See, gasahol is mostly gasoline--with a little ethanol (10%) or methanol (3%) mixed in. Back then, that's the way things had to be--cars were not designed to handle alcohols well, and gaskets and seals could easily corrode. Not anymore: since 1998, increasing numbers of American vehicles have been equipped to handle an ethanol-based fuel called E85--which has a little gasoline (15%) mixed in with the ethanol (85%). Add to this the facts that cars actually run better on ethanol (less knocking) and produce less emissions when they do, and ethanol-based fuels look quite attractive. In fact, the National Corn Growers Association recently showed off a GMC Yukon SUV that runs on E85 to help sell ethanol as the fuel of the future.
Which leads to the main problem of ethanol as currently produced--corn. Or, more specifically, foodstuffs being used to fuel our cars. Why problems? Because, first off, farmland being used to produce corn for fuel means less farmland used to produce other crops. It means oil-based fertilizers and pesticides being used to produce the corn. In addition, it means more of a chance of genetically modified crops being used, to boost crop yield, for example. And, because of the size of the crops needed, it means less work for family farms and more work for commercially owned farms. None of this is ideal, and what's more, there's no guarantee that there's enough arable farmland to grow enough corn to keep up with our energy needs. In short, it may not only be unethical in the larger sense, but ineffectual as well.
But corn certainly has its attractions, the most important of which is how sweet it is. (Think corn syrup.) And that's important because ethanol, like all alcohols, comes from the fermentation of sugars. We've got corn harvesting down pat, so it seems like a natural choice. Plus, we know how to make alcohols from corn, as whiskey drinkers know. But there are sugars, and there are sugars--and many things that are technically sugars don't necessarily taste that sweet.
Take cellulose. Unlike sugars like sucrose (baking sugar), glucose (blood sugar), and fructose (fruit sugars), cellulose is a a polysaccharide--meaning it is made when simple sugars are joined together chemically, like starch. And cellulose is perhaps the most common polysaccharide on the planet--all plants have it in abundance, from the most delicate grasses to giant sequoias. In fact, cellulose is to plants what calcium is to us vertebrates--it's used to build structure and to give strength to what would otherwise be an organic mush. So rather than using a foodstuff to fuel our cars, we could use practically any source of cellulose, from waste coming from paper mills and farms, to specially selected grasses that don't need much water and no fertilizers or pesticides. If we could use cellulose to make ethanol, we could start mowing our way to oil independence.
Cellulose gets its strength by forming chains from links of glucose. This produces water and releases energy. In order to reverse the process, we not only need to return water to the cellulose, but we have to add energy back in. But more to the point, cellulose is typically bound up with lignens, compounds that, like cellulose, are used to provide plant structure and strength. But lignins are not sugars and therefore unfermentable. As a result, turning cellulose into easily fermentable sugars can get expensive--at $1.40 a gallon, compared to the $0.88 per gallon cost of producing gasoline. That 50% markup is what's holding us back from adopting ethanol more broadly. So, how do we make it cheaper?
There are a couple of approaches available, but I'll start with the one that currently has the most traction--to wit, enzymes.
The Canadian company Iogen specializes in such enzymes, and they are leading the cellulose ethanol race. Already they have isolated the enzyme behind "jungle rot," which Korean War veterans will recall made cloth disintegrate. The enzymes break down the lignans, releasing the cellulose in a more extractable form. Once the cellulose and other wood sugars are extracted, the remaining waste can be burned, to provide the energy to convert the cellulose into simpler sugars and to power the plant in general. From that point forward, all you have to do is ferment and distill, and there's your ethanol!
So how much does this all cost, you ask? Right now, it's a little cheaper than typical cellulose ethanol--about $1.30 per gallon. But bear in mind that, as of now, Iogen has exactly one plant producing cellulose ethanol--and it isn't even using the process I just described. Iogen is currently looking for land for their first wide-scale plant, and plan to build 20 of them. As is, they estimate that by the fourth plant, the process will be refined so much that the price will drop under a dollar a gallon... at which point, E85 becomes cost competitive with gasoline, and perhaps eventually cheaper.
It's also worth noting that the SUNY College of Environmental Science and Forestry has recently invented a new process that uses membranes and natural fungi to extract xylan, or wood gum, from plant matter. The process also produces acetic acid, which is highly useful industrially. Since xylan can also be fermented into ethanol, the process is worth looking into when it matures, but for now, my money is on Iogen. So is Shell's, for what it's worth--and as much as you might want to sneer at the mention of a Big Oil player, Shell does have a better record at funding alternative fuels. Surely they know a winner when they see one.
Well, this is all great, but while ethanol may produce dramatically less emissions, there are still emissions to consider. After all, it's still being burned in the car. Overall, hydrogen fuel cells look much better, right? After all, fuel cells have efficiency rates up to 50%, while internal combustion engines are around 18%. Well, guess what--hydrogen is not the only fuel that fuel cells can use. Ethanol works, too. And since ethanol can directly substitute gasoline in our current infrastructure, we don't have to invest billions to build a hydrogen-only infrastructure. In the short term, we'll have less ethanol, plus any carbon released is carbon that is already in the carbon cycle, rather than carbon that's been locked away for aeons. And the carbon can be reabsorbed by--you guessed it--plants grown for cellulose ethanol.
I don't know about you, but ethanol sounds like a good deal all around. The only major drawback is that it is not quite as efficient as gasoline--you'd wind up with slightly lower mileage--but when you factor in all the advantages, and add the notion that it could turn out cheaper than gasoline, it makes me hopeful that one can make a more elegant, economically feasible transition soon.
(I owe much to Sam Jaffe's excellent essay, "Independence Way," from the July/August 1994 issue of the Washington Monthly, but I hope the additional background helps make it more apparent why this is such a beautiful path.)
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