Throughout history, windmills have been used primarily as grinding mills, saw-mills, or even water-pumping mills. Today they are used to harness the wind's kinetic energy. Wind moves the mill's blades, which rotate a shaft that in turn moves gears connected to a generator. The generator creates electricity.

Not only is wind renewable, it's clean, and it doesn't produce any deleterious by-products that other forms of energy do. Wind energy doesn't depend on process water as do coal and nuclear power. Wind power is generated domestically; there is no dependence on other countries to produce energy for local use. Also, harnessing wind power doesn't require mining operations as coal does, but there are some drawbacks to wind energy, including the negative impact of windmills on wild bird populations. Individual birds may be killed or injured by flying into rotating windmill blades.

Wind is the fastest-growing energy source, and per kilowatt, it is coming close to the cost to generate electricity using fossil fuels. The cost of installing windmills is recouped more quickly than other emerging technologies.

Wind turbines require an extensive amount of land, which can make them more difficult to site in urban areas. Beside land availability, wind turbine sites must be located within high wind energy areas either on land or over the water. Wind power also brings clean, high-tech jobs to the farmlands of the American West, rural Appalachia, and possibly coastal communities as well.

Research continues to improve this technology, making it more affordable. It's expected that wind power could eventually produce 20 percent of the electricity used in the United States. According to the U.S. Department of Energy, wind-produced energy totaled 11,603 megawatts of electricity in 2006. That's enough to provide for 2.9 million homes. Wind farms are more prevalent in the western United States than in any other part of the country. California has the most windmills, followed by Texas.

Puget Sound Energy owns and operates two wind farms in Washington State. The Hopkins Ridge farm has 83 turbines and supplies electricity to 50,000 homes. The Wild Horse wind farm is near completion. It will have 127 wind turbine generators capable of supporting 73,000 homes with electricity.

Xcel Energy is the largest supplier of wind energy in the country with customers in Colorado, New Mexico, and Minnesota. In 2006 the company produced 1,100 megawatts, and in 2007 the company expects to increase production to 2,300 megawatts. By 2012, it expects to add another 1,700 megawatts to the grid.

While not yet constructed, there are proposed plans for building offshore wind farms. On the Atlantic side, the Nantucket Sound wind farm, called Cape Wind, would include 130 wind turbines, and a wind farm in Buzzards Bay would have 90 to 120. The state of Texas currently has plans for a wind farm off Galveston Island and could possibly be the country's first offshore wind farm. Some of the challenges to these offshore wind farms include the visual impact on the landscape. Those living by the coast do not always favor offshore wind farms.

Offshore wind farms proposed for the United States are relatively close to shore, which helps restrain costs. While wind speeds are much higher farther off the coast, the wind turbine foundations must be constructed to withstand deeper water and higher waves, making construction more expensive. Another factor is the distance power must be relayed when farming offshore.

Organizations like the American Wind Energy Association are looking at safe wind farm designs that take marine life into account. They are comparing the potential dangers associated with constructing and operating offshore wind farms to other marine activities and other methods of generating electricity.

If you live in an apartment or other location where installing solar panels or windmills isn't an option, contacting the local electric utility is a good place to start. Some utilities offer green electricity that's generated from renewable sources, which often costs slightly more than standard electricity.

Because green electricity goes to the grid along with electricity produced from nonrenewable sources, customers choosing the green alternative are not necessarily receiving only green electricity. They are, however, supporting the utility's effort to produce electricity from renewable or more environmentally friendly methods.

Another option would be to consider approaching the building's owner or the homeowners' association about the possibility of adding solar panels or windmills to the apartment or condominium. Any local, state, or federal rebates or tax incentives would then go to the owner or association.