Wind energy is the conversion of wind power into a useful form of energy, such as using wind turbines to make electrical power, windmills for mechanical power, wind pumps for water pumping or drainage, or sails to propel ships.
Large wind farms consist of hundreds of individual wind turbines which are connected to the electric power transmission network. Offshore wind farms can harness more frequent and powerful winds than are available to land-based installations and have less visual impact on the landscape but construction costs are considerably higher. Furthermore, offshore poses problems when considering accessibility for maintenance issues; the sea state must be calm for substantial work to be undertaken on an offshore wind farm. Having to wait for a period of sustained calm weather can result in an offshore turbine being out of action for a considerable amount of time, which significantly reduces income/energy capture.
Small onshore wind facilities are used to provide electricity to isolated locations and utility companies increasingly buy surplus electricity produced by small domestic wind turbines.