Wind power is the conversion of wind energy into a useful form, such as electricity, using wind turbines. Wind energy has been used for centuries for tasks such as milling grain and pumping water. The first windmills were built in the Middle Ages in Europe and the Middle East. Today, wind power is being used to generate electricity on a large scale in many countries around the world.
The potential for harnessing wind energy has long been recognized. In the early days of sail-powered ships, wind was used to propel vessels across oceans. Windmills have been used since ancient times to grind grain and pump water.
The use of wind to generate electricity on a large scale only began in the late 20th century. Denmark was one of the first countries to develop commercial wind farms, followed by Germany, Spain, and other European nations. The United States lagged behind Europe in developing its own large-scale commercialwind farms until the early 21st century. China is now a leading country in both installed capacity and manufacture of wind turbines.
There are two main types of technology used for converting wind into electrical energy: horizontal-axis or vertical-axis turbines (or HAWTs and VAWT). The type most commonly seen today are horizontal-axis machines with three blades that look like giant propellers spinning on top of tall towers (these are called “utility-scale” because they are usually connected to an electric utility grid). Vertical-axis machines (sometimes called “small” or “distributed” because they can be smaller and more spread out) come in many shapes but most often look like Darrieus or Savonius rotors—two or three blades rotating around a vertical shaft at ground level (or close to it).
Turbines work by capturing kinetic energy from moving air molecules and converting it into mechanical energy that turns an internal generator to produce electricity; this process is known as the aerodynamic forces on rotor blades which drive rotation about a central shaft that spins an electric generator inside the nacelle (the housing at turbine top where all key components – including rotor blade assembly, gearbox ,and generator – are located). Utility-scale generators typically range between 1–2 MW although some new designs have capacities approaching 10 MW while small/distributed units start below 100 kW but newer designs have rated capacities up over 1MW . There are also intermediate or community -scale turbines with ratings between these extremes that provide power directly to local communities without connection to an electric grid; these Community Wind systems most often take advantage of VAWT configurations due largely due site constraints such as land availability .