Towards an Automated Approach for Compiling Hybrid Life Cycle Inventories

Abstract

There is an urgent need to reduce the environmental effects associated with the built environment. While a life cycle approach is considered essential for ensuring that these effects are not simply shifted from one life cycle stage to another, not all life cycle assessment methods provide the same level of detail. Three main approaches are currently used to compile a life cycle inventory capturing data on the inputs and outputs associated with a particular good or service: process, input-output and hybrid analysis. While process analysis is recognised for its specificity, it typically involves a truncation of the system boundary. Conversely, input-output analysis is systemically complete, but aggregates data at the economic sector or commodity level. Combining these two methods in a hybrid analysis has the potential to reduce their limitations, while maintaining their benefits. However, combining process and input-output data remains a highly manual and time-consuming process. The development of an automated approach for compiling life cycle inventories is a critical step in the uptake of hybrid analysis methods. This study aims to explore automating the hybridisation of process and input-output data using the Path Exchange method. Major practical barriers that usually prevent automating the integration of process and input-output data in hybrid life cycle inventories are discussed and a case study focusing on concrete is used for the purpose of illustrating the approach.