The output of a wind turbine depends on how big it is and how fast the wind moves through the rotor. Wind turbines being manufactured now have power ratings ranging from 250 watts to 1.8 MW. Wind turbines are modular and can be built in groups called wind farms that generate commercial quantities of electricity. At the end of 2008, the U.S. had 25,300 MW of wind power in use.
Much of the recent growth in the U.S. wind power industry has occurred in Texas. Electric utilities use wind power because of its cost-effectiveness. Turbines can be installed rapidly and produce electricity less expensively than new coal-fired power plants. Even so, it costs about $1 million per MW to build a wind farm.
Example: A 10-kW wind turbine can generate about 10,000 kWh annually at a site with wind speeds averaging 12 miles per hour, or about enough to power a typical household for a year. A 1.8-MW turbine can produce more than 5.2 million kWh a year--enough to power about 520 households.