How mega batteries are unlocking an energy revolution
As the evening drew in on a sweltering mid-August day in 2020, California’s strained electricity grid buckled. Amid an intense heatwave, surging power demand — amplified by soaring air conditioning use — forced the state’s grid operator to initiate two days of rolling blackouts. An inability to meet demand during the evening peak led to more than 800,000 homes losing power for up to two and a half hours.
It was the first outage of its kind in California in almost 20 years — and raised questions about the state’s reliance on intermittent renewable energy.
The fallout has spurred a boom in mega battery development. Enabled by state policies, California’s battery storage capacity has more than tripled to 13GW of power, with plans to add another 8.6GW by 2027.
Now, as cheap, plentiful solar power floods the grid in the middle of the day, hundreds of battery installations bank the energy and discharge it in the evening when people return home from work and demand — as well as prices — spike. This has shored up the grid, extended the state’s use of renewable energy and reduced its reliance on fossil fuels.
This is an extract of an article published by The Financial times on October 13th, 2025.
Read more on the Financial Times.