EIA: Hydroelectric plants are among the oldest still in use in U.S.

Hydroelectric power plants are among the oldest power plants still in use in the U.S., according to Energy Information Administration data.

The average hydroelectric facility in the U.S. has been operating for 64 years, Kallanish Energy has learned. Hydropower plants account for 99% of all currently operating capacity built before 1930, EIA said.

The 50 oldest electric generating plants in the U.S. are all hydroelectric generators, and all have been in service since 1908, EIA said.

Conventional hydroelectric generators account for 7% of operating electricity generating capacity and about 6% to 7% of U.S. electricity generation each year, it said.

Until 2014, hydroelectricity exceeded the electricity produced by all other renewable sources combined, EIA reported. Half of all U.S. hydroelectric capacity is in three states: Washington, California and Oregon.

Four states – Washington, Idaho, Oregon and Vermont – depend on hydroelectricity for at least half of their in-state, utility-scale generating capacity.

Only two states have no hydroelectric facilities: Delaware and Mississippi.