Imports versus domestic production of sustainable hydrogen-based fuels: Impact on energy system flexibility needs

The transition away from fossil fuels in the energy sector is accelerating with the increasing integration of renewable energy sources (RES) such as wind and solar photovoltaics (PV). However, these renewable sources introduce significant challenges, particularly in maintaining a constant balance between energy production and demand due to their intermittent nature. One promising solution lies in long-term energy storage by Power-to-X-to-Power (PtXtP), which allows surplus electricity from high-production periods to be used to produce a new energy carrier (X), which can then be used to produce electricity during low-production periods. This approach is particularly important for addressing seasonal imbalances, such as excess summer production and higher winter demand. Reliance on such systems should be avoided as much as possible, as PtXtP technologies are associated with high cost due to low round-trip efficiency (