Arizona public power utility Salt River Project and ESS, a leading manufacturer of iron flow long duration energy storage systems, on Oct. 9 announced an agreement to add Project New Horizon, a five megawatt, 50 megawatt-hour battery system, to the grid.
The pilot project will be installed at SRP’s Copper Crossing Energy and Research Center in Florence, Arizona. ESS will sell capacity to SRP under a ten-year energy storage agreement.
The ESS Iron Flow Battery (IFB) project will be part of SRP’s effort to evaluate emerging, non-lithium ion LDES technologies and support SRP’s reliability and sustainability goals.
The system, which will utilize ESS’ Energy Base technology, will store enough energy to power 1,125 average-size homes for 10 hours. This project is the result of an RFP issued by SRP in 2024 for LDES pilots.
SRP is working to at least double the number of generating resources on its power system in the next 10 years to meet increasing energy demand in the Phoenix metropolitan area.
SRP has nearly 1,300 MW of energy storage currently supporting its grid, which includes 1,100 MW of battery storage -- spanning eight facilities -- and 200 MW of pumped hydro storage.
“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’ technology uses a combination consisting mainly of iron, salt and water to store and discharge energy. The Energy Base will be designed to deliver 10 hours of discharge with “fast charging” of 10 hours or less.
"ESS’s products are safe and sustainable with no risk of thermal runaway, operate in a wide range of temperature environments and are Made in America with over 90% domestic content. They further offer a competitive levelized storage cost with a 25-year life expectancy," a news release said.
“SRP once again demonstrates its leadership with its commitment to non-lithium, long duration energy storage,” said Kelly Goodman, Interim Chief Executive Officer of ESS. “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.”
The Copper Crossing Energy and Research Center currently includes a 99-MW flexible natural gas facility. A 55-MW utility scale solar project is currently under construction at the site. The site will also host CMBlu Energy's “Desert Blume”, a 5 MW, 10-hour LDES project.
ESS will be partnering with industry leaders to deliver the project by December of 2027.
Design is already underway, and manufacturing will begin in 2026. SRP and ESS will work with the Electric Power Research Institute to monitor performance data of the project.
