California planned a nuclear exit. Now it's reconsidering

SAN LUIS OBISPO, Calif. — Diablo Canyon doesn’t look like a nuclear power plant that’s getting ready to retire.

Beneath its twin concrete domes here on the edge of the Central Coast, neutrons slam into uranium atoms billions of times each second, workers respond to blinking lights in a seafoam-green control room, and thunderous turbines generate steady electricity for nearly 4 million Californians.

At the building’s entrance, a massive banner celebrates the plant’s recently renewed federal operating license , proclaiming “You Made This Possible” above a photograph of smiling staffers.

It wasn’t supposed to be this way. A decade ago, the plant’s operator, Pacific Gas & Electric, agreed to methodically shut down Diablo’s reactors in 2025, replacing its 2.2 gigawatts of power with a portfolio of wind farms, solar arrays, battery storage and just plain using less electricity.

But as that deadline neared, state officials, including Gov. Gavin Newsom, waved a white flag . They weren’t ready to shut down an energy source that consistently provides up to 9% of California’s electricity. They extended its life to 2030.

Now there’s a growing movement to extend Diablo’s life once again — this time to 2045. Nearly 50 groups have joined a coalition that includes chambers of commerce, labor unions, nonprofits and the San Luis Obispo County Board of Supervisors to argue that the plant is a critical bridge to the state’s clean energy future. Nuclear power produces no greenhouse gas emissions, the primary driver of climate change.

Opponents of the plant, many of whom live in the area, are livid and say it is the latest in a string of broken promises. Extending the plant’s life through 2045 means 15 more years of nuclear waste and seismic risk as the 1980s-era plant gets older and more brittle.

Experts say the abrupt about-face on California’s once-heralded nuclear exit reflects a broader trend as the state grapples with an electricity future almost no one saw coming.

The Nuclear Regulatory Commission gave its stamp of approval, ending a three-year process to allow the plant to power on.

Like the rest of the nation, California has seen a remarkable explosion in demand for electricity, driven in large part by the rise of artificial intelligence data centers, electric vehicles and building electrification. The California Energy Commission projects that demand for electricity will increase by roughly 50% through 2045 after decades of remaining relatively flat.

At the same time, the state is legally mandated to switch entirely to 100% carbon-free energy by 2045 , meaning it must produce more electricity while simultaneously cleaning up the electricity it produces.

The question of how California is going to make major emissions reductions while keeping electricity affordable and reliable “starts in the 2030s and goes all the way to 2045,” said David Victor, a professor of innovation and public policy at UC San Diego. “And shutting down Diablo in the middle of all that was always going to be a stretch.”

It’s a conversation happening across the United States. Three Mile Island in Pennsylvania — the site of the worst commercial nuclear accident in U.S.