Our Competence Centre for Integrated Energy Infrastructures focuses on a holistic analysis of sector-coupled energy infrastructures in the electricity, heat and gas sectors, energy-relevant IT infrastructures and coupled energy/water infrastructures. We support the development of strategies and pathways for the transformation of the energy system, in which infrastructures and their interconnection are increasingly coming into focus. This concerns both structural considerations for the overarching systemic view of interactions and detailed modelling of transmission and distribution networks with the relevant technical and economic restrictions. Here, current models are reaching their limits, as the overarching coupling of all supply and downstream sectors through fully integrated infrastructures implies a significantly higher degree of complexity and at the same time some coupling options currently still have high uncertainties regarding their techno-economic characterisation. In the research field of Integrated Energy Infrastructures, we are developing models and methods for the analysis of sector-coupled infrastructures that meet the aforementioned challenges. The following cross-sectoral topics are particularly relevant: Description of the intermodal coupling of energy infrastructures, comprehensive infrastructure as well as system and site modelling and analyses, development of expansion and decommissioning strategies and alternative utilisation concepts (for example for data networks) for existing networks, and analysis of the systemic risks of the interaction of different infrastructures.