Calistoga Transitions from Diesel to Innovative Clean Power Backup System

CALISTOGA, Calif. – Residents of this charming tourist town located at the northern edge of Napa Valley are acutely aware of the wildfire threat looming over them. The hillside shows burn scars from a fire in 2020 that necessitated a complete evacuation of Calistoga, while the 2017 Tubbs fire, which claimed 22 lives in wine country, ignited just a few miles from the town center.

In the past, when fire hazards prompted the shutdown of transmission lines that could spark a blaze, the town relied on a bank of noisy diesel generators situated in a popular recreational area. These generators not only emitted choking diesel exhaust but also produced a racket that drove residents away.

However, Calistoga is now transitioning to a groundbreaking system that integrates two clean-energy technologies—hydrogen fuel cells and batteries—providing enough power to sustain the city for approximately two days. Experts believe this technology has the potential to do more than just supply clean backup power during emergencies; it may also support the electric grid year-round.

As the system underwent final testing in late May, in an area that includes a dog park, ball fields, community gardens, and bike trails, residents expressed their gratitude for the assurance of clean energy throughout the year. Lisa Gift, a resident and city council member, highlighted the urgency of addressing climate change, which is resulting in more frequent and intense wildfires. “Continuing to depend on fossil fuels was simply not sustainable,” Gift remarked. “That’s what excited me about this. It’s a clean and reliable energy solution that ensures the safety and resilience of our community.”

Energy Vault, a California-based energy storage company, constructed the new facility, which was set to become operational in early June. Once its application for full connection is approved next year, it could begin exporting power to the electric grid as needed.

The installation is located where Pacific Gas & Electric (PG&E) previously deployed nine mobile generators each year from late spring through fall. Behind a chain-link fence, six hydrogen fuel cells, manufactured by Plug Power in New York, tower two stories high. During an exclusive tour by the Associated Press, water vapor was observed wafting from one of the fuel cells being tested.

Storage containers house two sets of Energy Vault’s lithium-ion batteries. Nearby, a massive, double-walled steel tank holds 80,000 gallons (302,833 liters) of extremely cold liquid hydrogen, which is converted to gas to power the fuel cells.

California utilities, particularly PG&E, have faced significant settlements for igniting wildfires. In 2018, during one of the state’s deadliest and most destructive wildfire years, PG&E began cutting power to mitigate fire risks and started deploying diesel generators to a dozen towns for backup power. Calistoga, home to about 5,000 residents, has experienced power shutdowns on ten occasions. The diesel generators emitted harmful nitrogen oxides, carbon dioxide, and soot. PG&E considered replacing these generators with natural gas versions that would be less polluting but ultimately chose Energy Vault’s fully clean solution, according to Dave Canny, the utility’s vice president for the North Coast Region.

Robert Piconi, CEO of Energy Vault, stated that other communities, military bases, and data centers could benefit from similar systems, though potential customers wanted to see successful operation first. “There’s a massive proof point with this project,” he said. “I think it’ll have a lot of implications for how people think about alternative, sustainable solutions.”

Plug Power plans for these types of products to become its primary business within a decade. Energy Vault is sourcing clean hydrogen produced with low or no greenhouse gas emissions to operate the fuel cells in Calistoga. “This solution is just beautiful,” said Janice Lin, founder and president of the Green Hydrogen Coalition, a nonprofit advocating for green hydrogen projects to combat climate change. “No noise, no emissions. And it’s renewable. It’s dumping diesel.”

Calistoga, which caters to tourists with its main street filled with local shops, restaurants, tasting rooms, and art galleries, is proud of its small-town atmosphere and does not share the posh reputation of much of Napa Valley.

Initially, some residents expressed concerns about the hydrogen, which is flammable and potentially explosive. Fire Chief Jed Matcham acknowledged his attention was drawn to the “very, very large tank.” He collaborated with Energy Vault on emergency planning and training and expressed confidence in the safety measures implemented. Energy Vault’s batteries are equipped with alarms, detectors, and piping to extinguish fires.

When PG&E shuts off power to the area to prevent wildfires, they will notify Energy Vault when it is safe to restore electricity to Calistoga. The batteries will provide immediate power to the local microgrid, followed by the hydrogen fuel cells, which will generate a steady supply of energy for an extended period. Working in tandem—similar to a hybrid vehicle—the batteries and fuel cells are expected to keep the lights on for approximately 48 hours or longer.

Clive Richardson, owner of the downtown Calistoga Roastery, shared that residents become anxious when the winds pick up, and he knows the impact of power outages on his small business. The introduction of a year-round clean energy solution for emergency power offers him a sense of security. “This will give us far more security than we had before,” he said. “It’s fantastic that it’s come. Here we are, little ol’ Calistoga, and we’ve got the first-of-a-kind system that hopefully will be endorsed and implemented worldwide.”