California has emerged as the undisputed national leader in battery energy storage deployment. Over the past decade, the state has transformed its energy infrastructure through an extraordinary buildout of lithium-ion battery storage systems, growing from approximately 770 megawatts of installed capacity in 2019 to nearly 17,000 megawatts by late 2025—a surge of more than 2,100 percent. This expansion encompasses over 200 utility-scale systems, more than 250,000 commercial and residential installations, and a pipeline of projects pushing toward the state’s 52,000 MW target by 2045.