A coal combustion process is described using cleaned coal and processed biomass to reduce adverse by-products in a coal combusting apparatus including the reduction of carbon dioxide by at least 50 volume %. The coal feedstock comprises an aggregate blend of cleaned coal and processed biomass. The biomass feedstock comprises processed biomass pellets. The total energy density is predetermined and can be similar to the coal component or higher than the coal component. The intracellular salt in the processed biomass is at least 60 wt % less for the processed organic-carbon-containing feedstock used to make the processed biomass pellets than that of the starting un-processed processed organic-carbon-containing feedstock. The cleaned coal has a sulfur content that is 50 wt % less than that of un-cleaned coal before it passed through the coal-cleaning sub-system.