Hydro Power
"Hydro" means "water" in Latin - so "hydro power" is made from water.
It might sound odd that we can use water to make electricity - they're a dangerous combination, right? Actually, the water never comes in contact with the electricity. The water flowing down a river is used to spin the turbines inside the generator.
People have used water power for more than 2,000 years. Ancient Egyptians used water wheels for grinding grain, and early Americans learned how to use them for sawing wood.
In the 1880s, scientists learned how to use a flowing river to spin the turbines of a generator. The first hydroelectric power plant in the U.S. opened on the Fox River near Appleton, Wisconsin, in 1882.
By the 1940s, nearly half of the electricity in the United States came from hydro power. After World War II, coal power plants became more popular.
Hydro power isn't very common in the Midwest because most of our rivers are small and slow. Alliant Energy has two hydro power plants, including one in Kilbourn, Wisconsin, that's been making electricity for more than 100 years!
Most of the big hydroelectric power plants in the United States are in California, Oregon and Washington.
People built dams to control the power of the big mountain rivers. Workers can change the amount of water flowing through the dam depending on the weather and how much electricity people need.
The biggest hydroelectric dam in the United States is the Grand Coulee Dam in Washington. Started in 1933 and completed in 1942, it's the largest concrete structure ever built: 5,233 feet long and 550 feet high!
It has four power plants with 33 generators, making enough electricity for more than two million homes.
View photos of the Grand Coulee Dam
Want to learn more?
If you need more information about hydro power, visit these Web sites:
Hydropower: Energy from Moving Water
By the U.S. Department of Energy
Walk Through a Hydroelectric Power Plant
By the Foundation for Water & Energy Education
Links for teachers and parents:
Clean Energy Basics: Hydroelectric Power
By the National Renewable Energy Laboratory
National Hydropower Association
How Stuff Works: Hydropower
[Warning: This site includes multiple animated and pop-up ads]
Grand Coulee Dam: U.S. Bureau of Reclamation
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