Regulators Okay PG&E Increasing Diesel Backup

By Published On: December 2, 2021

California continues to tout its commitment to clean energy but state regulators voted to allow still more diesel-powered backup power. They approved a request by Pacific Gas & Electric to expand its diesel generation over fears of supply shortages during intense heat, continued drought, and low hydropower next summer. It’s one part of a three-part plan approved Dec. 2 to bring online 2,000-3,000 more megawatts and negawatts by the summers of 2022 and 2023.

The Thursday decision also allows San Diego Gas & Electric to install four 40 MW circuit-level energy storage microgrids, providing 160 MW hours of capacity. Two of the microgrids are supposed to come online by next summer and the other two in 2023.

The unanimous decision by the commission states diesel is “a necessary solution to prevent power outages” in wildfire-prone communities. But it acknowledges it’s “the least favorable of all reliability resources.”

Not everyone views the additional diesel as essential.

“There are so many other clean and preferred alternatives on the supply side,” California Energy Storage Alliance Policy Director Jin Noh told Current.

Last year, PG&E leased 170 MW diesel-fueled backup systems to use at its substations to keep power flowing when the lines that supply them are shut off to prevent fires.

The controversial decision allowing PG&E to add even more diesel backup was revised before the vote to require the utility to study its impacts and to inform local air districts of any added systems. If the systems are cranked up during grid emergencies, however, air quality protections are waived.

PG&E expects the study, to be done within 60 days, to determine whether it can make the needed infrastructure improvements at certain substations to accommodate diesel generators so they can supply the grid during system capacity shortfalls next summer, said Ari Vanrenen, utility spokesperson.

Diesel backup, which releases toxic emissions, continues to climb in California. Earlier this year, consulting firm M.Cubed found the diesel systems represented about 15% of the grid capacity.

Advocates insist clean microgrids provide climate adaptation

Last month, a group of clean energy and storage advocates called on the Office of Planning and Research to include in the draft California Climate Adaption Strategy an accounting of the harm caused by outages employed in response to risky fire conditions. They also are pushing to include climate resiliency and clean microgrids as successful adaptation strategies.

“Power outages endanger vulnerable energy-dependent people and have cost Californians billions of dollars,” according to a Nov. 17 joint letter from The Climate Center, Vote Solar, Sierra Club California, and California Alliance for Community Energy to the state planning office.

Both climate adaptation planning and implementation funding “should recognize and encourage the urgent need to deploy clean local energy resources that can provide electricity for essential functions when the grid is out of service and should prioritize frontline communities and vulnerable households,” the coalition argued.

The CPUC decision okaying PG&E’s use of more diesel generation notes it is required to use hydrotreated vegetable oil and renewable diesel, where feasible.

PG&E did not address Current’s query as to the feasibility of using alternative fuel.

The utility will use the “Tier 2 Advice Letter,” an expedited administrative procedure, to seek approval of the deployment of additional diesel generation.

Increasing energy efficiency

To beef up grid resiliency, state regulators also approved spending $180 million to increase commercial and residential energy efficiency over the next two summers. Nearly all of this money will go to the three investor-owned utilities for third-party energy savings programs. Marin Clean Energy, which piloted new performance-based efficiency programs, will receive $11 million.

Commissioner Genevieve Shiroma said the program seeks immediate and rapid deployment of efficiency measures.

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