The U.S. Nuclear Regulatory Commission has issued a 20-year license renewal for the Diablo Canyon Power Plant, a nuclear facility seen as key to California grid reliability as the state transitions to clean energy.

The renewed licenses for Diablo Canyon Units 1 and 2 run through 2044 and 2045, respectively, though extending operations past 2030 would require action from the California Legislature. The NRC issued the renewed licenses and a record of decision April 2.

Diablo Canyon, a 2,200-MW facility owned and operated by Pacific Gas and Electric, supplied about 10% of the state’s total electricity in 2024, including 16% of its zero-carbon electricity. It is the state’s last operating nuclear power plant.

PG&E CEO Sumeet Singh called the Diablo Canyon license renewal “an important milestone for California’s energy future.”

“Diablo Canyon is the state’s largest source of clean energy and a cornerstone of reliability,” Singh said in a statement.

In 2016, PG&E agreed to retire Diablo Canyon Units 1 and 2 when their operating licenses expired in November 2024 August 2025, respectively.

But rolling blackouts in California during a 2020 heat wave and close calls in subsequent summers prompted state officials, including Gov. Gavin Newsom (D), to reassess Diablo’s future.

In September 2022, Newsom signed Senate Bill 846, authorizing a five-year extension of Diablo Canyon.

A statement from Newsom’s office following the license renewal said Diablo Canyon will provide around-the-clock, carbon-free electricity “as California navigates growing electricity demand and hotter summers, while continuing investments in grid reliability and additional clean energy resources.”

Newsom noted that Diablo Canyon’s electricity isn’t subject to the fluctuation of fossil fuel-based power resources.

SB 846 authorized a loan from the state’s general fund and directed PG&E to apply for a grant from the U.S. Department of Energy’s Civil Nuclear Credit Program. In January 2024, the DOE awarded PG&E $1.1 billion to keep Diablo Canyon running. (See Diablo Canyon Secures $1.1B DOE Award to Support Operations.)

The NRC granted an exemption to allow PG&E to keep running the units past their license expiration dates, a move that a federal appellate court upheld. (See 9th Circuit Upholds NRC Decision on Diablo Canyon.)

The California Public Utilities Commission approved a five-year extension for Diablo Canyon in December 2023. (See California PUC Votes to Extend Diablo Canyon Nuclear Plant 5 Years.) In December 2025, CPUC approved PG&E’s request to recover about $382 million from ratepayers to keep running Diablo Canyon.

PG&E said it has received approvals from the State Lands Commission, the California Coastal Commission and the Central Coast Regional Water Quality Control Board to extend Diablo Canyon operations.

Jeremy Groom, acting director of the NRC’s Office of Nuclear Reactor Regulation, said during a signing ceremony that Diablo Canyon is “a stabilizing force for California’s electric grid.” He said the license renewal is the NRC’s 100th renewed operating license for U.S. power plants.

And more renewals likely are on the way. In March, Arizona Public Service notified the NRC that it plans to seek operating license renewals for all three units at the Palo Verde Generating Station, potentially extending operations through the mid-2060s. (See APS to Seek Palo Verde Extension through 2067.)