Pacific Gas & Electric (PG&E) could need to use diesel and natural gas generators to power communities affected by public safety power shut-offs (PSPS) beyond the 2020 fire season "as a necessary bridge until non-fossil-fueled alternatives are available," according to comments filed by the utility last week.
- The utility is proposing to deploy diesel generators during the shut-offs this year and multiple stakeholders want regulators to ensure fossil fuels are not used during future fire seasons. But "nothing in the record of this proceeding supports a determination that alternatives exist today that can provide reliable, long-duration mobile generation on the scale needed to mitigate the impacts of PSPS events," PG&E said.
- The California Public Utilities Commission (CPUC) is scheduled to vote on PG&E’s proposal as well as a suite of other programs to build resiliency and expedite the deployment of microgrids in California on June 11.
PG&E’s broader strategy to reduce the impacts of its shut-offs includes three programs: upgrading certain substations so they can operate as islands when transmission lines are de-energized, providing technical and financial support to communities that want to deploy microgrids, and its "temporary generation program," which initially included deploying up to 300 MW of temporary generators to power certain communities during the 2020 wildfire season.
In an update filed in April, the utility bumped up that number and said that "vendors offering temporary generators using fuels other than renewable or fossil diesel would face challenges" in handling the full scope of work. To date, PG&E has reserved around 450 MW of temporary generation for 2020.
The CPUC has tentatively approved that plan "for interim, short-term use for the upcoming 2020 wildfire season." Noting that large diesel generators can create health risks for communities, the commission recommended allowing the use of diesel generation for one year after PG&E signs vendor agreements in 2020. PG&E would also be required to submit a report to the commission before Feb. 15, 2021, detailing the number of diesel generators it deployed as well as the associated greenhouse gas emissions and air pollutant emissions. In addition, the proposal includes a suite of measures to accelerate microgrid deployments such as standardizing application processes and expediting interconnection processes for certain customers.
But environmental groups and other stakeholders have expressed concerns over relying on fossil fuels to make communities resilient to power shut-offs. Utilities that want to deploy fossil fuels should submit a proposal to the CPUC explaining how they will transition away from them within five years, the Clean Coalition said in comments filed earlier in May.
"Though this program only contemplates using diesel generation for the 2020 wildfire season, the same locations will require backup generation year after year, necessitating the transition to renewables-driven microgrids for a permanent resilient solution," the group said.
Sierra Club urged the commission to include in the decision a "clear, unequivocal direction that there is no place for fossil-fuel generation in future resiliency efforts." The group notes that California’s wildfire risk is related to climate change and continuing to rely on fossil fuels would entrench those impacts.
PG&E also wants to replace mobile diesel generation with cleaner alternatives, but developing and deploying cleaner mobile technologies will require a coordinated effort over time, according to utility spokesman Paul Doherty.
"Prohibiting diesel and natural gas mobile generators after 2020 for PSPS mitigation without a comprehensive analysis of alternatives, as some parties propose, that would need to include technical, operational, safety, and logistical perspectives, is a short-sighted approach that fails to adequately consider the critical importance and the operational and logistical complexities of utilizing temporary generation in reducing the impacts of PSPS events," he told Utility Dive via email.
A request for information issued by PG&E earlier this year indicated that cleaner, temporary generation faces multiple hurdles related to feasibility, supply and cost, he said.
Proposals to forbid diesel generation could harm public safety, PG&E said in its comments. It could also lead customers to turn to smaller gasoline and diesel generators, which are inefficient, present safety risks, and will likely result in higher emissions, according to PG&E.
"Further, keeping the grid energized with centralized mobile generators overseen by trained electrical staff is a safer solution than individual homeowners deploying makeshift back-up solutions on their own premises during high wildfire threat conditions," it added in its reply comments.
Temporary diesel generation is "a tough pill to swallow but at the same time, we’re really happy to see the proposed decision affirm it’s not a long-term resiliency strategy," Jin Noh, policy manager at the California Energy Storage Alliance, told Utility Dive.
Cleaner solutions like solar-plus-storage or fuel cells should be possible with a runway of a year or so to actually deploy the systems, he added. However, "solar-plus-storage alone doesn’t meet all resiliency needs and so naturally, there is a need to have fuel cells or generators fueled by renewable gas, for example," he added.
A report prepared by the Brattle Group for Enchanted Rock, a natural gas microgrid developer, came to a similar conclusion. Natural gas and renewable natural gas (RNG) generators, as well as "hybrid" systems with solar, storage and RNG, are economically and technically viable, the report found. But "while standalone solar-plus-storage systems have a highly positive outlook as bulk system resources for providing value in the California Independent System Operator market, microgrids running only on solar and storage are effectively infeasible for distribution system applications requiring 100% reliability over four consecutive days."
California’s state policy is leaning towards clean energy, Luis Amezcua, senior campaign representative with Sierra Club, told Utility Dive. Utilities should be looking at a mix of resources, specific to each area, that can provide resilience benefits and that mix could include distributed solar, distributed storage, demand response and energy efficiency, he said.
"It can’t just be storage or something else — it has to be a combination of different resources to really meet that need and I think putting in that effort and trying to figure out what the creative solution is should go first and be prioritized," over fossil fuel investments, he said.
CORRECTION: a previous version of this story said the amount of temporary generation PG&E plans to deploy is confidential. PG&E has reserved around 450 MW of temporary generation for 2020.