Pacific Gas & Electric is turning to a decidedly low-tech solution to keep its customers’ lights on for this year’s coming fire season: mobile diesel generators. 

The bankrupt utility is struggling to secure its grid from causing more deadly wildfires and has been stymied in attempts to set up natural-gas-backed microgrids to power substations during fire-prevention blackouts. But California regulators are adamant that PG&E must find a more permanent and less costly and polluting backup plan in the years ahead — even if it’s not clear yet what form it may take.    

On June 11, the California Public Utilities Commission plans to vote on a proposed decision that would greenlight PG&E’s plan to secure up to 450 megawatts of mobile generators to back up communities during public-safety power outage events this summer and fall. 

PG&E’s “Temporary Generation Plan” is a major expansion from its use of mobile generators last year, when forced switch-off events caused blackouts for millions of Northern California residents, some for days at a time. Those blackouts did, however, prevent a repeat of the catastrophic grid-sparked fires of 2017 and 2018 that killed scores of people and caused the tens of billions of dollars of damages that pushed PG&E into bankruptcy last year. 

This year’s $173 million plan, which includes $94 million in reservation fees to place a hold on hundreds of 2-megawatt diesel generators for quick deployment, “is not a long-term resiliency strategy,” CPUC administrative law judge Colin Rizzo wrote in the proposed decision. In fact, it has significant drawbacks, including the “potential health risks” for local residents exposed to generator exhaust, even when running on biodiesel PG&E plans to use to limit their greenhouse gas emissions profile. 

Even so, given the lack of alternatives for an upcoming fire season expected to be more dangerous than last year’s, and the threat that blackouts pose to medically vulnerable people and isolated communities, PG&E should be allowed to move ahead, Rizzo wrote. The approval for the diesel generators will only be for this year and will come with strict reporting guidelines. 

California's community-choice aggregators and solar and energy storage vendors want utilities to move faster on tapping the potential of distributed solar-battery systems. “PG&E’s approach to resiliency is the weakest step toward decentralized generation they could possibly take,” said Brad Heavner, policy director of the California Solar & Storage Association. 

"PG&E is working to reduce the frequency, scope, and impact of future Public Safety Power Shutoff (PSPS) events, and a key piece of this strategy for 2020 includes the reservation of temporary generators to support multiple PSPS-related workstreams," spokesman Paul Doherty said in a Thursday email. PG&E is also seeking to spend $13.5 milllion this year to prepare up to 48 substations to host mobile generators, and about $70 million over three years on a program to help communities and tribal governments coordinate future microgrid development with the utility.

How PG&E got to this point 

During last year’s outages, PG&E deployed about 20 megawatts of generators to prepared “resilience zones” that kept communities such as Angwin, Grass Valley, Calistoga and Placerville energized. It also used about 40 megawatts of generators to back up critical facilities such as hospitals and water treatment plants. 

PG&E hadn’t planned on relying entirely on mobile generators this year. In January, it proposed renovating up to 20 substations to be powered by large natural-gas-fired generators to support large numbers of connected customers, as part of a broader plan to provide community-scale microgrids in high-fire-threat areas.  

But it withdrew the proposal in March in the face of heavy opposition from groups including community-choice aggregators Sonoma Clean Power and Marin Clean Energy, as well as environmental groups. Vote Solar, an advocacy group, argued the plan could undermine solar, batteries and other carbon-free alternatives. 

PG&E's plan to develop its own microgrids also drew the ire of the Microgrid Resources Coalition, a trade group representing vendors including Engie, Eaton, Bloom Energy, NRG and Scale Microgrid Solutions. 

After last year's blackouts, California regulators asked PG&E and the state’s other two big investor-owned utilities for quick-turnaround microgrid plans for the 2020 fire season. But Southern California Edison determined that the only options would be “cost-prohibitive,” while San Diego Gas & Electric didn’t identify any new projects. Both utilities have used fire-prevention blackouts at a far smaller scale than has PG&E. 

While PG&E’s diesel generator proposal hasn’t gained much more support from the groups that opposed its original plan, it has won grudging acceptance that it’s probably necessary in the face of the wildfire and public-safety blackout threats this year. 

The benefits and limits of cleaner alternatives 

“I think that it’s apparent, given the short timeline left for preparation for fire season — which technically starts in a week — that all of the parties are resigned to diesel temporary generation being necessary for 2020,” said Allan Schurr, chief commercial officer of Enchanted Rock. The Texas-based microgrid developer has built more than 400 megawatts of microgrids centered on natural-gas generators that emit much lower levels of pollutants than do diesel generators, and it is seeking opportunities in California. 

Ed Smeloff, director of grid integration for Vote Solar, agreed that PG&E’s 2020 plan is “short-term, it’s only for very localized use, and they’re required to report all emissions.” But next year, he said, “They need to really focus on longer-term...[and] cleaner solutions.” 

Some solar groups worry that PG&E may not follow through on that front. “The CPUC seems intent on getting PG&E to consider cleaner sources, but we are concerned [that] if this doesn’t happen on a tight timeline, we’ll be in the same position a year from now,” said Heavner of the California Solar & Storage Association. 

But solar-storage systems that can only store several hours of energy, at least in cost-effective sizes, won’t be a viable alternative to fossil-fueled generators, Enchanted Rock's Schurr said. “There are opportunities for hybrid technologies [including solar and batteries] that further improve the economics. But at the core, you need something that can run indefinitely, can carry large loads, and can provide uninterrupted service for all customers.”