Life Cycle Input-Output Analysis Extended to Use, Disposal, and Recycling Stages Applied to Embodied CO_2 Emissions of a Refrigerator

摘要

Input-output analysis is widely employed to analyze inventories of a product's embodied energy and environmental burdens. However, input-output analysis focuses only on the production stage and ignores other life cycle phases. Input-output analysis is not exactly a LCA (life cycle assessment) method in the strict sense of ISO 14040 standards, which must cover all stages of a product's life cycle, "from the cradle to the grave", so to speak. A tiered hybrid LCA is a useful tool that covers all life cycle stages by combining a process analysis with the input-output analysis method. This study aims to extend input-output analysis to the use, disposal, and recycling stages by using matrix-based method. The new method is applied to the analysis of the embodied CO_2 emissions of a refrigerator as a case study. The entire life cycle CO_2 emissions are estimated to be 2.9 tons, including indirect emissions, and the reduction in CO_2 emissions due to recycling steel scrap is calculated as 48.5 kg. The authors conclude that the new method enables a consistent inventory analysis for all life cycle stages by combining process and input-output methods.