CFD-based risk analysis in Natech scenarios for hythane pipelines

Given the increasing relevance of natural hazard triggering technological disasters (Natech), this article contributes to understanding the complexity of the transition to the hydrogen economy. The study assesses the risks associated with integrating hydrogen into the existing natural gas infrastructure under Natech scenarios, focusing on increased safety risks due to natural hazards. A quantitative risk assessment is performed for different hydrogen/methane ratios on a case study pipeline in the Bondeno-Ferrara area, considering three losses of containment (earthquake, flooding and lightning). The contribution of this work lies in the application of advanced computational fluid dynamics modelling to accurately simulate large-scale turbulent diffusion of gas mixtures in the atmosphere. The results indicate that the individual risk of fires and explosions increases from 10−8 to 10−7 year−1, when moving from pure methane to 10 % hydrogen. The proposed framework can be adapted to other Natech scenarios by incorporating appropriate hazard and vulnerability models.