U.S. energy storage market hits record capacity amid AI data center demand

The United States energy storage system (ESS) market is experiencing significant growth, driven primarily by the rapid expansion of AI data centers. According to reports from Wood Mackenzie and the American Clean Power Association, the market reached a record 18.9 GWh of energy capacity deployments in the second quarter of 2026.

While power capacity saw a slight year-over-year decrease, total energy capacity rose by 16% due to a shift toward longer-duration battery systems. The average storage duration increased from 2.8 hours in the second quarter of last year to 3.5 hours in the current period. This trend toward four-hour or longer systems helps satisfy utility adequacy requirements and manage localized grid constraints.

Utility-scale installations remain the primary driver, with the residential sector also seeing a 48% jump in energy capacity as households deploy larger battery systems. Analysts have upwardly revised long-term outlooks, projecting that annual ESS installations could grow by more than 50% over the next five years as data centers require rapid power solutions to bypass the long lead times associated with new power plants and transmission lines.