In this study, BTL (Biomass to Liquid) process in which the steam gasification and the Fischer-Tropsch synthesis reaction were combined was studied in order to produce diesel fuel for vehicle. For the process, a process design and simulations were performed using a process simulator. It is indicated that woody biomass of 100t/d could be converted to the liquid fuel of 13.9t/d. From the viewpoint of environmental load such as a CO_2 emission, the effective utilizations of heat and electricity were considered and it was found that an optimum operation condition was present. Consequently, the combustion of a part of biomass as heat source let CO_2 emission decrease in this condition. The biomass power generation was not usefully.
