While not in mass production, there is strong interest from the marine shipping industry. It can be produced near ports, and meets the storage and combustion engine constraints (similar to diesel) of the use case.
A sibling comment mentions scrubbing NOx emissions as a significant issue, and it strikes me that the shipping/cruise industry is already a major polluter in that area. (Unlike cars, which must have catalytic converters because of local landlubber laws.)
I guess my point is that cleaner technology is already being avoided by those companies, because they can save a buck by polluting in international waters.