Inside the push to keep Diablo Canyon running: pro‑nuclear advocates, PG&E and a fast‑tracked political change that reshaped California’s power plan
California reversed its 2016 decision to close the Diablo Canyon nuclear plant, extending operations through 2030 under SB 846 amid reliability and climate concerns — a move that ignited debate among environmental groups, utilities, industry advocates and state officials.
- The 2016 agreement: PG&E and environmental and labor groups agreed to retire Diablo Canyon by August 2025.
- The reversal: In 2022 the Legislature passed SB 846 directing operation through 2029 (Unit 1) and 2030 (Unit 2).
- Why it mattered: Diablo Canyon supplies about 9–10% of California’s in‑state electricity and is cited as a major source of dependable, carbon‑free power — a point emphasized by PG&E.
How the plan changed: timeline and drivers
2016 deal: In 2016 PG&E reached a deal with environmental groups, labor and others to close the two reactors by 2025, saying the plant was no longer needed as renewables and storage grew.
Shifting pressures (2021–2022): State officials and grid analysts warned that rapid electrification, heat waves and growing demand risked shortfalls if large, dispatchable power left the system too fast. Studies and modeling suggested keeping Diablo Canyon online could cut emissions and reduce near‑term costs compared with replacing its output quickly with wind, solar and batteries.
Federal incentives and utility strategy: PG&E sought federal help and federal incentives emerged to support existing nuclear plants, creating an opening for arguments that a life‑extension was both reliable and low‑carbon.
SB 846 and a fast‑tracked political pivot
Legislative action: In September 2022 the Legislature approved SB 846, presented as an emergency reliability measure and pushed through with support from Gov. Gavin Newsom’s office.
What SB 846 did: The law directed state agencies and regulators to help secure the plant’s extension, authorized a state loan to PG&E to finance life‑extension work (with repayment through ratepayer revenues), and required environmental and coastal reviews before operation under the new timeframe — steps detailed in county filings and agency materials.
“The bill was framed as necessary to shore up near‑term reliability while California scales its renewable and storage build‑out.”
The role of PG&E and pro‑nuclear advocacy
Utility moves: PG&E applied to the U.S. Nuclear Regulatory Commission (NRC) for 20‑year license renewals that, if approved, would allow operation into the mid‑2040s — far beyond the current state law horizon.
Industry and policy voices: Industry groups, the American Nuclear Society (ANS) and several climate‑policy experts promoted keeping Diablo Canyon as a key source of clean firm power. ANS consultant Richard St. Onge described Diablo Canyon as the “backbone” of California’s clean, reliable electrical system and emphasized that the plant provides about 10% of the state’s electricity.
Tech and finance concerns: Tech and finance interests warned that expanding data centers and AI compute will increase demand for steady, low‑carbon capacity — an argument that aligned with utility and pro‑nuclear messaging, though public records show limited evidence that venture capital firms led SB 846 lobbying.
Regulatory approvals that followed SB 846
CPUC action: After the law passed, regulators moved to implement it. The California Public Utilities Commission (CPUC) voted in December 2023 to authorize operation through 2029 for Unit 1 and 2030 for Unit 2, citing near‑term reliability and emissions goals while urging continued build‑out of renewables and storage.
Local and coastal permits: The California Coastal Commission and local agencies later granted approvals tied to environmental mitigation and land‑use conditions, including conservation of about 4,000 acres and stricter protections for marine life and shoreline resources.
Federal review: At the federal level the NRC is reviewing PG&E’s 20‑year license application, focusing on safety, aging management and seismic risk; that review runs independently of state law, which currently limits operation to 2030 unless the Legislature acts again.
Arguments from both sides
Supporters: Proponents argue Diablo Canyon’s steady output avoids short‑term increases in fossil gas use, helps meet 2030 and 2045 climate goals, and can be cheaper to keep running than to replace quickly with new renewables, storage and transmission. Supportive coverage and utility messaging are documented in public reporting and PG&E materials.
Opponents: Critics contend the SB 846 process was rushed and heavily influenced by industry and pro‑nuclear groups, reversing prior commitments to communities and some environmental organizations. Concerns include seismic and safety risks, the lack of a permanent federal repository for high‑level waste, and the risk that an extension could slow investment in renewables, storage, transmission and demand‑side measures.
Costs and trust: Skeptics point to PG&E’s history of utility failures and question whether ratepayers should bear loan repayments and upgrade costs that could grow if life‑extension work proves more expensive than projected.
Who drove the lobbying push?
Public records and reporting show coordinated work by PG&E, the American Nuclear Society and other pro‑nuclear groups, allied climate‑policy experts and some business and labor interests to press for the extension. Reporting links tech and finance stakeholders to the pro‑reliability argument, though detailed public evidence that venture capital firms were primary funders or leaders of the lobbying is limited.
Status and possible futures
Short term: Under current law and CPUC action, Diablo Canyon may operate through 2029–2030 if it meets regulatory conditions.
Longer term: If the NRC issues 20‑year federal license extensions and the Legislature later changes state law, the plant could operate into the 2040s — but that would require additional political choices and continued regulatory approvals.
Implications for San Diego, California
- Grid reliability: San Diego relies on the statewide grid. Diablo Canyon’s continued operation helps avoid near‑term shortfalls during heat waves and peak demand events; if the plant closes sooner, San Diego could face greater pressure to add local firm capacity, more imports or emergency procurement. (coverage, PG&E materials)
- Emissions and air quality: Keeping Diablo Canyon online can reduce the need for gas‑fired backup generation that would raise regional greenhouse‑gas emissions and worsen air pollution in Southern California, affecting public health and climate targets. (analysis)
- Energy costs and ratepayers: The state loan and life‑extension costs will affect ratepayers statewide, including San Diegans; if upgrades cost more than projected, customers could face higher bills, while proponents say avoiding emergency procurement and extra peaker plants could limit near‑term price spikes. (county filings)
- Local planning and clean‑energy investment: San Diego’s clean‑energy plans — adding renewables, storage and transmission — remain vital. The extension provides time to build systems, but it could also reduce urgency and competition for transmission access if not managed carefully. (reporting)
- Emergency and coastal concerns: Continued operations keep seismic and coastal safety discussions alive. San Diego emergency planners watch statewide precedent on nuclear safety and waste handling and may press for stronger regional coordination on emergency response and public information. (coverage)
- Jobs and economy: The extension preserves Diablo Canyon jobs into the late 2020s and possibly beyond, with secondary economic benefits for Central Coast communities and indirect effects on statewide labor markets and energy supply chains. (PG&E)
Reporting and sources
Reporting for this article drew on public reporting and regulatory records, including the San Francisco Chronicle, CalMatters, PG&E newsroom materials, the American Nuclear Society, San Luis Obispo County filings and nuclear licensing coverage at NucNet.
