Hydrogen storage in salt caverns: Sizing, dynamic modeling and application for energy system analysis

Hydrogen is expected to play an important role in future decarbonized energy systems.Large-scale, economical storage of hydrogen gas can be achieved with artificial salt caverns created in natural underground salt rock deposits by the process of solution mining.Experience in operating natural gas caverns and compressed air caverns has shown that cavern thermodynamics, i.e., dynamic pressure and temperature evolution, play an essential role in operating behavior and dynamically influence discharge and charge limits and thus the market opportunities of such storages.In this work, we contribute two aspects to the current discourse on hydrogen caverns.Firstly, we present a dynamic model for hydrogen salt cavern storage, which is adapted to the simulation demands of the salt cavern as a storage component in energy systems.We combine this with a sizing approach to parametrize cavern models from very few input parameters.The model is validated by comparison with a commercial simulation software, "Kavpool", and shows excellent agreement.Secondly, we apply future dynamic load profiles generated from energy system transformation models to this cavern model.We distinguish between two application cases: Power-to-Gas (P2G) hydrogen caverns the provision of green hydrogen to industry and Power-to-Power (P2P) hydrogen caverns in a future climate-neutral Germany.We quantify the impact of this dynamic behavior for the respective application cases.The results indicate that the P2P application in future energy systems subjects the cavern to higher relative discharge loads and higher cavern throughput.It further results in larger temperature swings than the P2G application and can lead to inadmissible flow velocities in discharge operation close to the minimum operating pressure.