With its “Hydrohub” initiative, the Tüv Nord Group has been providing advice and information on the topic of hydrogen in Germany since July 2021. It answers central questions about the use of hydrogen in the mobility sector and provides information about the current state of development in this area.
How dangerous are hydrogen cars?
Hydrogen is a highly flammable element, but hydrogen vehicles are designed in such a way that even in the event of an accident, hydrogen can only be released with difficulty, so the risk of an explosion is low. Numerous crash tests have shown that a car would need to be totaled, to damage the hydrogen tank and release hydrogen.
Can trains run on hydrogen?
In principle, trains can run on hydrogen, but the technology is still in the test phase. In Lower Saxony, regional trains with hydrogen propulsion have already been tested. In comparison to hydrogen cars, the trains have a slightly higher range of 600-800 kilometres. The hydrogen is stored in tanks on the roof and converted into electricity in fuel cells, which is then used for propulsion or temporarily stored in a battery. In addition to providing the driving energy, the batteries also store the braking energy, thus contributing to the high energy efficiency of the overall system. The trains are refilled via a mobile hydrogen filling station. After the successful test phase in Lower Saxony, the Rhein- Main-Verkehrsbund also wants to use hydrogen trains in regional transport. This will primarily replace diesel trains, which account for 40 % of rail traffic. There are similar plans in Baden-Württemberg.
What is the range of hydrogen cars?
The range of hydrogen cars depends mainly on the tank capacity. The consumption and tank volume are – in contrast to combustion vehicles – not given in litres, but in kilograms. Some models manage a range of over 600 kilometres and are comparable to petrol or diesel vehicles in this range. Battery-powered electric vehicles must have a large battery storage to cover similar distances.
What are the advantages of hydrogen cars?
A key advantage of hydrogen-powered cars is the almost endless availability of hydrogen, which solves the problem of finite fuels such as petrol and diesel. Moreover, unlike diesel or petrol cars, vehicles with fuel cell technology emit neither fine dust, nitrogen oxides nor CO2 during operation. The only waste product is water (vapour). This makes them locally emission-free. Another advantage is the long range of hydrogen cars compared to conventional electric cars and the fact that they can be refuelled quickly.
Are there any disadvantages to hydrogen mobility?
The hydrogen filling station network in Germany is still far from being fully developed. Moreover, hydrogen is still produced in quantities that are too small and is therefore very expensive, which means that the cost of a hydrogen car remains high. Currently, for example, the Toyota Mirai, one of two hydrogen car models in Germany, costs between 64,000 and 74,000 euros.
Where does the use of hydrogen make sense?
In contrast to other fuels, the combustion of hydrogen does not produce any pollutants that are released into the atmos-phere. Compared to battery-powered vehicles, an important advantage of hydrogen cars is in the commercial vehicle segment, where a particularly high level of performance is required. To reach this level, immensely large batteries would have to be installed in the battery-powered variant. These are not only material-intensive, but also a major cost driver in the purchase of the vehicle. To reproduce the same stored energy of two full tanks of 700 bar hydrogen with battery cells, the batteries would take up many times the volume and mass of the hydrogen tanks. The additional weight would also have a negative impact on range and payload, especially for trucks. In terms of range, hydrogen cars are in no way inferior to conventional internal combustion and diesel vehicles.
How is hydrogen stored?
Depending on whether hydrogen is to be stored in gaseous or liquid form, there are various storage options: one form is compressed gas storage in an underground cavern. Here, large quantities of hydrogen can be stored in a gaseous state. A second method is storage in a liquid state: for this, the hydrogen must be cooled down to -253˚C in order to liquefy and be able to be stored in socalled cryotanks. Incidentally, hydrogen has less volume in its liquid state than in its gaseous state. LNG storage tanks are therefore ideal for transport over long distances. For this purpose, there are also LNG terminals where gas is liquefied and then transported by ship, for example.
We would like to thank the TÜV Nord Group for permission to reprint the texts they have published on www.tuev-nord.de