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WIND POWER
A Brief History of Wind Power
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WIND POWER
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The use of wind energy dates back many centuries, perhaps even thousands
of years. In many cultures, windmills were built for milling grain and
pumping water. Some windmills became typical of the cultural landscape in
many areas especially in Europe. The step from mechanical to electrical use
of wind energy was made in the USA. In 1888, Charles F. Brush developed an
automatically operating wind machine performing a rated power of 12 kW
direct current. The rotor had a diameter of 17 metres and 144 blades made of
cedar wood. Small-scale stand-alone systems continued to be the main focus
of wind power applications for another five decades. The first AC turbine was
built in the 1930s in the USA. At first, further use of wind power suffered from
the less expensive grid power but interest in wind energy grew through
energy emergencies such as World War II and the oil crisis in the early 1970s.
The development of modern wind power machines has been led by
Denmark, Germany, the Netherlands, Spain, and the USA. Through these
developments, wind power has become an important electricity option for
large-scale on-grid use.
Technology Status
The main components of a wind turbine are the rotor, generator, directional
system, protection system and tower. Wind spins the rotor blades, driving
the turbine generator. Sometimes gearing is used to increase the rotation
speed for electricity generation. The generator transforms the mechanical
energy from the rotating blades into electricity. Electricity is then transferred
to the grid or a storage system. Generator designs vary according to the
system and wind regime. A directional system enables horizontal axis
machines to swing into the wind: a tail assembly is often used for small
machines, whereas a “servo mechanism” orients large machines to the
direction of maximum power. Modern wind turbines are usually equipped
with a protection system (variable orientation of blades, mechanical brakes,
shut-down mechanisms) to prevent damage during excessive wind loads.
The tower raises the turbines well above the ground in order to capture wind
with higher speed and less turbulent currents.