Falling water in streams and rivers has been harnessed to produce electric energy for more than 100 years. Hydroelectric projects provide the most efficient means of producing electric energy (at about 90 percent efficiency).
Hydroelectric generation represents about 96 percent of our renewable energy production. We save 531 million barrels of oil each year by generating electricity via hydropower. Hydroelectric projects are:
- Free from air pollution.
- The fuel—falling water—is not consumed.
- Projects have long lives, often exceeding 50 years.
- Electric energy is immediately available for use.
In 1920, hydroelectric power represented about 30 percent of generating capacity in the U.S., and 40 percent of the energy supplied by electric systems. Today, hydro contributes only about 10 percent of the electricity produced in the U.S. or about 74,800 megawatts of generating capacity in the U.S.
FERC regulates only 56 percent of the hydroelectric projects in the U.S. The remaining projects have been built by the federal government. They are operated by the U.S. Department of the Interior (Bureau of Reclamation), the U.S. Army Corps of Engineers and the Tennessee Valley Authority. Most hydroelectric projects serve other purposes, such as navigation, flood control, recreation, irrigation and flow augmentation.