The amount of biomass available for cofiring is not easily estimated.  The total amount of available biomass exceeds 25% of our current coal consumption on an energy basis.  However, much of this is too dispersed to economically collect, inappropriate as a boiler fuel, or located at an economically prohibitive distance from a boiler.   Most people agree that 5% of the our current coal consumption could be displaced by biomass, and few people believe that more than 15% could be.  We take these as upper and lower limits of the cofiring potential.