Hydrogen Quality in Underground Storage

Sustainably produced and used hydrogen is key to achieving climate neutrality. To ensure that Germany can successfully manage the hydrogen ramp-up both financially and in terms of timing, the focus is on utilizing existing gas infrastructure, such as networks and storage facilities. Underground storage facilities are an indispensable component of this effort, as they offer the only large-scale structuring option within the hydrogen infrastructure. Depending on their previous use and the type of storage facility, the use of underground gas storage facilities can lead to changes in the composition of the gas. 

This study provides information on which components may be relevant and at what concentrations, and defines possible purification steps. It is based on the currently discussed quality requirements for H₂ ranging from 98 mol⁻¹TP6T to 99.97 mol⁻¹TP6T.

This study examines the use of all relevant categories of underground storage facilities for hydrogen storage, namely

• Freshly salted salt caverns


• Converted natural gas salt caverns with various blankets


• converted oil or product salt caverns and


• a retrofitted or newly constructed porous storage facility

The project was successfully completed, and the report was published in January 2026.