Wind energy comes from the uneven heating of the planet as it spins through the day and night, being warmed and cooled by the Sun. Temperature gradients between land and sea, and physical obstacles like mountains, also play a role in the complex dance of wind.
Wind power dates back to at least 5000 B.C.E., when it was used to propel boats along the Nile River. By 200 B.C.E., simple windmills were pumping water in China and grinding grain in the Middle East.
Windmills designed to generate electricity, known as turbines, first appeared in Denmark around 1890. They operate on a simple principle: Two or three propeller-like blades are attached to a rotor, which is in turn connected to an electrical generator. When the wind blows, the propeller turns the rotor, spinning the generator and creating electrical current. Utility-sized wind turbines are familiar horizontal-axis units, typically mounted on a tower 75 feet or more off the ground, to take advantage of faster, less turbulent winds. Smaller vertical axis turbines without towers are also used, particularly for low-speed winds.
Wind power is primarily a utility-scale technology, with hundreds of turbines arrayed in large "wind farms." Wind offers a number of advantages over fossil fuel in powering the grid:
Wind is a vast, free, and inexhaustible resource.
Wind helps reduce our use of the primary fuels for grid power: natural gas, coal, and to a lesser extent, petroleum. Recognizing that all ...