On January 11, 2018, members of California Public Utilities Commission voted unanimously to shut down the two nuclear reactors in Diablo Canyon Power Plant in 2024 and 2025, when their federal operating licenses expire.
The power plant is located near Avila Beach in San Luis Obispo County, California. After the permanent shutdown of the San Onofre Nuclear Generating Station in 2013, it is the last operational nuclear plant in the state. The plant is operated by Pacific Gas & Electric (PG&E Corp) and generates about 18,000 GWh of electricity, covering 8.6% of California’s electricity demand.
Diablo Canyon has been one of the most controversial nuclear power plants in the U.S. It has faced legal challenges and civil disobedience since its construction. In fact, a series of protests at Diablo Canyon Power Plant organized by anti-nuclear group Abalone Alliance resulted in the arresting of 1,900 protesters back in 1981, the largest of its kind in the U.S. anti-nuclear movement.
The safety concern especially the earthquake vulnerability of the plant is at the center of dispute PG&E Corp spent six years to convince regulators the site was safe and have the construction approved. Although it was deemed safe when construction started in 1968, a seismic fault known as the Hosgri fault was discovered several miles offshore from the site in 1973. The company added structural supports to reinforce stability, but the job was done poorly.
Since the Fukushima Daiichi nuclear disaster in 2011, public pressure to close down Diablo Canyon resurged. Like the facilities at Fukushima, the power plant is in an area prone to earthquakes and tsunami. After the Fukushima incident, the Nuclear Regulatory Commission (NRC) conducted a nationwide review of nuclear power plants for their capacity to respond to emergency and natural disaster. Its report stated that Diablo Canyon has "a high level of preparedness and strong capability in term of equipment and procedures to respond to severe events."
Despite its ability to continue to generate carbon-free electricity, PG&E Corp has decided in 2016 to retire the reactors, and close Diablo Canyon after the plant’s operation license expires in 2024 and 2025, because of the projected increases in renewable energy, the surge of power storage technology, and decreases in consumption.
In general, nuclear power plants across the U.S. are facing competition from natural gas generators, which consume inexpensive fuels and operate at a lower cost. Combined with other factors, six nuclear plants have announced early retirements in the last seven years, and more may follow suit in the near future. In the end, economics has achieved what anti-nuclear activists have sought for years.
Why is Closing the Diablo Canyon Nuclear Power Plant a Big Deal? Credit: Climate One