The winds that relentlessly blow across the face of the earth carry en enormous amount of energy. All that is needed is a way in which to harness this immense force. This is nothing new and has been done for decades now, be it by capturing the wind in the sails of a boat or by turning the blades of a windmill.
The current most successful methods of harnessing wind power is by the installation of wind turbines. A wind turbine converts the wind’s energy into mechanical energy and then into electrical energy by means of a generator. The maximum amount of energy a wind turbine could potentially recover is 59% and is known as the Betz limit.
This said, the efficiency of a wind turbine is not often used for comparison as the fuel is free. Systems are more often compared on the basis of cost/kW.
The types of wind turbine currently available can be easily classified into two types: Horizontal axis and vertical axis.
A horizontal axis wind turbine (HAWT) is the standard system employed in most projects. They are simple, can be maneuvered to face the wind (either by a vane or power-assisted) and have high power.
As with most renewable energy sources, reliability is a key issue. The amount of wind energy available to use depends entirely on the meteorological conditions.