GridStor Secures $220 Million for Arizona Battery Storage

GridStor has secured $220 million in financing for its 100 MW/400 MWh White Tank battery storage facility in Maricopa County, Arizona. The project will operate under a 20-year tolling agreement with Arizona Public Service (APS), the state's largest electric utility. Financial partners ING Capital, KeyBank, and Zions Capital Markets provided the tax equity bridge, construction, and term debt. This marks GridStor’s fourth major financing milestone in the past year.

The 400 MWh facility is designed to store electricity and deliver it during peak demand or grid constraints. It will add 100 MW of power capacity and four hours of energy storage to the Arizona market. GridStor, a US-based developer backed by Goldman Sachs Asset Management, targets data centers and large industrial facilities as key customer groups. The company has a pipeline exceeding 3 GW of battery storage projects in later-stage development or construction across the western and central United States.

Demand and reliability context

Arizona utilities are grappling with record power demand. APS, which serves approximately 1.4 million homes and businesses, recorded a new peak electricity demand on August 2 that was 5% higher than the previous record. The White Tank facility will add flexible capacity as Arizona’s population expands and new industrial facilities increase electricity requirements. Chris Taylor, CEO of GridStor, stated the company develops and operates utility-scale standalone battery projects to serve this rapid load growth.

Strata acquisition and pipeline

GridStor acquired the White Tank project from Strata Clean Energy in September 2025. Strata was originally awarded the project through APS's 2023 all-source request for proposals. GridStor expects to continue acquiring advanced-stage storage projects that serve utilities, data centers, and other large industrial customers. The company's recent activity includes the May 2026 acquisition of the 199 MW/796 MWh Birdseye battery storage project in Colorado.

Recent storage financing surge

The deal reflects a surge in funding for energy storage infrastructure. According to a recent industry report, publicly announced energy storage project funding reached a record $42.5 billion across 104 deals in the first half of 2026. This represents a 217% increase year-over-year. GridStor's own recent financings include a $120 million package in March 2026 for the 150 MW/300 MWh Gunnar Reliability Project in Texas.

Filipe Barreto, a Director at ING, said, "We are pleased to complete the financing of the White Tank battery energy storage project with GridStor." Greg Berman, Managing Director for Utilities, Power & Renewable Energy at KeyBanc Capital Markets, noted the financing reflects growing lender participation as battery storage becomes a larger component of U.S. Power infrastructure. The White Tank project is expected to enter service in the first half of 2027.