Walter L. Wagner said:
Billy T: (1)How long before Brazil is projected to become self-sufficient in terms of producing all of its liquid fuels (alcohol) from sugar-cane? (2)What percentage of the entire world production of petroleum could conceivably be replaced by Brazil's alcohol production, if most of the farmland were used for that purpose?
....(3)How feasible is it to use the world's agricultural fields to grow for alcohol and/or bio-diesel, while still retaining productivity for food? (4)Are we talking about 10% replacement of petroleum, or 90% replacement, by growing for alcohol, etc., while still keeping adequate lands in food production?...
(1):Far in the future, well past "peak oil." This is because Brazil's oil company (PetroBras, more than half government owned, but I have some of their ADRs, which are now showing a four fold gain for me.) turned "self sufficient" in petroleum products about 6 months ago. (This is not quite true, as Brazil's off shore deposits tend to be heavy crude and currently Brazil lacks enough refinery capacity for this type so some is sold and lighter is purchased. A new refinery will begin construction soon - various states were offering tax deals trying to be chosen. I think a site North of RIO has been selected. Brazil and Venezuela, I believe, are already building a new one together in Venezuela for heavy crude.)
(2) I doubt that it can be 50% for many years, mainly because demand (read China&India) is increasing faster than production. Clearly, after "peak oil" there is a good chance alcohol will provide most of the liquid fuel. (Let us hope via enzymatic conversion of ANY cellulose to some type of sugar and that some, yet to be developed (genetic engineered?), yeast can convert into a liquid fuel, probably alcohol. If world's liquid fuel still comes from sugar cane - I doubt even the current level of food + fuel demand is possible.) See (3) for the importance of "end user efficiency."
(3)Impossible, without considerable starvation, as already exists, plus great improvements in end user efficiency, especially electric powered public transport (driven by nuclear power). Bring back the trolley (or even cable cars, for short steep runs.)!
I also think that buses that run on "super flywheels" between stops where they pause a few (5?) minutes to spin the flywheel up again make a lot of sense. - Some "flywheel buses" of this nature I think were in experimental use in Sweden about 10 years ago, but they used a common iron flywheel and thus could not go kilometers between recharges. (I have not seen the final results of this experiment. - if you find it, please post.)
(4)Nothing to add to what I said in (2). At different times, both 10% and 90% may be correct and at other intermediate times, every percentage in between.