Impact of Power-to-X on Energy Systems as a Key Technology to Defossilization

The integration of the heat sector alongside the electricity sector in energy system analysis is nowadays widely practiced. However, in order to achieve the planned CO2 emission targets, the mobility and transport sector as well as the chemical sector must be considered. Besides a fully electrification or at least decarbonization of the passenger transport, the cargo sector is expected to stay fuel dependent. In the same way, chemical production will continue to be carbon-based in the long term. Therefore, a full decarbonization of the energy and material system is unlikely. However, a complete defossilization is achievable and has to be a long-term goal. One possibility is a purely power-based supply of chemicals und fuels (Power-to-X), which to a certain point would be technically feasible based on simplified estimates for the German energy system. Nevertheless, depending on different possible developments of the mobility, power, heat and chemical demands, a surplus of installed capacities of wind and solar power, as well as storage systems are needed. This paper uses optimization to evaluate different future demand scenarios for Germany, to determine the possibilities of defossilizing the German energy system. This study shows, that to reach CO2-emission targets, extensive changes in demand behavior and large renewable capacities are needed. In contrary, scenarios which follow the current trend, are not able to fulfill the emission targets. The best case scenario, with a 50 % reduction in mobility demand and a fuel switch to electricity and H2 based transportation systems enable net zero CO2-balances in the electricity and transportation sector. Only the chemical sector stays, to some extent, dependent on natural gas.