Prospective Life Cycle Assessment: Effect of Electricity Decarbonization in Building Sector

International audience The building sector is responsible for 43% of France’s final energy consumption and isstrongly associated with a high environmental impact due to its high consumption of energy andnatural resources. These impacts are significant in isolated islands. Due to its geographical isolationand an area of 2512 km2, Reunion Island has a heavily carbon-based economy with a high import rateof raw materials for the building sector. This study aimed to investigate the effect of electricity mixdecarbonization on residential house environmental impact. The methodology consists of three parts:(i) evaluating environmental impacts of Single-Family Houses (SFH) using life cyce assessment(LCA),(ii) defining SFH typologies using the K-means clustering algorithm, and (iii) implementing energyscenario in LCA of SFH to assess decarbonization effect. The environmental results were particularlysensitive in the operational phase, with a decrease of 83% between 2020 to 2040 of the global warmingpotential (GWP). The structural phase highlights the weight of imports in the building sector, asa decrease of only 1% is observed. This study clearly shows the necessary energy transition forReunion Island. In the structural phase, the study recommends that stakeholders reduce imports andincrease the share of recovered materials to achieve a substantial reduction in impacts.