Hydrogen is an ideal energy carrier. It is easy to transport and can store energy without any problems, even in the long term. If it is produced with renewable energies, it is also climate-friendly (green). Of course, it only makes sense to convert surplus electricity into hydrogen. The fluctuating power supply of renewable energies can be stabilized by temporarily stored hydrogen, by converting the hydrogen back into electricity via fuel cells during "dark periods". The much-criticized efficiency of this process loses its significance, since without this hydrogen production, the green electricity would not be used at all. Hydrogen thus becomes an important link between the industrial, heating and mobility sectors.