Coronado CO2 Battery

Executive Overview

Energy Dome and Salt River Project (SRP) announced on 15 June 2026 an agreement to add a 19 MW, 10-hour (190 MWh) CO2 Battery system to the grid, co-located at SRP's Coronado Generating Station (CGS) in St. Johns, Arizona. The project was selected through SRP's 2024 RFP for long-duration energy storage (LDES) pilots and is expected online in 2029.

How It Works & Differentiation

The system uses Energy Dome's proprietary thermomechanical process, compressing and storing CO2 then expanding it through a turbine to regenerate power. SRP and Energy Dome will work with EPRI to monitor performance, giving the project an independent technical validation partner alongside the developer and offtaker.

Commercialization & Traction

The project is developed under a 20-year tolling agreement, with Energy Dome owning and operating the facility and SRP dispatching its output. It forms part of Google and SRP's collaboration to accelerate non-lithium-ion LDES; Google funds a portion of the project through a cost-sharing agreement with SRP.

Scalability & Strategic Context

Coronado is one node in the broader Google–Energy Dome partnership to deploy CO2 Battery technology across multiple markets, and precedes the subsequent Rhode CO2 Battery project in Ireland, which follows a similar Google-backed structure. The co-location at an existing generating station site follows the same brownfield redevelopment logic Energy Dome has used at other CO2 Battery sites, reducing interconnection and permitting risk.