Summary
Highlights
Hydropower captures energy from moving water to generate clean, renewable, and affordable electricity. It converts the motion of water, flowing from higher to lower elevations, into electricity using turbines and generators. Hydropower has been used for over 100 years in America, making up about 7% of the nation's electricity and representing the largest source of renewable power.
Hydropower is renewable because it relies on the continuous water cycle. Water evaporates into clouds, returns as precipitation, and can be used to produce electricity as it flows, constantly recharging the resource.
There are several ways hydropower generates electricity. Impoundment technology uses dams to store water in a reservoir; when released, the water spins turbines to generate electricity. Diversion technology channels a portion of a river through a canal or pipe to a turbine and generator, often without a large dam. Pumped storage hydropower acts like a battery, pumping water to a higher reservoir during low energy use and releasing it to generate power during peak demand.
The Department of Energy is working to upgrade existing hydropower facilities by improving the efficiency of turbines and generators. Neighboring facilities are collaborating to optimize energy production across entire river systems. There's also potential to retrofit non-power-producing dams (like those for irrigation or flood control) with generators. Out of 80,000 dams in the U.S., less than 3% currently generate power, indicating significant untapped potential.
New technologies are making hydropower more environmentally friendly, particularly by reducing adverse impacts on fish and their habitats, for example, through the use of fish ladders around dams. Hydropower is a reliable, essential, and renewable source of clean energy that meets substantial energy demands. With ongoing technological advancements, it is expected to become even more efficient and productive, powering homes and businesses for centuries.