California is moving quickly to adopt microgrids to store wind and solar energy and to provide electricity during public safety power shutoffs (PSPS) in wildfire season, but long-term energy storage and resilience remain problems, panelists said last week at a California Energy Commission workshop on “Assessing the Future Role for Microgrids.”
Leaders of the CEC, the California Public Utilities Commission and CAISO met in three sessions over two days during the workshop, hearing from panelists and presenters on the challenges and promise of microgrids: small-scale generation and distribution systems that can power a single building or a whole community.
Over a total of six hours, participants discussed using microgrids to offset fire-prevention blackouts starting this fall and, in the longer term, to store renewable power and make up for possible capacity shortfalls during the switch from natural gas plants to renewable resources in the next three years.
Senate Bill 100, passed in 2018, requires load-serving entities to provide only zero-carbon electricity to retail customers by 2045.
“Microgrids are one of the tools that will help the state get to our 100% clean energy standard in the most efficient and equitable way possible,” said CEC Vice Chair Janea Scott, who led the sessions.
CPUC President Marybel Batjer said she’s worried about Pacific Gas and Electric’s plan to use diesel generators to supply electricity during PSPS events this summer and fall. PG&E intends to connect hundreds of diesel generators at substations to supply customers during the shutoffs.
“I am concerned that this wildfire season, we will see a lot of diesel generation used to ensure resiliency, and we have to get to a cleaner and quieter form of resiliency backup power,” Batjer said.
Neil Millar, CAISO’s vice president for transmission planning and infrastructure development, said it was important for the ISO to learn about the “different flavors of microgrids that are evolving” and to ensure “our existing processes are adequate for accommodating them.”
CAISO and the CPUC are working to manage the connection of microgrids to the statewide grid and to include microgrids in the state’s resource planning process, he noted.
Fast-tracked Measures
Senate Bill 1339, passed in 2018, directed the CPUC to “facilitate the commercialization of microgrids for distribution customers of large electrical corporations” by Dec. 1.
In response, the CPUC established a new section in its Energy Division focused on microgrids and fast-tracked rulemaking to speed the connection of microgrids in anticipation of this year’s fire season, which typically lasts from late summer through November.
In June, it adopted a proposed decision ordering investor-owned utilities to streamline and expedite interconnection processes for microgrid resilience projects and to work with local and tribal governments to bring the projects online by late summer, in time for the anticipated power shutoffs. (See California PUC Approves Microgrids, Fire Plans.)
The CPUC directed energy storage facilities to import power from the grid prior to PSPS events. It permitted PG&E to upgrade substations and install diesel generators, but only for the 2020 fire season. And it ordered IOUs to increase staffing to hasten microgrid interconnections.
“We’re really focused on … fast-tracking near-term strategies and actions we can put in place in time for this year’s wildfire season,” PUC Senior Analyst Jessica Tse said during the first microgrid workshop session on July 7.
Beyond the next few months, the CPUC and CEC are seeking ways to build microgrids that use wind and solar with battery storage to ride out power outages. (See CPUC Proposal Would Promote Microgrids.)
The CEC is funding millions of dollars in pilot projects to find microgrid solutions that can be replicated and installed on a larger scale. The projects are on military bases and tribal lands, at ports and airports, in industrial settings and wastewater treatment plants, and in low-income and disadvantaged communities.
Projects recently approved include $6 million to determine if it might be feasible to use banks of batteries that have been removed from electric vehicles, but still have plenty of useful life, for storage in microgrids. With 750,00 EVs sold so far, and millions more expected to hit California roads in the next decade, there will be a lot of used batteries, CEC Chair David Hochschild said. (See Calif. Energy Commission OKs $22M for Storage.)
In another CEC-funded project, the city of Fremont is using solar and battery storage to allow critical facilities such as fire stations to “island” from the grid for up to three hours. But local jurisdictions need the ability to provide power while disconnected from the grid for longer periods, said Rachel DiFranco, the city’s sustainability manager.
PG&E’s fire-safety blackouts in the fall of 2019, affecting hundreds of thousands of customers, lasted for days at a time. (See CPUC Orders Changes to PG&E Shutoff Rules.)
Earthquakes and wildfires could sever ties to the grid for even longer periods, said Rosa Vivian Fernández, CEO of the San Benito Health Foundation, a small clinic that serves thousands of farmworkers in the city of Hollister. In August 2019, San Benito became the first health care facility in California to run entirely on its own zero-carbon microgrid using a rooftop solar array and lithium-ion battery storage.
Fernandez said she learned from visiting Puerto Rico after Hurricane Maria in 2017 that health care facilities could be disconnected from power for weeks, unable to serve patients.
“When disaster strikes … [you] may have severe damage to infrastructure,” she said during the first of Thursday’s two workshop sessions.
Seth Baruch, director of energy and utilities for health care giant Kaiser Permanente, explained why Kaiser had decided to install microgrids at a growing number of its facilities.
In 2018, the Kaiser Permanente Richmond Medical Center was the first hospital in California to install a renewable-energy microgrid for backup power during outages. Hospitals generally use diesel generators for emergency power, but Kaiser is pursuing microgrids as it seeks to become carbon neutral and because diesel fuel can run short in emergencies, Baruch said.
“When you need diesel, everyone needs diesel,” he said. With power shutoffs and potential surges in COVID-19 cases, Kaiser wants to ensure its facilities have power “24/7” for days at a time, he said.
Hydrogen Fuel Cells
The need for microgrids that can supply long-term backup power prompted a discussion Thursday, during the workshop’s final session, on deploying microgrids that use hydrogen fuel cells, which produce electricity through an electrochemical reaction of hydrogen and oxygen.
Lithium-ion batteries can only provide power for short-duration outages. Fuel cells can provide power indefinitely given a supply of hydrogen and oxygen produced by separating water into its components with a solar-powered electrolyzer, advocates said Thursday.
Stone Edge Farm, a 16-acre Sonoma County winery, has a microgrid with solar panels, batteries, an electrolyzer that produces hydrogen from rainwater and a bank of hydrogen fuel cells, winery owner Mac McQuown told commissioners.
“Our objective in our microgrid is to be independent of the utility grid 24/7, 365,” McQuown said.
Microgrids using fuel cells power a low-income housing community in Brooklyn, a college in Bridgeport, Conn., and a high school and fire stations in Woodbury, Conn., said Jack Brouwer, director of the National Fuel Cell Research Center at the University of California, Irvine.
“Fuel cells have this opportunity to do that because they have very high power capabilities to power a whole community,” Brouwer said.
The big problem is cost. In applications such as microgrids, fuel cells produce electricity at $4,000 or more per kilowatt, the NFCRC says on its website. Fuel cells would be competitive in providing power for stationary loads if they reach an installed cost of $1,500 or less per kilowatt, it says.
Current research is seeking to reduce costs by using less expensive materials and producing fuel cells on a larger scale, the NFCRC says.
Brouwer said using hydrogen technology in conjunction with wind, solar and battery storage is another way to make fuel cells more practical. Existing natural gas pipelines might also be able to carry hydrogen, but that idea has proven controversial among clean-energy advocates who want to do away with natural gas entirely, he said.
Still, he said, California may ultimately need hydrogen fuel cells to provide electricity during long outages and to meet its ambitious decarbonization goals.
Hydrogen can “deliver resilience for weeks on end,” Brouwer said, and “the solution to get all the way to zero [carbon] needs something like fuel cells and hydrogen.”
Millar, with CAISO, said he agreed. “The solution here isn’t one or the other; it’s all of the above,” he said.