| The author of this editorial in my local paper I think makes a good case for better fuel efficiency instead of depending on ethanol, esp. corn derived ethanol as an alternative fuel. ~~~~~
Peter Wyckoff: Cellulose beats corn as a source of ethanol
Switchgrass and other plants capture more solar energy, yielding more fuel per acre.
Peter Wyckoff Published: April 03, 2006 Commentary Peter Wyckoff: Cellulose beats corn as a source of ethanol A system at odds with education I teach biology in Morris, Minn. Every fall a mountain of harvested corn rises on the south side of town. Then, slowly, the mountain is fed to our local ethanol plant. The plant converts the starches in corn kernels to the ethanol that is added to your gasoline. In nearby Benson, the same process is used to make terrific vodka. Ethanol is ethanol, whether for driving or for drinking. President Bush says that cellulose-based ethanol from crops such as switchgrass can help break our addiction to oil. He is right. Cellulose, a tough but energy-rich compound, helps give structure to corn stalks, trees and grasses. The problem? No ethanol plant in the United States can make ethanol from cellulose. Our Morris plant can only deal with the easily liberated energy found in corn kernels. Corn ethanol is a booming business. Our local ethanol plant was just sold for a handsome profit to an Australian company. That same company is planning to open a second plant nearby. Our region may become a net importer of corn, but three limitations to corn ethanol should give pause: • A gallon of ethanol has less energy than a gallon of gas. This is a property of all ethanol, not just corn ethanol. A gallon of ethanol has one-third less energy than a gallon of gas. If you drink vodka for the energy, you would be better off drinking pure gasoline. The new E-20 mandate in Minnesota will require that gasoline sold in the state be diluted with 20 percent ethanol. The net effect will be to make the gallons of gas sold in Minnesota 6.5 percent less energy-rich than those sold in South Dakota or Wisconsin. (There is probably some reason why the E-20 bill wasn't sold with a "we want to give you 6.5 percent less.") What does it mean to drivers that ethanol contains less energy? It means lower miles to the gallon. A flex-fuel Ford F-150 running on gasoline gets 19 highway mpg, but only 14 when running on E-85. A survey of flex-fuel vehicles (www.fueleconomy.gov) shows that they experience, on average, a 25 percent decline in mpg when running on E-85. • Corn ethanol provides little protection against global warming. Corn ethanol production requires fossil fuel combustion to make fertilizer, to drive the tractors, and to distill the ethanol. This combustion releases greenhouse gases. A 2006 study in Science magazine suggests that corn ethanol, per unit energy, produces 13 percent fewer net greenhouse gas emissions than gasoline. Thus, E-20 gasoline will reduce greenhouse gas emissions by only 2 percent per mile traveled. In contrast, trading a conventional Ford Escape for the hybrid version will save 28 percent. To be fair, ethanol fares far better if we look at foreign oil replaced -- much of the fossil fuel used to make ethanol is American coal. If our primary goal, however, is to fight global warming, then corn ethanol is of small benefit. • Plants make poor solar panels. When the sun shines down on a cornfield in western Minnesota, approximately 2 percent of the solar energy is captured and stored as plant material. To get the captured 2 percent you need to consume the whole plant, but corn ethanol is made from just the kernels. In class, I ask the following homework question: How much land would it take to grow enough corn to fuel all the automobiles in the United States? The answer varies depending on underlying assumptions, but ranges from six to 20 Minnesotas planted as corn. No lakes. No forests. No sprawling suburbs. Just corn. For comparison, the amount of land in this country currently devoted to corn is well under two Minnesotas. Cellulose-based ethanol would help us capture more of the solar energy trapped in plants. The cellulose, however, shouldn't come from corn -- after leaving enough cornstalk in the field to preserve soil quality, there is not much left over to make cellulosic ethanol. Switchgrass, on the other hand, could potentially make great cellulosic ethanol. So will the mountain of corn in Morris be replaced by switchgrass soon? Hopefully, but cellulose is hard to convert to ethanol at commercial scales using today's technology. Research could solve the problem. Another obstacle is economic. Farmers are heavily subsidized to grow corn. The taxpayers provide no such aid to growers of switchgrass. This biologist will defer to economists for solutions to our subsidy conundrums. In the meantime, we all can do a lot to reduce our dependence on oil and slow the increase of greenhouse gases: Simply drive more efficient vehicles. Peter Wyckoff is associate professor of biology at the University of Minnesota, Morris.
~~~~~ http://www.startribune.com/562/story/343991.html | 
