USA Today ran a story
about how ethanol is going to continue to keep America's "drive-in utopia" humming along.
While I think that ethonol does have some promise as an alternative motor fuel, the article itself missed a number of technical points that go a long way to explaining why it's not used more now, and why we should be skeptical that it has the potential to replace the 140 billion gallons of gasoline we consume every day.
More below the fold:
What the article didn't talk about:
- Ethanol is much more expensive to produce than gasoline from petroleum. (Though that will change whne Peak oil hits.) If people are whining today about $3/gallon gasoline, they'd better expect $5+/gallon ethanol fuel. Unless, of course, the government subsidizes it. But if they're willing to do that, why not subsidize alternative transportation modes that use less or no petroleum, like transit, intercity rail, and even animal traction (that's the letest buzzword for horse and craaiage) and bicycle and pedestrian infrastructure?
- Growing enough corn to provide the equivalent of 140 billion gallons of gasoline would be an environmental nightmare. The kind of "efficient" farming needed to make the yields needed to keep the net energy balance positive, would involve flogging the soils with chemicals and plowing it up with all the attendant water pollution and sediment runoff and soil erosion. Not to mention the fact that it might tak land land need to grow food crops. What shall we feed: our cars or ourselves? True, they're devoping technology to break down cellulose to sugar, which can then be fermented to ethanol, thus allowing even trash to be converted. But this technology is not fully developed, and the resulting ewthanol would be even more expensive (see 1)
- Ethanol blended with gasoline produces more smog. The blend produces amixture with a volatility (google "Reid Vapor pressure" for more details) much higher than either of the two components. What they call "evaporative emissions" has historically been one of the hardest sources of "ozone precursors" to control. In cities with air pollution problems, there are strict limits on "reid vapor pressure," and in cities where they use ethanol-blended gasoline (i.e. Chicago and Milwaukee), they need to use an exotic low-volatility blendstock in order to meet the requirements, especially in the summer. It drives the refiners crazy, becuase they can't use the crude as efficiently as they'd like, and thus there are only a few refineries that make the stuff for Chicago and Milwaukee. That's why gas is more expensive there and youhave periodic shortages if one othose refineries shuts down for some reason.
- ethanol is a pain in the neck to blend and transport. This is because it prefers to be dissolved in water than in gasoline hydrocarbons. If there is any water in the pipleline, gas tank, etc., say good bye to the ethanol. So they can't blend it into the gasoline in the refinery and ship it across the country in pipeline like regular gasoline, they have to ship the ethanol (by truck, train, or barge) to a terminal, where it then gets blended immediately before delivery to your neighborhood Jiffy-Mart.
Ethanol might be a decent motor fuel under the follwoing conditions:
It's made primarily from cellulosic feedstocks, not corn
It's used in a 100% ethanol blend
But everyone needs to understand that it will cost much much more than petroleum-based gasline now costs. But then, that will help, too. If the high cost reducies driving, then we can end our energy addiction even more easily.
Remember, one can reduce your gasoline use 100% by just not taking the trip.