Greenhouse Gas Emission Intensities Based on Economic Input-Output Tables and Case Studies of Product LCA

Abstract

In this paper, emission intensity tables of greenhouse gas (especially HFC, PFC and SF₆) are presented and LCA (Life Cycle Assessment) case studies using those tables are discussed.
The emission intensity tables of greenhouse gas are derived from Economic Input-Output Tables (I/O tables) and several statistical data. The emission intensities derived from the total amount transferred between sections in I/O tables become larger than the intensities derived from the actual amount of gases transferred between sections. In order to calculate the intensities of these gases, certain sections of the I/O tables should be decomposed. The I/O tables are modified, adding these sections, which correspond to ″HFC″, ″PFC″, ″HCFC″ and ″SF₆″ manufacturing industries. The emission intensities become large in not only ″HFC″, ″PFC″, ″HCFC″, ″SF₆″ subsections, but also ″Semiconductor devices and integrated circuits″, ″Liquid crystal devices″ and ″Relay switches and switchboards″ sections.
LCA case studies are conducted on a laptop PC and an air conditioner. The greenhouse gas emission at each stage of the life cycle is increased by about 20% for a laptop PC and by about 1% for an air conditioner with the CO₂ equivalent compared with the result calculated by the emission intensity tables of CO₂ and N₂O.