That's my understanding too. The "We don’t need any energy input, and it bubbles hydrogen like crazy." is pretty confusing to me, knowing how much of an energy

That's my understanding too. The "We don’t need any energy input, and it bubbles hydrogen like crazy." is pretty confusing to me, knowing how much of an energy sink producing aluminium from bauxite is… (I guess the question is if it's viable to replace e.g. Li-Ion batteries with an Aluminium + Water "tank") I don't see any mention of how hot the Aluminium + Water ⇒ Al₂O₃ + H₂ reaction gets — any heat released from that would be pure waste of energy…