Wind is the natural movement of air across the land or sea. Wind is caused by uneven heating and cooling of the earth's surface and by the earth's rotation. Land and water areas absorb and release different amount of heat received from the sun. As warm air rises, cooler air rushes in to take its place, causing local winds. The rotation of the earth changes the direction of the flow of air.
Wind electric generator converts kinetic energy available in wind to electrical energy by using rotor, gearbox and generator.
The wind turns the blades of a windmill-like machine. The rotating blades turn the shaft to which they are attached. The turning shaft typically can either power a pump or turn a generator, which produces electricity.
Most wind machines have blades attached to a horizontal shaft. This shaft transmits power through a series of gears, which provide power to a water pump or electric generator. These are called horizontal axis wind turbines.
There are also vertical axis machines, such as the Darrieus wind machine, which has two, three, or four long curved blades on a vertical shaft and resembles a giant eggbeater in shape.
The amount of energy produced by a wind machine depends upon the wind speed and the size of the blades in the machine. In general, when the wind speed doubles, the power produced increases eight times. Larger blades capture more wind. As the diameter of the circle formed by the blades doubles, the power increases four times.
Main components of a wind electric generator are:
An area where a number of wind electric generators are installed is known as a wind farm. The essential requirements for establishment of a wind farm for optimal exploitation of the wind are
| Availability | Usable as it exists | Have to be procured and made usable through laborious and environmentally damaging processes |
| Limitation on availability | Inexhaustible resource | Limited in reserves, expected to get completely exhausted in the coming 60 years |
| Transportation | Used where it is available | Have to be transported from the site for further processing exposing environment to danger |
| Use in production | Zero emission | Used in producing electricity releasing green house gasses |
| Geo-political Implications | Reduces our reliance on oil, safeguarding national security | Over-reliance on oil as a resource has undermined our energy security. E.g. OPEC crises of 1973, Gulf War of 1991 and Iraq War of 2003 |
| There is no adverse effect on global environment. The whole system is pollution free and environment friendly. |
