Energy Vault Begins Construction of the Largest Green Hydrogen Long Duration Energy Storage System in the U.S.

Energy Vault Holdings, Inc., a leader in sustainable grid-scale energy storage solutions, announced construction start of its previously announced deployment of a utility-scale green hydrogen plus battery ultra-long duration energy storage system (BH-ESS) with 293 megawatt-hours of dispatchable carbon-free energy.

Construction of the BH-ESS, which is being developed for Pacific Gas and Electric Company (PG&E) on less than one acre of land in the Northern California City of Calistoga, is expected to be completed by the end of Q2 2024. Upon completion, the BH-ESS, dubbed the Calistoga Resiliency Center, will be the first-of-its-kind and the largest utility-scale green hydrogen energy storage project in the United States. The battery portion of the system will be used to support grid forming and black start capabilities. The system will be prepared to power downtown Calistoga and the surrounding area for up to 48 hours during potential Public Safety Power Shutoffs (PSPS), which occur when the powerlines serving the surrounding area must be turned off for safety due to high wildfire risk. PG&E’s proposal for the system was approved by the California Public Utilities Commission (CPUP) in April 2023.

Energy Vault’s BH-ESS will replace the traditional mobile diesel generators currently used to energize PG&E’s Calistoga microgrid during PSPS events in the area. The project represents a major advance in community-scale microgrid development and a significant step toward realizing the CPUC’s vision of cleaner forms of microgrid generation.