LOS ANGELES (AP) — An aggressive push toward renewable energy has run headlong into anxiety over keeping the lights on in California, where the largest utility is considering whether to try to extend the lifespan of the state’s last operating nuclear power plant.

California is the birthplace of the modern environmental movement that for decades has had a fraught relationship with nuclear power, which doesn’t produce carbon pollution like fossil fuels but leaves behind waste that can remain dangerously radioactive for centuries.

Now environmentalists find themselves at odds with someone they usually see as an ally: Democratic Gov. Gavin Newsom, a green energy advocate who supported the 2016 agreement calling for the Diablo Canyon Nuclear Power Plant to close by 2025 but now is a leading voice to consider a longer operating run.

Newsom often is mentioned as a possible presidential candidate and an attorney for a consumer advocacy group that routinely challenges plant operator Pacific Gas & Electric in rate cases believes “national political ambitions” are at play.

The push to keep Diablo Canyon running “is clearly coming from the governor’s office,” said Matthew Freedman of The Utility Reform Network. Newsom “is mindful that problems with electric system reliability can become a political liability and he is determined to take all possible actions to avoid any possibility that the lights go out in California.”

Newsom certainly wants to avoid a repeat of August 2020, when a record heat wave caused a surge in power use for air conditioning that overtaxed the electrical grid.

There were two consecutive nights of rolling blackouts affecting hundreds of thousands of residential and business customers.

In a statement, Newsom communications director Erin Mellon didn’t address the question of politics but said the governor is focused on maintaining reliable energy for households and businesses while accelerating state efforts to meet his aggressive goals for reducing carbon pollution. He continues to support shuttering Diablo Canyon “in the long term.”

The debate over the plant comes as the long-struggling nuclear industry sees climate change as a reason for optimism.

President Joe Biden has embraced nuclear power generation as part of his strategy to halve greenhouse gas emissions by 2030, compared to 2005 levels.

Nuclear power provides roughly one-fifth of the electricity in the country, though generation produced by the industry has dropped since 2010. Saving a plant in green energy-friendly California would carry symbolic weight but the window to make an abrupt turnaround appears narrow.

PG&E CEO Patricia “Patti” Poppe told investors in a call last month that state legislation would have to be enacted by September to open the way for PG&E to reverse course. She said the utility faced “a real sense of urgency” because other steps would be required to keep the plant running, including ordering more reactor fuel and storage casks for housing spent fuel that remains highly radioactive.