Professor Dr.-Ing. Stefan Niessen MBA heads the technology field Energy Systems in the central corporate research department at Siemens since 2016. With seven research groups at various locations in Germany, Austria, Russia and China, he develops models, simulation and optimization methods for the design and operation of multimodally coupled energy systems of buildings, plants, cities and countries. By addressing the coupling of the supply of electricity, heating, cooling, drive energy, drinking water, and chemical forms of energy, costs can be reduced, environmental efficiency improved, and new flexibility potentials leveraged. Parallel to his work at Siemens, he holds the professorship for Technology and Economics of Multimodal Energy Systems at the TU Darmstadt. After completing his studies and doctorate at the Faculty of Electrical Engineering at RWTH Aachen University, Stefan Niessen was a member of the core team responsible for setting up the European Energy Exchange AG during its first six years. He acquired the necessary business knowledge with an MBA from Duke University. He then worked for ten years for a French plant builder as head of International Marketing and head of R&D.