U.S. large-scale battery storage breakdown by ownership 2019

As of 2019, 56 percent of total large-scale battery storage installed in the United States were owned by independent power producers. In that year, PJM Interconnection was the dominant power producer in the country, with 302 megawatts of power capacity. PJM has storage facilities in the states of Delaware, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia and the District of Columbia.

Investor owned utilities (IOU) were the second dominant ownership type in 2018. 26 percent of the existing power capacity of large-scale battery storage derived from this type of ownership, such as the California Independent System Operator (CAISO). In 2018, CAISO power capacity amounted to 180 megawatts.