yungman said:
I know H2 is EXPLOSIVE. Other than that, I want to know is there any other reason preventing it from being more popular?
Frankly, hydrogen-powered vehicles are a bad idea on multiple fronts.
Hydrogen is very flammable
It is very difficult to store, particularly if you want that storage to be safe in the event of a severe impact
It tends to make metal brittle
It has no natural source so it must be manufactured
The usual way to manufacture it at scale is through stripping it from hydrocarbons, thus producing all of the usual carbon emissions of fossil fuels
The alternative method of manufacturing it, electrolysis, is highly inefficient and would produce huge demands in the electricity grid if done at scale. If the local power grid is based on fossil fuels then it still produces carbon emissions.
Hydrogen based internal combustion engines need very large pistons and have relatively little power
Hydrogen based fuel cells use a lot of expensive materials in decently large quantities
IMO, it is a gimmick for getting research funding rather than a realistic solution to any current problem. In any case, calling hydrogen a fuel is false, it is an energy storage technology, one that is vastly inferior to other existing energy storage technologies