Utilities Capacity Systems Provider Energy Dome and (SRP), a not-for-profit public power utility serving the greater Phoenix metropolitan area, have inked an agreement to add a 19- megawatt (MW), 10-hour carbon dioxide-based (CO2) battery system to the grid.

The project will be co-located on the site of SRP’s Coronado Generating Station (CGS) in St. Johns, Ariz. Energy Dome will own and operate the facility, which will be developed under a 20-year tolling agreement, and SRP will dispatch its output.

The project is also part of a collaboration between Google and SRP to accelerate deployment of non-lithium-ion long-duration energy storage (LDES) technologies, which support reliability, affordability, and sustainability. It will store enough energy to power approximately 4,275 homes for 10 hours, officials said. Google will fund a portion of the project through a cost-sharing agreement with SRP.

“Arizona’s sustained growth makes it one of the most compelling energy markets in the country,’’ said Claudio Spadacini, founder and CEO of Energy Dome. “At a time when AI growth and rising demand are reshaping America’s energy landscape, the CO2 battery offers the scalable, dispatchable capacity needed to strengthen U.S. energy dominance.”

Spandacini added that SRP’s new CO2 battery system will be built quickly and manufactured domestically, “helping SRP increase energy security by harnessing locally produced Arizona power.”

The system uses Energy Dome’s CO2 battery and proprietary thermomechanical long-duration energy storage technology. It draws electricity from the grid to compress and store CO2, then, when needed, releases it through a turbine to generate power.

The project is a win-win for all. Energy Dome’s investment in U.S. supply chain development has been accelerated by the project, the company said, and supports its broader mission to bring affordable, reliable energy to benefit U.S. energy customers as well as create jobs.

“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.”

Google benefits because of its commitment “to catalyzing next-generation energy technologies to bolster grid resilience and introduce vital new capacity to the system,” said Lucia Tian, director of Advanced Energy Technologies. “This second project and important milestone in our collaboration with SRP builds on our long-term partnership with Energy Dome, and will help deliver dependable, cost-effective, and sustainable energy for Arizona’s ratepayers.”

The energy storage project is expected to come online in 2029. EPRI, an independent, non-profit energy R&D institute, will monitor performance data from the project.

SRP said its goal is 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.