【基調講演】若手研究者勉強会　産業連関表を用いた鉄鋼マテリアルフロー分析とエネルギーフローへの含意

抄録

A mathematical model of material flow analysis (MFA) based on Waste Input-Output model (WIO) (Nakamura and Kondo) is presented. The model (WIO-MFA) is based on two fundamental ingredients: yield ratios and the degree of fabrication. In the manufacturing process, multiplication of physical inputs by the yield ratios gives the portion that enters physical outputs, with the rest being discarded as process waste without entering outputs. In input-output analysis, the degree of fabrication can be visualized as triangularity of the input coefficients matrix (goods of a lower degree of fabrication can enter those of higher fabrication, but the reverse does not hold), which is known to emerge through an appropriate reordering of sectors. Application to the Japanese IO data indicates that the model can provide accurate estimates of the weight and the composition of metals (Fe, Cu, Pb, Zn, and Al) used in a passenger car. Furthermore, combined with the information on embodied energy, WIO-MFA can depict the energy flow in terms of intermediate flows.