Hydropower or water power, which is using the movement of water to generate mechanical energy, has existed for thousands of years. With the introduction of electricity came hydroelectric power, or the ability to generate electricity using the movement of water to turn turbines that power a generator. The world’s first hydropower plant began to generate electrical energy in 1882 in Appleton, Wisconsin.¹ By 1896, there were 300 hydroelectric power plants in operation in the United States.²

Today about 7% of U.S. power comes from hydroelectric sources.³ Dams (also known as impoundment), diversion, and pumped storage hydropower (pumped into a reservoir during low demand and released during high demand) are sources of hydroelectricity, although only a small percentage of existing dams are used for power. Most water power plants serve regional areas, and depend on access to water sources along with high precipitation levels.⁴

The U.S. Bureau of Reclamation is the second largest producer of hydroelectricity in the United States.⁵ This agency along with the U.S. Army Corps of Engineers, and the Tennessee Valley Authority, makes up approximately 49% of the installed capacity of hydropower, meaning under ideal conditions, they could supply 49% of the electricity needs that come from hydropower; private ownership, which including investor-owned utilities, independent power producers, and industrial companies, accounts for approximately 27% of the installed capacity; and public ownership, such as public utility districts, irrigation districts, states, and rural cooperatives, make up approximately 24% of installed capacity.⁶

The Federal Energy Regulatory Commission (FERC) regulates all hydroelectric projects. Their oversight starts at granting licenses, which are issued for 30 to 50 years. As part of issuing a license, FERC examines the use of U.S. federal government and Native American lands. FERC ensures licensed dams are in compliance with environmental standards, and oversees their safety and security.⁷