The complementary role of energy system and power grid models: An analysis of the European energy transformation from a holistic perspective

This paper describes a novel method for coupling energy system models with grid-planning models. The commonly used scenario building process, based on a review of existing studies and expert discussions, was enhanced by the use and further development of an open-source energy system model. The results were processed using a regionalisation method to couple the energy system model results with a power grid planning model. A grid analysis was then performed to simulate the load on the extra-high-voltage grid to identify grid congestion. This novel model coupling approach improves the consistency and transparency of the scenario-building process and enhances the analysis of grid development planning. The method was tested at the European level in a use case study analysing energy flows between sectors and countries, as well as the utilisation of electricity grids. Two scenarios with different assumptions regarding green hydrogen imports are considered. The key results indicate a large-scale expansion of renewable energy, with 844 GW to 970 GW of wind capacity and 2,136 GW to 2,460 GW of PV capacity in Europe. Compared to 2020, the EU therefore needs a five-fold increase in wind capacity and up to a 17.8-fold increase in PV capacity. In addition, the electricity grid interconnection capacity in the EU must almost triple to around 200 GW. A detailed analysis of the extra-high-voltage grid in Central Europe shows massive congestion and grid expansion needs at the national level. Furthermore, a successful energy transition will significantly reduce Europe's dependence on energy imports for gas by 63% and oil by 83% compared with current levels.