Central production of hydrogen from fossil fuel, while not optimally efficient, IS much cleaner on the air than independent engines, if for no other reason than the production plants can employ significant scrubbers before the air is released. Mother Jones always seems to skip over that, because it is an inconvenient fact. :)

But, all fossil fuel is, is bottled solar power. Everything outside of geothermal and nuclear is solar, eventually. So, it seems that we should be able to work through the middleman process until we can make direct hydrogen from solar seperation processes.... It's just got to be reasonably efficient.