SRP Brings 250-MW Battery Storage Project Online in Arizona

Salt River Project (SRP) and Aypa Power have placed the Pediment Battery Energy Storage System (BESS) into service in Mesa, Arizona, adding 250 MW/1,000 MWh of energy storage capacity to support the utility's growing electricity demand.

Located in Mesa's Elliot Road Technology Corridor, the lithium-ion battery project can provide enough electricity to serve approximately 56,250 homes for up to four hours during periods of peak demand.

The project comes online as the Phoenix metropolitan area continues to experience rapid population growth and increasing commercial and industrial electricity demand. SRP has indicated it expects to more than double its system capacity over the next decade, with battery energy storage expected to play a larger role in maintaining reliability and meeting peak load requirements.

"The addition of new battery energy storage resources provides SRP with flexibility and capacity that helps us reliably serve our customers," said Bobby Olsen, SRP associate general manager and chief power system executive, in a statement announcing the project.

Pediment is the first of two battery storage projects Aypa Power has under contract with SRP. A second project, rated at 250 MW/2,000 MWh, is currently under development and is scheduled to enter service in December 2028.

Combined, the two projects will provide 500 MW and 3,000 MWh of energy storage capacity to SRP's system. According to Aypa Power, the Pediment facility is located within one of the country's largest data center development corridors, positioning the project to help support rising demand from large-load customers while providing grid support services.

The battery installation was acquired by Aypa Power from Eolian in 2024 and created more than 200 construction jobs. The developers estimate the project will generate more than $16 million in direct economic impact over its first 20 years of operation, including approximately $14 million in property tax revenue for Maricopa County.

Battery storage has become an increasingly important resource for utilities across the Southwest as they seek to integrate additional renewable generation, manage peak demand and improve grid flexibility. SRP reports it currently has more than 1,570 MW of battery storage resources connected to its system, alongside more than 1,560 MW of solar generation and other carbon-free resources.

The utility is continuing to expand its energy storage portfolio as part of its long-term resource strategy and carbon-reduction goals, which include reducing carbon intensity 82% from 2005 levels by 2035 and achieving net-zero carbon emissions by 2050.