Developing a hydrogen seasonal storage strategy to support security of supply and carbon neutrality

Portugal, like other nations of the European Union (EU), has developed a national roadmap for hydrogen deployment as a key element of the Portuguese energy transition towards carbon neutrality, generating synergies between the electric and gas systems. Such synergies must be further developed, where hydrogen appears as a renewable energy carrier capable of guaranteeing not only the transformation of the gas system but also its integration with the power system, ensuring the conversion of excess of renewable electrical energy into storable energy, namely via the storage of hydrogen. Such approach, potentially solves security of supply issues of an power system based on renewable power sources, allowing the renewable energy harvesting throughout the year, managing renewable seasonality. A case study based on a national plan for the Portuguese generating system in 2030 demonstrates that the expected renewable energy surplus can be stored as hydrogen and converted back into electricity to assure adequate levels for the LOLE index throughout the year, supporting public policy models to accelerate the energy transition.