Wind farm in the North Sea off Belgium

A wind turbine is a rotating machine that transfers kinetic energy from the wind into mechanical energy. If the mechanical energy is used directly by machinery, such as for pumping water, cutting lumber or grinding stones, the machine is called a windmill. If the mechanical energy is instead converted to electricity, the machine may be called a wind turbine generator (WTG), wind power unit (WPU), wind energy converter (WEC), or aerogenerator.