The energy system needs to undergo major transformations before the system will fulfill sustainability criteria. To understand most of these changes, modelling of the system is necessary. This work sets out a modelling approach that is particularly suited to systems with significant geographical and temporal dependency - especially systems with a high share of renewable energy. The approach is implemented in a software tool called TASES. One scenario is presented comprising the existing european electricity grid with a high proportion of renewable energy added. A further example quantifies the competition of PV panels in the context of geographical dependency. Competitive limitations of a global grid with intermitting renewable energy derived from wind and sun are also investigated. The innovation of this modelling approach lies in the joint consideration of high temporal and spatial resolution to describe dispersed energy systems. The approach is particularly suitable for systems with a high percentage of renewable energies. Therefore the book is directed at people in charge of modelling or decision making especially in the framework of renewable energy carriers.