Embodied, operation, and commuting emissions : A case study comparing the carbon hotspots of an educational building

Abstract

Building operational energy, mobility energy, and materials embodied energy contribute to a significant portion of the global greenhouse gas emissions. Buildings stand at the intersection of these three contributors and, as a result, are largely responsible for the scale of society’s carbon footprint. The global consensus on limiting climate change to a 2o Centigrade temperature increase is forcing nations to become carbon-centric and to adopt a range of carbon-neutral strategies in their building standards and codes. However, most of these standards define carbon-neutrality only in terms of energy efficiency, with very few organizations introducing a holistic approach for assessing the built environment carbon footprint. Mobility of tenants, for instance, has been indicated as a carbon hotspot by several studies. Thus, several green building standards have been inclined to include mobility emissions in the short-term future. However, emissions from daily transportation of a building’s occupants are rarely measured and explored by building LCCO2A studies, thus the share of mobility emissions compared to embodied and operational emissions is not well-known. In this paper, we consider embodied, operational, and mobility of tenants as Carbon Intensive Stages (CIS). The study attempts to (1) quantify and compare the CIS of a building, and (2) propose a framework to facilitate the quantification of the carbon footprint of the building environment. We provided a case study on an US educational building, where we found that building operational phase accounted for 70% of the total carbon emissions, followed by mobility (24%) and embodied carbon (6%). These results help better understand the weight of mobility emissions in the built environment and, in fact, suggests that mobility, operational, and embodied carbon should be targeted as the triple bottom line of building carbon footprint assessments and highly encouraged by green building certification standards.