Summary of an Experimental Investigation to Evaluate Potential Technical Integrity Issues in Porous UGS containing Hydrogen

The storage of hydrogen in porous underground gas storages is a promising solution for large-scale energy storage in Germany. This solution provides a cost effective and large capacities in comparison to other storage types, however hydrogen interactions in UGS is a perplexing topic due to its foreign nature and therefore its behavior in the subsurface could be unpredictable. The HyInteger Project was tasked with investigating the integrity of subsurface equipment and near wellbore region in strongly corrosive environments in porous UGS containing hydrogen for long-term safe and reliable storage. Hydrogen interactions with the near-wellbore region in underground gas storages are investigated in small-scale laboratory experiments. Autoclaves are implemented to recreate typical underground gas storage conditions containing hydrogen gas. Pressures up to 200 Bar and temperatures up to 120°C can be achieved allowing for a huge range of testing possibilities and research avenues to be explored. Petro-physical, geochemical and material investigations are carried out in order to observe potential changes to the near-wellbore region and its subsurface equipment due to hydrogen presence.