How does hydrogen get from the producer to the consumer?

Hydrogen can be stored in its pure form. To achieve a high energy density, hydrogen is stored either in gaseous form and under high pressure or it is liquefied (LH₂). In order for hydrogen to be liquefied, it must be cooled to -253 °C. This means that about one third of the energy stored in hydrogen is used for cooling. On the other hand, LH₂ can be used without further pre-treatment, for example in fuel cells. LH₂ begins to evaporate immediately after cooling is completed. For the storage of gaseous hydrogen, salt caverns are being considered in addition to storage in pressure tanks.

Hydrogen can be combined with nitrogen to produce ammonia (NH₃). This important process is carried out on a scale of 150 million tonnes annually worldwide - mainly for the production of fertilisers based on natural gas. Therefore, ammonia is already traded and transported globally. Compared to LH₂, liquefaction only requires temperatures of around -33 °C, which means less energy is needed for cooling. However, energy is needed to synthesise the ammonia. Furthermore, ammonia is toxic and requires handling by trained personnel.

One option for carbon-based storage is synthetic fuels such as paraffin, diesel, natural gas or methanol. An advantage of these fuels is that existing infrastructures such as refuelling facilities can be used. They also offer the possibility of potentially defossilising the non-electrified vehicle fleet.

LOHCs are organic compounds that are liquid at room temperature and can be reversibly charged and discharged with hydrogen. The storage of LOHCs is less energy-intensive than the storage of LH₂ or ammonia. However, when using LOHCs, it must be taken into account that the discharged carrier must always be brought back to a loading station to complete the cycle.

Hydrogen can also be stored in the form of metal or boron hydrides, for example magnesium hydride (MgH₂) or sodium borohydride (NaBH₄). These hydrides offer the advantage of high hydrogen densities. However, not all aspects of charging and discharging with hydrogen have been technically solved yet, which is why these hydrides have not yet become established as storage options.