Salt River Project (SRP) has partnered with ESS to deploy a 5MW/50MWh iron flow battery as part of a new long-duration energy storage (LDES) pilot – Project New Horizon.
The public power utility, which serves the Phoenix metropolitan area, will install the system at its Copper Crossing Energy and Research Center in Florence, Arizona, under a 10-year energy storage agreement.
The pilot will utilise ESS’ Energy Base technology, capable of powering 1,125 average homes for 10 hours. It forms part of SRP’s strategy to assess non-lithium-ion LDES technologies and support its reliability and sustainability goals. The project follows a 2024 request for proposals issued by SRP to identify promising LDES solutions.
“As the Valley continues to see rapid commercial and residential growth, projects like this allow us to better understand the efficacy and impact of different kinds of LDES technologies as they mature,” said Chico Hunter, SRP manager of innovation and development. “This is another opportunity for SRP to evaluate the real-world performance of emergent technologies on our grid and in the Arizona climate.”
ESS’ iron flow batteries use iron, salt and water, offering 10-hour discharge and ‘fast charging’ in under 10 hours. With no risk of thermal runaway and a 25-year life expectancy, the system is designed for safe, sustainable operation across varied climates.
“This project is a significant validation in both the LDES industry and ESS as a technology provider. We are thrilled to be working with SRP to deliver more hours of clean energy to its customers”, said Kelly Goodman, interim CEO of ESS. The project is expected to be operational by December 2027.
