Reduction of Greenhouse Gas Emissions in the Introduction of Inversion System to Produce Sugar and Ethanol from Sugarcane

Abstract

This paper assesses the alternative sugarcane-based industrial systems concerning changes in productivity, the greenhouse gas （GHG） emission intensities of products and the reduction potential of GHG emission compared with the current sugar producing system. The following two systems are assessed; （Case A） Conventionally proposed system to produce ethanol from molasses without changing raw materials and sugar milling processes, （Case B） Inversion system that enhances the production of sugar, ethanol and electricity using a high-yielding sugarcane variety and the Inversion process. As a result, with Case A, ethanol production increased, but electricity output decreased, increasing the direct GHG emissions by 1.3% from the current level while the net GHG emission reduction was estimated to be 0.72 t-CO_2-eq./（ha･year） in the overall system. With Case B, the productivity of sugar, ethanol and electricity all increased at the same time. Despite an increase in the GHG emissions by 16.7%, it was estimated that there was a net reduction potential of 1.49 t-CO_2-eq./（ha･year） achieved by an enhanced avoided emission. Comparison with the past researches confirmed the validity of the results. The study demonstrated the advantages of the Inversion system in the model area quantitatively.