Goal 7 of Agenda 2030 is focused on renewable energy. This study proposes a multi-criteria and multi-disciplinary methodology for analysing different incentive scenarios in Italy according to the varying conditions of system installation and the chosen photovoltaic technology (PV). The method is based on three key factors: energy, economic, and life cycle assessment of the photovoltaic system to achieve the improvement of the energy performance through technical and financial solutions that suit the existing buildings and strategies to limit environmental impacts. For the validation of the methodology was chosen the engineering campus of the University of L'Aquila, Italy, was chosen since the energy retrofit of public buildings must be dealt with by considering numerous parameters. These include economic constraints related to the public budget; technical constraints, as not all the solutions on the market, are compatible with the existing building body; and social constraints, as public administrations set an example for their communities and pioneer positive actions inspired by sustainability from every standpoint. The study showed as for defining the optimal scenario a multi-criteria approach is necessary and that a decision based on only technical and economic evaluations can not conduct to an optimal scenario selection. Furthermore, it has shown how subsidies are fundamental for the profitability of PV investments, which, although considered a renewable energy source, can derive non-negligible environmental impacts from these investments. Thus, the methodology adopted, which can be exported to other contexts, allows policy-makers choices to be weighed from many points of view.