Arizona’s biggest battery system starts up

By Jason Plautz | 03/18/2024 06:45 AM EDT

New renewable and storage capacity will help Google cover data center energy use.

Salt River Project's Saint Solar Energy Center in Coolidge, Arizona.

Salt River Project's Saint Solar Energy Center in Coolidge, Arizona. Salt River Project

An Arizona utility said the state’s largest battery storage system is now operating, part of a deal with Google to help offset the tech giant’s electricity demand.

The Sonoran Solar Energy Center from utility Salt River Project (SRP) pairs a 260-megawatt solar facility with a 1,000-megawatt-hour battery storage system. The facility, which the utility announced was operational last week, will power Google’s planned data center campus in Mesa, Arizona, with excess power going back to the grid to serve other SRP customers.

One megawatt can power about 225 homes in SRP’s service area, which surrounds Phoenix and parts of central Arizona. A battery’s megawatt-hour rating reflects how much the battery can discharge over a period of time.


The solar and battery system is part of an energy supply agreement between Google and SRP to support more than 430 MW of new carbon-free energy capacity linked to the Mesa data center. In addition to the Sonoran development, the agreement includes a separate solar and battery system that opened in December 2023 and a planned wind farm near Flagstaff. All three projects have been developed with NextEra Energy Resources.