20 years? I say much less than that.
http://www.permaculture.com/ Find the stations near you that offer an alternative to gasoline.
If Congress passed one law and stepped back, the free market would take over and end the oil monopoly within a decade.
"All new cars sold in the US must be able to run off 100% gas, 100% methanol, 100% ethanol, or any complication by 2013." There is no new technology to achieve this goal- it can be done for an additional $200-500 per vehicle.
Considering that alcohol fuel is significantly cheaper than current gas prices (after factoring the mpg difference) this can only be a good thing for America.
And if we wanted to use this for national security interests we could totally eliminate the need for oil. You can even replace your personal lubrication products with an alcohol alternative. This would eliminate our national security interest for anything in the Middle East. It would end the need for wars in that region (with us involved that is) and it would let us allow them to wallow in 7th century levels of poverty for the foreseeable future. That my friends would be karma coming home to roost.
Yes, when I say 20 years I am thinking more along the lines of solar power. As far as alocohol goes I don't think there's enough vegetable matter to produce all that would be needed right now, but it is very enticing. Perhaps as the process becomes more efficient.
We know if the government backed out of it the free market could take it over, but what are the chances of that? None and slim, and slim just left town

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Your last point is a great one

To paraphrase Syriana, a hundred years ago they were living in tents out in the desert chopping each other's heads off, and that's where they'll be a hundred years from now.