US battery storage adds 57.6 gigawatt-hours in a single year as Texas prepares to overtake California
A 52 percent jump over 2024 pushes utility-scale storage past every prior annual tally, and the center of gravity moves from ISO-NE and CAISO toward ERCOT.
The curve did not just keep bending. It bent faster. The US installed 57.6 gigawatt-hours of new energy storage in 2025, according to Wood Mackenzie and the Solar Energy Industries Association's joint tracking, which amounts to the largest single year of additions on record and a fifty-two percent jump over 2024's already-record figure. Texas and California together accounted for roughly eighty-two percent of the total, and by the end of 2026 ERCOT is projected to overtake CAISO as the country's largest storage market outright.
The bending of the curve is structural rather than policy-driven. Lithium iron phosphate cell prices have kept falling through successive oversupply cycles in China; interconnection queues across ERCOT and the Southwest Power Pool are dominated by hybrid solar-plus-storage proposals; and retail tariffs in California have made behind-the-meter batteries pencil out in markets where they didn't two years ago. The cumulative California fleet now sits at 16,942 megawatts, a number the state's governor used at COP30 in November 2025, up roughly 2,100 percent from the 2019 base.
The specific mechanism matters for the next decade of grid planning. Storage is no longer an accessory to renewable generation; it is the dispatchable capacity class that is growing fastest on the system. Texas's leap ahead of California is partly a pricing story — ERCOT's energy-only market rewards fast-responding assets more aggressively than a capacity-market ISO does — and partly a siting story. Land, labour, and interconnection remain easier in West Texas than in the San Joaquin Valley, and the builders have noticed.
The winners are the integrators, the lithium cell manufacturers with US-sited assembly, and every developer whose pipeline assumed batteries would be available on the other end of interconnection. The losers are the peaking gas units whose capacity revenues are being directly cannibalised, and the utilities whose forecasting models still treat storage as a marginal resource rather than a central one.
What the year-end number forecloses is the assumption that renewables' intermittency problem is open-ended. The problem is being solved, cell by cell, at a cadence the forecasting community keeps underestimating. What it opens is a harder regulatory question: how to compensate assets whose value is measured in hours rather than megawatts, on a grid whose tariff structures were designed for neither.