Nowadays wind generators are used to produce electricity. The wind generators are made of several parts. The rotating part consists of a shaft, at the one end of which the wings are attached. The wind rotates the wings and therefore the kinetic energy of the wind is transmitted to the axis (rotating shaft) where it is converted into rotational kinetic energy. A system of gears helps to increase the speed of rotation. The generator (which is connected to the rotating axis) converts the kinetic energy into electrical energy. In some wind generators the pitch of the rotating wings can be adjusted according to the speed of the wind. Sometimes the pitch (which is the angle by which the wing "sees" the wind or exposes itself to it) is self-adjustable. When the wind speed becomes too high these rotating parts take a position towards the wind exposing itself less to the wind, and the generator stops rotating to avoid damages.
In all energy conversions the final energy is less (normally much less) than the one on the beginning.
This applies also to the wind generators; therefore not all of the wind's kinetic energy is converted into electrical energy. When the wings move with the maximum speed the generated electrical energy is around 45-60% of the original kinetic energy. When the wind speed decreases the efficiency of the wind generator is even smaller.
In many regions in Greece, (and in other countries also) wind farms have been installed. In these many wind generators have been placed.
The kinetic energy of the wind is also called Aeolian energy. The word comes from the ancient Greek god Aeolus. According to the ancient Greek mythology, he was the god of the winds.
Is it possible to electify Greece or any other country
by using only windmills? 
Advantages and disadvantages of the use of windmills.
