A comprehensive economic assessment of the global energy system has to comprise multiple costs and benefits of energy generation and usage. It has to account for the value of future energy consumption in an energy-relying world and for the various basic costs of production of this energy from different energy sources. In addition to that, it also has to capture side effects of energy usage, such as polluting emissions, cover the finiteness of non-renewable energy resources and consider aspects like security and reliability of energy supplies. This project therefore aimed to build up an energy system model to be used on a long-term basis to analyse re-occurring questions of energy and environmental policy. The model was used complementary to the existing instruments at ZEW and contributed to the institutionalisation of the know-how in the areas of modelling, technology and founding of data. In collaboration with the research group “Global change and the energy system” and the Excellence Initiative “Global Change and Globalization” of the University of Heidelberg a technological-scientific foundation of the modelling was aspired. The cooperation with the department of Environmental Economics of the University of Heidelberg was deepened.