The thinking has been that the efficiency of steam reforming of methane to hydrogen (up to 75%) times the efficiency of fuel cells (claimed to be up to ~60% tod

The thinking has been that the efficiency of steam reforming of methane to hydrogen (up to 75%) times the efficiency of fuel cells (claimed to be up to ~60% today) gives you system efficiency that is substantially better than conventional engines. There's problems with that, but I'm not prepared to write an essay on them.