Energy

Storage of liquid hydrogen

In order not to use big containers, it is possible to make use of liquid hydrogen, which occupies less volume than methane. But also this method causes some difficulties: hydrogen becomes liquid at –253°C and in order to keep it in this state special tanks and lots of energy are needed. Moreover, there are many problems related to safety (losses during refuelling or in case of accident). For this reason the most modern tanks for cars are made up of two very resistant steel layers with an empty space in between. Storage in liquid state is probably the best technology as it satisfies car requirements. However, it also has some cons, for example: the system is much more complex, not only on board of the vehicle but also on earth, when dealing with the distribution and refuelling, as well as higher costs connected to it. Also the energy cost for liquefaction is high, as it amounts to 30% of the energy content of the fuel, while cost for compressed hydrogen is between 4% and 7%.