Fluence's Arizona Battery Farm Sets World Record: 2 GWh Delivered in 4 Hours

Fluence, the Siemens-Mitsubishi Heavy Industries joint venture, has broken its own world record for grid-scale battery dispatch. The Hot Springs Grid Storage facility in Maricopa County, Arizona — a 2 GWh lithium-iron phosphate installation commissioned in February — delivered a continuous 500 MW for four consecutive hours during a peak demand event on March 28th, serving as the primary dispatchable resource for the Salt River Project grid.

The four-hour discharge cycle is significant because it covers the "evening ramp" — the window between 5 and 9 PM when solar generation collapses and demand peaks. Previous large-scale battery installations were typically limited to one to two hours of storage, insufficient to bridge the full evening gap without fossil backup.

Fluence CEO Marcus Kohn accepted the record with characteristic restraint: "Two gigawatt-hours is a lot of electrons. What matters more is that it stayed online, stayed stable, and made the local utility's life easier during the hardest hour of the day."

The Hot Springs project was partially financed through Arizona's Grid Resilience Tax Credit, administered by the Western Area Power Administration. The company is already constructing a 5 GWh facility in Nevada due to come online in Q2 2028, which will be paired with the Edwards & Sanborn solar-plus-storage project to create one of the largest hybrid renewable-storage complexes in North America.