to produce clean, emissions-free power for individual homes, farms and businesses.[5] As compared to large commercial turbines that may be 300 feet tall and are capable of producing several megawatts (“mWs”) of electricity, small wind turbines may have a 40-foot rotor mounted on a 130-foot tall tower, and cost thousands rather than hundreds of thousands of dollars to construct.[6] Adverse impacts of wind turbines include mortality to avafauna and bats, as well as generation of noise pollution. Unlike utility-scale turbines, small wind turbines offer increased siting flexibility and can be used on properties as small as one acre.[7] The electrical output of small wind turbines also avoids some of the capacity restraints on the grid’s distributions lines that cause problems for larger, commercial turbines.[8]

Impacts to Avafauna and Bats

The disproportionate numbers of threatened species killed by large wind turbines, is explained in part by the fact that many large raptors are vulnerable or endangered species. The following is a partial list of threatened avian taxa that are present in disproportionately high numbers (relative to the entire species population) in turbine kill counts:

  • Whooping crane (Grus americana) And Endangered
  • Greater prairie chicken (Tympanuchus cupido) With one subspecies Endangered
  • Greater sage grouse (Centrocercus urophasianus) Threatened, IUCN

A 2003 compilation of bird deaths by wind turbines indicated that the non-California mortality included an astonishing 78 percent of all bird deaths as protected passerines pursuant to the U.S.Migratory Bird Treaty Reform Act; moreover, this percentage is viewed as a possible underestimate of this group of threatened species, due to the relative difficulty of detected small passerine carcasses and a suspected lack of adequate sampling during passerine migrations.

Wind turbine in southern Alberta, Canada. Source: Saikat Basu, own work.


1 This estimate is accurate as of April 30, 2009. See U.S. Dept. of Energy, Wind Powering America, available at (last visited Dec. 15, 2009).

2 Texas State Energy Conservation Office, Small Wind Systems, available at (last visited Dec. 15, 2009).

3 Texas State Energy Conservation Office,Small Wind Systems, available at (last visited Dec. 15, 2009).

4 1,000 kW = 1 mW. Similarly, 1,000 kWh = 1 mWh. For a detailed explanation see American Wind Energy Association, How Much Electricity Can One Turbine Generate (2009), available at (last visited Dec. 15, 2009).

5 American Wind Energy Association, Small Wind, available at (last visited Dec. 15, 2009)

6 Kevin L Shaw & Richard D. Deutsch, Wind Power and Other Renewable Energy Projects: The New Wave of Power Project Development on Indian Lands, 5 Rocky Mountain Mineral Law Foundation Institute Paper No. 9, 5, (2005).

7 American Wind Energy Association,FAQ For Small Wind Systems, available at (last visited Dec. 15, 2009); See also Canadian Wind Energy Association, Planning for Your Small Wind Turbine, available at (last visited Dec. 15, 2009) (stating that “Small wind is great if you have at least 1/2 acre of property with good wind”).

8 Ryan Thomas Trahan, Social and Regulatory Control of Wind Energy – An Empirical Study of Texas and Kansas, 4 Texas Journal of Oil, Gas, and Energy Law 89, 100 (2004)


Birzon, J. (2014). Wind Energy and Wind Turbines. Retrieved from