On December 13, 2023, the California Energy Commission (CEC) approved a $30 million grant to long-duration energy storage developer Form Energy to build the state's largest long-duration energy storage project, capable of discharging energy to the grid for 100 hours.[1] The 5 MW/500 MWh iron-air battery storage project will be built at a Pacific Gas & Electric (PG&E) substation in Mendocino County. It is expected to come online by the end of 2025 and will help support grid reliability and demonstrate solutions needed to meet the state’s climate and clean energy goals. Form Energy’s iron-air battery is based on “reversible rusting,” meaning the system discharges energy by absorbing oxygen from the air and converting iron to rust and charges by using electrical current to convert the rust back to iron. The technology has lower costs compared to lithium-ion battery production.

The award is one of three approved under the commission’s Long-Duration Energy Storage program, which invests in the demonstration of non-lithium-ion technologies across California to create a diverse portfolio of energy storage technologies. As of August 2023, the state had 6,600 MW of battery storage, operating at the current industry standard of 4 to 6 hours of discharge. The number is projected to increase to 8,600 MW by the end of 2023. The state estimates more than 48 GW of battery storage and 4 GW of long-duration storage will be needed to meet the goal of 100% clean electricity by 2045.

[1] https://www.energy.ca.gov/news/2023-12/cec-awards-30-million-100-hour-long-duration-energy-storage-project