The United States Department of Energy's Global Energy Storage Database (GESDB) is a free-access database of energy storage projects and policies funded by the U.S. DOE, Office of Electricity, and Sandia National Labs.[1]
In 2013, the database covered 409 projects; it aimed to cover all energy storage projects globally by 2014.[2] By 2020, it covered 1,686 projects,[3] comprising 22 GigaWatt power of US grid storage capacity. Pumped-storage hydroelectricity is around 90% of the energy capacity. Storage facilities are 80% efficient.[4]
in 2019, the U.S. utility-scale battery fleet operated with an average monthly round-trip efficiency of 82%, and pumped-storage facilities operated with an average monthly round-trip efficiency of 79%. The {pumped-storage} facilities collectively account for 21.9 gigawatts (GW) of capacity and for 92% of the country's total energy storage capacity as of November 2020.