> See http://en.wikipedia.org/wiki/Fischer-Tropsch_process

Wikipedia also conveniently answers the "why don't we..." question
right there in the first paragraph:

"This synthetic fuel runs (so far) only in diesel engines and some
aircraft engines; typical gasoline-using engines ignite the vapors at
much higher temperatures, therefore making this synthetic fuel
unusable."

It's not synthetic gasoline, or synthetic diesel, or synthetic
avgas--- it's just a synthetic hydrocarbon that certain classes of
engine can be adapted to use. It's also not too cheap to make. You
have to be pretty desperate to use it exclusively. Plenty of folks are
looking at ways to convert coal--- there's a LOT of coal in the US---
but so far nothing economical has come of it.

--
John Bange
'90 Vanagon - "Geldsauger"
'90 Vanagon GL - "Wiesel"