“Our merchant power plants have delivered volatile returns in the challenging competitive market in the Midwest," Duke CEO, president and vice chairman Lynn Good said.

"This earnings profile is not a strategic fit for Duke Energy and we have begun a process to exit the business.

“We will be working closely with employees and community leaders during this transition to ensure a smooth process for all stakeholders.”

Of the 13 plants up for sale, the coal-fired ones include the Beckjord, Conesville, Killen, Miami Fort, Stuart, Zimmer power stations in Ohio.

Most of the other stations are gas-fuelled while one is oil-fired.

In separate news, Duke is increasingly under the risk of facing criminal charges over arsenic-heavy discharges into the Dan River in North Carolina, due to pipe failures at the large coal ash dump of its Eden power plant.

Reports suggest the bottom of the Dan River has been covered with toxic ash up to 70 miles downstream.