ESS Announces Agreement to Join Salt River Project and Google Long Duration Energy Storage Collaboration

ESS Tech, Inc. has agreed to join Salt River Project (SRP) and Google in Project New Horizon, a five-megawatt, 50-megawatt hour long-duration energy storage pilot at SRP’s Copper Crossing Energy and Research Center in Florence, Arizona. The project will deploy ESS’s iron flow Energy Base technology, marking a key validation step for utility-scale deployments. SRP selected the pilot through a competitive solicitation to evaluate non-lithium storage options, with design work underway and manufacturing expected to begin in 2026.

The collaboration includes operational testing supported by the Electric Power Research Institute (EPRI) under a multi-year research scope, with SRP and ESS conducting required tests and EPRI providing independent oversight. Google is participating through a cost-sharing arrangement with SRP, contributing to project funding. The pilot aims to assess real-world performance of non-lithium long-duration storage and its impact on grid reliability, renewable energy integration, and broader deployment pathways.

ESS’s Energy Base system is designed for utility-scale use and offers flexible configuration across diverse applications, differing from earlier containerized solutions. The pilot represents a commercial validation milestone for ESS’s next-generation platform and could unlock follow-on opportunities with utilities and large energy users seeking scalable storage. Delivery of the system is targeted for December 2027.

SRP and Google have stated goals to expand clean energy access and provide reliable, affordable electricity. ESS CEO Drew Buckley noted the pilot’s significance in demonstrating the relevance of non-lithium long-duration storage for grid reliability and carbon-free energy goals. SRP’s Chico Hunter and Google’s Lucia Tian emphasized the project’s role in advancing real-world understanding of long-duration storage for future system needs.