The increasing use of renewable energy is a deep going trend mainly supported by the sustained annual growth rate of solar photovoltaic, wind power and biogases. The expansion and evolution of the distribution grids is therefore a key issue to ensure a secure and sustainable supply of electricity in the future. This report presents an integrated approach for the elaboration of alternative scenarios for the future grid evolution. The proposed method allows to optimally design and schedule building energy systems within the context of smart grids. It combines geographical information system, process integra tion techniques and power flow analysis to model the holistic district energy system including heat cascading and network constraints to ensure power quality. The scenarios at district scale results form the aggregation of optimal energy technology configurations at building scale given as a function of the investment capacity. This approach therefore allows to evaluate the effect of the increase of prosumer capacities in the grid.