Pollution from smokestacks at the Cholla Coal-Fired Power Plant. The 995-megawatt Cholla Power Plant is located in northeastern Arizona near Holbrook. Arizona Public Service (APS) operates the plant and owns Units 1, 2 and 3, which are capable of producing 615 megawatts of electricity. PacifiCorp (PAC) owns the 380-megawatt Unit 4, the largest unit at the plant. Cholla is fueled by coal from the McKinley Mine in New Mexico.