Duke Energy will soon offer carbon offsets.

The North Carolina power company will allow customers to voluntarily pay more for their electricity, with the additional money used to promote renewable energy sources such as wind farms or other activities, such as planting trees.

Georgia-based green marketing firm Sterling Planet could be a partner.

The program is part of the company's attempt to recast itself as environmentally friendly, especially after a bruising fight with environmentalists over a planned coal power plant in the foothills of the Blue Ridge mountains.

Duke's proposal would be an expansion of the existing N.C. GreenPower program, which allows customers to buy renewable energy. (Char-O)