Aypa Power and SRP Bring the 250 MW/1,000 MWh Pediment Battery Online in Mesa's Data Center Corridor

Overview

Aypa Power has brought its 250 MW/1,000 MWh Pediment energy storage project online in Mesa, Arizona, the company and utility Salt River Project (SRP) announced on June 16, according to Energy-Storage.News. The lithium-ion battery system sits in the Elliot Road Technology Corridor, one of the metropolitan Phoenix area’s clusters of data center development, and is the first of two storage projects Aypa has under contract with SRP.

What We Know

Pediment is rated at 250 megawatts of power and 1,000 megawatt-hours of energy, a four-hour-duration system. According to the SRP statement, the project has “enough capacity to power up to 56,250 Valley homes for four hours.” Storage of that duration is typically used to shift solar generation into the evening peak and to provide capacity during periods of high demand.

Aypa Power, described in its own announcement as “a Blackstone portfolio company and leading developer and operator of utility-scale energy storage and hybrid renewable energy projects,” acquired the Pediment project from independent power producer Eolian in 2024, Energy-Storage.News reported. The developer closed a $398 million financing package for the project in December 2024, a deal led by Société Générale with ING Capital and Bank of America among the coordinating arrangers, Aypa said in a release at the time.

Pediment is the first of two contracted projects between Aypa and SRP. A second 250 MW/2,000 MWh lithium-ion battery system is scheduled to begin operations in December 2028, per Energy-Storage.News.

Aypa said the project created over 200 construction jobs and is expected to deliver over $16 million in direct economic impact, including $14 million in property tax revenue to Maricopa County during its first 20 years of operation, according to the financing announcement.

In its statement, SRP tied the addition to grid reliability. “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’s Associate General Manager and Chief Power System Executive, in the SRP release. Aypa pointed to the surrounding data center demand. “Located in one of the nation’s leading data center corridors, our local projects are well-positioned to support growing demand from large-load customers, while strengthening overall grid reliability,” said Moe Hajabed, Chief Executive Officer at Aypa Power, in the same release.

Pediment came online during a busy stretch for the utility. SRP completed the 200 MW/800 MWh Flatland project with EDP Renewables on June 9 and announced a 19 MW/190 MWh project with Energy Dome in St. Johns on June 15, Energy-Storage.News reported.

What We Don’t Know

The public announcements do not disclose the battery cell supplier or the contract price SRP is paying for Pediment’s capacity. Performance terms such as round-trip efficiency, expected cycle life, and the dispatch arrangement between Aypa and SRP were not detailed. The sources also do not break out how much of SRP’s incremental capacity is being driven specifically by data center load versus broader population growth in the Phoenix area.

Analysis

Pediment fits a pattern visible across the U.S. Southwest, where utilities are pairing rapid load growth with four-hour lithium-ion storage to firm up solar and meet summer peaks. SRP framed the buildout in the context of its decarbonization targets, saying it is “reducing carbon intensity (from 2005 levels) by 82 percent by 2035 and achieving net zero carbon emissions by 2050,” according to the utility’s statement. With the second Aypa project due in 2028, the two facilities together would add 500 MW of power and 3,000 MWh of storage to SRP’s system, a sizeable block of flexible capacity aimed in part at the large-load customers clustering in Mesa’s technology corridor.