The Business Area Integrated Planning of Infrastructures, Districts and Buildings with its Competence Centres "Integrated Energy Infrastructures", "Integrated District Planning/Open District Hub", "Building Energy Supply/Integration" and "Business Models of System Transformation & Technology Transfer" conducts research on sector-coupled energy infrastructures and integrated district planning in order to understand and address infrastructure as a critical cornerstone of the energy transition. This is just as necessary for the system strategy of the energy transition as it is for implementing the energy supply of neighbourhoods. We develop and operate models to analyse the European transport networks for electricity, natural gas and hydrogen, to calculate municipal distribution networks for electricity, heat, natural gas and hydrogen, and for sector-coupled neighbourhoods. By integrating the infrastructures in planning and operation, we efficiently couple supply and demand and tap into flexibility potentials. We support policy-makers and companies as well as planners and developers of neighbourhoods with models, methods and solutions for the analysis of sector-coupled infrastructures that meet the new challenges. In our work, we combine the technical, economic and regulatory aspects with the conditions on the ground. Of central importance is the perspective of the actors and stakeholders. We are committed to a holistic and balanced view and use Open Data and Open Models wherever possible.