Operating on the same principles as the windmills that powered America's farms for years, today's sophisticated wind turbines generate electricity by harnessing the power of air moving over the Earth's surface. Grouped together in "wind farms," these turbines can produce enough energy to light up a whole city.

Wind is a proven clean, renewable energy technology that can now compete with other traditional forms of power generation. In several regions of the country, wind technology has become commercially viable, supplying electricity to the power grid. According to the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy, the cost of energy from wind has dropped 85 percent in the last 20 years.