APS to Convert Retired Cholla Coal Plant to 380 MW Gas
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- Arizona Public Service announced it will convert two retired coal units at the Cholla Power Plant in Navajo County, Arizona, to natural gas generation, adding up to 380 MW of capacity to the grid.
- Cholla's coal units were retired over the past decade due to federal environmental mandates, with the final retirement in March 2025; at peak the plant supplied approximately 1 GW of power.
- APS expects its electric sales to grow 4% to 6% annually through 2027, driven by large new loads, and the Arizona Corporation Commission said the utility estimates peak demand for large customers will reach about 13.1 GW this year.
- Construction on the gas conversion is expected to begin in 2028, with a target in-service date of 2029, after the project clears formal permitting and planning processes that include public comment through open houses, phone, and email.
- Johnny Penrod, APS vice president of generation, said Cholla has been "foundational to Arizona's energy grid" for the communities of Joseph City, Holbrook, and northeastern Arizona, and that repurposing the plant "allows us to build on that legacy."
- APS said the new gas facility will complement its diverse energy mix, which already includes nuclear from the Palo Verde Generating Station, natural gas, coal, solar, wind, and battery energy storage.
Why it matters: APS is repowering a retired coal site rather than building greenfield generation, adding 380 MW of dispatchable gas to a system facing 4-6% annual demand growth through 2027. With construction not starting until 2028 and in-service in 2029, Arizona's grid will run increasingly tight in the interim — a timeline that underscores how slowly new capacity comes online.
