They have been around for a hundred years, but still, we barely understand electrolyzers. Significantly though, these devices can be used to produce green hydrogen, therefore playing an essential role in the energy transition. That’s more than enough reason to unravel the secrets of the electrolyzer and to engineer one that is efficient, affordable, and modular so that it can be used on a large-scale. TU/e is doing exactly this, within the so-called Dutch Electrolyzer consortium, together with partners and companies. In six questions we take you through the enigma of anodes, bubbles, and electrolytes.