Calistoga used to brace for Public Safety Power Shutoffs (PSPS) with rows of diesel trailers. This summer, the town’s Calistoga Resiliency Center (CRC)—a hybrid of lithium-ion batteries and hydrogen fuel cells—is taking over that role, engineered for about 48 hours of local backup with up to 8.5 MW of peak output.
The big update: on July 31, 2025, the California Public Utilities Commission approved the CRC to participate in CAISO markets. Energy Vault and PG&E marked the milestone with a ribbon-cutting on August 1 in Calistoga. The approval opens a path to earn revenue from energy and ancillary services when the grid is healthy—lowering the lifetime cost of resilience and turning a community backup asset into a market participant.
What makes this project more than a one-off is the architecture and operating model. The system is grid-forming and capable of black start, so during PSPS events the substation can island and ride on hydrogen fuel cells while batteries handle transients and fast control. Between events, the same hardware can serve the broader grid under market rules. That “island when it matters, earn when it doesn’t” pattern is exactly why state briefings and trade coverage have begun holding Calistoga up as a template for non-diesel community backup in wildfire country.
For engineers tracking the details: the facility pairs a ~293 MWh BESS with PEM fuel cells and an on-site ~80,000-gallon liquid-hydrogen tank, all supervised by Energy Vault’s EMS/market software. Reporting this summer emphasized not just emissions and noise benefits versus diesel, but also the practicalities—fuel logistics during extended PSPS periods and how market participation offsets O&M.
Calistoga’s shift matters beyond Napa Valley. It shows a path for other PSPS-exposed towns to retire diesel, keep critical services powered, and finance the asset with market revenues the rest of the year. With CPUC approval in hand and the system showcased publicly last week, expect more communities to copy the playbook as long-duration storage and clean-backup procurement mature.
If you want to build—or lead—the next clean, islandable microgrid, the Microgrid Systems Certificate Program (Telepath Systems + Cleveland State University) covers hybrid-DER architecture, grid-forming controls, and model-based validation—skills used in projects like Calistoga.