Although hydrogen produced from renewable energies has been under discussion for decades as a possible alternative to fossil fuels, it has so far only played a minor role. Recently, however, there have been signs of change, so that “green” hydrogen could gain momentum in the energy sector: More and more powerful electrolysis systems are available, and the prices for these systems are falling. If, however, PEM electrolysers were to be added on a large scale, iridium could become scarce and thus more expensive and thus stand in the way of a reduction in the already considerable investment costs.