For the German trains, luckily there is plenty of hydrogen that is a waste product of existing chemical industry in Germany. In many places there is extra power

For the German trains, luckily there is plenty of hydrogen that is a waste product of existing chemical industry in Germany. In many places there is extra power from wind, solar, and hydro which is wasted when production is too high. So the idea is to use this excess power for hydrogen production. Additionally hydrogen can use the existing natural gas pipeline infrastructure. In times of high wind, there can be enough energy to power all of Europe/Japan in a few days. New types of turbines need to be put into production that can actually use this however. Current ones are shut down so they are not damaged. So far I'm only aware of prototypes, but it's being worked on.