Normalising and assessing carbon emissions in the building sector: A review on the embodied CO2 emissions of residential buildings

Towards zero emission and zero energy buildings, literature reviews highlight the importance of embodied energy and embodied carbon emissions. The current review analyses 95 case studies of residential buildings, as an effort to identify the range of embodied carbon emissions and the correlation between the share of embodied energy and carbon for different levels of building's energy efficiency. The assessment identifies a range of embodied carbon emissions between 179.3 kgCO2e/m2-1050 kgCO2e/m2 (50-year building lifespan) that reflects a share between 9% and 80% to the total life cycle impact. That same share follows similar trends with the respective for embodied energy and ranges between 9% and 22% for conventional, between 32% and 38% for passive and between 21% and 57% for low energy buildings, while the normalised results indicate a sensitivity for the share of operating emissions that relates to the electricity mix. Considering the deviation of the results, even though a two-step normalisation procedure increases the homogeneity and comparability of the sample, the differences in the electricity mix, in LCI databases or even in the overall building design could not be neutralised and confirm the need for further standardisation in LCA.