Diablo Canyon nuclear power plant — the last of its kind in California — has received federal approval to operate another 20 years, with its license now stretching until 2045.

The U.S. Nuclear Regulatory Commission will issue PG&E a 20-year operating license for the power plant, the utility announced during a news conference at the facility on Thursday.

However, PG&E will also need permission from the state Legislature to keep the power plant open that long.

So far, the state has only authorized Unit 1 to stay open until 2029 and Unit 2 until 2030.

“I am so excited my heart is just going to pop out of my chest,” PG&E senior vice president and chief nuclear officer Paula Gerfen said during a news conference on the renewal Thursday. “Today the NRC’s approval confirms what we already know … we are safe, and we are environmentally sound.”

She said PG&E will “continue to maintain world-class safety standards” moving forward, and thanked staff for sticking by the plant as its future was uncertain.

“Your unwavering dedication is what’s gotten all of us to this point” she told assembled Diablo Canyon employees through tears.

NRC representative Jeremy Groom, who also spoke during the news conference Thursday, said safety “remains the guiding principle of every action taken here.

“Diablo Canyon is a facility unlike any other,” he said. “You have my most heartfelt congratulations for everyone involved in this work.”

PG&E Reverses Decommissioning Plan

Tucked into the hillside near Avila Beach, Diablo Canyon nuclear power plant generates about 2,200 megawatts of energy — accounting for about 8.5% of the state’s power, according to the California Public Utilities Commission.

The power plant’s twin nuclear reactors were originally scheduled to stop operating in 2024 and 2025.

In 2022, however, the state Legislature passed Senate Bill 846, which directed PG&E to take action to extend the plant’s operating license to support California’s energy grid. According to the bill, not enough clean energy had been produced in the state to replace the power plant.

Normally, the Nuclear Regulatory Commission requires plant operators to submit a license renewal application at least five years before the existing license expires.

In October 2022, however, PG&E applied to the commission for an exemption to the five-year deadline, asking permission to submit another license renewal application.

The Nuclear Regulatory Commission granted PG&E’s request in March 2023, allowing the utility company to operate the nuclear plant past its scheduled closure dates while waiting for the federal agency to review the application — as long as PG&E submitted the application by the end of the year.

The commission said continued operation of the plant was justified by California’s energy needs, outlined in SB 846, and would not jeopardize public health and safety.

In December 2023, the California Public Utilities Commission extended the power plant’s lease from its planned decommissioning dates of 2024 for Unit 1 and 2025 for Unit 2 to 2029 and 2030, respectively.

Members of the public, nuclear watchdog organizations and environmental advocates have challenged continued operations of the power plant.

Some groups are concerned about embrittlement, which occurs when radiation from operating the nuclear reactor causes its materials to become more likely to break.

Other groups are concerned about the impact of the once-through cooling system, which sucks in about 2.5 billion gallons of seawater per day, killing marine organisms and negatively impacting about 14 square miles of nearshore waters, according to the California Coastal Commission.

Despite those concerns, PG&E acquired all the necessary permits to keep the power plant running until at least 2030.

In December, the California Coastal Commission issued PG&E a coastal development permit for the power plant, which requires the utility to conserve thousands of acres of land to mitigate the impact of the once-through cooling system.

The commission also certified that extending the power plant’s operating life another 20 years complies with the California Coastal Management Program.

Then, in February, the Central Coast Regional Water Quality Board issued a five-year National Pollutant Discharge Elimination System permit, which allows the power plant to release up to 2.76 billion gallons of wastewater per day into the Pacific Ocean.

The board also certified that operating the plant for another 20 years would comply with the Clean Water Act — a decision challenged by three nonprofit organizations on Friday.

Finally, the operating license from the Nuclear Regulatory Commission allows PG&E to operate the plant until 2044 for Unit 1 and 2045 for Unit 2.

To operate the plant past 2030, PG&E would need permission from the state Legislature and a new wastewater discharge permit from the Central Coast Regional Water Quality Board.

Meanwhile, the California State Water Resources Control Board ordered PG&E to stop operating the once-through cooling system by Oct. 31, 2030.

Until then, PG&E pays annual mitigation fees to the Ocean Protection Council or State Coastal Conservancy for fish deaths caused by the system.

PG&E would need an exemption to the order by the State Water Resources Control Board, too, to keep operating.