The wind has been a source of energy for thousands of years.
Before the development of the steam engine, most ships relied on wind power to fill their sails and push them along. Windmills were used to turn grindstones and pump water.

Now scientists are turning to wind power again. This time they are using it to generate electricity.
Windmills have been used to produce electricity since the early 1900’s. It is easy to produce electricity from a wind turbine. This is simply a windmill that converts the kinetic energy of the wind into electricity.
Small wind turbines are used by farmers in remote parts of Australia and North America. In wide, open spaces, these turbines can make some of the electricity that farmhouses need. However, the winds are sometimes so strong that they damage the turbines and put them out of action.
Engineers have designed many different kinds of wind turbines to try to solve this problem. Some turbines look like old-fashioned windmills, with four blades, or sails. Other, more modern ones have two blades like those of an aircraft propeller.

In North America, this type of traditional windmill is used to pump water.

One of the largest wind turbines in the world stands in Hawaii, in the Pacific Ocean. It has two blades 165 feet (50 meters) long on top of a high tower. There is a smaller turbine on Orkney, off the coast of Scotland. It can generate enough electricity for about 1,000 homes. Most wind turbines are mounted on a cap, or swivel, on top of a tower. This means that they can be turned to face the wind when its direction changes.
A huge power station driven by wind has been built in the Mojave Desert in California. Its owners call it a “wind farm.”  Hundreds of wind turbines are arranged in rows and all are linked together by wires. The electricity they produce is supplied to the California power pool.

These wind turbines supply electricity to homes and factories.