U.S. large-scale battery storage capacity by region 2019

PJM Interconnection has the largest capacity of large-scale battery storage installations in the United States. As of 2019, it owned a total of 302 megawatts. PJM Interconnection has facilities throughout the states of Delaware, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia and the District of Columbia. The second highest power capacity in large-scale facilities was seen in the California Independent System Operator region, at 199 megawatts.

Independent power producers hold the greatest large-scale battery capacity in the country.