Enhancing the accountability and comparability of different campuses’ energy profiles through an energy cluster approach

International sustainability ranking systems generally set criteria in order to monitor global achievement of universities in terms of sustainability. However, current sustainability ranking systems do not provide specific consumption thresholds according to the different buildings’ function or characteristic and the comparison among universities lacks of precise criteria. Thus, this paper proposes different energy clusters enabling a meaningful comparison among campuses within the international rankings. Energy profiles of two university campuses—Politecnico di Torino (Italy) and Hokkaido University (Japan)—similar for climate, surface, and population have been collected for 4 years as a relevant case study. Five different clusters of homogeneous consumption have been identified: cluster 1 (around 1 GJ/m2/year) includes the Art departments, cluster 2 (2 GJ/m2/year) includes the Science faculties, cluster 3 (3 GJ/m2/year) includes the hospital and the medicine departments, cluster 4 includes the Data Centre (9 GJ/m2/year), and cluster 5 includes special research facilities with consumption over 10 GJ/m2/year. Findings show how comparisons between different buildings should also take into account the electrification rate (dependence on electricity) and the leveling rate (variation of consumption during a year), which variations are directly related to the main building function (e.g., hospitals/data centers have high values, while arts or humanities departments have low values for both rates). The proposed energy cluster approach and the introduction of proper weights for energy performances based on the proposed clusters can significantly enhance the accountability and comparability of different campuses’ energy profiles, contributing to a better evaluation of universities’ energy performances.