A wind turbine is a rotating machine that converts the kinetic energy in wind into mechanical energy. If the mechanical energy is used directly by machinery, such as a pump or grinding stones, the machine is usually called a windmill. If the mechanical energy is then converted to electricity, the machine is called a wind generator, wind turbine, wind power unit (WPU) or wind energy converter (WEC).
This article discusses the various types of wind turbines used for electric power generation, as well as the relative advantages and disadvantages of each specific type. (See Renewable Energy for a more discussion and wind power.