Muskogee
Muskogee is an operating 1,716 MW power plant in Fort Gibson, Muskogee County, Oklahoma, comprising three approximately 572 MW steam-turbine generators. Units 4 and 5 entered service in 1977 and 1978, originally coal-fired; they were permanently converted to natural gas in 2019 to meet Regional Haze Federal Implementation Plan sulfur-dioxide requirements. Oklahoma Gas & Electric Co owns and operates the facility. The conversion of Units 4 and 5 involved replacement of coal-handling equipment, installation of natural-gas burners and air registers, gas-supply piping, boiler-control modifications, and construction of an auxiliary boiler; the conversion estimate was approximately $72 million, exclusive of AFUDC and ad valorem taxes. A 20-year natural-gas supply contract with Enable Oklahoma Intrastate Transmission LLC supported the conversion, with the gas pipeline entering service December 1, 2018. OG&E expects both converted units to operate in compliance by March 2019. Unit 6 has a planned retirement date of 2049 per OG&E's integrated resource plan, though OG&E has explored potential repowering or life extension.