Hydroelectric generators are oldest power plants in US

Hydropower plants represent 99 percent of all currently operating capacity built before 1930, the U.S. Energy Information Administration (EIA) recently said.

The 50 oldest power plants in the United States are all hydroelectric generators that have been operating since 1908. The average hydroelectric facility has been in service for 64 years.

Conventional hydroelectric generators make up seven percent of the United States’ total operational generating capacity and produce six to seven percent of its electricity each year. This does not include pumped-storage facilities, which produce electricity with water that has been pumped into an upper
reservoir and is then released to a lower one.

Conventional hydropower represents just 1.7 gigawatts (GW) of the approximately 200 GW of generating capacity installed from 2007 to 2016. More than half of that 1.7 GW was installed in Washington state. Until 2014, hydropower produced more electricity than all other renewable energy sources combined.

Washington, California and Oregon have half of U.S. hydroelectric capacity. Washington, Idaho, Vermont and Oregon use hydropower for half of their in-state utility-scale generating capacity. Various states have little hydroelectric potential, but only two, Delaware and Mississippi, have no hydro capacity.

Hydroelectric capacity in the United States has increased slightly in recent decades. Adding turbines at existing facilities or previously unpowered dams and repowering older turbines can increase capacity, according to the EIA.