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Corn-waste biofuels might be worse than gasoline in the short term

The views expressed are those of the author and are not necessarily those of Scientific American.


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Biofuels made using corn waste could release 7 percent more greenhouse gases in the early years compared to conventional gasoline. As a result, this type of cellulosic ethanol could be inelligible to meet quotas under the 2007 Energy Independence and Security Act (EISA).

According to a new study published yesterday in Nature Climate Change, this type of cellulosic biofuel could result in a 7% net increase in emissions. The government-funded research states that the main cause of this increase comes down to absolute changes in soil carbon content.

The carbon content of soil is broadly a function of new inputs (plant and animal material) and losses (predominately via erosion and respiration). Conventionally, corn crop residue is left on the field after harvest in order to reduce soil erosion and maintain the carbon stocks and soil fertility.

By removing corn waste from fields, models indicate that soil carbon content will decrease over time. In turn, corn-waste ethanol will effectively produce 7% more carbon dioxide equivalent than conventional gasoline in the short-term. While the results vary according to the amount of carn residue that is removed, any removal resulted in a net increase in emissions in the model.

In the longer-term, the study says that these types of biofuels will result in a net emissions decrease. However, the short term increase is enough to keep this type of biofuel from complying with regulations in the 2007 Energy Independence and Security Act (EISA). This Act requires that biofuels produce 60% less pollution than conventional gasoline. This level is shown in relation to the study’s results below:

David Tilman, a professor at the University of Minnesota who has done research on lifecycle emissions from biofuels has stated that ”The study says it will be very hard to make a biofuel that has a better greenhouse gas impact than gasoline using corn residue.” According to TIlman, this new study is the best that he has seen so far related to the corn-residue debate.

However, the study has already received significant criticism from the biofuels industry and Obama Administration officials. As a result, the sigificance of this study has been called into question, resulting in lingering uncertainty regarding the question “is corn-based ethanol (residue or otherwise) an advisable means of reducing energy-related greenhouse gas emissions?”

According to Jan Koninckx, global business director for biorefineries at DuPont ”the core analysis [in this study] depicts an extreme scenario that no responsible farmer or business would ever employ because it would ruin both the land and the long-term supply of feedstock. It makes no agronomic or business sense.” Furthermore, EPA spokeswoman Liz Purchia has stated that this study “does not provide useful information relevant to the life cycle greenhouse gas emissions from corn stover ethanol.”

According to a 2012 peer-reviewed study performed at the Energy Department’s Argonne National Laboratory, biofuels made with corn residue were 95% better than gasoline in greenhouse gas emissions. However, this study assumed some of the residue harvested would be used to replace coal-based electricity production (and their greenhouse gas emissions), which is not a certain outcome in ethanol biorefineries.

Photo Credit:

1. Photo of roasted corn on the cob in a bowl © stevendepoloby and used under this Creative Commons License.

2. Graph from Liska, et al. Biofuels from crop residue can reduce soil carbon and increase CO2 emissionsNature Climate Change (2014) doi:10.1038/nclimate2187 Received 13 August 2013. Accepted 05 March 2014. Published online 20 April 2014

Melissa C. Lott About the Author: An engineer and researcher who works at the intersection of energy, environment, technology, and policy. Follow on Twitter @mclott.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. jwake05 4:55 pm 04/21/2014

    If the administration doesn’t like the result, they criticize it and denigrate the authors as un American, eco-terrorists and not in the main stream science. The Washington bureaucrats are the terrorists and the ugly Americans of the day.

    Link to this
  2. 2. jgrosay 5:59 pm 04/21/2014

    Ethanol has a very good issue in the current times of Unleaded gas: it increases RON the same as lead additives, but it has no added toxicity, Methanol can be deadly, and Ethanol having a lower heat released after burning than Gasolines, it reduces flame temperature inside combustion chamber, thus reducing NOx emissions. Hard to beat!

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  3. 3. anumakonda.jagadeesh 12:33 am 04/22/2014

    Good article.
    The alternative is Biofuel/biogas from Agave and Opuntia,bot care-free growth plans and regenerative. Being CAM Plants they act as Carbon Sink. These can be grown on a massive scale in wastelands especially in developing countries. Mexico is already pioneer.
    Dr.A.Jagadeesh Nellore(AP),India

    Link to this
  4. 4. Jerzy v. 3.0. 5:07 am 04/22/2014

    For me, it is very good reason for restraint in ‘preventing global warming’. Not because it doesn’t exist, but because supposed solutions (like biofuels) don’t take into account all effects on climate and may be waste of money or even counter-productive. Apologies to lobbyists hoping for billions of subsidies approved by AGW-panicked scientists.

    I remember how WWF and all the other NGOs loved, promoted and propagandised biofuels. And now what?

    Link to this
  5. 5. EricJennings 7:56 am 04/22/2014

    Still, given how this site is committed to the global warming hoax, we note the spin in the article. It talks of corn “waste”, implying the subject is some kind of leftover, whereas the reality is that we’re talking about good ol’ corn, period. It also tried the ol ‘long term, short term’ dodge, whereas most articles on the subject just flat-out reject the whole insanity of turning food into fuel.

    It also forgot to mention the food riots around the world due to increased corn prices. Probably just an oversight on the author’s part.

    Here’s an article that isn’t ‘sanitized’ like the above piece:

    “It’s Final — Corn Ethanol Is Of No Use”

    http://www.forbes.com/sites/jamesconca/2014/04/20/its-final-corn-ethanol-is-of-no-use

    And here’s a fresh AGW article:

    “The global-warming apocalypses that didn’t happen”

    http://www.washingtontimes.com/news/2014/apr/21/rahn-the-world-did-not-end

    Does any of the following sound familiar?

    “The Arctic Ocean is warming up, icebergs are growing scarcer, and in some places the seals are finding the water too hot. Reports from fishermen, seal hunters, and explorers all point to a radical change in climate conditions and hitherto unheard-of temperatures in the Arctic zone. Exploration expeditions report that scarcely any ice has been met as far north as 81 degrees 29 minutes. Within a few years it is predicted that due to the ice melt the sea will rise and make most coastal cities uninhabitable.”

    That’s a Washington Post article from 1922.

    Link to this
  6. 6. hkraznodar 3:24 pm 04/25/2014

    Living in Nebraska, although not by Mead, and with friends and relatives that grow corn, I can say quite certainly that corn in any form is a lousy source for ethanol. Sugar beets would be better. Why not find a persistent plant that grows rapidly and is hard to kill such as bindweed? Figure that out and you could have a few billion tons worth of it ready to process almost over night.

    Link to this
  7. 7. Trakar 6:12 pm 04/28/2014

    please explain why the carbon neutral biofuel’s carbon content is being compared to the carbon emissions from burning previously sequestered fossil carbon fuel carbon emissions? Biofuel carbon takes carbon from the air and returns carbon to the air post combustion, it is not adding new carbon to the atmosphere. There is important information being left out of this article or the research it represents.

    Link to this

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