The entire energy system of electricity-, gas- and heat-supply faces major changes. These changes are driven by evolution of the generation structure on the one hand and by changes in the consumer behavior on the other hand. Because of that, especially the electrical power system is brought to its limits. The coupling of existing energy infrastructure could be a possible solution to this problem, which could also result in a better utilization of energy networks. This paper describes methods and achieved results for planning, analyzing and operating hybrid grids (“universal grids”), developed in research projects associated with this field at the Institute of Energy Systems and Electrical Drives (ESEA) at the TU Wien.