Check out the "Clean Hydrogen Ladder" document.

Hydrogen wastes a large amount of energy.

Unless you produce it using the Sulfur-Iodine cycle in a high-temperature nuclear reactor.

See: https://en.wikipedia.org/wiki/Sulfur%E2%80%93iodine_cycle

and: https://www.jaea.go.jp/04/o-arai/nhc/en/research/hydrogen_he...