I seem to recall folks praising places like Brazil for their progressive biofuels program and environmentally-friendly sugar ethanol.
But make it from corn and people start complaining about rising food prices and ADM subsidies.
What’s the straight dope?
Corn is an inefficient way or producing ethanol. There are other crops that will do so much more efficiently, but in the US we have given some tax breaks for using corn for political reasons.
“Bio-fuel” is alcohol. Alcohol is produced by conversion from Sugar(s) using yeast. Just like Beer and Liquor production. Well, more like liquor, since they need to distill off the alcohol, although there’s no need along the line to preserve any flavor components. You’re just going for the alcohol. (Think: Everclear)
Producing from pure sugar is easy. Throw it in water, throw in the yeast. Allow to ferment, boil off the alcohol.
Producing from Corn (starch) requires an initial conversion to sugars (heat and enzymes) before the fermentation process. It is the need for that heat that requires the use of fossil fuels (oil/gas fired burners) and makes the process a lot less efficient. Now there are plants that burn crop waste and residue and are therefore more efficient, but those plants are much more expensive to build and there are not nearly as many of them being thrown up.
I read somewhere that the ideal would be to harvest certain plants (some kind of tall grass IIRC) that is easily converted. No planting, no pesticides, etc., just harvest it. We wouldn’t take a food source away, either, but the corn lobby wouldn’t much like it.
Props, Johnny!
I think the conversion of food crops to ethanol is strictly a stop-gap measure. The economics of ethanol production are going to drive the production of syngas, a mixture of carbon monoxide and hydrogen produced by the gasification of pretty much any carbon containing fuel, including municipal waste, lawn clippings, sawdust, etc… With CO and H2 gas as a feedstock you can synthesize just about any hydrocarbon you would want, a lot of which have a lot more value added than ethanol.
That’s as long as Big Agribusiness doesn’t lie down on the tracks, of course. How long do you think they can hold out on lobbying alone?
Production of ethanol from sugar cane is much more efficient than making it from corn. It yields 8 to 10 times more energy than it costs to make it. Corn is just barely positive; sugar cane does 7 times better.
Sugar cane isn’t as beneficial as so-called cellulosic systems, that convert cellulose instead of using sugar, but those methods haven’t really been worked out yet. However, it is much better than corn.
They may try, but the cellulose processing people have lobbying groups of their own. I was at the TAPPI (Technical Association of the Pulp and Paper Industry) Engineering, Pulping, and Environmental conference last fall, and there’s a lot of interest in cellulosic syngas. Cost of capital being what it is it’s not happening tomorrow, and naturally we’d all like for someone else to be serial number one, but it’s going to happen.
I went to an Ag conference here in NC last fall, where NCSU scientists were introducing Miscanthus (an ornamental grass that lends itself to quick Ag production) as a ethanol producer. It was very promising: along with switchgrass (Panicum sp.), it has ability to get up and growing quick, very resilient and low maintenance, without the needs of corn.
This is up and coming with research, so look for wider uses soon.
I believe its simple maths. The key point that with sugar cane, the energy for converting the sugar into ethanol comes from burning the unused “waste” portions of the plant itself. Corn takes extra energy (how much is debatable, but certainly far more than husks themselves can generate).
I also believe Bio DESIEL make more sense, as again the energy requirement is far less (in fact no more that to produce for food oil). But of course that takes change on the side of auto manufactures (in the US at least, in Europe Desiel cars and SUVs are far more common)
Another advantage of Sugar Cane is that its a cash crop, unlike corn, which is a staple. So its not in direct competition with people’s critical food supply (unless of course if you’re replacing “Staple” crops with Sugar to use as biofuels).
Suger cane needs a tropical climate to thrive. In the US it is grown in the deep south and Hawaii. The bulk of US agriculture is based in the midwest, and farmers (and large agribuisness) are already invested in the equipment, infrastructure, and knowlege associated with corn production.
Minor hijack: How would suger beets work out? These will grow in similar climates to corn. Beet suger has kind of gone out of fashion.
A common misperception. Big Agribusiness doesn’t care what you grow to produce ethanol or biodiesel from.
Think about it. You need a lot of land and someone with the equipment and knowledge necessary to grow and harvest a crop – farmers.
You need to transport that crop from rural areas to a fuel processing plant – that infrastructure is already in place, thanks to Big Ag.
You need someone who knows how to ferment and distill the crop into fuel – guess who already has experience doing that?
The reason you don’t see a lot of switchgrass being turned into biofuel is because it’s a lot harder to squeeze sugar out of cellulose than it is out of corn (and corn is less efficient than sugarcane.) Iogen has been trying for several years, and can’t make it commercially viable.
Insisting that Big Something is suppressing the technology to make cheap fuel is like insisting that the 100 mpg carbureator is being suppressed.
One problem with either corn or sugar cane based biofuels is the relatively low energy density of the feedstocks. It makes it hard to store enough to run from harvest to harvest, and shipping costs limit the area you can economically transport the raw material to the refinery.
Now trees store cellulose quite efficiently in something we call logs, and can be harvested twelve months a year. You still have transport limitations, but a cubic meter of wood chips contains more carbon than the same volume of either corn or cane. It’s harder to convert wood chips to biofuel, you’ve got to make syngas first, while corn or sugar will ferment to ethanol, but fermentation leaves a lot of carbon behind that gasification converts to carbon monoxide.