Not only some environmental issues, but I would suspect that those technologies can in no way produce the amount of oil required by the rest of the world. I think that Africa probably uses very little oil compared to Industrialized countries..
1 ton of coal= 1.5 barrels of gasoline with the process as it currently exists.
THe U.S. has
ENOURMOUS coal reserves: as of last year, the U.S. had 17.9 billion in recoverable reserves-that is to say,the amount that is available in mines that are currently being worked. The most recent estimate of total resources-all the coal in the ground, mineable or not- is 4 trillion tons- a great deal of this figure may not be recoverable with current mining practices, though. The best estimate of total recoverable coal is around 489 billion tons.
489000000000X1.5X55=40342500000000 gallons of gasoline
That's over 40 trillion gallons of gasoline.
Average annual gasoline usage in the U.S. is about 329 million barrels a year, or about 2.75 trillion gallons per year. So, worst case, the goal that we know we can currently get out of the ground represents nearly 15 years of Saudi-free, Venezuelan-free, Canadian-free, Kuwaiti-free, Iraqi-free, Irani-free oil-our own somewhat limited oil production in addition to this notwithstanding.
Best case, that 4 trillion tons, represents
120 years of gasoline.
Of course, we use a great deal of coal to make electricity, so both figures are optimistic, but one can see how the production of gasoline from coal, coupled with conservation, could not only wean us away from foreign oil dependency, but lower the price of foreign oil by decreasing that demand.
And yeah, the best thing to do is come up with something besides internal combustion-it's bad for the environment, anyway.....