PG&E, Energy Vault plan largest US utility-scale battery, green hydrogen long-duration storage project

Dive Brief:

Pacific Gas & Electric Co. and Energy Vault, a Swiss-based energy storage developer, announced Thursday a partnership to operate a utility-scale battery plus green hydrogen long-duration energy storage system in Northern California.
The hybrid system, with at least 293 MWh of dispatchable carbon-free energy, would be capable of powering about 2,000 electric customers on a PG&E microgrid in Calistoga, California. It’s expected to provide a minimum of 48 hours of backup power in outages and would be the first of its kind and largest utility-scale green hydrogen project in the U.S., Energy Vault said.
The energy storage system, which must be approved by California regulators, would be owned, operated and maintained by Energy Vault, headquartered in Lugano, Switzerland, while providing power in a long-term tolling agreement with PG&E. The system’s capacity may be expanded to 700 MWh, allowing it to operate longer without refueling, Energy Vault said.

Dive Insight:

Calistoga, a city in California’s wine country, is vulnerable to high winds and fire, During disruptions on the region’s electrical grid, the microgrid would use lithium-ion batteries and fuel cells running on hydrogen to power the city without greenhouse gas emissions, unlike mobile diesel generators providing backup power at substations.

Fuel cells use an electrochemical process instead of combustion to generate electricity. Emissions are nonpolluting water vapor.

Laura Snideman, city manager of Calistoga, a city with a population of about 5,200, told PG&E in a December letter the area is “prone to high winds, wildfires and extreme temperatures and home to many seniors and low-income residents.”

“We are very pleased that Pacific Gas and Electric Co. is investing significant effort to address Calistoga’s challenges in obtaining reliable power and we support these efforts,” she said.

The 10.5-year agreement calls for Energy Vault to provide energy service using grid-forming generation and storage resources, potentially in combination with demand-side resources. The system will be developed on less than one acre and is expected to serve as a model for Energy Vault’s future utility-scale hybrid storage system deployments.

PG&E submitted the project contract for approval by the California Public Utilities Commission on Dec. 30, seeking a final resolution by May 15.

Construction is expected to begin in the fourth quarter with commercial operation anticipated by the end of the second quarter of 2024.