California’s nearly five-decade-old ban on new nuclear power plants is colliding with the state’s own clean energy ambitions, and the contradiction is becoming harder to ignore. The moratorium, enacted in 1976, blocks construction of new fission reactors while the state simultaneously fights to keep its last operating nuclear facility online. With extreme weather straining the grid and a legal mandate to reach 100 percent zero-carbon electricity by 2045, the ban is no longer a precaution. It is an obstacle.
A 1976 Rule Built for a Different Era
In 1976, California placed a moratorium on new nuclear reactors. The policy reflected anxieties of that era: unresolved questions about spent fuel storage, safety concerns that intensified after the Three Mile Island accident three years later, and a general belief that the state could meet its power needs without splitting atoms. For decades, the moratorium attracted little political resistance. California had multiple operating reactors, and natural gas was cheap, abundant, and politically acceptable as a bridge fuel.
That calculus has shifted. The state now faces binding decarbonization targets under Senate Bill 100, which requires electricity to come from renewable and zero‑carbon sources. Solar and wind have scaled dramatically, but they cannot run around the clock, and long-duration battery storage remains expensive at grid scale. The gas plants that fill the gaps produce the very emissions the state is trying to eliminate. Nuclear energy, which generates electricity continuously without carbon output, is exactly the kind of resource SB 100 envisions. Yet the moratorium prevents California from building any new plants to provide it, locking the state into a technological mix designed for a different century.
Diablo Canyon and the Cost of Delay
The tension between the ban and the state’s energy needs is most visible at Diablo Canyon, California’s only operating nuclear plant. The facility was originally scheduled for retirement, but in 2022 the legislature passed Senate Bill 846, which authorized extending operations beyond the original license dates and provided state financing through loan authority. The law sets maximum end dates of October 31, 2029 for Unit 1 and October 31, 2030 for Unit 2, according to the California Public Utilities Commission’s implementation. In other words, the state has written into statute that a plant it once viewed as expendable is now essential enough to justify extraordinary legislative action.
The federal government has backed the extension with real money. The U.S. Department of Energy finalized a credit award of up to $1.1 billion in support for Diablo Canyon through the Civil Nuclear Credit Program, issuing a Record of Decision on January 2, 2024. PG&E submitted a license renewal application to the Nuclear Regulatory Commission, and the NRC has produced environmental review documents including a supplemental impact statement for extended operation. The scale of this effort, involving two federal agencies, a state law, and more than a billion dollars in credits, reveals how much California depends on a single aging plant it once planned to shut down, and how costly it has become to preserve capacity that could have been replaced by new reactors if the moratorium did not exist.
Grid Reliability Hinges on Baseload Power
The California Energy Commission has been blunt about why the extension matters. In early 2023, the CEC approved a staff analysis recommending extended operation of Diablo Canyon through 2030, citing a risk of supply shortfalls during extreme weather. Heat waves that push air conditioning demand to peak levels while reducing hydropower output have repeatedly exposed the fragility of California’s grid. Without Diablo Canyon’s steady output, the state would need to lean even harder on gas generation or imported power, both of which undercut its climate goals and expose ratepayers to volatile fuel prices and transmission constraints.
Data from the Energy Commission’s total system generation reports underscore the challenge: even as renewables grow, natural gas still supplies a large share of annual electricity, and imports remain significant. The CEC’s Clean Energy Reliability Investment Plan, produced under SB 846, lays out near-term reliability needs and an investment strategy to accelerate clean resource deployment and demand response. But the report also makes clear that replacing firm nuclear baseload with intermittent renewables alone requires a buildout pace California has not yet achieved. This is not an argument against solar or wind; it is an acknowledgment that removing a zero-carbon source before adequate replacements exist creates real risk for both reliability and emissions trajectories.
The Ban Blocks What the State Needs Most
Here is the core contradiction most coverage of Diablo Canyon misses: even if the extension succeeds and the plant runs through 2030, California still has no legal pathway to build new nuclear capacity. The 1976 moratorium remains on the books. Every dollar spent keeping Diablo Canyon alive is a short-term fix applied to a structural problem. The state has effectively conceded that nuclear power is necessary for grid reliability and decarbonization while maintaining a law that prevents it from ever adding more. If the goal is a resilient, zero‑carbon grid, preserving one aging plant while banning its successors is a strategy with a built‑in expiration date.
Advanced reactor designs, including small modular reactors that can be sited on smaller footprints and paired with renewable installations, are attracting federal research investment through programs at agencies like ARPA‑E. These technologies could offer California flexible, zero-carbon generation that complements solar and wind rather than competing with them, potentially operating in load‑following modes that match variable output from renewables. But none of that matters if state law prohibits construction. Other states without similar bans are already positioning themselves to host demonstration projects and future commercial deployments, while California (home to some of the world’s most ambitious climate policies) has legally sidelined one of the few firm, zero‑carbon options that can backstop its renewable fleet.
Reconciling Climate Policy With Nuclear Law
California now faces a choice between clinging to a moratorium rooted in 1970s fears and updating its laws to reflect twenty‑first‑century climate realities. One path would be to leave the ban intact, continue relying on Diablo Canyon until its extended licenses expire, and attempt to close the resulting gap entirely with renewables, storage, and demand management. That approach would demand unprecedented buildout speeds and flawless execution, all while the grid weathers hotter summers and more volatile hydrology. The other path would be to revise or repeal the moratorium, allowing regulators to evaluate new nuclear proposals on their merits, subject to modern safety standards and local scrutiny, rather than blocking them outright.
Revisiting the ban would not guarantee a wave of new reactors, nor should it. High capital costs, siting challenges, and public skepticism remain real barriers. But maintaining a legal prohibition while simultaneously relying on federal credits, emergency legislation, and regulatory contortions to keep one existing plant online is a contradiction that grows sharper every year. Aligning California’s nuclear policy with its climate laws would at least give planners the full toolbox they need to build a reliable, zero‑carbon grid, one that does not depend on a single aging facility or on fossil fuels that SB 100 is explicitly designed to phase out.
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*This article was researched with the help of AI, with human editors creating the final content.
