GridStor secures $220M financing for 100 MW / 400 MWh White Tank BESS in Arizona

Type: Financing · Technology: Storage · Country: United States · Capacity: 400 MWh · Value: $220M · Announced: 2026-09-23

GridStor, backed by Goldman Sachs, secured $220 million in financing for its White Tank Battery Energy Storage System in Arizona, structured as a tax equity bridge, construction, and term debt agreement across three banking partners. The 100 MW / 400 MWh facility will operate under a 20-year tolling agreement with Arizona Public Service (APS) and is located in Maricopa County, where most of Phoenix is situated. The project is expected to be placed in service in the first half of 2027, reinforcing APS system reliability amid record-breaking power demand driven by population growth, manufacturing, and data center expansion. This financing marks GridStor's fourth move within the past twelve months as it builds out or acquires more than 3 GW of BESS capacity.

Analysis

GridStor secured $220 million of financing for a 100 MW/400 MWh White Tank battery energy storage system in Maricopa County, Arizona. GridStor, a Portland‑based developer backed by Goldman Sachs Asset Management, has built or acquired more than 3 GW of BESS capacity in its first four years. Arizona Public Service will purchase the output under a 20‑year tolling agreement. The financing package includes a tax‑equity bridge, construction loan and term debt provided by KeyBank N.A., Zions Capital Markets and ING Capital LLC, and the facility is slated for commercial operation in the first half of 2027.

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