Jun. 22--CHARLOTTE -- Duke Energy said that about 70 alternative energy providers submitted proposals to sell power to the Charlotte-based utility.

Duke is accepting proposals as part of the company's plan to offset 1,700 megawatts of conventional electricity, the equivalent of several power plants. It will accept bids until July 27 and plans to negotiate contracts this year for approval by the sta e Utilities Commission. About 20 percent of the proposals are for solar energy, 20 percent for biomass, 15 percent use wind and 10 percent generate power from landfill gas.