Wind Energy, energy contained in the force of the winds blowing across the earth’s surface. When harnessed, wind energy can be converted into mechanical energy for performing work such as pumping water, grinding grain, and milling lumber. By connecting a spinning rotor (an assembly of blades attached to a hub) to an electric generator, modern wind turbines convert wind energy, which turns the rotor, into electrical energy.
Because wind is a clean and renewable source of energy, modern wind turbines had been installed in 26 countries by 2007, including such nations as Germany, Denmark, India, China, and the United States, to supplement more traditional sources of electric power, such as burning coal. Design improvements such as more efficient rotor blades combined with an increase in the numbers of wind turbines installed, have helped increase the world’s wind energy generating capacity by nearly 150 percent since 1990.
Windmill, machine that converts wind into useful energy. This energy is derived from the force of wind acting on oblique blades or sails that radiate from a shaft. The turning shaft may be connected to machinery used to perform such work as milling grain, pumping water, or generating electricity. When the shaft is connected to a load, such as a pump, the device is typically called a windmill. When it is used to generate electricity, it is known as a wind turbine generator.
Besides milling grain and irrigating farmland, windmills developed from the 15th century to the 19th century were adapted to a variety of tasks, including pumping seawater from land below sea level, sawing wood, making paper, pressing oil from seeds, and grinding many different materials. By the 19th century the Dutch had built about 9000 windmills. In 2006 the United States became the world’s third largest producer of energy from wind power, generating more than 11.5 megawatts of electricity.
Wind Energy System Components...