US-based electricity generator, Duke Energy will shut down two of its coal-fired power plants, Riverbend west of Charlotte and Buck in Rowan County in April, two years ahead of schedule.

Riverbend Steam Station is located near Mountain Island Lake on the Gaston-Mecklenburg County line, while the Buck plant in Rowan County, North Carolina, US.

The two stations were slated for retirement in April 2015, but Duke Energy elected to retire Buck Units 5 and 6, and Riverbend Units 4 through 7 on 1 April 2013.

The company is planning to close many smaller coal-fired power plants as converting them to meet federal pollution regulations is expected to cost millions of dollars.

Duke Energy Regulated Utilities executive VP and COO Keith Trent said the investments made in the last decade allow the firm to retire older plants and continue transitioning to cleaner sources of electricity.

"These stations played pivotal roles in the 1920s and 1930s in helping to electrify the industries and homes of the Carolinas, and we honor all those employees who contributed their time and talents over the years to ensure safe, reliable operations," Trent added.

Buck Steam Station had entered commercial operation in 1926, while Riverbend Steam Station in Gaston County had began operating in 1929.