RALEIGH, N.C., Sept. 28, 2012 /PRNewswire/ -- As announced in July, Progress Energy Carolinas, a subsidiary of Duke Energy (NYSE: DUK), on Oct. 1 will officially retire two coal-fired power plants, including the utility's first coal-fueled facility built in 1923. The utility will close the Cape Fear power plant, near Moncure, N.C., and the H.B. Robinson Unit 1 power plant, near Hartsville, S.C., as part of its ongoing fleet-modernization program. Closing older, less-efficient coal plants and replacing them with state-of-the-art natural gas-fueled power plants helps ensure continued grid reliability, reduces air emissions and water usage, and offers new economic development opportunities. "For decades, these two power plants have helped us provide the region with safe, reliable and affordable electricity," said Jeff Lyash, Duke Energy's executive vice president of energy supply. "This legacy reflects the exceptional dedication of hundreds of current and former employees." The 316-megawatt (MW) Cape Fear plant, located in Chatham County on the Cape Fear River, has been a vital part of meeting the needs of Progress Energy Carolinas' customers since 1923. A total of six coal-fired units were located at the site, the last two completed in 1956 and 1958. At that time, the Cape Fear plant was the largest power plant on the utility's system. Two of Cape Fear's six coal-fired units were retired in 1977 and two in 2011. The last two units will close Oct. 1. Along with the coal units, one of four oil-fueled combustion-turbine (CT) units on the site is also being retired Oct. 1. The remaining three CT units will remain open, though their operation will generally be limited to periods of high electricity demand. Meanwhile, the 177-MW H.B. Robinson Unit 1 power plant near Hartsville, S.C., in Darlington County, is Progress Energy Carolinas' only coal-fired power plant in South Carolina. It has been a key part of meeting the needs of the utility's customers since it began commercial operation in 1960. The Robinson coal unit retirement does not affect the 724-MW Robinson nuclear plant on the same site, which is licensed for operation through July 2030. Nor does it affect Progress Energy Carolinas' other major power plant in South Carolina—the 790-MW Darlington County Plant, which is located in the same county as the Robinson plant and includes 13 combustion-turbine units fueled by natural gas and oil. Progress Energy Carolinas has been working to minimize employee impacts resulting from its power plant retirements. All employees at Cape Fear and Robinson Unit 1 electing to stay with the company have been able to do so through the company's redeployment efforts.