Analyzing Temporal Changes in Initial and Recurrent Embodied Energy Using an Input-Output-based Hybrid method

Abstract

Buildings consume over 40% of global energy annually in their initial construction and operation as embodied and operational energy, contributing to over 39% of global carbon emissions. Embodied energy (EE) is consumed directly in construction processes and indirectly using construction materials, each of which uses energy during its manufacturing. All direct and indirect embodied energies used in maintenance, repair, and replacement processes of buildings is termed recurrent embodied energy (REE). Because REE accrues over 50-100-year life cycle of buildings, it may be equal to, or more than the initial embodied energy (IEE) used during buildings’ construction. Both REE and IEE must be optimized to help effectively reduce the environmental burdens of buildings. However, calculating IEE and REE is a data-intensive process requiring temporally representative data that may not be readily available. Consequently, studies may use older data. This paper offers a temporal analysis of the IEE and REE of healthcare buildings to demonstrate how energy source-specific EE values may change over time and introduce errors in IEE and REE calculations if old data is used. Using macroeconomic modeling, the IEE and REE intensities of healthcare building sector are computed. The results indicate that using 5-year and 10-year-old data may underestimate IEE by 5% and overestimate it by 26%, respectively, whereas the REE may be overestimated by 20% and 33%, respectively. The results also show that the share of electricity in EE may be increasing over time. The findings underscore the importance of using temporally representative EE data for energy analysis.