Environmental assessment at the urban level combining LCA-GIS methodologies: A case study of energy retrofits in the Barcelona metropolitan area

Abstract

This study proposes a combined life cycle assessment (LCA) and Geographical Information Systems (GIS) methodology to develop complex LCA inventories for multiple applications. The study focusses on the environmental implications of buildings retrofits, especially in the European context, where the building sector is one of the largest energy consumers. In this context, a new and holistic perspective is needed that expands from the building scale to the urban scale.The combination of LCA and GIS methods includes the development of an urban characterization model based on bottom-up methodologies. The environmental implications associated with increasing the thermal insulation of existing buildings to the current standard are determined based on LCA methods. In this step, common construction systems for building retrofits are used, and insulation materials are compared. Then, absolute and relative extrapolations are performed considering different urban morphologies.The results confirm the importance of the energy retrofitting of residential buildings in large functional urban areas such as the Barcelona metropolitan area, which is examined as a case study. The LCA results indicate that the selection of proper construction systems and thermal insulation materials is important to the environmental performance of building retrofits, and these selections can lead to CO2 emission differences of up 16% in the region. The relative extrapolation results indicate significant environmental differences between urban morphologies. The LCA results show the potential strategic impacts of the inclusion of LCA methods in retrofit policies at the urban scale.