The Diablo Canyon Power Plant was supposed to close last year. Now the five-year extension that kept the plant open may become a 20-year extension. Over the past few months, the San Luis Obispo County Board of Supervisors and several local city councils with an eye on tax revenues have been urging state legislators to extend Diablo’s life all the way to 2045. Now would be a good time to revisit the serious questions about Diablo Canyon’s continued operation.
Specifically: How much will extending Diablo’s life cost California taxpayers and ratepayers? Is Diablo safe? Is Diablo a needed power source?
When the Legislature voted to extend Diablo’s operations to 2030, it required the state to double check if Diablo is safe, affordable, and necessary before the extension is finalized—essentially guardrails to ensure sufficient consideration of the public good. These assessments must be completed before any further extension is even considered, let alone supported.
Is Diablo’s true cost even affordable?
PG&E is required to prove that Diablo is cost-effective, but the costs of Diablo are growing. As it stands, the state of California gave a $1.4 billion forgivable, interest-free state loan to PG&E to keep the plant open. It hoped PG&E would receive a federal grant to pay back the state, but now PG&E’s repayment will have a shortfall of at least $300 million, which now may reach over $650 million. Meanwhile, Diablo’s operating and maintenance costs continue to accrue. PG&E’s 2026 cost recovery forecast for Diablo estimates an annual average loss of $90 million a year. The state of California still has yet to do a full cost-benefit analysis of Diablo’s operations. Right now, it looks like the bulk of Diablo’s costs will be borne by the state budget, PG&E customers, and also by ratepayers across California.
Is Diablo safe?
Diablo’s earthquake safety was a local hot topic this week. PG&E’s updated seismic assessment must be reviewed by the California Public Utilities Commission’s (CPUC) Independent Peer Review Panel (IPRP) before the assessment can be deemed complete. Publication of the IPRP’s most recent critique of PG&E’s seismic assessment was delayed for six months, and the reason why was not good news.
As IPRP member and county Supervisor Bruce Gibson put it in a Jan. 14 memo, “The IPRP has not accepted PG&E’s [updated seismic assessment] responses, …[and] believes that [PG&E’s] update excluded or downplayed information from various studies conducted post-2015 that should be included in calculating the revised seismic hazard.” The IPRP has now requested additional documentation from PG&E.
Then, at a meeting in Avila Beach, Gibson dropped the other shoe: “On Jan. 22, senior staff of the CPUC and the California Natural Resources Agency issued back to the IPRP edits that they wanted to see put into Report 16a. That is deeply concerning. It was a deeply concerning action because we are after all the Independent Peer Review Panel, and … the technical experts whose opinions are to be heard. We saw no authority, no justification, for any senior agency staff to be editing it. And, in fact, some of these edits did substantively modify the technical conclusions the IPRP had made in the draft of Report 16a.”
The IPRP refused the edits, and the agencies backed down. Now the waiting begins for PG&E’s response, which will hopefully include a statement of its willingness to use “the best quality data” in its seismic assessment, as urged by the IPRP.
Do we still need Diablo’s energy?
Just as Diablo’s financial burden on the state treasury, ratepayers, and taxpayers has grown substantially, so has California’s renewable energy production. COVID-era supply chain constraints turned out to be less than projected, resulting in a better-than-expected buildout of renewable energy resources. There has been a “2,100 percent surge in storage capacity since Gov. Newsom took office in 2019,” according to the governor’s office. California Energy Commission officials have expressed confidence in California’s grid stability in a future without Diablo.
Even PG&E affirmed this reality in the 2016 joint proposal to close the plant, saying, “Given California’s energy goals that require increasing reliance on renewables—at least 50 percent by 2030—the California electric system will need more flexible resources to integrate renewable energy and has less need for baseload electricity resources. PG&E’s need for baseload power from Diablo Canyon will decrease after 2025.”
On the issues of Diablo’s cost, safety, and necessity, new questions are arising for which old answers and stale data do not suffice. Whether the question is about seismic studies or operating costs, the state should not allow updated information to be “excluded or downplayed” any longer. Our local government officials must check the guardrails before they hit the gas and speed down the highway toward extending Diablo to 2045. ∆
Gianna Patchen is chapter coordinator for the Santa Lucia Chapter of the Sierra Club. Andrew Christie served as chapter director from 2004 to 2023. Send a letter for publication to letters@newtimesslo.com.
This article appears in Weddings 2026.
Other than medicine, let’s just abandon modernity altogether if it involves an ancient nuclear reactor, traffic jams, pollution, micro plastics, B-52 bombers, tax breaks for the rich, dead end jobs, declining living standards, warfare, and concentrated wealth.
Let’s just return to the plow and clipper ships. Modernity isn’t worth it.
This article is exactly what is it says: Opinion.
This opinion is being held by fewer and fewer people, in light of the facts.
The points being made above about safety, affordability, and necessity aren’t even the right questions. The situation is nuanced, yet we don’t often communicate this well.
Is it safe? Nothing is “safe”. Safe means zero risk. Is it better than literally every other option to go forward? Yes.
Is it affordable? There is work to do, but band-aid five-year extensions aren’t helping that situation. Long-term planning is necessary for the longevity of large and robust infrastructure. And making a company out to be a villain without understanding many of the constraints is an easy (and political) out.
Is it necessary? Depends if you’re okay with continued fossil fuel usage. I would prefer to replace California’s natural gas supply, which still makes up nearly 40% of our generation. It’s a step in the wrong direction to shut down existing clean electricity infrastructure, especially a source that’s available during peak hours.
Questions about nuclear geneerally? I had them too. Let’s chat. MothersforNuclear.org
This is an excellent fact based article that, outlines that Diablo Canyon Nuclear Power Plant should not have its licenses extended any longer then the originally proposed 2030; not to 2045.
With the aging encasement domes, and Diablo’s proximity to nearby active earthquake faults, DCNPP should be retired in 2030. Then the CPUC can make sure that PG&E disposes of all of the spent nuclear fuel rods responsibly, and clean up the site so that all the nuclear waste is removed, for future generations.