The selection of power supply technology for buses is a critical task given the increasing attention paid to environmental sustainability in the public transport sector. Indeed, the compliance of vehicle operational requirements with service characteristics is essential to provide users with an efficient offer. To this end, this study investigates the factors affecting such choices by performing two evaluation procedures, with the integration of different techniques and the engagement of an expert panel. The Analytic Hierarchy Process (AHP) method was used to identify the best power supply technology among a few solutions in both procedures, which differed in the number of analyzed criteria. A literature review suggested a wide set of criteria considered in the first assessment, which were then limited to the most influential criteria using the fuzzy DEcision-MAking Trial and Evaluation Laboratory (DEMATEL) method. Notably, the latter enabled the reduction in the number of the criteria owing to the revealing of cause–effect relationships among them. The methodology was applied to a case study in the city of Trieste, Italy, comparing rankings obtained from the two appraisal procedures, which showed the predominance of internal combustion engine buses over hybrid and electric buses in terms of operational and financial aspects, despite their environmental impact.