Harnessing hydrogen and thermal energy storage: Sweden's path to a 100 % renewable energy system by 2045

Sweden plans to decarbonize its energy sector by 2045 through initiatives such as electrification of transport & industry, wind power expansion, HYBRIT and increased use of biomass. Hitherto studies have predominantly focused on electricity sector. Nevertheless, the targets for 2045 necessitates studying the Swedish energy system at national scale in the context of sector coupling & storage. This work examines the role of thermal energy storage (TES) and hydrogen storage (HS) in the future energy system with high proportions of wind power. Three scenarios SWE_2045, NFF_2045 and RES_100 representing three different energy systems were simulated in EnergyPLAN modelling tool, incorporating TES, HS and sector integration. The results indicate that both TES and HS can improve flexibility of the system by enhancing wind integration. Heat pumps (HPs) coupled with TES can increase wind integration by 5-9% and also reduce the operation of thermal boilers and CHP, resulting in total fuel reduction by 2-3%, depending on the scenario. However, HS is not a viable option for storing excess electricity alone, as shown in SWE_2045 since it does not facilitate additional wind integration. It demonstrates better outcome mainly when there is a significant demand for hydrogen in the system, resulting in wind integration of 6-9%. However, HS does not contribute to the reduction in total fuel since it does not have an impact on the fuel input in district heating sector.