A Decision-Making Tool for the Selection of Potential Hydrogen Storage Geological Sites: Application to Salt Caverns

The rapid expansion of hydrogen production from low-carbon sources requires large-scale, flexible and reliable storage solutions to balance supply and demand and support the integration of hydrogen into future energy systems. Underground hydrogen storage, and particularly storage in salt caverns, offers significant potential due to the favorable characteristics of salt formations and the possibility of storing and recovering large quantities of hydrogen. However, identifying and comparing prospective storage sites requires the simultaneous consideration of geological suitability, uncertainty in the available data, operating characteristics, and project-specific requirements. Existing screening approaches generally address only subsets of these aspects, limiting their applicability to comprehensive site comparison and ranking. This study develops a holistic Decision-Making Tool (DMT) for the preliminary screening and comparative ranking of potential hydrogen storage sites in salt formations. The methodology integrates four complementary information categories: Static, Static-Probabilistic, Dynamic, and Operator’s data. Deterministic suitability assessment, Monte Carlo-based uncertainty propagation, engineering feasibility calculations of hydrogen storage performance, and operator-defined requirements are sequentially combined into a scenario-dependent final ranking. The methodology has been implemented in an Excel-based, transparent tool, allowing multiple candidate sites and alternative storage scenarios to be evaluated without changing the underlying calculation framework. Application to three prospective evaporite areas in western Greece demonstrates the ability of the tool to distinguish between sites not only according to geological suitability but also according to data confidence, storage performance and proximity to hydrogen production and consumption hubs. The resulting framework provides a practical bridge between early-stage geological screening and engineering-oriented site selection, while retaining the flexibility to adapt the ranking to different project objectives and levels of decision-making.