California grid saw 10-fold increase in battery storage capacity since 2020
Battery storage capacity in California has reached more than 5,000 MW, according to the latest from the California Independent System Operator (ISO), representing a more than 10-fold increase in dispatch capacity since 2020.
As of July 1, 2023, total battery storage figures reached 5,600 MW. That’s enough to power approximately 3.8 million homes for up to four hours. Such batteries are charged during the day while solar power operates at peak capabilities, then dispatch their power largely in the evening hours when demand remains high but solar capacity begins to flag. Many have also been paired with new or existing solar resources at the same location for increased efficiency and flexibility.
“With our state experiencing more frequent climate extremes such as record heat waves and droughts, it is essential to invest in innovative technologies like energy storage to make sure we can continue to reliably power the world’s 4th largest economy,” Elliot Mainzer, the ISO’s president and CEO, said. “Just three years ago, we had about 500 MW on the grid and this rapid growth of energy storage in California has significantly improved our ability to manage through challenging grid conditions.”
Driving the change has been a series of procurement orders greenlit by the California Public Utilities Commission (CPUC), which made utilities add storage capacity to their portfolio and plan for more in the years ahead. In all, the commission called for more than 10,000 MW in aggregate storage capacity to enter the grid by 2026.
Those batteries have already been put to the test. Last summer, when record heat and demand pummeled the Californian grid, batteries helped maintain reliability during evening hours as solar capabilities fell. According to Gabe Murtaugh, storage sector manager in the ISO’s Market Design group, at its current capacity the storage fleet is able to serve about 10 percent of load during strenuous conditions and can often provide more during peak load periods.
“The storage fleet has been performing largely as planned,” Murtaugh said. “It has allowed us to dispatch additional power when it is most needed to help keep the grid balanced and the power flowing. We look forward to the further growth and technological diversification of this valuable new resource.”
Each megawatt of electricity is able to power the rough equivalent of 750 homes’ worth of demand. Going forward, the ISO expects to see new storage technologies and longer-duration storage resources able to bump their value further. How this will affect energy prices remains to be seen, though, as storage resources don’t necessarily rely on the same factors as traditional energy use.
