Chart: The remarkable rise of California’s grid battery capacity

In 2020, California had 500 megawatts of grid battery storage. Now, just three years later, it has over 5,000 megawatts.
By Julian Spector, Maria Virginia Olano

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A row of large grid storage batteries inside an industrial facility
(Patrick T. Fallon/AFP/Getty Images)

Canary Media’s chart of the week translates crucial data about the clean energy transition into a visual format.

Grid batteries are the latest crop to flourish in the California sunshine: The state’s energy storage capacity has surged tenfold in just the past three years.

Battery storage is coming online faster than any other sort of power plant, according to a recent report from the California Independent System Operator, which coordinates grid operations for most of the Golden State. Battery capacity jumped from 500 megawatts in 2020 to 5,000 megawatts by May; that amounts to 7.6% of the electricity system’s nameplate capacity.

Batteries are soaking up solar power during the sunniest hours and delivering it back to the grid after sunset when power is more expensive and carbon-intensive. They’ve already proven valuable in the state, bolstering the grid during crucial evening hours in the September 2022 heat wave. More batteries arriving on the scene will further protect against power shortages during those hours when air-conditioning needs surge, but solar production fades away.

California got to this stage through futuristic policy that gave storage a chance to solve tangible grid problems.

Back in 2010, California lawmakers ordered the state’s utilities to install energy storage, anticipating all the renewable energy that would be built in the coming decades. It took a few years to finalize the rules; regulators made it official in 2013, ordering the three big utilities to procure 1,325 megawatts by 2020 and install it by the end of 2024.

Utilities like to start small and slow with new technologies, but energy storage proved too useful for unhurried adoption. When the Aliso Canyon gas storage facility leak was discovered in 2015, a horrendous amount of fossil gas had escaped into the atmosphere. That greenhouse emissions bomb also reduced the supply of gas for Southern California power plants, raising concerns about blackouts for the coming summer.

Battery storage proved the only tool ready to deploy fast enough to avoid grid outages. Several developers won contracts and built projects within four months; the Aliso Canyon batteries added up to 100 megawatts, which seemed like a lot then. They helped avoid blackouts that summer, laying the groundwork for the wider adoption the state is seeing today — a crucial development for coping with the heat-wave-driven power shortages the state is increasingly experiencing.

Luckily for California, developers have already built nearly four times the state’s original storage target, more than a year ahead of schedule. 

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Julian Spector is a senior reporter at Canary Media. He reports on batteries, long-duration energy storage, low-carbon hydrogen and clean energy breakthroughs around the world.

Maria Virginia Olano is editorial producer at Canary Media.