Sugarcane's efficiency is mostly due to the sugar yield per acre. The only valuable part of the corn is the kernel, whereas maybe 80% of the cane plant (stalk minus the leaves, which are called "straw") has sugars that can be extracted.
The other part of Brazil's ethanol "efficiency" lies in what they *don't* do, which is install decent pollution controls on the production facilities. The skies around those mills is brown for miles and miles and miles. The sugar facilities there could never be constructed in the US or Europe. That is supposed to be changing with new environmental regulations.
http://upload.wikimedia.org/wikipedia/commons/1/16/Panorama_Usina_Costa_Pinto_Piracicaba_SAO_10_2008.jpg
Yuck! As I recall, they burn the "straw" part, too. Leave it in the field. Not quite slash and burn, but also not the nicest.
It bugs me because they're losing heat right up the stack. That soot and smoke could be burned. Is it that hard to stoke bagasse? In an automated process, maybe, I don't know...
What all the ethanol production has *not* translated to is cheaper fuel prices for Brazilians. 100% ethanol fuel costs just as much as the E25 ethanol/gas mix after one takes into account the BTU differences. Ethanol has also not translated into energy independence for Brazil. Key evidence of this is that the United States is Brazil's offshore petroleum refiner. Because no one wants to risk building a refinery in Brazil, crude oil in excess of what Petrobras can process is shipped to the US Gulf Coast, where it is refined and returned to Brazil in the form of liquid fuels, etc. A second piece of evidence is that Brazil continually has to alter the ethanol/gasoline blend ratio because of ethanol shortages. So, even for the most "efficient" ethanol producer in the world, biofuels have not been a silver bullet for the liquid fuels problem.
I remember when E85 was introduced here. It came in at a surprisingly competitive price (back when gas was $2.50ish (the first time), I think?). Don't recall passing a station with it when gas peaked over $4.something, but the ones I've seen more recently, it hasn't been competing at all.
The only way you can drum up widespread adoption of something like that is by heavily subsidizing it, then restricting the original until people are screwed with the new stuff and you ramp the price back up (which arguably satisfies certain global warming people doubly). Obviously, they weren't willing to go that far, not just yet anyway. (Perhaps equally apparent, they didn't have the capacity to go there, either?)
I'm not anti-nuke, but I really don't get why people romanticize nuclear power so much. In the US, at least, the civilian nuclear power industry has been decades and decades of disappointments and failure. Blaming politics isn't going to cut it either. The industry had plenty of political cover, money and plenty of chances to get their shit together, decades worth. Perhaps I'd feel differently if I thought they were our only remaining option. I don't.
The record is surprisingly good for what mess it's created in some places:
http://en.wikipedia.org/wiki/List_of_nuclear_power_accidents_by_countrythe worst offender being Russia(/former USSR), really.
Inventing nuclear power has been messy, especially under military control. Several excellent scientists died in the course of early experiments (Slotkin and others). Early reactors were unstable and deadly (SL-1). The general area of Hanover, WA is an EPA Superfund wasteland, and likely to stay that way for oh about the next 100,000 years or so. But that pales in comparison to
http://en.wikipedia.org/wiki/Lake_Karachay and nearby areas, which contain almost as much material as Chernobyl released over a huge area.
Operating nuclear power stations has not been messy. The commercial record since, oh, 1965, and not counting plutonium-proliferating relics like Chernobyl (an inherently unstable graphite-moderated design), has been quite good. The accidents have been very expensive, from time to time, and occasionally messy, but fatalities have been negligible.
The worst incident in the US was TMI, but to be fair, it did exactly what it was supposed to. Gas was released, but no fallout, and all the contained materials have been/are being dismantled and stored with other waste. (Ah, not that anyone has decided what to do with our mounting piles of waste...)
After Russia, and early US development, Japan is surprisingly a big part of the record. It seems they tend to push things much farther; smarter than the Russians did, but still dangerous in the end.
The biggest fear people have is that they don't know anything. There's no education, because, why would people want to know about something they already think is impossibly dangerous?
The biggest hazard, in my opinion, is that failures quickly ramp up in severity. Whereas most human endeavor escalates gradually, which provides a nice negative feedback mechanism for squishy brains to learn from. If you want to eliminate high level nuclear accidents, you need to design systems to fail or decay gracefully, to generate that negative feedback, and incentiveize safety rather than punish for accidents and cost.
The biggest hazard is the incessant and inevitable force to improve investor yield. Nuclear power shouldn't be considered an investment opportunity. It should be infrastructure, you know, that "non sexy" thing. It should be made as solid and reliable as possible, then kept to those standards. If it starts making more money than usual, that should be seen as a warning sign if anything!
And really, this isn't exclusive to anything. It applies to all things of greater than personal human scale: coal and other power plants, dams, building construction... even driving a car (which is still greater than personal human scale because your legs can't push two tons at highway speeds, can they?). All of which have catastrophic problems for someone or other when they go bad.
Tim