Identification and quantification of risks of subsurface hydrogen in salt caverns

This report describes the research contribution of TNO to the project “Testen van opslag waterstof in zoutcaverne ter flexibilisering duurzaam energiesysteem” with subsidy reference DEI4819001. 
TNO performed this research during 2020 and the beginning of 2021 which concerned the development of a generic methodology for identification and quantification of risks that come with subsurface hydrogen storage in salt caverns. 
The research consisted of the following two studies: 

1. Performing a so-called BowTie analysis targeted at events that can cause a loss of integrity of the storage system with leakage of hydrogen as a consequence, provision of examples of relevant high-risk failure scenarios (which describe potential future situations and developments of the storage system and that can lead to undesirable events), and formulation of applicable risk-mitigation measures and suitable monitoring techniques.
2. A modelling study to quantify the effects of uncontrolled partial or full free outflow of hydrogen due to leakage at the wellhead (from tubing, casing) or, as an extreme case, due to a blow-out.