Numerical investigations into the comparison of hydrogen and gas mixtures storage within salt caverns

Salt caverns, long used for natural gas storage to manage peak loads, are being considered for hydrogen storage as part of the shift towards greener fuels. This transition necessitates re-evaluating heat and fluid transport to ensure the suitability of storage sites. A comparative analysis between current (natural gas and compressed air) and prospective (hydrogen and gas mixtures) storage systems was conducted using a standardized historical cycle over thirty days to identify trends. Hydrogen exhibited the lowest cumulative temperature and pressure increase (17 °C, 0.40 MPa), but the greatest variability per cycle, with an average range of 26 °C and 1.6 MPa. This higher fluctuation could potentially limit its use in short-term cycles compared to natural gas. Moreover, hydrogen's storage capacity was found to be a third of natural gas's, at only 6.6 GWh for the cavern design and specified pressure limits. These findings indicate that while hydrogen presents a greener alternative, its high variability and lower storage capacity pose challenges for its use in existing infrastructure, highlighting the need for further research to optimize its storage and utilisation in energy systems.