The plant is jointly owned by Arizona Public Service (APS) and PacifiCorp.

[1] In 2010, the Environmental Protection Agency (EPA) notified Cholla that pollution controls were needed for Units 2 through 4.

[2] Unit 2 was retired in 2016 as the cost to add pollution controls outweighed the benefits.

APS announced that while a conversion to natural gas had been an option, it was no longer being considered.

A proposal was put forth to convert a unit to burn biomass, however regulators at the Arizona Corporation Commission voted down that plan in 2019.