Keeping contentious nuclear plant open could cost Californians $45B: report

Extending operations of the Diablo Canyon nuclear power plant through 2045 could cost California ratepayers as much as $45 billion, a new report has found.

The state’s biggest utility, Pacific Gas and Electric (PG&E), is currently in the process of seeking a license renewal that could enable the aging facility to run for another 20 years — with the widespread support of state legislators, but in opposition to environmental activists.

If the plant ends up staying online for two more decades, total costs to run the site could range from more than $20 billion to nearly $45 billion from 2023 through 2045, according to a new analysis from the Environmental Working Group (EWG).

“Keeping Diablo Canyon open past its closure date is a terrible idea for many reasons, including the staggering price tag that unwitting ratepayers will face for keeping the dilapidated and dangerous nuclear plant operating,” EWG President Ken Cook, who is also a Bay Area resident, said in a statement.

While PG&E in 2016 had announced plans to retire the site and decommission its two reactors when their licenses expire — in November 2024 and August 2025, respectively — California enacted legislation last fall seeking to extend operations until 2030.

About six months later, the federal Nuclear Regulatory Commission granted PG&E an exemption that enabled the plant to stay open under its current licenses while the agency considers renewal application — whose terms would apply for 20 years.

Located about 25 miles southwest of San Luis Obispo along California’s Central Coast, the Diablo Canyon plant first began operating in 1985. Both Gov. Gavin Newsom (D) and state legislators have long advocated for the extension, arguing that the site provides critical support during California’s transition to a renewable energy economy.

Environmental activists, on the other hand, have vehemently opposed the plans as both reckless and irresponsible with regards to public safety.

The EWG analysis — based in part on testimony filed by the Utility Reform Network, a consumer advocacy group — estimated that keeping the plant open would likely require hundreds of millions of dollars every year.

Because that cost would need to be passed on to the consumer, households could then expect an increase of between $55–124 per year on typical utility bills, according to the analysis.

“It’s clearly a high-cost, no-reward and puzzling scenario for California, given its decades-long leadership on the environment,” a statement from EWG said.

The environmental group’s conclusion is a stark departure from a 2021 study from the Massachusetts Institute of Technology and Stanford University, which determined that operating the plant until 2045 could save ratepayers up to $21 billion.

A 10-year extension alone would reduce carbon emissions in California’s power sector by more than 10 percent annually from 2017 levels, as well as decrease dependence on natural gas and save ratepayers about $2.6 billion, the MIT-Stanford study argued.

Keeping Diablo in operation to 2045 could spare about 90,000 acres of land by avoiding the need for an additional 18 gigawatts of photovoltaic solar power, the researchers found.

By then constraining photovoltaic siting by land use to a total of 60 gigawatts — which the authors described as “consistent with recent annual deployment rates” — savings could amount to $21 billion, per the study.

Tuesday’s EWG analysis acknowledged the MIT-Stanford research, characterizing the findings as “the leading — if flawed — projection about just what it would cost to keep Diablo Canyon running.”

The analysts explained that they used PG&E’s own numbers and the Utility Reform Network’s calculations for capital and operating costs — noting that the former excludes the company’s profit margins, administrative costs and various state and federal taxes.

The estimated $20 billion–$45 billion cost to ratepayers could be even higher, the EWG analysts argued, stressing that these projections don’t account for expenditures associated with disasters, such as radiation leaks or earthquake damage.

Grant Smith, EWG energy advisor and co-author of the report, argued that the 6-8 percent of California’s electricity that is provided by Diablo Canyon could easily come from cleaner and safer sources.

“California added enough renewables in the past year to match the power output of Diablo Canyon,” Smith said.

“Proven, reliable clean energy choices such as energy efficiency, solar, wind, battery storage and demand response are far safer options than allowing Diablo Canyon to continue operating,” he added.