State of knowledge on the storage of hydrogen in salt caverns


The 2019 energy and climate French law plans to significantly increase the share of renewable energies in the final gross energy production. As some of these energies are intermittent or fluctuating, their increasing integration will require the use of massive energy storage solutions. One such solution is to convert the electricity produced into hydrogen by electrolysis of water and then store it underground. There are already more than 600 underground storage sites in the world, mainly dedicated to the storage of natural gas and hydrocarbons, including 23 in France. Of all the options under study, salt cavern storage now appears to be the most mature solution to meet the needs of the energy transition, particularly because of the remarkable natural seal offered by salt.

From 2016 to 2021, the ROSTOCK-H research project dealt with the risks and opportunities of geological storage of hydrogen in salt caverns in France and Europe. It has improved our knowledge of the phenomena involved in such underground storage facilities, so that they can be optimized and operated safely. Supported by Air Liquide, this project brought together research teams from Géostock, ARMINES, the University of Lorraine and Ineris.

This document summarises the main work carried out throughout the project and proposes guidelines for the design and management of underground hydrogen storage in a saline cavity. It presents the concept of underground hydrogen storage in a salt cavity (chapter 2), the applicable regulatory framework and associated administrative procedures (chapter 3), the specificities of this type of storage (chapter 4), its design (chapter 5), its technical and economic analysis (chapter 6), its risk analysis and environmental monitoring (chapter 7) and, finally, the societal acceptability of this emerging technology (chapter 8).