Wind Turbine

A wind turbine is a tall machine that uses moving air to make electricity. It looks like a giant fan on a pole, but it works the opposite way. A fan uses electricity to push air. A wind turbine lets the air push it, and turns that pushing into electricity. Wind turbines are one of the main sources of renewable energy in the world today.

Most modern wind turbines have three long blades attached to a central hub. When wind blows past the blades, it pushes them, and the hub spins. The hub is connected to a shaft inside a box at the top of the tower called the nacelle. Inside the nacelle, the spinning shaft turns a generator. A generator is a machine that turns motion into electricity, using magnets and coils of wire. Wires inside the tower carry the electricity down to the ground and out to homes, schools, and businesses.

The blades are huge. On a large modern turbine, each blade can be more than 250 feet long, longer than a football field is wide. The whole tower can stand 500 feet tall, taller than the Washington Monument. The blades only seem to spin slowly, but the tips can travel more than 180 miles per hour through the air.

Wind turbines work best in places where the wind blows often and steadily. Many of them stand together in groups called wind farms. Some wind farms are built on land, often in open plains or on hilltops. Others are built in the ocean, where the wind is usually stronger. Offshore wind farms can have dozens or even hundreds of turbines lined up in the water.

Wind power has real trade-offs. The good news is that it does not burn fuel and does not release the gases that warm the planet. The trade-offs are that turbines only make power when the wind blows, they can be loud up close, and their spinning blades sometimes kill birds and bats. Engineers are working on ways to fix these problems, like painting one blade black to help birds see the turbine and avoid it.

People have used wind for power for a very long time. Old-fashioned windmills in places like the Netherlands ground grain and pumped water hundreds of years ago. The first wind turbine that made electricity was built in Scotland in 1887. Today, wind makes about 10 percent of all the electricity used in the United States.