And what about small vehicles such as motorcycles?

When it comes to hydrogen, a special approach is required for small vehicles such as motorcycles. After all, they can’t simply roll up to the hydrogen station and fill up with gas – the pressure on the fuel tank would be too great. Besides, it would be impossible to achieve the required storage density by means of a high-pressure tank small enough to be fitted on a motorcycle. Now, however, a new development from Fraunhofer IFAM in Dresden aims to cater to such applications. PowerPaste is a solid fuel based on magnesium hydride. Instead of heading to the filling station, motorcyclists simply have to replace an empty PowerPaste cartridge with a new one and then top up a tank with water. “PowerPaste stores hydrogen in a chemical form at room temperature and atmospheric pressure,” explains Dr. Marcus Vogt, research associate at Fraunhofer IFAM. Were a motorcycle to stand for hours in the baking sun, there would still be no danger, since PowerPaste only begins to decompose at temperatures of around 250°C. In fact, PowerPaste would also be an option for larger vehicles, especially where there is a lack of infrastructure in the form of hydrogen stations. After the cartridge is inserted, a plunger forces out the PowerPaste in the precise quantity required by the fuel cell. Water from an onboard tank is then added, and the ensuing reaction produces hydrogen. As with the HyMethShip propulsion system, half of the hydrogen produced comes from the added water. “PowerPaste has an enormous energy storage density,” says Vogt. “It is substantially higher than that of a high-pressure tank designed to withstand 700 bar. And compared to batteries, it has ten times the energy storage density.” Fraunhofer IFAM is currently building a production plant for PowerPaste at the Fraunhofer Project Center for Energy Storage and Management Systems ZESS. Scheduled to open in 2021, this new facility will be able to produce up to four metric tons of PowerPaste a year – not only for motorcycles.