Saying that it was an American Fukushima waiting to happen, environmentalists throughout California and elsewhere have long been putting pressure on Pacific Gas & Electric to fully shut down the Diablo Canyon Power Plant in San Luis Obispo County, and today PG&E is making the official announcement. Rather than try to extend California's only remaining nuclear power facility any further, the plant will cease operations in 2025. As the Chronicle reports, reps from the utility flew in to the plant Tuesday to hold a series of meetings with its staff.

Diablo Canyon, which in the years since it began operations in 1973 has become a flashpoint in the anti-nuke movement, is notably surrounded by fault lines on nearly all sides. Experts discovered more faults over the years, as an interactive map on SFGate shows, with some underwater faults having previously caused earthquakes of up to 7.3 magnitude.

These days, PG&E downplays the potential for major shaking at the site — and it was the ensuing tsunami that caused much of the trouble at Fukushima, after all. The reason for the closure decision, says PG&E, is that renewable energy sources will all but render the power generated at Diablo Canyon unnecessary, especially by the middle of the next decade. The plant current generates 8.6 percent of the state's power, but the rise of energy-efficient homes and offices, the use of solar and wind power, and the rise of public power projects like San Francisco’s CleanPowerSF will mean that the plant won't even need to operate the full year in the coming years. Further, PG&E says it will entirely replace the energy from Diablo with sources that do not produce carbon dioxide, with 55 percent of the utility's total electricity coming from renewables by 2031.

In 2013, with the closure of the San Onofre Nuclear Generating Station near San Diego, Diablo Canyon became the state's last remaining nuclear plant. Calling it "a 20th Century mistake," Damon Moglen, senior advisor with Friends of the Earth, celebrated Tuesday's news, telling the Chron, "We’re not only going to close this plant, but we’re going to do it with greenhouse gas-free energy."

Daniel Hirsch, director of the program on Environmental and Nuclear Policy at UC Santa Cruz, tells the LA Times that PG&E's plan is "thoughtful," but he cautions that an earthquake risk remains while the plant is still operational. "Diablo really does pose a clear and present danger," he says. "If we had an earthquake larger than the plant was designed for, you could have a Fukushima-type event that could devastate a large part of California. We have to get lucky for the next eight years, but the risks are massively reduced by not having to face that risk thereafter."

In total, it's estimated that it will cost PG&E $3.8 billion to decommission the plant, $2.6 billion of which it has already stashed away in a fund for this purpose.