Aypa Power and utility Salt River Project have placed the Pediment battery energy storage system into operation, bringing a 250MW/1,000MWh facility online in Mesa, Arizona. The company announced the milestone on 16 June, identifying the project as located within the Elliot Road Technology Corridor in Mesa and noting the project will form part of SRP’s growing energy storage portfolio.
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Aerial view of Aypa Power’s newly commissioned Pediment battery energy storage site in Mesa, Arizona, showing rows of containerised battery units and the access road. The 250MW/1,000MWh facility was brought online in June under a Salt River Project contract.
The Pediment project, which delivers 250 megawatts of power and 1,000 megawatt-hours of storage, was acquired by Aypa Power from independent power producer Eolian in 2024. The Mesa installation is the first of two projects Aypa is developing under contract for SRP; the company is also developing a second lithium-ion battery system that will have the same power rating but a larger energy capacity — 250MW paired with 2,000MWh — which is scheduled to begin commercial operations in December 2028.
Financing for Pediment was completed in late 2024. A US$398 million financing package closed in December 2024 to support the 250MW/1,000MWh installation, with French bank Société Générale leading the financing group and ING Capital and Bank of America serving as coordinating lead arrangers for the transaction. That financing supported construction and commissioning activities that culminated in the June in-service date.
Aypa has also put broader capital arrangements in place to support its U.S. pipeline. Earlier this year the company secured a US$1.5 billion construction warehouse revolving credit facility, which included an additional US$500 million accordion feature. The company described that warehouse facility as a first-of-its-kind transaction and as the largest warehouse financing arranged for a storage-focused independent power producer, and said it would serve as the principal funding source for projects expected to reach operation through 2028. Shortly after announcing the warehouse facility, Aypa completed a US$500 million upsizing of the original US$1.5 billion facility.
Construction of the Pediment site generated local employment and is expected to produce a measurable fiscal benefit for the county. The development created more than 200 construction jobs during its build phase. Projections for the project’s first 20 years of operation anticipate more than US$16 million in direct economic impact, including approximately US$14 million in property tax revenue to Maricopa County.
The Pediment commissioning comes amid a busy month for Salt River Project’s energy storage activity. On 9 June, SRP and EDP Renewables North America completed the Flatland Energy Storage project — a 200MW/800MWh battery system. On 15 June, SRP announced a separate agreement with carbon dioxide-based long-duration energy storage developer Energy Dome for a 19MW/190MWh energy storage system to be sited in St. Johns, Arizona. That smaller project was selected through an SRP request for proposals issued in 2024 for long-duration energy storage pilots and is part of a wider collaboration between the utility and technology company Google to accelerate deployment of non-lithium-ion long-duration storage technologies.
With Pediment now operational and other projects advancing, the region’s portfolio of large-scale batteries and pilot long-duration systems continues to expand. The combination of completed projects and those under development is being supported by project-level financing and larger-scale warehouse facilities intended to cover construction and near-term development for a series of storage assets slated to enter service through the remainder of the decade.
Per SRP’s announcement, Pediment can power up to 56,250 Valley homes for four hours and supports efforts to double the utility’s energy storage capacity within a decade amid rapid growth in the Phoenix area. (SRP press release)