2011 年 90 巻 6 号 p. 562-568
Cellulosic energy crop has been expected as a feedstock of second generation biofuels which can avoid the competition with food production. However, concern about impact of land use change still exists, for cultivation of cellulosic energy crop requires vast land area to supply biofuel as an economically-viable alternative energy source. Therefore, this study evaluated the greenhouse gas (GHG) emission by land use change (LUC) from marginal land to plantation of cellulosic energy crop such as grass crop and fast wood forestry. First, the GHG emissions by LUC were estimated by using default value which was set based on IPCC methodology and literature review. Five warm temperate and tropical climate regions were selected in this paper. The results showed that the GHG emissions by LUC were estimated to be -5.3~10.4 g-CO2eq/MJ for grass crop and -2.3~5.6 g-CO2eq/MJ for fast wood forestry. The minimum emissions were observed in climate zone of warm temperate dry, whereas the maximum emissions were observed in tropical wet. The maximum emissions were accounted for 13 % of GHG emission by gasoline use. Finally, this study discussed the condition of biomass carbon stock for the previous land use to archive 50% GHG reductions from gasoline use.