Impact of coupling the electricity and hydrogen sector in a zero-emission European energy system in 2050

The design of future electricity systems depends, among others, on reducing costs for renewable technologies. Particularly costs for PV panels and batteries are predicted to decrease significantly. At the same time, as the share of renewable energies increases, there is a greater need for flexibility. Energy policies are promoting the use of hydrogen generated by electricity which offers an alternative to provide flexibility to the system. This study investigates flexibility provision due to the coupling of the electricity and hydrogen sector in Europe in 2050 with a cost optimization model. The results show that investment cost reductions lead to a balanced contribution of wind and solar energy in the optimal generation mix but requires immense transmission and storage capacities. Batteries balance the daily feed-in from PV panels, whereas salt caverns with low-capacity costs compensate the irregular availability of wind resources. Implementing joint optimization can reduce total costs by up to 14%, while the coupling of electricity and hydrogen sectors can decrease electrical storage needs by 35% and substitute 40% of electrical transmission capacity. It also improves the integration of renewable energies and reduces curtailment by two-thirds. Thus, this coupling offers valuable additions in providing flexibility to the energy system.