Calistoga Transitions from Diesel Generators to Innovative Clean Energy Backup System

CALISTOGA, Calif. – Residents of this charming tourist town located at the northern edge of Napa Valley are constantly aware of the wildfire threat. The surrounding hills bear scars from the devastating 2020 fire that forced an evacuation of Calistoga, and the 2017 Tubbs fire, which tragically claimed 22 lives in wine country, ignited just a few miles from downtown.

In the past, when fire danger necessitated the shutdown of power transmission lines to prevent ignitions, the town relied on a bank of diesel generators situated in a popular recreation area. These generators emitted noxious diesel exhaust and produced a loud rumble that deterred visitors.

However, Calistoga is now transitioning to a groundbreaking system that combines two clean-energy technologies—hydrogen fuel cells and batteries—capable of providing enough power to sustain the city for approximately two days. Experts believe this technology not only serves as a clean backup power source during emergencies but also has the potential to bolster the electric grid throughout the year.

As the system underwent final testing in late May, residents expressed their gratitude for the assurance of clean energy year-round. City Council member and resident Lisa Gift highlighted the urgency of moving away from fossil fuels, stating, “Continuing to depend on fossil fuels was simply not sustainable. 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, developed the new facility, which was set to become operational in early June. Once approved, it may begin exporting power to the electric grid as early as next year.

The installation is located near where Pacific Gas & Electric used to deploy nine mobile generators annually from late spring through fall. Six hydrogen fuel cells, each standing two stories tall and manufactured by Plug Power in New York, are now secured behind a chain-link fence. During an exclusive tour by The Associated Press, water vapor could be seen rising from one of the fuel cells undergoing testing.

In addition, shipping containers house pairs of Energy Vault’s lithium-ion batteries, while 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 substantial settlements for their role in igniting wildfires. In 2018, one of the state’s most destructive wildfire years, PG&E began cutting power to reduce the risk of fire. The company has since deployed diesel generators to around a dozen towns for backup power during these outages.

Calistoga, with a population of about 5,000, has experienced power shutdowns ten times. Unfortunately, these generators released harmful nitrogen oxides, carbon dioxide, and soot. Although PG&E considered replacing the diesel generators with a natural gas option, which would be less polluting, they ultimately chose Energy Vault’s entirely clean alternative, according to Dave Canny, the utility’s vice president for the North Coast Region.

Energy Vault’s CEO, Robert Piconi, noted that similar systems could be beneficial for other communities, military bases, and data centers, but potential customers wanted to observe the system in action first. “There’s a massive proof point with this project,” he stated. “I think it’ll have a lot of implications for how people think about alternative, sustainable solutions.”

Plug Power, the fuel cell manufacturer, plans to make these types of products its primary focus within the next decade. Energy Vault confirmed that it is procuring clean hydrogen, produced with minimal or no greenhouse gas emissions, to run the fuel cells in Calistoga. “This solution is just beautiful,” said Janice Lin, founder and president of the Green Hydrogen Coalition, a nonprofit that advocates for green hydrogen initiatives to combat climate change. “No noise, no emissions. And it’s renewable. It’s dumping diesel.”

The introduction of this year-round clean energy system provides reassurance to residents. Calistoga, known for its local shops, restaurants, tasting rooms, and art galleries, prides itself on maintaining a small-town atmosphere, distinct from the more upscale vibe of much of Napa Valley.

Some residents initially expressed concerns about the hydrogen, given its flammability and potential explosiveness. Fire Chief Jed Matcham acknowledged the size of the hydrogen tank but has since collaborated with Energy Vault on safety planning and training, assuring the community that adequate safety measures are in place. Energy Vault’s systems also incorporate alarms, detectors, and firefighting piping.

When PG&E next turns off the power to mitigate wildfire risk, they will notify Energy Vault when it is safe to restore electricity to Calistoga. The batteries will discharge stored energy to the local microgrid, followed by the hydrogen fuel cells, which will provide a consistent power supply for an extended duration. This hybrid approach is designed to keep the lights on for about 48 hours or longer.

Clive Richardson, owner of the Calistoga Roastery, which serves as a social hub for locals, understands well the anxiety that arises when the winds pick up, as it often signals potential power outages. A reliable clean power source eases his concerns. “This will give us far more security than we had before,” he remarked. “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 go all over the world.”