California spent another summer without Flex Alerts. Experts say thanks to batteries

Rolling blackouts and emergency calls to conserve energy have been part of California life for decades — a reluctant summer ritual nearly as reliable as the heat waves that drive them. But the state has undergone a quiet shift in recent years, and the California Independent System Operator has not issued a single emergency request, known as a “Flex Alert,” since 2022.

Experts and officials say the Golden State has reached a tipping point that reflects years of investments to make its grid stronger, cleaner and more reliable. Much of this is new battery storage, which captures and stores electricity for later use.

In fact, California officials say batteries are already transformative for the state. In the late afternoon, when the sun stops shining on solar panels and people use electricity at home, the batteries deliver stored solar energy to the grid.

California has invested heavily in the technology in recent years, helping it mature and reduce costs. The state’s battery storage has grown more than 3,000% in six years, from 500 megawatts in 2020 to more than 15,700 megawatts today.

“There is no question that the rapid growth of battery packs since 2020, along with the nation’s expanding mix of other supply and demand-side resources, is a true game-changer for reliability during peak summer demand,” said Elliot Mainzer, CAISO president and CEO.

Just five years ago, a record-breaking heat wave pushed the power grid to its limits and plunged much of the state into darkness. After that incident, California energy leaders vowed to take action to make the grid more resilient.

Since then, CAISO has overseen a massive buildout of new energy and storage resources, totaling more than 26,000 megawatts of new capacity, which has also helped make the grid more stable, Mainzer said. The state has not experienced rolling blackouts since 2020.

“Extreme weather events, wildfires and other emergencies can create reliability challenges for any large power system,” he said. “But the CAISO battery pack, along with the additional capacity and close coordination with state and regional partners, provides undisputed benefits for reliability.”

Batteries are now key to California’s climate goals, including a goal of becoming 100% carbon neutral by 2045.

Solar panels and battery storage units at the Eland Solar and Storage Center in the Mojave Desert in Kern County on Nov. 25, 2024.

(Brian Vanderbrugge/Los Angeles Times)

Batteries already enable the grid to operate with significant reductions in the use of fossil fuels that contribute to planet warming. Now they are becoming a more cost-effective and reliable alternative to aging gas-fired power plants, said Maia Leroy, founder of California energy consulting firm Lumenergy LLC and co-author of a recent report on the rise of battery storage relative to natural gas generation in California.

“Historically, Flex alerts have always gone out in the summer when it’s really hot and everyone has their air conditioners on,” Leroy said. “But in the summer, we find that natural gas plants don’t perform as well because combustion doesn’t adapt well to ambient heat. So when we can shift that demand from having to use natural gas plants to something more stable, dispatchable and flexible, like battery storage, we’re able to meet that demand in the summer without having to rely on those natural gas plants that aren’t performing as well.”

However, battery energy storage is not without its challenges. Lithium-ion batteries are the most common type of energy storage and typically have a capacity of about four to six hours. That’s enough to support the grid during peak hours when the sun sets, but can still leave some gaps that need to be filled with natural gas.

Nikhil Kumar, program director at the energy policy nonprofit GridLab, said technologies for longer-lasting batteries already exist, including through different chemistries, such as iron-air batteries, which release energy through oxidation, and flow batteries, which store energy in liquid chemicals that flow through a reactor.

These batteries are not yet mature and will likely be more expensive and larger than lithium-ion batteries, Kumar said. But a recent report from GridLab suggests that’s changing, with the average cost of a new natural gas power plant typically being on par with a four-hour lithium-ion battery and only slightly cheaper than longer-lasting battery technology.

“Battery batteries are going to get cheaper,” Kumar said. “Gas is not.”

The shift to battery storage is happening as the Trump administration takes steps to curb solar and other forms of renewable energy in favor of fossil fuels like oil, natural gas and coal. At the end of September, the government announced that it would Opening 13 million acres of federal land to coal mining and provides $625 million to recommission or modernize coal-fired power plants, which officials say will help strengthen the economy, protect jobs and boost U.S. energy development.

During an hour-long news conference about the initiative, Interior Secretary Doug Burgum described wind and solar as intermittent energy sources that “really depend on the weather,” but neither he nor any other official mentioned that the growth of battery storage makes these energy sources more reliable and promising.

This is not a partisan issue. ERCOT, which operates the Texas power grid, has more than 14,000 megawatts of batteries online, nearly three times more than at the beginning of 2023. California and Texas continue to swap positions as the number one states for battery storage.

A battery storage unit at the Eland Solar and Storage Center in the Mojave Desert in Kern County on Nov. 25, 2024.

(Brian Vanderbrugge/Los Angeles Times)

But Trump has taken steps to support U.S. battery production. About three-quarters of the world’s batteries are currently made in China, and Trump’s tariffs — including a proposed 100% tariff on China — would be beneficial to at least one Sacramento-based battery manufacturer, Sparkz.

“The government wants critical materials to be manufactured in the United States,” said founder and CEO Sanjiv Malhotra. “They’re basically very supportive of domestic battery manufacturing.”

Sparkz is making lithium-iron batteries that don’t use nickel and cobalt, ingredients that have long been an industry darling but relied on imported metals. Instead, Malhotra said, their supply chain for lithium iron phosphate batteries is entirely located in the United States, which means they can take advantage of federal tax credits that favor the production of clean energy components made primarily from domestic components. The company’s customers include data centers and utilities.

Malhotra added that California has done an excellent job over the past few years in “enhancing” grid storage capacity. He said batteries are the main reason the state hasn’t seen Flex alarms since 2022.

“The numbers basically say it’s all because of energy storage,” he said.

There is still work to be done. While the state’s electrical grid has improved, it is more than a century old and was primarily built for natural gas power plants. Experts and officials agree that additional substantial upgrades and reforms are needed to meet current energy needs and goals.

Permits are also a hurdle, as California typically requires lengthy environmental reviews for new projects. The state, sometimes controversial, is speeding up reviews and recently approved a large solar and battery storage site, the Dutton Clean Energy Project in Fresno County, through a new expedited permitting program. It has enough power to power 850,000 homes for four hours, according to the California Energy Commission.

Security remains a concern. In January, a fire broke out at one of the world’s largest battery storage facilities in Moss Landing in Monterey County. The facility contains approximately 100,000 lithium-ion batteries, which are extremely dangerous if ignited because they burn at extremely high temperatures and cannot be extinguished with water, triggering a violent chemical reaction. Dangerous levels of nickel, cobalt and manganese released by the fire were measured miles from the site.

“Generally speaking, when you’re dealing with large technology, there’s always some kind of danger,” said Lumenergy’s LeRoy. “This shows how much we need to diversify the technologies we use.”

Other forms of energy, such as oil and coal, also pose considerable health and safety risks, including emitting air pollution – soot, mercury, nitrogen dioxide and carbon dioxide – that contributes to climate change.

California is eliminating coal power and is expected to be completely coal-free by November. While natural gas still accounts for a large portion of the state’s electricity generation, renewable energy will account for nearly 60% of California’s electricity generation by 2024, according to the U.S. Energy Information Administration.

The numbers continue to trend upward. In the first six months of this year, the CAISO power grid was powered by 100% clean energy, averaging nearly 7 hours a day.

“We actually just proved that California can run on super clean resources with natural gas as a backup,” said GridLab’s Kumar. “And it works. We don’t have Flex Alerts.”