It is important to note that hydrogen, due to the small size of the molecule, is really hard to contain as a gas. Moreover, leaked hydrogen gas is an indirect but potent greenhouse gas via interfering with the degradation of existing methane in the atmosphere. If we leak enough hydrogen, we might not be helping the climate very much.

I was once in a presentation which claimed formic acid to be a better alternative, but I'm not an expert in that field, so I can't comment on its merits.