PG&E and Energy Vault to build green hydrogen storage in US

In order to install and run a utility-scale battery plus green hydrogen long-duration energy storage system (BH-ESS) with a minimum of 293 megawatt-hours (MWh) of dispatchable carbon-free energy, Energy Vault Holdings and Pacific Gas and Electric Company (PG&E) have partnered.

During planned outages and potential Public Safety Power Shutoffs (PSPS), which occur when the powerlines serving the surrounding area must be turned off for safety due to a high wildfire risk, the BH-ESS is intended to power downtown and the surrounding area of the Northern California City of Calistoga for at least 48 hours.

On December 30, 2022, PG&E submitted the project contract to the California Public Utilities Commission (CPUC) for evaluation and approval, requesting that the project be given final approval by May 15, 2023. In accordance with a long-term tolling agreement with PG&E, Energy Vault will own, operate, and maintain the energy storage system while it provides dispatchable electricity. The system’s capacity might be increased to 700MWh, allowing it to run without refueling for longer and giving PG&E and the City of Calistoga more flexibility.

The usual, mobile diesel generators that are now utilized to power PG&E’s Calistoga microgrid during larger grid disruptions will be replaced with Energy Vault’s BH-ESS. The project is a key step in achieving the CPUC’s goal of greener types of microgrid production and a significant advancement in the construction of community-scale microgrids.

With a hybrid architecture that will enable grid formation and black start capabilities, the system is expected to offer carbon-free electricity for the Calistoga community’s more than 2,000 electric customers for a period of 48 hours. In the future, the project’s capacity may be increased up to 700MWh.

Beginning in the fourth quarter of 2023, construction is projected, with commercial operation predicted by the end of the second quarter of 2024. This undertaking is anticipated to be the first of its kind and the biggest utility-scale green hydrogen project in the country once it is finished.