The American Nuclear Society supports keeping Diablo Canyon open

Diablo Canyon is a well-performing nuclear power plant that has operated safely for nearly 40 years under the strict oversight of the U.S. Nuclear Regulatory Commission. Diablo Canyon’s nuclear generation produces clean electricity without harmful emissions of greenhouse gases and other combustion products. Additionally, Diablo Canyon’s energy is available around the clock in all seasons and weather conditions.

Closing California's remaining nuclear power plant will cause more grid instability and rolling blackouts for the state because Diablo Canyon reliably supplies approximately 10 percent of in-state power. Along with further weakening California’s fragile power grid, the premature closure of Diablo Canyon will deprive California of its largest carbon-free energy resource and worsen the state’s growing dependency on electricity from out-of-state fossil power plants. The premature loss of Diablo Canyon will result in millions of tons of additional greenhouse gas emissions per year, ruining state and federal plans for decarbonization.

Blackouts are harmful and deadly. During the August 2020 heatwave that strained California’s already overloaded power grid, the California Independent System Operator (CAISO) ordered rolling blackouts across the state to cope with a power supply shortage of 4,400 megawatts that left approximately 3.3 million households in the dark and without air conditioning. The blackouts would have been far worse and more extensive without Diablo Canyon’s 2,240 megawatts of safe, reliable, fuel-secured, and dispatchable zero-emissions baseload power.

Solar, wind, geothermal, and battery storage will surely be an important part of any decarbonization plan for California, but the state will need every clean energy resource that it has – including Diablo Canyon – to meet its climate goals. A reliable grid requires a strong backbone of always-on and available baseload generation like Diablo Canyon. Intermittent sources alone cannot replace Diablo Canyon’s reliable 24/7 production of dispatchable carbon-free electricity for Californians. If the planned closure goes ahead, Diablo Canyon’s carbon-free electricity would be replaced by carbon-emitting natural gas- and coal-fired generation.

Without Diablo Canyon, California will be forced to depend on the charity of neighboring regions to make up for shortfalls in power supplies, including meeting demand after sunset when solar resources become unavailable. Given the inevitable potential for conditions limiting the availability of out-of-state energy, including the current drought impacting hydropower sources throughout the western United States, that is not a prudent situation.

According to CAISO, about 25% of California’s total electricity needs are currently met by imports. California’s vulnerability to blackouts and pipeline disruptions – including those caused by wildfires and earthquakes – demonstrates the necessity in keeping Diablo Canyon’s clean baseload power online beyond 2025 for the safety and prosperity of 40 million Californians. In wake of any blackout or extreme event, Diablo Canyon’s fuel-secured, reliable, firm, and dispatchable baseload power will surely be needed by Californians.

Years ago, California made a decision to shut down the Diablo Canyon units. However, circumstances have changed. The clean energy imperative is even stronger, and the importance of Diablo Canyon to the reliability of California’s current and future supply of carbon-free electricity is undeniable. It is time to revisit outdated decisions made in the last decade in the light of today’s facts and prepare for the continued operation of Diablo Canyon. ANS calls upon Gov. Newsom to reconsider the decision and keep Diablo Canyon online.