Life Cycle Assessment for Urban Planning: A Modular Approach to Integrating Buildings and Infrastructure

Life cycle assessments (LCAs) in the construction sector often analyse buildings or their individual components. Applying LCA to determine the environmental impact of entire settlements is less established and the structural infrastructure is often not taken into account. The research project ‘Q-LCA - Analysis of the ecological impacts of different settlement types in new urban development projects over their life cycle’ follows the objective of determining and comparing the material flows, energy consumption including grey energy and the associated emissions of urban settlement components with a focus on global warming potential (GWP). Based on a modular approach, the GWP for 972 different settlement scenarios was determined through an LCA-based model in which six key parameters - building type, settlement density, road layout, building construction method, energy efficiency level and heating system - were systematically combined. The study demonstrates how modularity enables the assessment of large-scale systems such as urban settlements, contributing to an enhanced reflection of their inherent heterogeneity. Besides quantifying the infrastructure share of settlements’ GWP, further results indicate a high influence of operational energy consumption as well as choice of construction method on the area-based GWP. Underground garages are moreover responsible for high GWPs in densified settlements with large building types. This research fills a critical gap in existing literature by emphasising the potential of modular LCA approaches to assess urban development and additionally provides valuable insights for urban planners as well as policy makers seeking to lower environmental impact, identify circularity potentials and mitigate climate change effects in settlements.