The wind turbine, also called a windmill, is a means of harnessing the
kinetic energy of the wind and converting it into electrical energy. This
is accomplished by turning blades called aerofoils, which drive a shaft,
which drive a motor (turbine) and ar e connected to a generator. "It is
estimated that the total power capacity of winds surrounding the earth is
1 x 1011 Gigawatts" (Cheremisinoff 6). The total energy of the winds
fluctuates from year to year. Windmill expert Richard Hills said that the
wind really is a fickle source of power, with wind speeds to low or
inconsistent for the windmill to be of practical use. However, that
hasn't stopped windmill engineers from trying. Today, there are many
kinds of windmills, some of which serve differen t functions. They are a
complex alternative energy source.