Wind Power

Using the wind to create electricity has been around for a long time - you've probably seen windmills on farms. When the wind turns the blades of a windmill, it spins a turbine inside a small generator to produce electricity, just like a big coal power plant.

A windmill on a farm can make only a small amount of electricity - enough to power a few farm machines. To make enough electricity to serve lots of people, power companies build "wind farms" with dozens of huge wind turbines.

Wind farms are built in flat, open areas where the wind blows at least 14 miles per hour. Iowa currently has more than 600 wind turbines, producing enough electricity to power 140,000 homes. Minnesota and Wisconsin are also home to wind farms – and the number is growing every day.

Some schools in the Midwest have their own wind farms! In Spirit Lake, Iowa, the school playground is right underneath two wind turbines.

They sure are big!

When it comes to size, bigger is better – the bigger the wind turbine, the more wind it reaches and the more electricity it produces.

The turbines at Flying Cloud Wind Plant in northwest Iowa are about 240 feet tall. The largest wind turbine in the world, located in Hawaii, stands 20 stories tall and has blades the length of a football field!

The tower is usually hollow and made of steel. The blades, called rotors, are made of fiberglass and polyester.

View photos of the Spirit Lake wind turbines being built

A wind farm might have only two or three turbines, or it could have as many as 150 spread across a big field. One of the largest wind farms in the U.S. is in Altamont Pass, California. It has more than 900 wind turbines.

How a wind turbine works

A wind turbine works the opposite of a fan. Instead of using electricity to make wind, a turbine uses wind to make electricity.

The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity. The electricity is sent through transmission and distribution lines to a substation, then on to homes, business and schools.

The diagram below shows some of the pieces and parts inside a wind turbine:

Wind turbines have an emergency shut-off if a wind storm or tornado happens.

You can see a wind turbine in action at the U.S. Department of Energy Web site:

Wind Turbine Animation