Analysis of effect on CO2 emission reduction and cost estimation for the use of Bio-coke: a case study of Osaka, Japan

Bio-coke (BIC) is drawing attention as a coal-coke substitute in industry. Though BIC can be used as a carbon-neutral fuel, its overall benefits, including the environmental impacts associated with its production processes and its merits as an alternative fuel, remain unknown. In this study, we investigate the overall impacts and benefits related to BIC production processes and alternative fuel applications by looking into the case of Takatsuki in Osaka Prefecture, the only commercial BIC plant in Japan. Based on the system boundary set, we calculated CO2 emissions per ton of BIC associated with its manufacturing and transportation processes to be 1.01 t CO2. CO2 emission from electricity consumed in the process was found to be the largest, accounting for 74.7 % of total emission. The analyses also revealed that using one ton of BIC as alternative fuel in industry instead of coal-coke could result in avoiding 2.16 tons of CO2 emissions, showing a clear environmental benefit. While BIC's calorific value is almost same as pellet's, BIC had higher gross margin and energy density than pellet produced in the same facility. These findings enhance the merits of producing BIC from wood biomass and could lead the way to revitalizing forestry in Japan.