California PUC Will Rule Soon on Diablo Canyon’s Future

The fate of Pacific Gas & Electric’s (PG&E’s) Diablo Canyon Power Plant is expected to be decided by year-end, with the California Public Utilities Commission (CPUC) set to hear final arguments about the plant’s future on November 28.

The 2.2-GW nuclear plant has operated near Avila Beach, California, since 1985. A judge in early November supported PG&E’s plan to retire the plant’s two Westinghouse-designed 4-loop pressurized-water reactors when their federal operating licenses expire in 2024 and 2025.

PG&E has said several factors entered into its decision to shutter the plant, which is the last operating nuclear facility in California. On its website, the utility says, “California’s energy landscape is changing dramatically. State policies that focus on renewables and energy efficiency, coupled with projected lower customer electricity demand in the future, will result in a significant reduction in the need for electricity produced by Diablo Canyon Power Plant past 2025.”

Proponents of keeping the plant in operation argue it was built to last a century. Californians for Green Nuclear Power say nuclear power is more efficient than renewable sources, such as solar and wind, and contend that electricity costs for PG&E ratepayers will rise significantly if the plant closes. They also say safety concerns about the plant have been overstated.

The safety of the plant has been at the forefront of arguments against its continued operation, particularly after the Fukushima disaster in Japan in 2011. Diablo Canyon is located near two major faults—Hosgri and San Gregorio—and concerns about seismic activity in the region have been cited often by the plant’s opponents, most notably The Utility Reform Network (TURN), a San Francisco-based ratepayer advocacy group. PG&E in 2015 submitted documents to the federal Nuclear Regulatory Commission (NRC) that said the plant could safely withstand earthquakes, tsunamis, and flooding, of particular importance due to Diablo Canyon’s seaside location.

TURN and others also note problems with another now-shuttered nuclear plant in Southern California, the San Onofre Nuclear Generating Station (SONGS), as evidence nuclear power is unsafe. San Onofre—taken offline in 2012—was permanently closed in 2013 due to a flawed design that resulted in leaking tubes in steam generators installed in 2010 and 2011 as part of upgrades at the plant. SONGS’s first unit—decommissioned in 1992—began operation in 1968; Units 2 and 3 came online in 1983 and 1984, respectively.

TURN earlier this year won a case it brought against PG&E; the group asked the CPUC not to allow the utility to pass along the costs of decommissioning Diablo Canyon to ratepayers. The CPUC in May rejected nearly $1.4 billion, or 91%, of PG&E’s proposed rate increase to pay for the decommissioning.

TURN has said that closing Diablo Canyon “in the mid-2020s gives plenty of time for the state to plan for replacement options.”

The Diablo Canyon closure would bring an end to nuclear power plants in California, but not nuclear power; part of Southern California continues to receive electricity from the 4-GW Palo Verde nuclear plant in Arizona, which is partly owned by Southern California Edison (SCE), the Los Angeles Department of Water and Power, and the Southern California Public Power Authority. Nuclear generation in California dates to the 1957 opening of PG&E’s Vallecitos plant, and the Santa Susana plant operated by SCE. Six nuclear plants have operated in the state at various times over the past 60 years.

The shuttering of Diablo Canyon would leave just one nuclear plant—the Columbia Generating Station near Richland, Washington, a POWER Top Plant in 2017—operating on the U.S. West Coast.

Darrell Proctor is a POWER associate editor (@DarrellProctor1, @POWERmagazine).