The power went out during a California heat wave in 2020. Two years later, only a last-minute intervention by state officials prevented rolling blackouts. But last week, as temperatures soared past 100 degrees, the state didn’t have to hit the emergency button.
The state’s fortunes shifted due to a massive battery boom.
“The bulk power grid is currently stable and energy supply is sufficient to meet demand,” Anne Gonzales, a spokesperson for the California Independent System Operator, said Monday.
Batteries, which store electricity during the day when solar energy is cranking and discharge it at night, have alleviated the reliability challenges that threatened to undermine climate action in America’s most populous state. The result could be a power grid that can withstand extreme temperatures without contributing to global warming.
“What’s happening in California is a gradual, but pretty rapid transition, from total reliance on natural gas in these conditions to a mix of new technologies that provide the same level of reliability but without the greenhouse gas emissions or local air pollution,” said Michael Wara, a professor at Stanford University who tracks climate policies and energy markets.
California has long relied on a mix of renewables and natural gas to keep the power flowing and air conditioners humming. On a typical day, solar generation surges in the daytime and natural gas picks up the slack after sunset.
The state ran into challenges during previous heat waves because it did not have enough power to meet demand. It was especially acute in the evening, when temperatures were hot, power demand was high and solar facilities had stopped producing.
In August 2020, the state grid operator was forced to implement rolling blackouts amid a searing heat wave. Two years later, it issued a so-called Flex Alert, instructing consumers to reduce their power use. Demand fell by 3,000 megawatts, enough to power as many as 3 million homes, after the governor’s office sent a text to consumers.
Those difficulties quickly became political fodder for opponents of California’s climate policies. Republicans railed against California’s clean energy plans during the 2020 presidential election.
“In California, Democrats have intentionally implemented rolling blackouts — forcing Americans in the dark,” Donald Trump, then president, tweeted in 2020. “Democrats are unable to keep up with energy demand.”
Trump is once again the Republican nominee for president after losing his reelection bid to President Joe Biden that year.
California’s power grid has improved considerably since then. The state grid operator issued 10 Flex Alerts in 2020, eight in 2021 and 11 in 2022. But it has not issued one since 2022, as extreme heat worldwide reached levels never before recorded by humans.
Analysts said California’s improved performance owes to several factors. The California Independent System Operator has improved coordination with neighboring grid operators to manage the flow of electricity across state lines. Last week, demand was also lower than in 2022, peaking at almost 48 gigawatts Thursday, according to Gridstatus.io, a website that monitors real-time grid data. That was less than the 51 GW reported in September 2022 but more than the 47 GW peak reported in 2020, according to Gridstatus.
There were some reports of power outages due to heat last week. But those differed from the blackouts experienced in previous years. San Diego Gas and Electric had 14,000 customers without power Sunday. A spokesperson told POLITICO’s E&E News that the outages were due to heat-related issues at a substation.
The Los Angeles Department of Water and Power said up to 15,000 customers were without power Sunday. The utility’s CEO told the LAist that its transformers had overheated after high temperatures persisted through the night.
But those issues were relatively small. The Los Angeles utility serves 1.5 million customers.
Batteries were the biggest reason California didn’t see the power go out, analysts said. The state added 5.8 gigawatts of battery capacity since the summer of 2022, bringing its total battery fleet to 9.1 GW, said Gonzalez, the California ISO spokesperson.
The battery boom is a result of several factors, analysts said. Building batteries is profitable in California because it is cheap to charge during the day, when abundant solar power reduces prices, and dispatch electricity in the evening, when solar generation falls. But the growth in batteries also owes to a 2021 order by state utility regulators that effectively directed power companies to build more storage systems, said Arne Olson, a senior partner at Energy and Environmental Economics.
The uneventful summer for the power grid “underscores to me the importance of doing good, long-term, fundamental forecasting,” he said.
California is not the only state to benefit from a solar and storage boom. A similar situation has unfolded in Texas, where a wave of new solar and battery facilities has helped ease reliability concerns during heat waves, said Aidan Tuohy, director of transmission operations and planning at the Electric Power Research Institute, which partners with companies and governments to study the power sector.
“Battery storage has been added over the past two years and just really made things a lot more smooth and straightforward,” Tuohy said.
Additional solutions are still needed to solve winter reliability challenges or seasonal drops in renewable production, he said. But “the summer type issues are really being met with the solar and storage and maintaining some of the other existing plants around as well,” he added.
This story also appears in Energywire.
Correction: An earlier version of this story incorrectly said the grid operator sent a text message asking consumers to reduce electricity demand in 2022. It was the governor’s office.
