Risk Assessment of the Large-Scale Hydrogen Storage in Salt Caverns

Abstract

Salt caverns are accepted as an ideal solution for high-pressure hydrogen storage. As well as considering the numerous benefits of the realization of underground hydrogen storage (UHS), such as high energy densities, low leakage rates and big storage volumes, risk analysis of UHS is a required step for assessing the suitability of this technology. In this work, a preliminary quantitative risk assessment (QRA) was performed by starting from the worst-case scenario: rupture at the ground of the riser pipe from the salt cavern to the ground. The influence of hydrogen contamination by bacterial metabolism was studied, considering the composition of the gas contained in the salt caverns as time variable. A bow-tie analysis was used to highlight all the possible causes (basic events) as well as the outcomes (jet fire, unconfined vapor cloud explosion (UVCE), toxic chemical release), and then, consequence and risk analyses were performed. The results showed that a UVCE is the most frequent outcome, but its effect zone decreases with time due to the hydrogen contamination and the higher contents of methane and hydrogen sulfide.

Toward a Fundamental Understanding of Geological Hydrogen Storage

“…may promote bacterium growth in the cavern’s “Fillings” and sump. Microorganism living in the fillings may consume anhydrite salt causing H 2 loss, permeability increment, H 2 leaking, and H 2 S generation in the system. , More importantly, the fillings problem is common in the bedded salt cavern system and may emerge as undissolved rock layers, e.g., anhydrite and mudstone as H 2 leakage hot-spots.…”

“…Microorganism living in the fillings may consume anhydrite salt causing H 2 loss, permeability increment, H 2 leaking, and H 2 S generation in the system. 165,203 More importantly, the fillings problem is common in the bedded salt cavern system and may emerge as undissolved rock layers, e.g., anhydrite and mudstone as H 2 leakage hot-spots. its high thermal conductivity, self-healing properties, impermeable behavior, and plastic properties, it could establish a potential sealing to mitigate H 2 leakage in the system.…”

The Role of Salt Tectonics in the Energy Transition: An Overview and Future Challenges

“…Third, modelling the final geometries of leached caverns, and hence safely designing cavern fields, requires an understanding of the likely distribution of intra-stock lithologies and other heterogeneities as cavern geometry is highly sensitive to spatial variations in solubility (e.g., Wilke et al, 2001;Cartwright and Ratigan, 2005;Rautman and Lord, 2007;Czapowski et al, 2009;Looff and Rautman, 2010a,b;Warren, 2016;Cyran, 2020) (Figure 9). Fourth, maintaining the required purity of stored hydrogen requires an understanding of what lithologies and mineralogical alterations will outcrop on cavern walls since hydrogen can be highly reactive to some minerals such as anhydrite which may form contaminants such as H 2 S that also pose a significant safety issue (e.g., Panfilov, 2016;Portarapillo and Di Benedetto, 2021).…”

Selection of Underground Hydrogen Storage Risk Assessment Techniques

“…Yang et al [54] used the Fault tree models and AHP methods. Other methods of assessing the risk of hydrogen storage in salt caverns were used by Portarapillo and Di Benedetto [55]. The preliminary quantitative risk assessment (QRA) method was used for the risk analysis, while the bow-tie analysis was used to indicate all possible causes and effects of the discussed process.…”