SAFE-T – Salt As the Future of Energy Transition. Is Romanian salt an option for storing hydrogen, other resources or waste?

Abstract: The global climate will be strongly affected unless we can improve our energy sector in almost every respect. In light of this recent challenge humanity faces, one of the solutions is a transition from fossil fuels to a more sustainable strategy. The research project (SAFE-T – Salt As the Future of Energy Transition. Is Romanian salt an option for storing hydrogen, other resources or waste?) focuses on possible applications of salt storage in energy transition applications, such as energy storage as hydrogen or compressed air in salt caverns, CO2 storage in near-salt structures, geothermal energy or storage of nuclear waste. The project aims to assess and understand a series of risks related to salt-related storage projects in the Romanian Carpathians. The objectives are to determine the distribution, origin and effects of heterogeneities and shear zones on salt deformation and to understand the Quaternary to recent movements and displacement rates within the salt bodies. A team of early career scientists with a wide variety of skills will tackle this topic using multiple research methods: field-based mapping, UAV-based mapping, salt microstructural analysis and inclusions analysis for determining lithology and source area, and, various methods to quantify and understand recent uplift/subsidence rates of salt structures. The results of this project are expected to push forward our understanding regarding the internal deformation of salt structures and the implications for salt storage applications.

Project results (executive summary):

Within the SAFE-T project, we advanced the understanding of salt deformation processes that are critical for evaluating the feasibility and safety of salt-related energy transition applications in the Romanian Carpathians. A key outcome is the development and validation of an integrated methodological framework combining field-based observations, UAV-derived digital outcrop models, radiocarbon dating, and PSInSAR analysis to quantify Quaternary to present-day salt deformation rates.

Applying this approach to the Manzălești salt diapir, one of the largest exposed halite bodies in Europe, we demonstrated that previously enigmatic near-horizontal white surfaces within the salt are sediment-filled dissolution notches formed by paleo-river terraces, rather than internal shear zones. Radiocarbon dating of vegetal remains preserved within these notches allowed us to constrain their formation to the last ~720 years and to calculate relative uplift rates of the salt body. The derived uplift rates (approximately 10–30 mm/year) are among the highest documented for salt diapirs in humid continental climates.

These long-term rates are independently confirmed by high-resolution PSInSAR data, which reveal ongoing present-day uplift averaging ~10 mm/year and locally exceeding 50 mm/year. Together, these results fill a critical data gap regarding recent salt diapir dynamics in the Romanian Carpathians and demonstrate that salt bodies can remain highly mobile on historical and societal timescales.

Overall, the project delivers new quantitative constraints on salt deformation, clarifies the origin and significance of heterogeneities within exposed salt structures, and provides a robust framework for assessing geological risks associated with subsurface storage, geothermal exploitation, and infrastructure development in salt-bearing regions.

Cognitive and socio-economic impact:

The SAFE-T project contributes significantly to both scientific understanding and societal decision-making related to the energy transition. Cognitively, the project advances conceptual models of salt tectonics by demonstrating that measurable salt deformation occurs on centennial to decadal timescales in humid continental settings. By integrating geomorphological indicators, geochronology, and satellite-based ground motion monitoring, the project promotes a holistic, process-based understanding of salt as a dynamic geological material rather than a static storage medium.

From a socio-economic perspective, these findings are directly relevant to risk assessment and land-use planning in regions underlain by salt. Quantified uplift rates and spatial patterns of deformation provide essential baseline information for evaluating the long-term integrity of salt caverns considered for hydrogen or compressed air energy storage, as well as for CO₂ storage and waste isolation. The results also have implications for infrastructure safety, groundwater protection, and hazard mitigation, particularly in areas prone to sinkholes, landslides, and surface deformation.

By improving the predictability of salt-related ground movements, the project supports more informed investment decisions and reduces uncertainty for stakeholders in the energy, mining, and civil engineering sectors. In addition, the identification and dating of sediment-filled dissolution features open new interdisciplinary links with archaeology and geoheritage studies, strengthening public awareness of the geological and cultural significance of salt landscapes in Romania. Collectively, SAFE-T enhances scientific capacity, supports sustainable resource management, and contributes to safer and more resilient energy transition strategies.

List of publications:

• Tămaș, D.M., Tămaș, A., Hajdas, I., Sava, G.O., Poncos, V., Teleaga, D. 2025. Quaternary to recent uplift ratesof salt diapirs in the RomanianCarpathians determined fromradiocarbon dating and PSInSARdata. Scientific Reports, 15(1), https://doi.org/10.1038/s41598-025-08293-8

List of conference presentations:

• Tamas, D.M., Tamas. A., Hajdas, I. 2025. Radiocarbon Dating and InSAR Mapping of Quaternary Salt Diapir Uplift in the Romanian Eastern Carpathians. 1st SaltAges conference, 31 Mar – 4 Apr 2025, Krakow, Poland.
• Tamas, D.M., Palcu, D.V., Tamas, A. 2025. Salt Formations in Romania and the Salt Ages COST project. EUsalt Annual Conference 2025, 10-13 June, Bucharest, Romania.
• Tamas, D.M., Tamas. A., Hajdas, I. 2025. Quaternary Salt Diapir Uplift in the Romanian Eastern Carpathians: Insights from Radiocarbon Dating and InSAR-Based Mapping. AAPG’s 2025 International Conference and Exhibition (ICE), 30 Sep – 3 Oct 2025, Rio de Janeiro, Brazil.