Salt River Project (SRP) said on July 21 it will ask its board in September to approve development of the Marigold Energy Center, a mixed-resource generation complex about 45 miles south of Phoenix designed to keep pace with fast-growing electricity demand in Maricopa and Pinal counties.
What Marigold contains
The project pairs 400 MW of lithium-ion battery storage with 600 MW of solar generation and up to 675 MW of natural-gas capacity, plus a new substation and four miles of 230-kV transmission lines. The gas plant is intended as a firm-capacity backstop for the solar and battery portfolio during Arizona's evening peaks and multi-day heat events, when even utility-scale storage can be stretched.
Why the utility is moving now
Arizona is one of the epicenters of the U.S. data-center build-out, and SRP has been steadily expanding storage on its grid to firm renewables. The public power utility has previously tapped Google-backed Energy Dome for a 19 MW / 10-hour CO2 battery pilot co-located at its Coronado station and picked ESS Tech for a 5 MW / 50 MWh iron-flow deployment last October. Marigold is an order of magnitude larger than either.
Community process, September vote
SRP said it will host an in-person open house in Stanfield on July 28 and a virtual open house on July 29, following earlier information sessions the utility ran in December and March. The project also has a potential offtake tie-in with Electrical District No. 3, a regional public power utility evaluating a partnership to purchase a share of Marigold's output.
Marigold slots into a broader Arizona storage pipeline that includes deals like Brookfield's $7 billion acquisition of Aypa Power from Blackstone and continued interconnection queue growth in the region. If approved by SRP's board in September, construction planning would begin ahead of a target in-service window later this decade.
Reporting based on coverage from Utility Dive, KJZZ and Salt River Project.