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Hydrogen demonstrator in Thun: A step in the direction of sustainable mobility

Hydrogen as a sustainable alternative for powering vehicles has long been the subject of discussion among experts. In fact, hydrogen offers several advantages compared with other alternative energy suppliers. In order to gather experience in the sustainable production, storage and transport of hydrogen, armasuisse Science and Technology is planning the construction of a hydrogen demonstrator in Thun, together with other agencies of the DDPS.

Dr. Hanspeter Kaufmann and Elianne Egli, armasuisse Science and Technology

A fuel cell vehicle in front of a hydrogen filling station on the EMPA premises
In Thun, a hydrogen filling station, like one on the EMPA premises, and a mobile filling station for field operation are planned.

Environmental protection and an ecologically sustainable lifestyle have become very important, not only for many private individuals, over the last few years and decades. Both the Federal Administration and the DDPS have set themselves the goal of reducing their ecological footprint – for example, by increasing the share of renewable energies. Mobility is a major driver of the CO2emissions. In Switzerland, mobility is responsible for around one-third of energy consumption and causes almost 40% of CO2emissions. In the DDPS, mobility causes 75% of the CO2emissions, with 50% of these due to air traffic. The DDPS consumes altogether around 80 million litres of fuel each year (cf. mobility).

Trial operation of hydrogen-operated vehicles 

Various promising approaches exist to reduce the fossil CO2emissions. One of these is the use of renewable hydrogen in mobility. For many years, hydrogen has been seen as having significant potential in green mobility.

In order to examine the possible uses of hydrogen technology in military mobility according to the current state of the art, armasuisse Science and Technology (S+T) as the technology centre of the DDPS is planning the construction of a hydrogen demonstrator together with other agencies of the DDPS. The aim of this project is the trial operation of hydrogen-powered vehicles with self-produced hydrogen, using renewable energies.

But what in fact is hydrogen? Hydrogen most frequently occurs on earth in combination with oxygen (O2) in the form of water (H2O) or water vapour.

To generate hydrogen, water is broken down into its two components, oxygen and hydrogen. The cleanest method of doing this is electrolysis through sustainably produced electricity. If hydrogen and oxygen are then combined again, electrical energy and heat are generated. This process can occur, for example, in electric vehicles which are powered by a fuel cell. Unlike battery-powered electric vehicles, electricity with a fuel cell is thus generated directly during propulsion.

Hydrogen no more dangerous than petrol

Each innovation, however, usually evokes reservations as well as enthusiasm. Reservations which often emanate from the competition. It is thus hardly surprising that various myths are circulating on the disadvantages of the use of hydrogen. For example, it is claimed that hydrogen is so volatile that it can diffuse through storage tank walls, which means that hydrogen can only be stored with heavy losses. It is true that this substance can «move through walls» due to its comparatively small atomic size. However, while these losses used to be restricted in industrial use through skilful warehouse management, car manufacturers today have material combinations which can restrict this hydrogen leakage, as it is known, to a minimum.

Another persistent myth claims that vehicles driven by hydrogen are potentially highly dangerous. In fact, hydrogen is just as flammable as petrol and can form explosive mixtures with oxygen. In addition to electricity generation in fuel cells, hydrogen is therefore also highly suitable for combustion in engines. In contrast to heavy petrol fumes, the low density of hydrogen means that, in the event of accidental leakage in road traffic during an accident, for example, it immediately volatilises in an upward direction, so that any flammable mixtures tend to form above the vehicle, while petrol vapours spread over the ground.

The range of hydrogen propulsion is higher than battery-electric vehicles 

The question of whether hydrogen will be able to establish itself as a fuel at all in mobility depends not only on its suitability as a fuel for electric vehicles or internal combustion vehicles.

And if this question were to be judged solely on the basis of the different efficiencies of energy use in battery and fuel cell-powered vehicles, hydrogen would not be very attractive as a fuel. For mobility, however, other factors such as the range and the payload are significantly more important. And here, hydrogen offers distinct advantages over purely battery-electric mobility, particularly for transport purposes, thanks to its high energy density. Whether these advantages, which basically also apply for military vehicles, would also prove themselves in realistic deployment scenarios, must be clarified in greater depth with the demonstrator at armasuisse S+T.

If hydrogen is produced via renewable energies, it is also a sustainable resource which can be used not only for mobility, but also for supplying electricity (electricity storage) and for raw material production in chemistry. The fact that the materials required for production and storage can in principle come from the neighbouring, regional environment certainly does not detract from the matter.

Gaining experience with the Defence Future Mobility Demonstrator 

armasuisse S+T’s planned hydrogen demonstrator aims to enable the Armed Forces, the AFLO and other agencies in the DDPS to use hydrogen as an energy source under the general conditions of military operation. As hydrogen is particularly interesting as an alternative fuel for vehicles, this demonstrator is called the «Defence Future Mobility Demonstrator», abbreviated to DFMD. Technologically, the DFMD is based on the preliminary work of the EMPA, which has already implemented and refined a similar demonstrator for civilian users in Dübendorf.

armasuisse S+T is intending to gather experience with the DFMD – on the one hand concerning the sustainable production and storage of hydrogen, and on the other hand regarding the transport and distribution of hydrogen. Hydrogen has long been used in civilian life, in particular for industrial purposes, but experience is still lacking with regard to its use for mobility purposes and specifically with regard to its military usage.

The planned system in Thun will enable the various users to have test operation with vehicles which use hydrogen either as a fuel for an electricity-generating fuel cell, or for a combustion engine. In addition to measuring various operating data and analysing the flows of materials during the trial phase, we also pay special attention to the qualitative aspects, such as reliability and ease of use of the system. This also applies in particular for field refuelling with hydrogen, one of the biggest challenges in this project.

It is aimed to implement this demonstrator in the next few years, with the goal of starting test operations between 2023 and 2025.