Underground Gas Storage as a Resilience Factor for European Energy Systems During Energy Crises

Underground gas storage (UGS) facilities serve to balance natural gas networks within a given area. The nature of natural gas network balancing is twofold: long-term (seasonal) during periods of significant gas withdrawal (the cold half-year) and short-term (daily) during periods of peak natural gas demand throughout the day. The first type of balancing has been a standard characteristic for many years, covering increased demand during the winter season. In contrast, the importance of daily balancing is growing alongside the ongoing energy transition, where natural gas-based power generation sources flexibly replace renewable energy sources that are dependent on the time of day or weather conditions. The necessity for increased balancing of energy systems makes them more sensitive to crisis situations. This article presents the key role of UGS as a fundamental resilience factor for European energy systems, particularly in the face of energy crises triggered by geopolitical instability. Conflicts are redefining the role of UGS as a pillar of energy security. This study analyzes how strategic gas reserves mitigate the effects of sudden supply disruptions and price shocks caused by geopolitical factors. It describes impact scenarios of two conflicts: Russia’s invasion on Ukraine and the conflict in the Persian Gulf leading to the closure of the Strait of Hormuz. While UGS is essential for the short-term management of natural gas supply flows, its long-term value lies in providing a “strategic buffer” that allows energy systems to adapt to unforeseen geopolitical conflicts. Integrated storage management is indispensable for maintaining the operational integrity of the European transmission and energy system during periods of heightened instability. The paper also identifies necessary directions for the development of UGS systems. Between 2016 and Q1 2026, the share of eastern gas imports declined from over 40% to 5.2%, while LNG increased to 41.7% of total inflows, confirming the strategic importance of underground gas storage in maintaining energy system resilience.