Technology Developments on Hydrogen Production from Biomass and Waste in Japan

Sakai, S.; Hirai, Y.; Deguchi, S.; Nakamura, K. (2008) Proceedings of the 5th International Conference on Combustion, Incineration/ Pyrolysis and Emission Control, pp. 779-784

The biomass available in Japan was estimated at 280 × 106 t-wet/yr (31.5 × 106kL/yr oil equivalent), the largest percentages on an energy basis being accounted for by unused forest trees, waste timber from the construction industry, waste paper, agricultural residue, and food waste. The effective use of biomass is necessary to establish a sound-material-cycle society, reduce CO2emissions, and provide a stable energy supply. We aim to develop and evaluate clean and highly efficient technologies toproduce hydrogen gas from biomass. We are developing technologies for thermal gasification and reforming for dry biomass, hydrogen-methane fermentation for wet biomass, and reforming and fuel-cell utilization of biogas, and we have identified some of the practical challenges in using these technologies. On the basis of the supply-demand balance fornitrogen and phosphorus in farmland, we conducted a systems analysis to determine the optimum utilization system forbiomass and waste, taking greenhouse gas (GHG) emissions into consideration. GHG emissions for the current situation (with surplus fertilizer application) were estimated at 12,650 kt-CO2 eq/yr, whereas they were -6,790 kt-CO2 eq/yr when new technologies were used (the negative number indicates net energy production). GHG emissions would be considerably reduced by the hybrid utilization of energy and compost created from the gasification and fermentation of biomass that is currently disposed of. In this hybrid utilization system, energy would be recovered through methane fermentation of biomass that is currently composted, and the residue formed during fermentation would be used as compost on farmland.


biomass utilization; greenhouse gas reduction; fuel cell; systems analysis