What I often don't see mentioned in the discussion about using hydrogen power is solving the volumetric capacity problem of storing hydrogen.

One potential solution is to instead use formic acid as stable energy storage. There have been recent advances in catalysts that make it feasible to convert hydrogen to formic acid and back again. Formic acid is stable, not very toxic, and has an energy capacity of 1.77 kWh/L.

The only party I know of that is trying to bring this to market is Dens [1], formed out of a student group at the University of Eindhoven [2]. Their website is a bit high on the rhetoric (including trying to coin "hydrozine"), and their mockups looks like, well, mockups, but there are real technology advances behind this, for example their trial with a city bus [3] (Dutch).

[1] https://dens.one/our-products/

[2] https://teamfast.nl/technology/

[3] https://www.volkskrant.nl/nieuws-achtergrond/deze-stadsbus-i...