Energy Dome and Salt River Project on June 15 announced an agreement to add a 19 megawatt, 10-hour carbon dioxide-based battery system to the grid.
The project is planned to be co-located on the site of SRP’s Coronado Generating Station in St. Johns, Arizona, and it will be developed under a 20-year tolling agreement, with Energy Dome owning and operating the facility and SRP dispatching its output.
The project is also part of Google and SRP’s collaboration to accelerate deployment of non-lithium-ion long-duration energy storage (LDES) technologies that support reliability, affordability and sustainability, SRP said.
The project was selected through a Request for Proposals for LDES pilots issued by SRP in 2024. Google will fund a portion of the project through a cost-sharing agreement with SRP.
The system will utilize Energy Dome’s CO2 Battery and proprietary thermomechanical long-duration energy storage process.
The technology works by using power from the grid to compress and store CO2, then, when power is needed, expanding the CO2 through a turbine to generate energy to send back to the grid.
"As energy demand continues to grow, SRP is evaluating new energy storage technologies that could support SRP’s effort to diversify its battery energy storage portfolio as we work to meet the Valley’s growing energy needs with affordable, reliable and sustainable power,” said Chico Hunter, SRP Manager of Innovation and Development. "This project will enable SRP to test the real-world performance of Energy Dome's technology in the Arizona climate."
SRP is working to at least double the number of generating resources on its power system by 2035 to meet increasing energy demand in the Phoenix metropolitan area. Energy storage is an important part of that effort, it noted.
The energy storage project is expected to come online in 2029. SRP and Energy Dome will work with the Electric Power Research Institute to monitor performance data from the project.
The American Public Power Association’s Public Power Energy Tracker is a resource for association members that summarizes public power energy storage projects that are currently online. The tracker is available here.
