Co-firing of coal and biomass. Case of industrial boilers

Co-combustion is part of the effort to modernize existing coal-fired power plants. Improving the efficiency of a coal-fired power plant by 10 points is equivalent to reducing its CO ₂ emissions by 20%. The stakes are therefore high, and it is estimated that rehabilitating all existing power plants worldwide, using the best available technologies, would reduce global CO ₂ emissions by 1.5 to 2 Gt per year.

This dossier deals with the application of coal and biomass co-firing on existing large pulverized coal-fired power plants, typically with a capacity in excess of around 20 MW. Introducing or increasing the proportion of biomass in the fuel of these power plants reduces their CO ₂ emissions, and lowers their contribution to the greenhouse effect. Nevertheless, this practice has impacts on plant operation, which vary according to the biomass/coal pairing used. This dossier describes the consequences of co-firing on fuel preparation, introduction methods, combustion control and quality, as well as impacts on equipment and the environment. Fluidized-bed plants, which are more recent and use different technologies, are not covered here.