US City to Replace Diesel with 293 MWh Green Hydrogen Plus Battery System

The system will provide clean power for at least 48 hours during shutdowns


Pacific Gas & Electric Company (PG&E), a combined natural gas and electric utility of PG&E Corporation, and Energy Vault, a utility-scale energy storage solutions developer, have signed a 10.5-year agreement to deploy and operate a utility-scale battery plus green hydrogen (H2) long-duration energy storage system (BH-ESS) with a minimum of 293 MWh of dispatchable carbon-free energy.

Owned, operated, and maintained by Energy Vault, the BH-ESS will replace the conventional, mobile diesel generators that are used to power PG&E’s microgrid in Calistoga, a city in Northern California, during border grid outages.

The power generated using the new system will give over 2,000 customers in the downtown and surrounding areas of Calistoga access to carbon-free electricity for a minimum of 48 hours during planned power outages and potential Public Safety Power Shutoffs.

Such power shutdowns occur during high risk of wildfire, which might lead to electricity-related accidents.

With the system, Energy Vault will provide Distributed Generation-Enabled Microgrid Services which is a type of energy service involving the usage of grid-forming generation and storage resources.

The California Public Utilities Commission (CPUC) received the project contract on December 30, 2022, and the issuance of final approval is scheduled for May 2023. Energy Vault said that it is further planning to expand the capacity of the BH-ESS system to 700 MWh allowing it to operate for longer durations without refueling.

The BH-ESS facility will avoid the emission of localized pollutants like oxides of nitrogen and particulate matter when generating electricity to power the microgrid. A hydrogen fuel cell will be powered by electrolytic hydrogen derived from renewable energy sources, to produce power.

Regional Vice President, North Bay, and North Coast, PG&E, Ron Richardson said, “This breakthrough collaboration between PG&E and Energy Vault provides a template for future, renewable community-scale microgrids that successfully integrate third-party distributed energy resources, which is expected to cost customers less than the benchmark set by state regulators based on the alternative use of mobile diesel generators.”

In December, the U.S. Energy Information Administration said that project developers and owners in America would add up to 30 GW of utility-scale battery storage capacity until 2025.

According to a report from last September released by the Lawrence Berkeley National Laboratory, California hosted most solar photovoltaic and battery storage paired systems, with attachment rates of 11% in the residential segment and 5% in the non-residential segment.

In April 2022, NTPC inked a memorandum of understanding with Energy Vault to formalize a long-term strategic partnership for deploying the latter’s EVx gravity-based energy storage technology and software solutions based on the outcome of the joint feasibility study.