How "green" is ethanol from corn?
New, more efficient ethanols (like cellulosic ethanol) contain more of the corn plant than standard production ethanol. Accordingly, they have the potential to provide a greater yield of ethanol per acre or crop. (Roadsidepictures).
Not as green as you might think, according to economist Liz Marshall.
In 2005, the U.S. government passed the Renewable Fuel Standard, mandating that 7.5 billion gallons of biofuels be integrated into the nation’s fuel supply by the year 2012.
But biofuels create their own challenges. Most biofuels today are made from corn or soybeans. Liz Marshall is an economist with the World Resources Institute in Washington D.C. She co–authored a study predicting negative environmental effects of a sudden growth in the corn ethanol industry.
Liz Marshall: We end up seeing disproportionate increases in the amount of fertilizer applied, disproportionate increases in the amount of nitrogen runoff, and we see increases in soil erosion because land is managed more intensively. We also see increases in agricultural greenhouse gas emissions.
Marshall’s study advocates for agricultural conservation programs – and continuing to explore new, more efficient ways to produce ethanol – such as cellulosic ethanol, which can use more of the plant than the standard process.
Liz Marshall: So, cellulosic opens up a whole range of possible feedstocks, it has the potential to provide a much greater yield of ethanol per acre, and the greenhouse gas benefits are hugely improved over corn.
Read our interview with Liz Marshall.
Another cost of ethanol is how many people could have been fed with the corn or soy beans used to make the ethanol. I read somewhere that the grain needed to make 25 gallons of ethanol would feed one person for a year.
Can the world really afford to burn food?
It’s been widely reported that tortilla prices in Mexico have gone up because of ethanol’s demand for corn in the U.S., with hikes of about 60%. But the L.A. Times gives this report:
“Food industry executives have blamed the price increase on a variety of factors, including rising fuel and electricity costs. But one of the most popular explanations is tight supplies of corn stemming from the ethanol boom in the United States, which is consuming millions of bushels of the grain.
Experts say this explanation rings hollow because U.S. ethanol plants aren’t consuming the type of corn used to make tortillas. Ethanol is made from yellow corn, which has limited uses for human consumption. Tortillas and cornmeal are made from white corn, which is not used in the production of bio-fuels. Mexico imports very little white corn from the U.S. And Mexico’s farmers produced a good-sized crop of white corn in 2006, more than 21 million metric tons, according to government statistics.
Critics say intermediaries are deliberately withholding corn and cornmeal from the market. Respected Mexican central banker Guillermo Ortiz cited “speculation” for driving prices higher.”
Thanks for a very balanced perspective. All options have trade-offs. Coal, oil and natural gas- they’ve served us very well and will continue to play an important role. We just need to realize what their use costs us and reduce our addiction to them as rapidly as possible. Looking at some of the current alternatives…Nuclear- probably the most unlimited source, but with the most dangerous downside risks. Wind- relatively free, but I’ve seen their prominent marring of an otherwise beautiful vista…wouldn’t want one in my backyard. Ethanol- just don’t let the price of my corn-fed beef and fresh summer corn go up. Solar- seems to be a tremendous opportunity, but only if the technology becomes readily understood, easy to install, and recognized as only a parttime supplement in most of the country.
The ultimate, no down-side answer? As a Southerner, the answer is obvious…find a low-polluting, high-efficiency use of kudzu.
Again, thanks for your perspective. My own expectation is that the world will progress with a combination of many energy options beyond the historically easy carbon-based sources. We’ll make more progress when most folks realize that this is not a standard political issue. There is no silver bullet answer to this question.
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