Energy Developer GridStor Acquires Major BESS Project in Arizona

An Oregon-headquartered developer and operator of utility-scale battery energy storage systems said it has acquired a major project in Arizona that will serve customers of Arizona Public Service (APS).

GridStor on September 18 announced the acquisition of the 100-MW/400-MWh White Tank battery storage project from Strata Clean Energy, a solar power and energy storage developer based in Durham, North Carolina. Strata, also an independent power producer, has more than 300 projects in its portfolio, including more than 3 GW of its own construction. The company, a group that performs engineering, procurement, construction, along with operations and maintenance, also has more than 7 GW of solar and 21 GWh of storage in development.

GridStor on Thursday noted that the acquisition, and plans to build more standalone battery storage in Arizona, come as the state experiences rapid demand growth. APS and other utilities in the state set all-time records for peak power demand in August of this year.

The White Tank project also has a battery supply agreement and long-term service agreement with e-STORAGE, a Tier 1 global provider of energy storage solutions. That company, part of Canadian Solar, is providing about 120 of its SolBank 3.0 battery enclosures for the project, according to an announcement earlier this year.

20-Year Tolling Agreement

The White Tank project will be operated via a 20-year tolling agreement with APS, which is Arizona’s largest electric utility and which serves about 1.4 million homes and businesses. The project is sited in Maricopa County. White Tank is expected to enter commercial operation in the first half of 2027. Strata will continue to serve in a consulting role for the project during construction.

“Through this acquisition, GridStor is proud to extend our commitment to supporting Arizona utilities to meet the fast-growing power needs of their residents and businesses,” said Chris Taylor, CEO of GridStor and a former energy executive with Google. “Battery storage remains a highly scalable, cost-effective and near-term solution to powering rapidly growing energy capacity needs across the Southwest. We look forward to serving as a trusted partner to APS to meet the needs of Arizona’s residents and businesses.”

The White Tank battery storage project under its tolling agreement will allow APS to charge and discharge electricity as needed, helping to ensure customers have access to power when they need it and supporting the region’s expanding population and new industrial facilities.

“Strata is proud to play a foundational role in advancing Arizona’s clean energy infrastructure,” said Markus Wilhelm, CEO of Strata Clean Energy. “The White Tank project reflects our commitment to delivering grid-scale solutions that support utility partners like APS in meeting rising demand with reliability and resilience.”

The successful close of the project marks GridStor’s fourth acquisition within the past year, and its second in Arizona. GridStor, backed by Goldman Sachs Asset Management, manages a project pipeline of more than 5 GW of battery storage projects in later-stage development or under construction across the western and central U.S.

—Darrell Proctor is a senior editor for POWER.