Developing a new data-driven LCA tool at the urban scale: The case of the energy performance of the building sector

[Display omitted] •The article describes a new tool for evaluating cities' environmental profiles.•16 environmental impact categories were considered using the EF 3.0 method.•The tool was tested on the buildings of the city of Milan.•Approx. 81,000 buildings were considered, 11% of the total floor area of the city.•The climate change impact of different energy systems was evaluated and discussed. Given the ambitious greenhouse gas emissions reduction targets set by the European Union and the importance of cities in achieving these goals, there is an increasing need to analyze their environmental footprint with a life cycle approach. The life cycle assessment is considered the leading methodology for environmental metrics, permitting a holistic environmental perspective of cities. Developing a complete life cycle assessment can be difficult and time-consuming, particularly discouraging to non-experts. Life cycle assessment software applications are aimed at single product evaluation, making urban scale data management and environmental assessment complicated or impractical. The novelty of this work is a new tool, utilizing a data-driven approach, that allows an extensive environmental evaluation of buildings (of the operational phase). The tool expands the application of the life cycle assessment method at the urban scale where the existing software applications are not specifically designed to be implemented and fail mainly due to the massive data processing. The tool was applied to analyze the city of Milan. Approximately 81,000 building units and 161,935 energy systems were investigated and compared using ecoinvent 3.7 as a secondary database and the Environmental Footprint 3.0 method. The results show that the space heating service is the main contributor to the climate change impact category, followed by domestic hot water and space cooling (41.70, 6.50, and 5.92 kgCO2eq / m2 year, respectively). Of practical relevance, no scientific research has ever been carried out on a plurality of buildings and energy systems at an urban scale. Thus, the article's novelty can also be traced to the innovative outcomes obtained by testing the tool on the city of Milan. Additionally, the tool can be used to establish reliable environmental benchmarks to implement policies for buildings and assess the environmental footprint of energy requalification initiatives.