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Why do people wrongly believe that corn ethanol has a negative energy yield?

When every new study indicates otherwise. And ethanol plants are using renewable sources for power to save money.
Impressive statistics, Matthew. Didn’t realize wind power can be converted to ethanol.


  1. Several new studies, including a gigantic one released this year from the US Department of Energy, show the corn to ethanol process to have a significantly larger positive net energy yield than previously shown. These improvements were largely due to greater efficiency modifications and technological advancements at ethanol plants. In some cases, specific ethanol plants have an almost infinitely positive net energy yield due to groundbreaking technologies used to power the plant such as wind turbine technology.
    This study published in january 2009 shows the net energy yield of corn to ethanol to be +50% to 80%:
    Here are the latest numbers from the Dept. of Energy, published in May 2009. Go to page 16 of the 20 page summary. In the conclusions section the US DOE concludes that the entire corn to ethanol process yields at least 34% more energy that it takes to make the numbers could be as high as 67% due to rising corn yields secondary to farming improvements and ethanol plant technology improvements. The DOE concludes that corn ethanol is “energy efficient and becoming more energy efficient as time goes on”. They study also concludes that only 17% of the energy used to make ethanol actually comes from fossil fuels:
    Lastly, some ethanol plants are producing ethanol and using virtually zero fossil fuels at all. Many are converting to wind power to generate the electricity for their plants. This makes sense for several reasons. First, wind and corn go hand in hand. The areas in the midwest that grow corn tend to be very windy in general. Secondly, the plants see this as a way to save huge amounts of money on energy costs. Thirdly, using wind turbines makes the net energy yield of producing ethanol even more hugely positive. Cornplus ethanol in Winnebago, Minnesota is one such plant that is producing ethanol from almost entirely renewable sources. Here are 2 links to read about it:
    And here is one more study that shows corn ethanol yields 67% more energy than it takes to produce:
    Now, I want to hear arguments from people that dispute these facts. All 3 studies mentioned above have been published in 2009. Can you provide a newer more current study that shows differently? If you want to argue that the yield is negative please back it up with FACTS and DATA and provide LINKS, as I have done. Otherwise your argument has no weight. If you are going to argue against the net energy yield of ethanol back up your argument with facts, not just your false beliefs. Then again, I guess ignorance is bliss.
    Chui, please see my link which addresses the issue you mentioned. We have thousands and thousands of miles of unused land in the US to plant corn and other crops.

  2. Excellent research about the positive yields dear Matthew Smith. Only one problem with mass production of the required corn to substitute fossil fuels… Earth’s bio-productive land is getting pretty low to produce food for 6 billion people. Where are we gonna plant this corn? Unless we are able to engineer a crop that may planted in the deserts… I don’t see a great future in this.

  3. It’s really a matter of how many factors you wish to take into consideration. Do you take into consideration the fuel needed to plow the fields, sow the seeds, irrigate, fertilize, harvest, heat the mash, distill, recondition the zeolite and transport the ethanol to market? If you do then the energy yield is likely to be negative or at the very least very small. You could even go further and take into consideration the energy needed to fabricate the stills, the tractors, the trucks and the roads but at some point you’ll need to distinguish between capital investment of energy versus operational however the capital investment still needs to be amortized. In general it takes the energy equivalent of 1.2 gallons of gasoline to produce the ethanol energy equivalent of 1 gallon of gasoline. Calculations have varied to numbers as high as 1.7 times the energy produced required to a gain of 38% in energy depending on how thorough the analysis is but it is clear that the more complete the analysis, the less beneficial ethanol appears to be.
    Ultimately, the maximum efficiency of photosynthesis is 6.6% and ethanol production uses far less of a plant so the efficiency of biological ethanol production is a mere fraction of a fraction of 1%. Even using gasification and Fischer Tropsch synthesis is more efficient than using yeast to transform food crops into ethanol because gasification would use the entire plant. More so, the current record for photovoltaics is 42.8% efficiency. The major difference is that we have to fabricate photovoltaics while nature is quite prolific at manufacturing leaves.
    Ethanol represents only the first generation of biofuels, the next generation of biofuels based on gasification/pyrolysis and synthesis are much more promising and may not require different vehicles or distribution networks.
    As to converting wind power into ethanol. Any energy source can be used to synthesize liquid hydrocarbons like ethanol from simpler components such as CO2 and H2O, essentially reversing the combustion process. Sandia Labs does this with a solar furnace. It isn’t converting power into ethanol but using the power to synthesize ethanol thereby storing the energy chemically (Sandia Labs was thinking of methanol, butanol, iso-octane etc.). Batteries actually work the same way. When you recharge a battery, the energy added reverse the chemical reactions that release the energy in the first place.

  4. hate to say it but it depends on how and what you measure….mathew goes by what cones out of the factory/distillery…..but john has another point,,,fossil oil has infrastructure and refinery’s and a 100 yr history….tough for corn alc to match it dollar for dollar..

  5. did you read the 20 page study conducted by the DOE, John W? obviously not. The study accounts for all the factors you mentioned and still has a positive 67% net energy yield. And that does not include the newe ethanol plants which are harnessing wind power.

  6. lets get simple, why are all the ethanol plants shut down??? because it cost more money and nearly more energy to make it.
    As for wind power to ethanol, just plain stupid, you lose 60% of the electricity in the conversion. STUPID!!!


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