Jules Verne wrote in his book 'The Mysterious Island' in 1874. “Yes, my friends, I am convinced that one day water will be used as fuel and that hydrogen (…) will be an inexhaustible source of heat and light!" He was a visionary and now he gets it right. Why now, and what role will hydrogen play in a sustainable energy system? Hydrogen, just like electricity, is not an energy source but an energy carrier, but why do we need that energy carrier? In the keynote, I will discuss this systemic role of hydrogen and how hydrogen can be made, transported, stored and used.