Potential for Co-Utilisation of Coal with Other Fuels to Reduce Greenhouse Gas Emissions

Abstract

The prospects for coal use in power generation have always been affected by energy reserves, price, and security of supply of fuels in different regions. Environmental issues are playing an increasingly important role. Energy reserves, price, and security of supply issues have been discussed in the context of the prospects for coal and policies to reduce greenhouse gas (GHG) emissions. Projections indicate that coal will remain a major source of energy for the foreseeable future with most of the demand growth in developing countries. Power generating technologies that are currently available, deploying coal with other fuels (natural gas, biomass and refuse derived fuels) have been examined in the chaper. These include pulverized coal-fired boilers, cyclone boilers, circulating fluidized bed combustion, and integrated gasification combined cycle. Examples of successful, partial substitution of coal by other fuels in power stations have been highlighted, including the GHG emissions reductions achieved as well as the costs, wherever available. Among various options for use of coal with other fuels, hybrid gasification and parallel co-firing of coal with biomass and natural gas appear to have the greatest potential to reduce GHG emissions. Much may be achieved by cofiring, reburning and repowering with gas turbines. The best method differs among different power systems. Co-utilization of biomass with coal is a least cost option to reduce GHG emissions where the fuel prices are comparable, usually due to subsidies or taxes. The role of biomass is likely to increase in future due to greater use of subsidies, carbon taxes and emissions trading. The CDM, and joint implementation (JI) mechanisms and emissions trading, outlined in the Kyoto Protocol, should provide opportunities for clean coal technology transfer and diffusion. This will, sometimes, be associated with co-utilization, particularly with biomass.