Corn-based fuel fares poorly in new analysis
Smithsonian scientists back Swiss analysis that declares corn, soy, and sugarcane counterproductive.Posted Jan 28, 2009
You’ve heard the claim: corn, soy, sugarcane, and other “bio-fuels” can help wean America and the world off of petroleum.
And folks using recycled deep-fryer restaurant oil to run their diesel vehicles – like the tour busses for Willie Nelson’s and Dave Matthews’ bands – are being awarded halos.
But how real are the benefits claimed for ethanol from corn or soy, or bio-diesel from french-fry pits and Malaysian palm oil plantations?
The devil is in the details, according to the authors of a new Swiss study, whose conclusions were reviewed and ratified by scientists at the Smithsonian Institute.
The Swiss say that recycled deep-frier oil is indeed a good alternative to petroleum for diesel engines, because it is recycled, and because its environmental impacts are much less than those of the oil it is replacing.
But corn, soy, and sugarcane – currently, the three main sources of ethanol for cars – didn’t fare nearly as well in their comprehensive new analysis.
Prompted by subsidies offered to growers of corn for ethanol, American farmers, mostly in the Midwest, have been rushing to expand their corn plantings.
US ethanol subsidies cost American taxpayers some $11 billion a year, and are raising food prices and contributing to eco-destruction here and overseas.
Ethanol refiners get a 51 cent tax allowance for every gallon produced. And the International Institute for Sustainable Development found that ethanol subsidies amount to some $1.38 per gallon, or about half of ethanol’s wholesale market price.
In America, conventional methods of growing corn accelerate soil erosion and deplete aquifers, which are essentially irreplaceable.
Corn fields also require vast amounts of petrochemical fertilizers and pesticides that end up in rivers and groundwater and continue to expand an already enormous “dead zone” in the Gulf of Mexico.
None of these costly impacts get considered when politicians tout the alleged societal benefits of corn-based ethanol.
Nor do proponents like to mention the huge amounts of petroleum needed to grow corn for ethanol. (Conventional fertilizers and pesticides are made from oil.)
By most calculations – including those of the new Swiss study – these energy inputs match or exceed the energy provided by ethanol made from corn.
In other words, we are wasting public money and irreplaceable water and soil resources in pursuit of a false promise of energy independence.
America’s corn boom destroys Amazon acreage indirectly
The rise in corn production in the US is having unintended negative consequences on one of the world’s most precious bio-resources.
From 2006 to the end of 2007 US corn production rose 19 percent, entirely due to demand for ethanol, while soy harvests fell by 15 percent. This has pushed up prices for corn, and for conventional beef and pork raised on the grain.
And, this subsidy-driven shift from corn to soy has nearly doubled global soy prices since late 2006.
After the US, Brazil is the world’s largest soy producer. Higher world prices for soy are accelerating destruction of that nation’s Amazon rainforest and tropical savannas, to make room for more soy acreage.
The main soy-producing states in Brazil have seen a spike in Amazon fires and forest destruction over the last several months, with no explanation other than fast-rising soy (and beef) prices (STRI 2007).
Swiss study highlights environmental impacts of bio-fuels
Most studies that have attempted to evaluate different bio-fuel crops have focused on their capacity to cut greenhouse-gas emissions or fossil fuel use.
Some studies suggest that corn-derived ethanol in the United States and Europe consumes more energy than it produces (Adler PR et al 2007, Ulgiati S 2001), while others show a small net energy gain (Crutzen PJ 2007).
Compared with oil, nearly all bio-fuels reduce greenhouse-gas emissions, but input-free weeds such as switchgrass easily outperform input-heavy corn and soy (Bala G et al 2007).
Earlier this month, scientists at the Smithsonian Tropical Research Institute analyzed a new study commissioned by the Swiss government, whose authors sought to gauge the relative merits of 26 bio-fuels.
The Swiss scored each fuel using an index that takes into account relative reduction of greenhouse-gas emissions and environmental impacts, which include harm to human health and ecosystems and natural resource depletion.
The Smithsonian scientists – Jörn Scharlemann and William Laurance – summarized the results:
- “The Swiss study identifies striking differences in the environmental costs of different bio-fuels.Fuels made from US corn, Brazilian soy and Malaysian palm oil may be worse overall than fossil fuels.”
- ” The best alternatives include bio-fuels from residual products, such as recycled cooking oil and ethanol from grass or wood.”
If anything, the Swiss study understates the negative consequences of growing the wrong crops for bio-fuel. As the Smithsonian researchers said, “The … study falls short in that it fails to consider secondary consequences of bio-fuels, such as rising food costs, but it is a big step forward in providing a way to compare the environmental benefits and costs of dozens of different bio-fuels.
Dr. Laurance put the issue this way in a press release, “Different bio-fuels vary enormously in how eco-friendly they are. We need to be smart and promote the right bio-fuels, or we won’t be helping the environment much at all.” (STRI 2008)
- Adler PR, Del Grosso SJ, Parton WJ. Life-cycle assessment of net greenhouse-gas flux for bioenergy cropping systems. Ecol Appl, 17, 675–691, 2007.
- Bala G et al. Combined climate and carbon-cycle effects of large-scale deforestation. Proc Natl Acad Sci U S A. 2007 April 17; 104(16): 6550–6555. doi: 10.1073/pnas.0608998104.
- Crutzen PJ, Mosier AR, Smith KA, Winiwarter W. N2O release from agro-biofuel production negates global warming reduction by replacing fossil fuels. Atmos. Chem. Phys Discuss, 7, 11191-11205, 2007.
- Scharlemann JPW, Laurance WF. Science 4 January 2008: Vol. 319. no. 5859, pp. 43-44 DOI: 10.1126/science.1153103.
- Smithsonian Tropical Research Institute (STRI). Corn… fuel… fire! U.S. corn subsidies promote Amazon de forestation. December 17, 2007. Accessed onloine January 6, 2008 at http://www.stri.org/english/about_stri/headline_news/news/article.php?id=736
- Smithsonian Tropical Research Institute (STRI). Smithsonian scientists highlight environmental impacts of biofuels. January 3, 2008. Accessed onloine January 6, 2008 at http://www.eurekalert.org/pub_releases/2008-01/stri-ssh010308.php
- Ulgiati S. A comprehensive energy and economic assessment of biofuels: when “green” is not enough. Crit Rev Plant Sci 2001;20(1):71-106.
- Zah R et al. Ökobilanz von Energieprodukten: Ökologische Bewertung von Biotreibstoffen (Empa, St. Gallen, Switzerland, 2007).
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