A Classification of Existing and Emerging Hydrogen Storage Technologies

Hydrogen as an energy carrier is expected to play a significant role in the energy systems of the future. Storing hydrogen at utility scale is a relatively new application for which technologies are yet too mature. This paper provides a review of the existing and emerging hydrogen storage technologies. The technologies are categorized based on the phase at which hydrogen is stored - gas, liquid or solid - and the type of bonds - compound or free hydrogen. For each category, the storage technologies are compared based on technological operational conditions, technology efficiency, safety, and economic projections.