GridStor, a U.S.-based developer and operator of utility-scale battery energy storage systems, has completed the acquisition of the White Tank project in Arizona. The project, with a capacity of 100 MW/400 MWh, was sold by Strata Clean Energy, which will continue in a consultative role until commissioning expected in the first half of 2027.
20-year tolling contract with Arizona Public Service
The project will operate under a twenty-year tolling agreement with Arizona Public Service (APS), the state’s largest electric utility, serving approximately 1.4 million customers. Located in Maricopa County, the system will allow APS to store and dispatch electricity as needed, particularly during peak demand periods.
APS registered record demand this summer, particularly in August, amid rapid population growth and industrial expansion. The integration of battery storage is intended to enhance grid reliability in response to increasing load.
Strategic expansion in the Southwest market
GridStor stated this transaction marks its fourth acquisition in twelve months and its second in Arizona. Backed by Goldman Sachs Asset Management, the company manages a portfolio of over 5 GW of battery storage projects in late-stage development or under construction across the western and central United States.
The White Tank project is part of GridStor’s strategy to deliver flexible energy solutions to utilities, data centres, and industrial facilities. Financial terms of the transaction have not been disclosed.
Continued consultation by Strata until commissioning
Strata Clean Energy, the project’s original developer, will retain a consultative role until commercial operations begin. The company stated that this deal reflects its commitment to supporting partners with large-scale grid solutions.
The long-term agreement between GridStor and APS highlights the growing deployment of standalone energy storage projects in regions facing sustained demand growth.
