Following the pioneering work of the AGS Tokyo half project, a geographical information system has been developed to model the energy requirements of an urban area. The purpose of the platform is to model with sufficient detail the energy services requirements of a given geographical area in order to allow the evaluation of the integration of advanced integrated energy conversion systems. This tool is used to study the emergence of more efficient cities that realize the integration of energy efficiency measures, of energy efficient conversion technologies, and that valorize the use of endogenous renewable energy. The model is illustrated with case studies for the energetic planning of the Geneva district (Switzerland).