When it rains in hills and mountains, the water becomes streams and rivers that run down to the ocean. The moving or falling water can be used to do work. Energy, you’ll remember is the ability to do work. So moving water, which has kinetic energy, can be used to make electricity.

For hundreds of years, moving water was used to turn wooden wheels that were attached to grinding wheels to grind (or mill) flour or corn. These were called grist mills or water mills.

Water can either go over the top of the wheel or the wheel can be placed in the moving river. The flow of the river then turns the wheel at the bottom.

Hydro means water. Hydro-electric means making electricity from water power.

Hydroelectric power uses the kinetic energy of moving water to make electricity. Dams can be built to stop the flow of a river. Water behind a dam often forms a reservoir Dams are also built across larger rivers but no reservoir is made. The river is simply sent through a hydroelectric power plant or powerhouse. NPPD operates one of these “run-of-the-mill” hydroelectric plants near Spencer, NE.

Hydroelectric Power Plant on Niobrara River, near Spencer

Hydroelectric Power Plant on Niobrara River, near Spencer

 Hydro is one of the largest producers of electricity in the United States. Water power supplies about 10 percent of the entire electricity that we use. In states with high mountains and lots of rivers, even more electricity if made by hydro power. In California, for example, about 15 percent of all the electricity comes from hydroelectric.

How does water make electricity? – Check it out!

Cool interactive of Water Cycle!