California suffers from "single-fuel dependency" that could increase the state's vulnerabilities during "extreme weather conditions," says the association of electric grid operators in a new report.
"Natural-gas-fired generation comprises 68 percent of on-peak anticipated capacity [in California] by 2021," the National Electric Reliability Council (NERC) notes.
"Minimal dual-fuel capable units and immediate resource constraints from the outage at the Aliso Canyon underground natural gas storage facility increase the risks associated with single-fuel dependency."
And that high level of dependence on natural gas would increase if California closes its last nuclear power plant, Diablo Canyon, in 2024/25.
Already, California gets 66 percent of its in-state electricity from natural gas — an amount that rose from 58 percent in 2011, and could rise to 74 percent if Diablo Canyon is closed.
NERC writes that "a single point of disruption, such as unavailable storage facilities, pipeline rupture, or other gas infrastructure failure" could reduce the reserve generation needed in emergencies.
NERC warns that "Minimal dual-fuel capable units and immediate resource constraints from the outage at the Aliso Canyon underground natural gas storage facility increase the risks associated with single-fuel dependency."
Nuclear plant closures risk making other grids over-reliant on natural gas, NERC notes:
"While new nuclear facilities are being built in Georgia, Tennessee, and South Carolina, potential retirements have been announced for nuclear facilities in Illinois, California, Nebraska, Massachusetts, and New York, creating longer-term uncertainty for system operators and planners. While replacement capacity may be advanced to mitigate resource adequacy concerns, unconfirmed nuclear retirements create uncertainty around local transmission adequacy and the ability to plan for future resource and demand needs due to their large baseload contribution."