Over at The Oil Drum, Gail has just penned an exhaustive and, we think, invaluable post clarifying the perceived benefits and disadvantages of using corn-based ethanol as an alternative to fossil fuels. While we've already touched on this issue at length several times in the past (see here and here for some recent posts), we thought this post in particular would provide a perfect springboard for further discussion.One common misperception is that most of the corn ethanol produced is used as E85 (85% ethanol/15% gasoline mixture). In fact, as Gail explains, the vast majority of corn ethanol is actually used as a fuel additive for two simple reasons: E85 isn't very popular and MTBE (methyl tertiary-butyl ether), the substance previously used as an additive, is being phased out for health liability concerns. Having said that, however, she is quick to point out that E85 is not a perfect substitute for MTBE in several respects.
Another important question she takes on is the extent to which corn-based ethanol production could be increased. Currently, about 20% of the corn produced in the U.S. is used to make ethanol, and she estimates that, under the best scenarios, this amount could be tripled to the equivalent of 60% of the 2006 corn production. At this level, ethanol would still replace only approximately 10% of the volume of gasoline used, and it is questionable whether we would ever want to shift so much of our corn production to ethanol. Indeed, an article in Popular Science cites a study by the Center for Agricultural and Rural Development at Iowa State University that predicts that U.S. ethanol production could consume more than half of corn, wheat and coarse grains by 2012, ratcheting up food prices and potentially causing massive shortages.
What about ethanol's oft-vaunted effect on curbing greenhouse gas emissions? As Gail notes, this is far from the truth: "This simplistic model is not correct for the production of corn-based ethanol because fossil fuels are used in the growing of corn and the production of ethanol, and these contribute to global warming gasses. Nitrogen used in fertilizer also tends to produce nitrous oxide, which is 300 times as potent a global warming gas as carbon dioxide."
In fact, secondary impacts precipitated by an increase in U.S. corn production, such as further deforestation in countries like Brazil to increase the production of soybeans, would likely tend to increase greenhouse gas emissions. And let's not forget some of the harmful biological and environmental impacts incurred by a shift to more ethanol production: huge use of water, increased soil erosion, more fertilizer use and more herbicide/pesticide use.
Two studies, one conducted by the Congressional Research Service for Congress and the other by the United Nations, both urge caution in expanding the production of biofuels because of the uncertainty surrounding possible side-effects. The Congressional Research Service report, which scrutinized corn-based ethanol, raised concerns that weather could have a significant impact on the variability of supply.
So is there a silver lining to using corn-based ethanol? Not really: even if more cost-effective approaches are adopted to make ethanol (increase renewable energy use and lower consumption of natural gas and coal in the process), it's not clear yet whether these will have a drastic impact on the total amount produced. Furthermore, whether the production of ethanol can be greatly expanded without causing more harmful secondary impacts is in doubt.
We've only just skimmed the surface here, so we heartily recommend you check out the rest of Gail's post if you're interested in this issue. Also please feel free to weigh in with your recommendations and/or concerns about the increased production of corn-based ethanol. We'd love to hear your comments!
See also: ::Food Fight: Is Corn Food or Fuel?, ::Final Word on Ethanol's Efficiency as Vehicle Fuel, ::Not All Ethanol is Created Equal, ::Corn Demand from Ethanol Distilleries Vastly Understated, ::They Can Have their Cellulose and Digest it Too