Following the pioneering work of the AGS Tokyo half project, a geographical information system has been developed to model the energy requirement of a urban area. The purpose of this platform is to model with sufficient details the energy services requirement of a given geographical area 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 and of energy efficient conversion technologies and that valorize the use of endogenous renewable energy. The model first uses a geographical system to identify the building characteristics in the area. A typification procedure is used to define the energy characteristics of each building, to model its energy requirement and their perspectives. A data base of typified building models has been constituted. The parameters have been identified using data from monitoring tools installed in the area. In order to practically compute the annual performances of the energy conversion systems, the building requirement model considers heating and cooling requirements and provides the temperatures of the hydronic system as a function of the ambient temperature. Combining the requirements using the composite curves concepts defines the enthalpy-temperature of the requirement of each geographical sector. This information is then combined with the geographical catalog of the available energy resources like lake water, underground water, geological resources, or waste water treatment plants in order to compute the annual COP for each kind of decentralized heat pump. In addition, heat (cold) distribution system costs are estimated in order to evaluate the integration of combined heat and power options and/or centralized heat pumping systems. Considering the available resources, an aggregation method is then proposed to estimate the best coverage of heat distribution systems. The generated maps have then been used to define the heat and power production strategy in the concerned geographical sectors. An application to the Geneva canton will be presented.