Underground Hydrogen Storage in the European Union: Regulatory Status, Gaps, and Recommendations

Underground hydrogen storage (UHS) is emerging as a key enabler of the green energy transition, ensuring energy system stability and supporting large-scale integration of renewable sources. Despite its technological readiness, UHS deployment in Europe faces significant barriers due to the absence of a clear legal status and a dedicated regulatory framework. Current EU energy, climate, and environmental directives do not explicitly define hydrogen as a storage medium, creating legal ambiguity. Lessons from underground gas storage (UGS) and Carbon Capture and Storage (CCS) provide valuable reference points; however, direct transfer of these frameworks is insufficient due to hydrogen’s the distinct physicochemical characteristics and associated safety and monitoring challenges. Major regulatory gaps have been identified in legislation, liability, ownership, technical standards, and monitoring. To address these issues, a hybrid UHS model is proposed—combining the operational practices of UGS with the regulatory rigour of CCS—to accelerate safe and efficient implementation of UHS in Europe and support the broader transition to green energy.