Will California keep the lights on when Diablo Canyon shuts down?

The massive 2,200-megawatt Diablo Canyon Power Plant is scheduled to shut down beginning in 2024, ending California’s reliance on nuclear energy. 

Now, California faces the challenge of weaning itself from nuclear power, without jeopardizing the reliability of our electric grid, and without triggering an increase in emissions from fossil fuel power sources. 

The decision to retire Diablo Canyon, the largest power plant in California, is no longer up for debate. In 2016, the plant’s owner, Pacific Gas and Electric Company, decided not to renew its operating licenses. PG&E determined it was too costly to continue operating the plant and that cheaper sources of energy could be developed to replace it. Since then, the state Legislature and the California Public Utilities Commission have ratified the decision to close Diablo Canyon. 

Five years after the decision to close the nuclear power plant in San Luis Obispo County, the CPUC is running out of time to develop reliable, cost-effective and clean energy sources to replace Diablo Canyon.

A recent report by the Union of Concerned Scientists demonstrates that California can dispense with nuclear power and still keep the lights on without triggering an increase in global warming and emissions from fossil fuel power sources by making large investments in new, clean energy projects. But the report also confirmed there is no time to lose: We have to get started right away if we are going to succeed. 

A large group of environmental advocacy organizations, including the Union of Concerned Scientists, has petitioned the CPUC to tackle this challenge in a serious way. We have argued that the commission is legally obligated under California’s clean energy laws to develop pollution-free replacement resources for Diablo Canyon. This is not just a legal mandate, but good public policy. 

The state’s high-voltage grid operator, known as the California Independent System Operator, also has warned the commission that the grid faces a serious reliability crisis if the CPUC does not act promptly to replace the Diablo Canyon plant when it is retired in 2024-25. The grid operator is predicting that the rolling blackouts we experienced last summer could reoccur and be worse, if California does not build substantial new resources in the next few years to replace the Diablo Canyon plant. 

Unfortunately, California’s electricity providers, who are ultimately responsible for procuring the clean energy resources to replace Diablo Canyon, have no plans to acquire or build enough new clean energy resources, at least in the short term. 

This leaves the CPUC in the leadership role. The five-member commission needs to show clear thinking and a strong focus. California’s electricity providers cannot be counted on to do this on their own. 

California’s legislative and executive branches have already made it clear, through legislation enacted in 2018, that they expect the CPUC to replace Diablo Canyon without triggering “any increase” in global warming emissions. Senate Bill 1090, authored by Sen. Bill Monning of San Luis Obispo County, amended the Public Utilities Code to codify this mandate.  

The state has no time to spare in planning for and investing in new, clean energy resources. To get the job done, California will need to develop lots of clean, cost-effective resources, including wind farms, solar generating stations, energy storage facilities and transmission lines. Energy providers also need to step up investments in energy efficiency and conservation measures.  

There is no reason why California’s leaders should find themselves, three years from now, in the embarrassing situation of presiding over a large increase in pollution, as well as grid reliability problems like rolling blackouts, when Diablo Canyon is retired.  

But our success depends on the fortitude and vision of the five members of the California Public Utilities Commission to lead the effort. The whole nation – in fact, the whole world – will be watching whether California can solve this challenging problem.