Dr. Gregor Czisch, a fully qualified agriculturist, studied physics at Munich Technical University, specializing in energy supply. He wrote his PhD in electrical engineering on scenarios for a future electricity supply with renewable energies. Since 1987, he has worked on various topics in the energy-related field at Munich TU, the DLR Stuttgart, the Fraunhofer ISE in Freiburg, and the Max Planck Institute for Plasma Physics (IPP) in Garching. Among his key areas of scientific focus were solar building engineering, utilization of biomass, wind energy and hydropower, primary energy analyses, emission analyses, high temperature heat storage and solar thermal power plants. During his work in the R&D division Information and Energy Economy at the Institute for Solar Energy Supply Techniques (ISET) and at the Institute for Electrical Energy Technology/Rational Energy Conversion (IEE-RE) at the University of Kassel, he worked on potential-analyses for renewable energies and on simulating their production behaviour, on conceptualizing energy transport systems and on developing scenarios for a CO2-neutral electricity supply. This work resulted, among other things, in a PhD with the title "Scenarios for a Future Electricity Supply – Cost-Optimized Approaches to Supplying Europe and its Neighbours with Electricity from Renewable Energies", for which he was awarded the distinction summa cum laude. One key role was played by models he created for energy supply systems as the basis for system configuration, operation planning and power plant dispatch by means of mathematical optimization. Questions of business and economics meant that a detailed analysis of the typical market costs of all kinds of different components in energy supply systems needed to be carried out in addition to the analysis of technical aspects. Since completing his doctorate, parallel to his research at the University of Kassel, Dr Gregor Czisch has worked as a consultant to the Scientific Advisory Council on Environmental Change of the German Federal Government (WBGU) and was, among other things, invited as an expert to hearings in various ministries, parliaments and utilities.