Energy storage, less common renewable resources make up 4 percent of US power capacity

Hydroelectric pumped storage, batteries, flywheels, and renewable fuels other than hydro, wind, and solar accounted for four percent of the electricity generating capacity in the United States in 2016, according to the U.S. Energy Information Administration (EIA).

Hydroelectric pumped storage plants tend to be the oldest facilities among this group. At the end of 2016, there were 23 gigawatts (GW) of capacity in operation, 88 percent of which was in operation before 1990. The largest hydroelectric pumped storage plant in the United States, at slightly over 3 GW, is located in Virginia’s Bath County.

By the end of 2016, 195 utility-scale geothermal generating units totaling 3.7 GW were in operation. Almost a quarter of that capacity is housed at a complex located in Northern California called the Geysers.

Wood and wood waste biomass represents the largest share of biomass technologies with 10.2 GW of capacity in 2016. Municipal solid waste, landfill gas, and other waste biomass have total capacities of 2.2 GW, 2.1 GW, and 0.8 GW, respectively.

California leads the United States in capacity of hydroelectric pumped storage, geothermal, landfill gas, and batteries. Florida’s municipal solid waste and other waste biomass generators have the most capacity of any state.

All geothermal capacity is located in seven states in the western United States. Landfill gas, as well as wood and wood waste, generators are more common, with generators in 44 states and 32 states, respectively.

Batteries and flywheels, which provide electricity storage, are some of the newest operating units. Almost all of them have been added since 2010. California, Illinois and West Virginia are home to half of the nation’s 540 megawatts (MW) of batteries. Almost all of the 44 MW of utility-scale flywheels in the United States, which provide electricity storage through rotational kinetic energy, are located in New York and Pennsylvania.