[plus]

If HFC vehicles ever become mainstream, hydrogen is going to have to be produced on-site at filling stations. Hydrogen is extremely difficult and dangerous to transport. If you try to use pipes, the hydrogen will be able to leak out of even the smallest of cracks, and can even diffuse through metals. It's extremely difficult to compress and becomes a serious explosion hazard.

I'm somewhat optimistic that HFC will play a role in the future of transportation, but there are still a lot of issues that need to be ironed out.