Employing different energy carrier networks in connection with distributed renewable energy generation is an attractive way to improve energy sustainability in urban areas. An effective option to increase local renewable energy production is to convert surplus electricity into e.g. thermal energy. Here a methodology to study such multi-carrier urban energy systems is presented which enables to analyze spatial energy demand and supply, and spatial energy flows. The results indicate that in a northern midsized city wind power coupled both to an electric grid and a district heating network could raise the allowable wind capacity over the non-heat case by 40-200%. In an Asian megacity dominated by cooling demand, employing dispatched local photovoltaics and tri-generation could cover even beyond 30% of all energy demand and lead to major carbon emission reductions. (C) 2012 Elsevier Ltd. All rights reserved.