On Monday, PG&E Corp. has formally asked federal regulators to extend the life of Diablo Canyon, California’s last operating nuclear plant, as part of Gov. Gavin Newsom’s efforts to improve the reliability of the power grid.

The state’s largest utility announced it has filed an application with the U.S. Nuclear Regulatory Commission to extend Diablo Canyon’s license and delay the planned 2025 shutdown of San Luis Obispo County, which provides about 9% of the state’s electricity.

Newsom, reversing his earlier opposition to extending the life expectancy of Diablo Canyon, signed into law in September this will keep the plant open until 2030. The legislation also allows the state to loan PG&E up to $1.4 billion for upgrades needed to delay the plant’s closure.

The governor appealed to lawmakers to preserve Diablo Canyon to prevent blackouts. The power grid is increasingly dependent on solar power and other renewable energy sources. This makes it vulnerable to shortages during extreme heat waves, like the one in August 2020, when solar power fades in the early evening but temperatures remain high.

California narrowly avoiding a blackout in early September, shortly after Newsom signed the bill, during a series of 110-degree days.

PG&E decided to close the 37-year-old plant because it wasn’t performing particularly well as cheaper energy sources like wind and solar became more common. But the utility relented when Newsom demanded an extension. The governor’s aides told lawmakers that without Diablo Canyon, the state’s grid could become increasingly unstable.

“We are proud of the role Diablo Canyon plays in providing safe, reliable, low-cost and carbon-free energy to our customers and the people of California,” Paul Gerfen, the company’s chief nuclear officer, said in a statement Monday. “This request to renew our licenses is another step to help California reliably achieve its bold decarbonization goals.”

This story was originally published October 31, 2022 at 4:43 p.m.