The following HTML text is provided to enhance online
readability. Many aspects of typography translate only awkwardly to HTML.
Please use the page image
as the authoritative form to ensure accuracy.
Environmental Impacts of Wind-Energy Projects
FIGURE 1-2 Total installed U.S. wind-energy capacity: 11,603 MW as of December 31, 2006.
SOURCE: AWEA 2007. Reprinted with permission; copyright 2007, American Wind Energy Association.
Like all sources of energy exploited to date, wind-energy projects have effects that may be regarded as negative. These potential or realized adverse effects have been described not only in the Mid-Atlantic Highlands (MAH) (Schleede 2003) but also in other parts of the country, such as California (CBD 2004) and Massachusetts (almost any issue of the Cape Cod Times, where the proposed and controversial wind-energy installation in Nantucket Sound is discussed).
GENERATING ELECTRICITY FROM WIND ENERGY
Two percent of all the energy the earth receives from the sun is converted into kinetic energy in the atmosphere, 100 times more than the energy converted into biomass by plants. The main source of this kinetic energy is imbalance between net outgoing radiation at high latitudes and net incoming radiation at low latitudes. The global temperature equilibrium is maintained by a transport of heat from the equatorial to the polar regions by atmospheric movement (wind) and ocean currents. The earth’s rotation and geographic features prevent the wind from flowing uniformly and consistently.
The kinetic energy of moving air that passes the rotor of a turbine is proportional to the cube of the wind speed. Hence, a doubling of the wind speed results in eight times more wind energy. A modern 1.5 MW wind turbine with a hub height (center of rotor) and tower height of 90 meters (m),