gasoline: 45.8 MJ/kg hydrogen: 120 MJ/kg
What about safety? I visited the Zeppelin museum in Friedrichshafen last week...
Wouldn't it be nice if turning CO2 into gasoline would enable us to re-use tall the existing infrastructure?
AFAIK liquid hydrogen tanks are orders of magnitude safer (as in “a totally different problem”).
- Liquid hydrogen is so cold that many metals weaken
- Exposure to hydrogen itself weakens many metals (hydrogen embrittlement)
- Liquid hydrogen expands rapidly if exposed to heat, so venting is needed
- Hydrogen leaks through the smallest of seams
Now imagine trying to build a tank that prevents all that from happening, and it has to be lightweight for usage on spacecraft / aircraft.
In french we differenciate "batterie" and "pile", "pile" are one use, but I thought due to the name that the hydrogen cell would store energy.
Furthermore, the flames seen in the film were from kerosine fuel. All the hydrogen released went up, up, up. It is quite difficult to ignite hydrogen at atmospheric pressure; it requires oxygen mixed in a narrow range of partial pressures.
So, no, safety of H2 fuel is not a problem.