Tucson Electric Power (TEP) is planning to build a second large-scale battery system in southeast Tucson to store solar and other energy sources for use later in the day, meeting customers’ peak energy demands. The 200 MW Roadrunner Reserve II system will have the capacity to store 800 MW hours of energy, which is sufficient to power around 42,000 homes for four hours when operating at full capacity.
Furthermore, the system is expected to be operational by early 2026, one year after the similarly sized Roadrunner Reserve energy storage system begins operations at the same location. TEP plans to charge both grid-connected batteries during the morning and early afternoon hours, taking advantage of peak solar energy production. The stored energy will then be dispatched later in the day when energy consumption is typically at its highest.
The projects will be constructed adjacent to a TEP substation on the southeast side. While construction of Roadrunner Reserve is currently underway, work on Roadrunner Reserve II is slated to commence later this year. TEP will both own and operate the Roadrunner Reserve systems, which will be designed and constructed by Scottsdale-based DEPCOM Power, Inc. These systems will incorporate lithium iron phosphate battery units, a newer technology known for its longer lifespan and safer operation compared to other battery types.
Earlier this year, TEP announced plans for Winchester Solar, an 80-MW solar array combined with an 80-MW battery system, set to go online in 2027. Torch Clean Energy will build, own, and operate these systems for TEP at a site approximately 18 miles west of Willcox. The facility will generate enough energy annually to meet the needs of about 11,000 homes.
