Tucson Electric Power plans to begin construction before the end of the year on an estimated $294-million battery system for solar energy that, at peak efficiency, would store 800 MW hours. The system, sited near its Vail substation in Tucson, Ariz., would have the capacity to power approximately 42,000 homes for four hours, according to TEP.
If completed as scheduled in the summer of 2025, the Roadrunner Reserve Battery Energy Storage System, which will use lithium-iron phosphate battery cells not lithium ion cells, would be the largest battery facility of its kind on the utility’s grid and among the largest in Arizona. TEP, which will own and operate the Roadrunner Reserve BESS, currently has 51 MW of battery storage capacity.