Influence of Alternative Energy Carriers on Tunnel Safety – A Quantitative Consequence Analysis

The composition of road traffic is nowadays clearly dominated by petrol and diesel powered vehicles. However, one of the major goals against further climate change is the decarbonisation of road traffic by the use of vehicles with alternative energy carrier technologies. The currently most promising ones are the Li-Ion battery-powered vehicles, fuel-cell-powered vehicles and vehicles powered with internal combustion engines using hydrogen or liquefied natural gas. Although the latter do currently represent only a small share of the total traffic, it can be assumed that alternative powered vehicles will soon take on greater significance. Therefore, a deeper understanding of possible additional risks, especially in considering incidents in tunnel structures, is of greatest interest and is currently investigated in various research projects, such as [1], [2], [3]. In these projects, the focus lies only on one of the alternative energy carriers mentioned above. However, in order to obtain a thorough overview of relevant possible additional dangers as well as related consequences on the safety of tunnel users, the aim of the BASt-project FE 15.0675/2020/ERB [4] as well as of the present paper is to consider all relevant alternative powered vehicle types in order to identify possible need for adaption of the risk-analytical assessment method for road tunnels. To this aim, dangerous zones according to, for example battery fires, jet fires or vapor cloud explosions have been assessed by using numerical as well as analytical models. In the course of a detailed evacuation model, considering a large variety of agents with different velocities and respiratory volumes, the corresponding consequences of alternative energy carriers on tunnel users can be assessed. This paper will demonstrate and discuss in detail the foundation of the research project with focus on the evacuation simulation, as well as the resulting consequences analysis on tunnel users.