This ambitious endeavor involves the development of a 5-megawatt (MW) / 500 megawatt-hour iron-air battery storage project, representing the largest long-duration energy storage initiative in California. It also marks the state's inaugural utilization of this cost-effective technology. The project's location is set at a substation owned by the Pacific Gas and Electric Company in Mendocino County, where it will supply power to local residents. The system is scheduled to commence operation by the conclusion of 2025, contributing to grid reliability and showcasing solutions aligned with the state's climate and clean energy objectives.
CEC Chair David Hochschild commented, "A multiday battery system is transformational for California's energy mix. This project will enhance our ability to harness excess renewables during nonpeak hours for use during peak demand, especially as we work toward a goal of 100 percent clean electricity."
This grant award represents one of three approvals within the framework of the CEC's Long-Duration Energy Storage program, a part of Governor Gavin Newsom's historic multi-billion-dollar commitment to combat climate change. This program fosters investment in the demonstration of non-lithium-ion technologies across the state, contributing to the creation of a diverse portfolio of energy storage technologies.
As of August, California had 6,600 MW of battery storage actively deployed statewide, operating within the prevailing industry standard of 4 to 6 hours of discharge. By year-end, this figure is projected to expand to 8,600 MW. Longer-duration storage, spanning from 8 to 100 hours, holds the potential to expedite the state's shift away from fossil fuels while reinforcing grid stability. California estimates that more than 48 gigawatts (GW) of battery storage and 4 GW of long-duration storage will be requisite to achieve the objective of 100 percent clean electricity by 2045.
Energy storage serves as a cornerstone of California's clean energy future, offering a means to capture and store surplus power generated by renewable resources. The state's battery infrastructure plays a pivotal role during the summer when electricity demand peaks in the early evening hours as solar resources decline, preceding the later surge in wind energy.
Iron-air battery technology operates on the principle of reversible rusting. These battery cells contain iron and air electrodes and are filled with a water-based, nonflammable electrolyte solution. During discharge, the battery absorbs oxygen from the air, converting iron metal into rust. During the charging phase, the application of an electrical current converts the rust back into iron, releasing oxygen. This technology is cost-competitive compared to lithium-ion battery production.