The terms “wind energy” and “wind power” describe the process by which the wind generates mechanical power or electricity. Wind power is a clean, renewable source of energy.
Wind power is generated by wind turbines. When the wind blows against a wind turbine, it turns its blades. The wind turns the blades of a turbine around a rotor that spins a generator either directly or through a shaft and a series of gears that speed up the rotation from the blades and allows for a smaller generator to be used. This creates electricity.
Wind turbines can be built on land or offshore in large bodies of water.
There are two types of modern wind turbines: horizontal-axis turbines and vertical-axis turbines. Horizontal-axis turbines are more common, and have three blades that operate “upwind.” Horizontal turbines are like windmills but larger and modern. Vertical-axis turbines have several styles, such as an eggbeater style that looks like a whisk. Vertical-axis turbines are omnidirectional, so they don’t need to be adjusted to point into the wind.
Wind turbines have a range of sizes. Single, small turbines are smaller than 100 kilowatts and are typically used for residential, agricultural, and small commercial or industrial applications. Utility-scale turbines range from 100 kilowatts to several megawatts and are used to power electrical grids. These are much larger and are typically grouped into wind farms. The third size is offshore wind turbines, which are the largest and typically taller than the Statue of Liberty. Offshore wind turbines can harness powerful ocean winds and generate very large amounts of electricity.
Modern wind turbines start generating electricity when wind speeds reach six to nine miles per hour. This is known as the cut-in speed. If winds reach over 55 miles per hour, the turbines shut off to prevent damage to the equipment. Over year, modern wind turbines can generate usable amounts of electricity over 90% of the time.
Wind Power Around the World
Wind power’s total cumulative installed electricity generation capacity has increased rapidly since 2000. At the end of 2019, the total capacity amounted to 651 gigawatts. By 2018, wind power made up about 4.8% of the world’s total electricity usage.
Wind power is used commercially by over half of the world’s countries. Seven countries in Europe have achieved high levels of wind power penetration, including 41% of production in Denmark, 28% in Ireland, 24% in Portugal, 21% in Germany, and 19% in Spain.
China is the largest producer of wind power in the world, generating 236,402 megawatts in 2019, about 36.3% of total capacity produced. The United States is the second-largest producer of wind power generating 105,466 megawatts in 2019. Together, China and the United States generated over 52% of the world’s total wind power generated electricity.