EDP Renewables North America and Arizona utility Salt River Project have commissioned the Flatland Energy Storage facility in Coolidge, Arizona, bringing online a 200 MW/800 MWh battery energy storage system designed to strengthen grid reliability and support rising electricity demand across the state.

The project, located in Pinal County, is the largest battery energy storage system in the EDP Group’s global portfolio. According to the companies, the facility can supply enough electricity to power the equivalent of approximately 44,500 Arizona homes during periods of peak demand.

The commissioning highlights the accelerating deployment of large-scale battery storage across the U.S. Southwest, where rapid population growth, expanding data center development, and increasing renewable energy penetration are driving demand for flexible grid resources. Utility-scale batteries are increasingly being used to shift solar generation into evening hours, improve grid resilience, and reduce strain on transmission networks.

Flatland Energy Storage is expected to generate more than $20 million in lifetime economic benefits for the region, including $19.2 million in tax revenues supporting local infrastructure, schools, roads, and emergency services. The project also contributed more than $1.3 million in regional spending and supported approximately 142 construction jobs.

SRP said the facility forms part of its broader strategy to maintain a diverse power portfolio while meeting customer demand with reliable and affordable electricity. The utility has been steadily expanding its battery storage fleet as Arizona experiences sustained growth in electricity consumption.

The project further expands EDP Renewables’ presence in Arizona, where the company now operates roughly 600 MW of solar and storage capacity. Its existing assets in the state include the 158 MW Sun Streams Solar project, the 200 MW Brittlebush Solar facility, and the Table Top Solar & Energy Storage complex, which combines 96 MW of solar generation with 96 MW of battery storage.

The completion of Flatland comes amid a broader industry trend toward longer-duration battery systems. With four hours of storage capacity, the project is designed to deliver power during critical evening demand peaks and help balance increasing volumes of renewable generation on the grid.

EDP Renewables North America has developed more than 12.9 GW of renewable energy projects across North America and currently operates more than 12.3 GW of utility-scale wind, solar, and storage assets.

By Charles Kennedy for Oilprice.com

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