Save Nic's Finger, page-49

"Hydrogen isn't an energy source, it's storage medium"

You're confused there. Every "source" of energy is just stored energy. Fuel, food, tree, even you can explode in gigantic nuclear explosion if something gets atoms in your body to fuse or split.

Electricity is used to extract hydrogen just like electricity is used in oil refineries to extract unleaded fuel or other derivatives. But neither unleaded fuel nor hydrogen is stored energy into like lithium battery.
You use hydrogen to propel rockets into space. It needs no energy stored into it lol