[eru]

Hydrogen isn't really anything you'd be more keen to sit on top than other batteries, or is it?

[jojobas]

Hydrogen by itself has the energy density of zero. Batteries are nearing the energy density of high explosives (and for some types, such as Li-S, exceed it), and, unlike hydrogen, have all the components required for energy yield within micrometers of each other.

[eru]

> Hydrogen by itself has the energy density of zero.

Not sure how you measure that? Oxygen from the air is plentiful.