Wind energy is harnessed for the generation of electricity by setting up turbines that run electrical generators. The most simple design involves a propellor attached to a horizontal axis. The wind causes the propellor to move which in turn powers the generator and electricity is produced. At the current time there is 3500 MW installed wind capacity worldwide.
The major advantages of wind power is that it is inexhaustible and environmentally safe. The land used for wind power generation can also be farmed, ranched or otherwise cultivated. Current projects in the western United States have shown wind "farms," as they are called, to be feasible supplemental sources of electricity.
There are multiple drawbacks however to wind power. The first is that compared to other sources of electricity wind power is fairly expensive. The second problem is reliability. Wind power is only considered feasible if winds in the area under consideration exceed 13 mph 90% of the year and even when such sites are found there is the additional problem that winds change from year to year in any given area. Additional worries include excessive noise and danger to birds.