One thing I’ve been hearing a lot lately is discussions about Ethanol, and it’s been
really pissing me off. Can ethanol be a serious replacement for oil as a source of energy? I don’t know. Because *both* sides are using really bad math to make their arguments.
There are two fundamental questions about ethanol as fuel where the bad math comes in:
1. How much energy does it cost to *produce* ethanol compared to the amount of
energy released by *consuming* ethanol?
2. How much pollution is generated by the process of producing ethanol?
There are numerous reports or studies from both sides of the political spectrum that quote the
supposed “fact” that ethanol product consumes more energy than can be produced by burning ethanol. But that fact dates back to a single study, which is at best misleading, and at worst, deliberately deceptive.
The classic bad argument about question one comes from the work of Profesor David Pimentel at Cornell. Professor Pimentel isn’t entirely to blame for this; while I believe that his work was intended to be deceptive, the way that it’s been used is even *more* deceptive than I think he intended.
Pimental studied the production cost of ethanol. What he was trying to determine was the *total* energy cost of producing ethanol. The end result of his study was that it costs approximately 1.3 gallons of gas to generate the energy needed to produce one gallon of ethanol. And since burining one gallon of gas produces as much energy as 1.5 gallons of ethanol, the effective energy cost of ethanol is close to twice the amount of energy yielded by burning it.
This is *very* frequently cited as an argument against Ethanol. For an example of just how widely this argument has spread, here’s an example of an [an environmentalist group using it to argue against ethanol.][env]
The problem is that the figure is calculated to produce the highest possible cost for ethanol. What would you guess would be included in the energy cost of producing ethanol? My off-the-top-of-my-head guess would be “growing and harvesting the crop, transporting it to the ethanol factory, operating the factory, transporting it from the factory to the user”. The Pimentel calculation includes all of those, but it doesn’t stop there. It also includes:
* The cost of producing and transporting fertilizer for the crops.
* The cost of producing and maintaining the farm equipment used in growing the crops.
Reasonable. I wouldn’t have thought of those, but it’s fair to include them. But it doesn’t stop there either. It also includes:
* The cost of producing the materials used to construct the ethanol factory (including
everything from the cost of mining the ores that are used to produce the steel for
girders used in the plant on up).
That’s starting to get silly. But it doesn’t stop there. He even goes so far as to include:
* transportation costs for the workers commuting to the farm and the ethanol plant.
* the energy consumed by the *workers* on the farm and in the ethanol plant in order
to do their work!
That’s just ludicrous. The idea that it’s *reasonable* in an assessment of the production costs of ethanol to include the *food* consumed by the workers is just crazy. But that’s what the most widely cited argument does.
To give you a sense of how much is wrong with this, we can just look at a Pimentel calculation
on the energy cost of oil. By Pimentel calculation, you’d conclude that *oil* is a net
*consumer* of energy. Including drilling, refinement, transportation, pumping, and the kinds
of associated worker and supply costs, *at best* you wind up with a computation that it takes
the amount of energy produced by 1.1 gallons of gas to produce 1 gallon of gas. [(And that’s
*Pimentel’s own calculation!)][pim]
But the other side isn’t any better. Ethanol promoters use calculations of the energy cost of producing ethanol that *omit* things like the energy costs associating with growing the
ethanol crops, the transportation costs, etc., and focus *only* on the cost of the
ethanol fermentation and refinement. That’s equivalent to computing the energy cost of
oil while omitting the costs of drilling for oil, and transporting it from the drilling site in the middle east to the refineries in the US.
Either way – including too many things to make it look bad, or omitting things to make it look good – either way, it’s faking numbers with bad math. And the end result is that it’s *very* difficult for anyone to figure out honestly what the costs and benefits of ethanol really are! Is ethanol production a good idea? Will it help us produce more energy without importing oil? It’s almost impossible for the general public to figure it out, because both sides are faking their numbers, and we simply don’t have access the information to figure out what the real, honest number is!
There’s also a similar kind of argument about carbon dioxide and ethanol. Various oil-industry
front groups have pushed the fact that an ethanol production factory produces an enormous
amount of carbon dioxide. And that’s [absolutely true.][co2] The fact that they neglect to
mention is that nearly all of the carbon dioxide produced by the factory, plus the carbon
dioxide produced burning the ethanol as fuel, is carbon dioxide that was *removed from the
atmosphere* by the plant. It’s a nasty little game of math: when they’re trying to show that
ethanol’s cost is high, you skew the numbers by including every conceivable cost from the farm
to the factory to the point of delivery. But when they’re trying to show that ethanol isn’t
better when it comes to pollution, suddenly the farm, the process of growing the crop for
producing ethanol just *poof*! disappears.
This is more clear cut. I can’t find *any* examples of ethanol promoters overstating the
carbon-fixing capacity of ethanol crops, whereas there are plenty of examples of ethanol opponents lying about the carbon dioxide produced by ethanol fermentation.