Energy Dome and Salt River Project (SRP) have agreed to add a 19 MW, 10-hour CO2 battery to the grid in Arizona, with the project planned for the Coronado Generating Station site in St. Johns. The facility will be owned and operated by Energy Dome under a 20-year tolling agreement, while SRP will dispatch its output.
The project is part of a broader collaboration involving Google and SRP to speed up deployment of non-lithium long-duration storage technologies that can improve reliability and affordability. Google will help fund part of the project through a cost-sharing arrangement, and the system was selected through SRP’s 2024 request for proposals for long-duration storage pilots.
Energy Dome says its CO2 battery stores energy by compressing carbon dioxide when power is available and later expanding it through a turbine to generate electricity when needed. SRP says the project will let it test the technology in Arizona conditions as it works to expand and diversify its generation portfolio by 2035 to meet rising demand in the Phoenix metropolitan area.
The system is expected to store energy for up to 10 hours and is scheduled to come online in 2029.
SRP and Energy Dome will work with the Electric Power Research Institute (EPRI) to monitor performance data once the project is operating.
