Hydrogen is a chemical element with chemical symbol H and atomic number 1.
It is used in water electrolysis during the power-to-gas process as a storage medium for excess electricty.
https://docs.google.com/document/d/1aK4yYqHWIJF1k-XG7cnN2DooUs_sveXaR6iOKjBmN54/edit; https://www.enargus.de/pub/bscw.cgi/d4022323-2/*/*/Wasserstoff.html?search=Wasserrstoff&scope=all&op=Wiki.getwiki