EFFECTIVE UTILIZATION OF WOODY BIOMASS FOR ELECTRICITY PRODUCTION IN JAPAN. - COMPARATIVE ASSESSMENT OF CO-FIRING IN COAL FIRED POWER PLANT AND FUEL CELL WITH GASIFICATION -

摘要

This paper discusses the effective utilization of woody biomass for electricity production. Co-firing of biomass with coal in a coal power plant and a small-scale fuel cell system with gasifier are compared as a biomass utilization technology. Sawmill wastes, pruned fruit tree branches pruned road-side tree branches and fallen leaves & branches in forests around city area in the mid-land area in Japan are taken into account as woody biomass available for electricity production. First, based on literatures survey and some calculations, we estimate the amount of woody biomass supplied from 325 cities. Then, we evaluate the reduction in primary energy consumption and CO_2 emission by co-firing of biomass at a utility's large-scale coal power plant. The required energy for transporting woody biomass from each city to a utility's coal power plant is taken into account. The comparative assessment shows that, for reducing CO_2 emission, 80% of woody biomass excluding fallen leaves & branches can be more efficiently used in a co-firing system than a small-scale fuel cell system.