I was under the impression that for normal ambient temperatures, hydrogen can't be liquified at any feasible pressure. Is that what you are referring to, Tim?
Pretty much. Liquid Hydrogen is very expensive, which is why most hydrogen cars use either compressed hydrogen(which has a lower energy density) or just reform some sort of hydrocarbon onboard, which defeats the whole purpose of the hydrogen car to begin with. Its one of the many problems with the whole hydrogen fallacy. Storage is difficult. Production is difficult. Distribution is difficult. All are expensive.