Reducing the embodied carbon using bio-based building materials: the biogenic carbon content of timber

In recent decades, several efforts have been made towards the reduction of operational energy and therefore carbon, thanks to the introduction of mandatory compliance in many national regulations, achieved by using specific certification tools. As operational carbon diminishes, the significance of embodied carbon - emissions released before the building and infrastructure begins to be used - will continue to increase as a portion of total emissions. Strategy for reducing embodied carbon include the use of building components derived from plants, which absorb atmospheric carbon during their growth through photosynthesis. Wood stands out among building materials, not only for its ability to store biogenic carbon but also for its lower emissions as per life-cycle assessments (LCA). The purpose of this paper is to conduct an LCA of a wooden building using a Whole-Building Life Cycle Assessment (WBLCA) software, and to explore three methodologies for assessing biogenic carbon in LCA. It follows the two primary calculation methods provided by the EN 15804 and ISO 21930 standards for LCA, along with an additional “dynamic approach”. Key procedural discrepancies between the explored methodologies arise, guiding designers to adopt varying strategies in minimising a building's carbon footprint. This research aspires to underscore the shortcomings and advantages of prevalent methods.