I think the best argument for hydrogen is for automobiles. Existing cars can be converted to use it, doesn't spray pollution all over the city, and can be refilled quickly unlike a battery.
Can existing cars be converted? Yes for CNG/methane or LPG/propane but not sure I've heard of Hydrogen conversions. Wikipedia says conversion to Hydrogen requires:
... hardened valves and valve seats, stronger connecting rods, non-platinum tipped spark plugs, a higher voltage ignition coil, fuel injectors designed for a gas instead of a liquid, larger crankshaft damper, stronger head gasket material, modified (for supercharger) intake manifold, positive pressure supercharger, and high temperature engine oil.
For CNG or LPG conversion I think some fuel system components need to change but the rods, valves, head gasket, etc. are all unchanged.
My guess as to the reason is that hydrogen will basically detonate in the cylinder, whereas methane or propane will burn more like gasoline.
Hydrogen is no good for cars because it sneaks into the metal and ruins it (hydrogen embrittlement). Your car is mostly metal, especially the part that stores the fuel and the part that makes it go boom.
You can probably make electricity directly from H2, and you can probably make special pressure vessels that'll store that H2 (though even then it'll have a 7 year "inspect thoroughly" and a 15 year "throw it out regardless" lifespan.)
H2 is a silly fuel unless you're making rockets. Or if you're trying to distract people.
... hardened valves and valve seats, stronger connecting rods, non-platinum tipped spark plugs, a higher voltage ignition coil, fuel injectors designed for a gas instead of a liquid, larger crankshaft damper, stronger head gasket material, modified (for supercharger) intake manifold, positive pressure supercharger, and high temperature engine oil.
For CNG or LPG conversion I think some fuel system components need to change but the rods, valves, head gasket, etc. are all unchanged.
My guess as to the reason is that hydrogen will basically detonate in the cylinder, whereas methane or propane will burn more like gasoline.