Extracting Embodied Energy Paths from Input-Output Tables: Towards an Input-Output-based Hybrid Energy Analysis Method

Embodied energy is defined as the energy consumed in all activities necessary to support a process, including upstream processes. The Leontief inverse input-output (IO) matrix gives results that are practically complete, because of the aggregation of direct and indirect requirements, but which are also unreliable, because of inherent assumptions. Although accurate for the system boundary considered, process analysis results are incomplete relative to the pure IO system boundary. Attempts to combine process and IO analysis tend to be based on process analysis data. The system boundary is still significantly incomplete—although not as incomplete as for pure process analysis. An IO-based hybrid analysis technique that requires the extraction of particular paths from the direct IO matrix has been developed. The potential for embodied energy paths to be used as the basis for a hybrid analysis of the Australian residential building sector is discussed. The results indicate that less than three-quarters of the total embodied energy of this sector is likely to be able to be validated, because of the complexity of the embodied energy paths.