Net-zero emissions and positive energy districts: An evaluation using attributional and consequential life cycle assessment approaches

Net-zero emissions and positive energy districts are gaining wide attention as a solutions for achieving climate neutrality in the built environment, aligning with the European Union’s 2050 target. Process-based life cycle assessment is the recognized metric tool selected for evaluating the emission profile of buildings and districts indicated by the recast Energy Performance Buildings Directive of the European Union (2024). The directive, as well as the articles published on the subject, approach the problem using the attributional life cycle assessment. On the other hand, the consequential life cycle assessment approaches can be used in the analysis to describe the consequences of a decision (i.e., effect-oriented or change-oriented) by introducing market mechanisms. To this end, the authors show and describe a case study related to a new district that will be built in Bologna - Northern Italy (41 400 m2 of heated/cooled floor surface area). The outcomes were analyzed using the attributional (176 kgCO2-eq/m2) and consequential life cycle assessment (763 kgCO2-eq/m2).