Energy from Wind

Since ancient times, people have har¬nessed the winds energy. Over 5,000 years ago, the ancient Egyptians used wind to sail ships on the Nile River. Later, people built windmills to grind wheat and other grains. The earliest known windmills were in Persia (Iran). These early windmills looked like large paddle wheels. Centuries later, the people of Holland improved the basic design of the windmill. They gave it propeller-type blades, still made with sails. Holland is famous for its windmills.
American colonists used windmills to grind wheat and corn, to pump water, and to cut wood at sawmills. As late as the 192os, Americans used small windmills to generate electricity in rural areas without electric service. When power lines began to transport electricity to rural areas in the 1930s, local windmills were used less and less, though they can still be seen on some Western ranches.
The oil shortages of the 1970S changed the energy picture for world. It created an interest in alternative energy sources, paving the way for the re-entry of the windmill to generate electricity. In the early 1980s
. wind energy really took off in California, partly because of state policies that en¬couraged renewable energy sources. Cali¬fornia still produces more than twice as much wind energy as any other state in the USA.

How wind machines work

Like old fashioned windmills, today's wind machines use blades to collect the wind's kinetic energy. Windmills work because they slow down the speed of the wind. The wind flows over the airfoil shaped blades causing lift, like the effect on airplane wings, causing them to turn. The blades are connected to a drive shaft that turns an electric generator to produce electricity.
With the new wind machines, there is still the problem of what to do when the wind isn't blowing. At those times, other types of power plants must be used to make electricity. The largest wind machines in the world have blades longer than a football field! Wind machines stand tall and wide to capture more wind.