Balancing construction and operational carbon emissions: Evaluating neighbourhood renovation strategies

Compliance with the global decarbonisation commitments set out in Horizon 2050 undoubtedly involves optimising the conditions of the housing stock. In this respect, the massive energy renovation of obsolete housing blocks in southern EU countries holds the key for the achievement of such compliance. This research strives to demonstrate the suitability of intervention strategies at district scale. For this purpose, an innovative methodology that combines open data, Geographic Information Systems (GIS), Urban Energy Modelling (UBEM), and Life Cycle Assessment (LCA) is proposed and tested in a case study, whilst considering several renovation and new-building hypotheses. As an innovative approach, this study concurrently analyses greenhouse gas emissions arising from both use-related energy consumption (operational carbon footprint) and the construction process (embodied carbon footprint). This dual perspective provides added value to the results obtained, since it offers a more comprehensive representation of reality. Based on the results from the LCA and UBEM models, this study unveils the entire impact of residential energy use combined with either the carbon footprint of energy renovation or that of new buildings. The case study analysis reveals that total emissions, encompassing both embodied and operational aspects, are lower for retrofitting existing buildings when compared to new construction, up to Horizon 2050. Remarkably, this preference for renovation persists even as far as 2100. The study underscores the critical importance of upgrading the existing residential stock in order to achieve the ambitious goal of net-zero greenhouse gas emissions by 2050.