Quantification of environmental burdens associated with imported resources and the analysis of influence by allocation rule on life cycle inventory analysis

Abstract

CO2 and NOx emissions per unit amount of basic materials and secondary energy products were analyzed, by taking following two factors into account. The first is the influence by imported raw materials, and the second is that from allocation rule. CO2 emission from mining and transportation of fossil fuels accounts for a few percents to a quarter of direct emission by combustion. International marine transport of fossil fuels and metal ores largely contributes to life cycle NOx emission, because of the very high emission factor of NOx per unit amount of energy consumption by diesel engine of vessels. Allocation of environmental burdens by calorific unit and by monetary unit was discussed, using the following two examples; burdens associated with supply of crude oil and their refinery to secondary petroleum products; energy cascading of blast furnace gas. A case study on the average automobiles revealed that burdens associated with imported resources are significant compared to domestic emissions in their production stage and use stage, and allocation rule may also give large influence upon their life cycle inventory.