State of the Art of the Underground Hydrogen Storage in Salt Caverns

The global energy system is undergoing a significant transformation, driven by the need to reduce greenhouse gas emissions and transition toward renewable energy sources such as wind and solar power. One of the key challenges in this transition is the intermittency of renewable energy, which requires large-scale, long-term energy storage solutions that has become a critical requirement for balancing energy production and demand. \\ Hydrogen is increasingly recognized as a truly key energy vector (for storing renewable energy) in the transition to a low-carbon economy by many domain experts and some of the major Energy companies. However, large-scale storage remains a significant challenge due to hydrogen's low energy density and its physical and chemical properties. Among the various underground storage options, salt caverns stand out due to their geological properties, such as low permeability, low porosity and self-healing capacity. \\ This thesis provides a comprehensive review of the state of the art in Hydrogen Underground Storage in salt caverns, focusing on the technical, geomechanical and chemical challenges associated with key challenges such as the long-term stability, the storage capacity, and operational challenges according to the most recent updates available in literature, highlighting then future projects under study by many major Energy Companies needed to optimize the UHS in salt caverns.