‘The biggest transformation in a century’: how California remade itself as a clean energy powerhouse | California

AAs officials from around the world gathered in Brazil for the Cop30 climate summit last month, the US president was nowhere to be found, nor were any members of his cabinet. Instead, the most important American voice in Belém was that of California Governor Gavin Newsom.

During his five days in Brazil, Newsom called Donald Trump an “invasive species” and condemned his rollback of policies aimed at reducing emissions and expanding renewable energy. Newsom, long considered a presidential hopeful, argued that as the United States withdraws, California will take its place as a leader and “stable and reliable” climate partner.

Among the talking points he used to demonstrate California’s leadership were its progress in renewable energy — and the battery capacity needed to store that energy.

“We lead the world’s fourth largest economy [on] 67%, or two-thirds, clean energy nine out of 10 days in 2025,” Newsom said. “Aside from China, there is only one other jurisdiction in the world – California – that has implemented this much battery storage. »

The Golden State has transformed how it powers its main electricity grid in recent years, setting ambitious goals to create an emissions-free grid by 2045 and investing heavily in solar, wind and battery storage. And as the federal government abandons climate initiatives, California appears poised to take on an increasingly important global role.

The state appears to have plenty of reasons to celebrate. Since 2019, the state has added 30,800 megawatts of clean energy and battery storage. And although natural gas remains the state’s primary source of energy, it is in decline: California experienced its largest annual decline in natural gas production this year.

Meanwhile, solar power and batteries, which store energy for later use, providing an alternative to gas, are mobilizing to replace it, said Mark Jacobson, a Stanford professor and renewable energy expert: “This is a remarkable change. »

“A leader in the field of clean energy”

In touting his accomplishments as governor, Newsom frequently highlighted California’s network. State lawmakers passed a bill in 2018 requiring California to generate 60% of its electricity from renewable, carbon-free sources by 2030 and 100% by 2045.

So far, California appears to be on the right track, Jacobson said. Clean energy accounted for 67% of retail electricity sales in 2023, according to the most recent data available. For the first time, clean energy – which the state recognizes as renewables such as solar, wind, small hydro, geothermal and biomass, as well as large hydro and nuclear plants – provided 100% of the electricity to the state’s main grid almost every day for at least part of the day in 2025.

Renewable energy is booming around the world and is expected to grow faster than any major energy source over the next 10 years, with more projects in the next five years than in the last 40 years, according to the International Energy Agency (IEA).

California is no exception and is in the midst of what the state Energy Commission (CEC) has described as the “largest transformation of its power grid in a century.” The state is seeing new solar and battery storage projects in “record numbers” and is soon expected to completely eliminate coal from its electricity supply, according to the CEC.

Key to this growth has been the expansion of battery storage, a crucial tool for conserving energy produced from renewable sources. In 2019, California had 771 megawatts – as of October this year, it had nearly 17,000. The state has 2.5 times more battery storage available than in 2022.

The batteries helped the state avoid repeated power outages and allowed the California Independent System Operator (Caiso), the nonprofit that manages the flow of electricity on the state’s main grid, to store solar energy in case there was a surplus during the day.

“We can then take this stored energy and release it in the evening when the sun goes down,” said Mark Rothleder, Caiso’s senior vice president and chief operating officer. “Having a mix of resources that can produce when needed is an important addition as we try to make this transition to renewable resources. »

But, he added, solar and wind power are intermittent sources, meaning they can only be generated when there is sun or wind and the state’s main grid continues to rely on gas resources that can be used as needed.

Natural gas was the main resource for electricity generation in 2024, but natural gas production fell 8% that year, partly due to the growing role of solar and wind power and improved battery storage, according to the CEC.

Nuclear power also plays a role: By 2024, it would account for nearly 10 percent of the state’s total electricity generation, but not without controversy. California has been a center of anti-nuclear activism for decades, but supporters argue it could be a crucial tool for providing reliable energy as the state transitions away from fossil fuels.

Although natural gas is in decline, it is far from obsolete and is a critical backup source during periods of peak energy consumption. California has nearly 200 natural gas plants that provide about a third of the state’s electricity generation, said Julia Dowell, lead campaign organizer at the Sierra Club.

“California is considered a leader in clean energy,” Dowell said. “But we’re really struggling to figure out how to meet demand during the evening hours when we see the highest demand for electricity, and that’s historically when we rely on gas plants.”

A 2025 report from Regenerate California, which Dowell helped author, found that batteries are a cheaper, more reliable alternative to gas plants and reduce toxic air pollution.

“They can compete directly with gas plants, and they can offer even more advantages because of their ability to ramp up so quickly,” said Heena Singh, of the California Environmental Justice Alliance and author of the report. “This is a big thing in California, where we have all these heat waves and natural disasters.”

Pushing back against the Trump administration

California has long been a frequent target of the Trump White House — and conflicts have only intensified during his second term.

With Trump returning to power, the federal government has focused on expanding fossil fuels and putting the brakes on any efforts to reduce emissions. The White House has proposed offshore lease sales along the California coast. The president blocked California’s first rule banning the sale of new gasoline-powered cars by 2030, and his EPA ended a $7 billion program aimed at bringing solar power to low-income communities.

The administration has canceled $679 million in funding for offshore wind development in the United States – California is expected to spend about $427 million on a project to build the first offshore wind terminal on the West Coast. A few months earlier, California and nearly 20 other states successfully sued after the federal government decided to suspend offshore wind energy development.

Further prosecutions are expected. The state attorney general’s office created an office to oppose the president’s agenda.

Republicans and the Trump administration have also sought to blame the transition to renewable energy on high utility bills — California has some of the most expensive energy in the country. But experts attribute those costs to power companies passing the costs of wildfires onto their customers.

Despite these pressures, California’s energy transition is well underway – and unlikely to be reversed.

“You’re going to see California fiercely pursue every federal government effort to roll back the fight against climate change and the fight against clean energy,” said Noah Perch-Ahern, an environmental lawyer. “I think this will continue for years.”

Meanwhile, advocates and experts hope to see California continue to expand clean energy with more rooftop solar projects that can reduce demand on the grid and ultimately phase out gas plants.

“We really hope that people will start to understand that we don’t need these gas plants,” said Maia Leroy, author of the Regenerate report, adding that there are significant costs to running them even when the state isn’t using them to produce electricity. “It’s time to shut them down. It’s an expensive insurance policy.”

She hopes California continues to make progress despite federal obstacles.

“We survived the first Trump administration. California survived and we never gave up on our clean energy goals. So I don’t anticipate that being an issue again this year,” she said.