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The Case for More Ethanol

Why green critics are wrong about this corn-based fuel additive

The use of E10, a blend of gasoline and 10% ethanol, is the most common fuel available at U.S. pumps.
Image Credit: Michael Coté / CC BY 2.0 / Flickr

For almost as long as there have been cars, gasoline has been the dominant fuel in transportation. But for a host of reasons — environmental, climate change, public health, and economic — the time has come to consider mixing higher blends of biofuels with gasoline. And in the United States, the best source for that biofuel today, surprisingly, is corn.

Such a suggestion will surely elicit cries of protest from the environmental community: A few years ago there was a flood of articles and reports about the allegedly disastrous ecological impacts of growing crops for biofuels. But we believe that ethanol has been unfairly stigmatized in the conventional wisdom and that the reasons for concern about corn ethanol deserve reexamination.

Here is a link to a rebuttal to this column: “The Case Against More Ethanol.”

In the U.S., now is the time for that second look. In June, the Environmental Protection Agency will begin a mid-course evaluation of President Obama’s ambitious fuel economy target, established in 2012, to have cars and light trucks reach 54.5 miles per gallon by 2025. Increasing the ethanol blend in gasoline from the current 10% to roughly 30% would not only help boost gas mileage, it would significantly cut U.S. carbon emissions and air pollution. And because higher-ethanol blends greatly reduce the need to use toxic additives — known as aromatics — to gasoline, increased reliance on ethanol would sharply cut the emissions of deadly fine-particle pollutants.

Today, U.S. sales of ethanol have grown to nearly 15 billion gallons a year, due to the near-universal use of E10 (10% ethanol, 90% gasoline) to fuel the nation’s cars and light trucks. We maintain that in the U.S., the principal reasons for concern about ethanol — the use of a food crop (corn) as a feedstock and the environmental impacts of high-production agriculture — are no longer valid.

New studies show that, thanks to ever-improving agricultural productivity, the food-versus-fuel debate appears to be over, and the verdict is in: There is no conflict. Increased demand for corn has not dramatically increased the cost of grain. Only a small share of corn is grown for human consumption, and global food prices are more affected by the cost of petroleum than they are by the price of corn. If anything, ethanol, by reducing the demand for gasoline, may lower the price of food by lowering the price of oil.

More corn is grown for animal feed than any other use. The ethanol process takes only the starch from the corn and leaves a high-protein byproduct — dried distillers grains — for animal feed, so cattle are not short-changed by ethanol production, either.

Farming practices have changed

As for the environmental impact of corn, a quiet revolution — aimed at restoring the health of the land — has been taking place on American farms. The iconic image of endless fields of bare, furrowed soil ready for planting in the spring is no longer the norm. More and more farmers are choosing to leave the summer’s residues — corn stalks, for example — on their fields after harvest, injecting seeds into the undisturbed soil in the spring. Some are planting winter cover crops to further stabilize and enrich the land.

These practices have many names — “no-till” or “low-till” or “precision” agriculture, for example — but they are reversing decades of soil depletion and are turning cropland into a carbon sink. In the process, they enrich the soil with natural carbon and reduce the need for chemicals and water. According to the most recent Census of Agriculture, 62% of U.S. cropland (173 million acres) was farmed in 2012 with conservation tillage or no-till practices.

Farming practices have changed, with more farmers choosing to leave the residue of summer crops, such as corn stalks, on their fields after harvest.

A recent nine-year study conducted in Nebraska by the U.S. Agricultural Research Service found that “no-till” corn increased the amount of carbon in the soil by nearly a ton per acre, per year. The researchers were surprised to find more than half of this captured carbon one to five feet below the surface: Corn has deep and extensive roots, but most previous studies sampled for carbon only to a depth of 18 inches.

The carbon footprint of ethanol has also been reduced, thanks to greater efficiency on the farm and in the production process. According to a team at Argonne National Laboratory, which for the past two decades has assessed the life-cycle greenhouse gas emissions from fuels — from extraction and production to use in a vehicle, taking into account indirect impacts on land use elsewhere — ethanol today results in 37% less carbon pollution per mile than gasoline. Adding in the now-uncounted carbon benefits of soil sequestration could potentially yield a zero-carbon fuel. At the same time, gasoline is becoming more carbon-intensive because of the increasing use of tar sands and other oils that are hard to extract and process.

More ethanol, fewer greenhouse gas emissions

The Obama administration’s fuel economy rule is one of the pillars of the president’s climate legacy, but it does not take into account the carbon content of the fuels in use. Crediting the life-cycle carbon footprint of fuels would provide an economic incentive for ethanol blends and encourage farming practices that enrich the soil by storing carbon: Carbon credits could be based on an annual field-level certification process.

Even without those benefits included, the use of “mid-level” blends — up to 30% ethanol — would reduce greenhouse gas emissions under the new fuel economy standards by at least 10%.

In addition, higher ethanol blends are rich in octane, and higher-octane fuels enable automakers to increase the “compression ratio” of an engine without damage from knock — creating more power with less fuel. (Race cars in the IndyCar series use blends of 85% ethanol.) Mid-level blends would thus make it easier for automakers to achieve the 2025 fuel economy targets (and go beyond them after 2025), while at the same time delivering more greenhouse gas reductions.

U.S. automakers have advocated for higher octane in fuels while remaining neutral as to the octane source. Designing cars to accept mid-level ethanol blends with a higher compression ratio is a simple engineering task, and many cars that require premium fuel today would require little or no modification. A senior Mercedes-Benz engineer said such a combination would be attractive to car buyers because it would provide “ridiculous power and good fuel economy.”

Aromatics used in gasoline are neurotoxins

Currently, oil refiners supply octane through a distilled component of petroleum called aromatics — hydrocarbon chains with a stable benzene ring that resist combustion and prevent engine knock. These aromatics, mostly toluene and xylene, are neurotoxins; they comprise on average 25% of every gallon of gasoline, and their emissions are implicated in a variety of serious health impacts, especially affecting the heart and lungs.

A 2013 assessment by the Harvard Center for Risk Analysis estimated that exposure to fine-particle pollution from aromatics in gasoline results in 3,800 premature deaths per year and a total social cost of more than $28 billion annually.

Most worrisome of all are the secondary pollutants that form in the atmosphere after combustion, especially PAHs — polycyclic aromatic hydrocarbons — which are carried along on particles so tiny that, once inhaled, they can penetrate the bloodstream and reach the brain. A careful long-term assessment of women in New York City found a correlation between exposure to PAHs during pregnancy and reduced IQ in their children — an effect similar to that of airborne lead.

The study’s leader, Frederica Perera, director of the Columbia University Center for Children’s Environmental Health, calls PAHs “carcinogenic, immunotoxic, neurotoxic, mutagenic, and endocrine disruptors.” The use of mid-level ethanol blends could reduce the content of aromatics in gasoline by 60%.

Lower demand for oil

Ethanol’s economic value has been widely mischaracterized and misunderstood. Ethanol does have less energy content per gallon than gasoline, leading some to say that consumers get a bad bargain from its use. In mid-level blends, however, the improved efficiency made possible by ethanol almost completely compensates for its lower energy content, evening out the economic equation.

A more powerful economic benefit for consumers comes from weakened demand for oil. Much has been made of the effect of shale oil from North Dakota on world oil markets, but before it came along, the widespread use of 10% ethanol blends already had displaced a similar amount of oil, saving consumers nearly $1 per gallon of gasoline, based on a number of economic estimates. That has meant $100 billion per year for U.S. consumers.

Over the last decade, ethanol production more than tripled, even as federal tax credits for its use and import tariffs were eliminated. This rapid growth in demand contributed to a temporary price spike for corn. But corn prices have since retreated to recent historical norms, putting the lie to the notion that using crops for fuel will make food unaffordable.

The reason is clear: One of American farmers’ most recurrent problems historically has been overproduction. The combination of favorable soils and climate in the Midwest, together with the astonishing innovation that continually increases yields per acre, means that the acreage planted in major crops has remained within a narrow band (315 to 325 million acres) for the last 15 years, despite the increased demand for corn. Indeed, farmers need growing markets just to keep up with their own rising productivity.

With a sensible ramp-up, yield increases alone could meet additional demand for ethanol in mid-level blends, using land already in production. To be ready for widespread use in 2025, the transition of fuels, vehicles, and refueling infrastructure must begin very soon.

Many obstacles remain to more ethanol use

The obstacles to this growth, however, are formidable. Once gasoline was established as the only way to move a car, the petroleum industry had a complete monopoly on transportation fuel, reflected in vehicle design and refueling infrastructure. (Electric vehicles may provide a viable competitor one day, but such a fundamental shift in American habits will take a generation or more to achieve. And vehicles that run on electricity will only be as clean as the source of the electricity.)

The successful phase-out of leaded gasoline in the 1990s suggests that the same could be done with aromatics, and the fuel economy rule provides a ripe opportunity. The mid-term evaluation required by the rule will begin with a draft technical assessment this June and conclude with a final rule in April 2018. It will consider a wide range of factors, including developments in powertrain technology, consumer acceptance, and trends in fuel prices. Missing from this list, however, is an assessment of other fuel choices.

Engineers in the U.S. Department of Energy’s national laboratories are examining a large number of different fuel formulations to see which is optimal; clearly, increased levels of aromatics would be unacceptable. A mid-level ethanol blend is the best available alternative today, and the EPA should consider this in its mid-term review.

For automakers to demonstrate the benefits of higher-octane fuels, they need a green light from the EPA to proceed with a mid-level ethanol-blend test fuel that could become the standard for the car designs of the next decade. To be ready for widespread use in 2025, the transition of fuels, vehicles, and refueling infrastructure must begin very soon. The benefits of these blends for octane and performance justify this action on the basis of reduced carbon pollution alone. Beyond that, it is incontrovertible that substituting ethanol for toxic aromatic hydrocarbons will have benefits for public health. Rather than regulating aromatics directly, EPA could simply displace them by encouraging higher ethanol blends.

These benefits to climate and health have emerged through a combination of new practices and new research. The EPA should embrace the opportunity of its mid-term review to support higher-ethanol fuels and the myriad advantages they offer.

Timothy Wirth, formerly a member of the U.S. Senate and the House of Representatives from Colorado, is vice chair of the United Nations Foundation. C. Boyden Gray is the founding partner of the law firm Boyden Gray & Associates. This post originally appeared at Yale Environment 360.


  1. Dana1 | | #1

    Spend the subsidy on electrification of transport.
    In terms of both oil use reduction and aromatics + carbon emissions and all local air & water pollution issues there is a much better return on investment in subsidizing electric vehicles (EVs) & infrastructure than in any agriculture based liquid fuels.

    The "...54.5 miles per gallon by 2025..." or the proposed 30% ethanol for cars & light trucks by 2025 is pathetic, when other countries are either talking about or already legislated banning the use of internal combustion engines for cars & light trucks in that time frame. Even the large developing country India is talking about banning internal combustion for cars & light truck by 2030. From a cost of ownership perspective EVs are already have a lower lifecycle cost than internal combustion engine cars, even 55mpg hybrids. Getting over the first-cost hurdle of the battery pack may take a subsidy initially but that won't be the case by 2025, given the rapid learning curve of automotive battery technology.

  2. JC72 | | #2

    @D Dorsett. Big Agriculture wants their piece as well.
    What's not to like about monoculture ?!? *sarcasm*

  3. RedDenver | | #3

    arable land
    Ethanol comes from corn (mostly). Industrial corn is grown on the same land as food crops. That's a losing combination.

    And +1 to Chris M for the monoculture comment.

  4. STEPHEN SHEEHY | | #4

    No till
    As far as I know, no till farming is accomplished by growing corn or other commodity crops, the seeds of which have been genetically modified to be resistant to glyphosate, the most commonly used herbicide. The primary virtue is that it's cheap. I think the jury is still out on what may be the long term implications of heavy herbicide use on soils and whether weeds will develop resistance.

  5. BobHr | | #5

    lets plant more corn and use
    lets plant more corn and use more pesticides. Its only rural america we are polluting.

    I read a report on e85 versus gas. something many people dont know is that a car running e85 will only go 2/3 as far on a gallon of e85 versus 100% gas. ethonal has fewer btu's than gas and requires more to do the same work. So it takes more than 1 gallon of ethanol to replace a gallon of gas. So for every gallon of gas you want to take out of cars you need to replace it will about 1.5 gallons of ethanol.

    When you factor in it takes more ethanol than gas to go the same distance you will find that the amount of emissions is within a percentage point or 2.

    Other considerations are that there are by products from ethanol production. Distillers gain is sold for livestock feed. So we are pushing more corn in to cattle. When you look at corn feed beef versus grass feed beef you find that the fat profile of the animal changes. Gas feed has a higher Omega 3 content where as corn feed beef has a higher Omega 6 content. In our diets where are weighted way to far in omega intake and not enough in omega 3. Fats in your food are not bad for you but rather is it the ratio of good fats ie omega 3 versus bad fats omega 6.You can lump corn oil and soy bean oil in the high omega 6. What are the social, economic and environmental impacts of pushing more omega 6 in our diets via creating markets for the corn byproducts.

    We have taken a product of nature, corn and other crops, and allowed agri business to modify and claim owner ship. These crops have cross pollinated and essentially wiped out non gmo crops. If a gmo crop cross pollinates with a non gmo crop a farmer can not use it as it contains gmo traits.

    As we have planted more corn we are taking land away that was used as animal habitat and that serves are natural filters for water. In Nebraska and Iowa you find that in some area section line roads have been eliminated. The road side ditches are gone. Marginal land than had never been plowed has been plowed under for corn. All of this is lost in the discussion. roughly 1.3 millon acres of untiled land has been plowed under for more and more corn. How many more acres will be required. Who is making the money from this?

    The push for more ethanol is as much a ploy by the agribusiness and chemical companies as it is about the so called benefits of ethanol. I dont see a benefit of ethanol. We would be better off subsidizing electric cars and more efficient energy use in general.

    Instead of subsidizing and pushing more corn we should subsidize more healthy fruits and vegetables


  6. Brent_Eubanks | | #6


    The jury is in, and the verdict is guilty. Roundup resistance is very much a current problem, as was predicted by every crop scientist (and a basic understanding of biology) who did not work for the companies developing and promoting Roundup-Ready crops:

    The response, naturally, is to develop a new generation of crops that are resistant to a different herbicide, and start the whole process over again. Because that makes SO much sense:

    I have personally worked with 2-4D (trying to kill bermuda grass) and read the MSDS and other documentation. This stuff is nasty. It makes glyphosate look like mother's milk. For all of the "Roundup is a carcinogen" you read in the media, glyphosate is actually rather benign (for a poison). 2-4D is not benign.

  7. AlanB4 | | #7

    This is a joke
    Using oil as an argument for more ethanol is ludicrous, we have other alternatives, such as EVs [facepalm]
    Hungry people on the planet, population expected to grow, lets use more farmland and fertilizers and pesticides for fuel and deny the consequences. [double facepalm]
    If you truly have overproduction there are many people who would love to have that food instead we want to burn it. That is just in America, never mind the rest of the planet [triple facepalm]

  8. jkstew | | #8

    Published just to see the fireworks fly?
    I stopped reading after the author claimed more ethanol will increase gas mileage and reduce emissions. It does neither. Ethanol doesn't have as many BTUs/gallon as gasoline and the ethanol dissolves plastic fuel system components which increases pollution when they burn. By now, everyone knows that the ethanol mandate is the worst form of crony gifting to the ag lobby and ADM and other ethanol producers. It allows corn farmers to effectively set their crops on fire and have everybody else pay for it. It literally causes starvation in poor countries because the diversion of farmland to corn ethanol production puts upward prices on all food grains.

  9. Expert Member
    Dana Dorsett | | #9

    The EV tsunami is a lot closer than most understand (@ Alan B)
    In 1900 you could shoot a cannon down a large urban street in the US and not hit a car, but you'd have surplus of dead horses. By 1910 that had flipped.

    EVs are cost-rational in most of the US even at 2016 battery and gasoline/diesel pricing. But the learning rate of batteries are well into double digits of price reduction per doubling of production, and the current rate of production doubling of suitable cells is less than a year, world wide, with multiple large scale factories already being built beginning to come on line. The rapid build out of giga-factory production factor makes both PV solar and EVs much more disruptive to the utility & automotive businesses than even the most out-there analysts were predicting as recently as 2 years ago. (Two years ago RMI was estimating maybe by 2030 grid defection would be cost-rational in higher than average elecricticity cost states such as California. That's now been pulled in by almost a decade based on this year's real-world Li ion battery pricing.)

    Most major car manufacturers are scrambling to get their own EVs into the market before their bread & butter products become obsolete and too expensive to own. By 2025 it will be difficult to buy new personal cars that can't be plugged in, even though some will still be hybrids. We're still in the early stages of the flip, the thin edge of the rising tide as it were, but it's coming, and quickly. The primary thing holding back EV has been range (limited by the cost of the battery required for reasonable range.) That cost is falling fast.

    Whatever else ethanol is by 2025, at the learning curves of both PV and batteries, by 2030 ethanol used in an internal combustion engine will be substantially more expensive per mile than PV + EV (it may be already), and other arguments for/against ethanol & gasoline mixtures at what fraction become as relevant discussing which breeds of horses are better suited for personal transportation. Spending time & money thinking about or implementing ethanol production may have still made sense in 1985 or 1986, but not in 2016 or 2025. Any relevance it might have had in the US is rapidly waning.

  10. jackiestewart | | #10

    This is a shill post
    I agree with Jay S's post, the article has zero credibility due to the claim that increased ethanol would help manufacturers get to 54 mpg. That's a doozy. The internal combustion engine is on a long slow death, but without need of any life support.

  11. Dana1 | | #11

    A shill perhaps...
    ...yet it was originally published a month ago on Yale University's Enviroment 360 site:

    ...accompanied by a counter argument piece:

  12. GBA Editor
    Martin Holladay | | #12

    GBA's guest blog policy
    Authors of guest blogs published on GBA express a wide range of opinions. It never hurts to hear opinions that differ from the consensus view, as long as those opinions are (at least to some extent) supported by a reasonable argument.

    GBA readers may conclude, of course, that the argument underlying a guest blogger's position is weak.

    Here is a link to C. Ford Runge's rebuttal to this article: “The Case Against More Ethanol.”

  13. stuccofirst | | #13

    We already know the ill
    We already know the ill effects of 2-4D as a component of agent orange, yet the USDA has approved it's use, due to crops developing a resistance to roundup. So will we finally learn our lesson after gross amounts of 2-4D end up in the water system? We already now have the health hazards of lead and PFOS in public water systems, as well as nitrate run off from pesticides. Big Agriculture is a big problem, in that, it is an unsustainable model. You don't s*** where you eat.

  14. AlanB4 | | #14

    @ Dana
    I agree that electric cars have incredible disruption potential, but turnover to completely electric will take decades. Thats why i agree with subsidies (within reason) to encourage electric vehicle adoption and even gas car retirement. Not to mention carbon taxes and withdrawal of fossil fuel subsidies
    In time the ethanol problem will evaporate itself to zero, and lets hope the crazy party does not force some kind of nonsense that increases subsidies to corn and oil, since they are actively against repealing fossil fuel subsidies and fight to the death against renewable subsidies.
    If we end up in a situation where the law says you must sell X gallons of ethanol and there is no demand for it we either all get screwed with high ethanol levels even in cars only certified for E10 or we may have taxpayers paying for the stuff and it being dumped into the ocean or wherever they can find a "bottomless" pit, Japan stockpiled rice because they were forced to by the WTO and stockpiled it in warehouses with no intention of ever consuming it. Fortunately it was still edible and was put to use. We could always supercharge our vodka with the extra ethanol, no one has to know its not food grade ;)

  15. user-1121196 | | #15

    Why corn at all?
    Why are we even promoting corn crops at all, much less for ethanol?

    Now, I'm what you would definitely call a skeptical environmentalist. I bet I'm far more conservative than most readers here. But I've had an interest in these things and from my investigations over the years, it seems to me that corn, overall, is one of the worst crops and land uses humanly possible.

    It is literally good for almost nothing. Its crap crop or junk food. It's terrible as feed stock, as has been mentioned, causing most animals to have health problems (because mammals by and large are not designed to eat these seeds). It's land use intensive requiring many inputs. Even the food byproducts we make from it are terrible for our health. The only legitimate place it has is in cob corn and some corn food products (not additives like high fructose corn syrup). Even then it is of little nutritional worth.

    Economically, I'm not sure how it could survive without subsidy and artificial markets (like ethanol, high fructose corn syrup, dubious feed product). It requires vast uses of land for very little output of a cheap commodity. Remove these and corn would become, comparatively, a novelty crop grown in small stands on other more fruitful farms.

    On the other hand, many other food crops produce more of value with less input or environmental impact. Intensive organic permaculture produces vastly more economic value per unit of land at considerable net environmental benefit.

    It's not just ethanol that's the problem. Ethanol is being pushed because that subsidy and artificial market is required to even begin to make corn profitable -- and that's along with the other subsidies, loss protections, and artificial feed and industrial byproduct markets (e.g. high fructose corn syrup). Corn is a disaster from all perspectives, a useless waste crop that destroys wealth and health and trashes the land. It's a weed that should be purged from our agricultural base.

  16. Expert Member
    Dana Dorsett | | #16

    Turnover takes decades? @ Alan B
    The US automotive fleet turnover averages about 15 years, a decade an'a half, not decades:

    EVs will likely have a longer lifecycle, so the overall turnover rate will stretch out once EVs become a double-digit fraction of total sales, but the cars that will be turning over will be the fossil burners (or fossil/biofuel blend burners.)

    Encouraging EV market penetration earlier than later has a bigger effect on net carbon emissions in 2025 than increasing the ethanol content to 30% by 2025. With the right incentives the EV fleet could easily be over 15% of the total existing fleet circa 2025. Depending on how competitive the EV market is by 2020, the 2025 fleet could be 40% EV. The pre-production sales of the Tesla Model 3 indicates a high pent up demand for EVs that have decent range. Battery costs has dropped 70% in just the past 18 months due to the surging production capacity, so it's really a matter of how fast the auto companies can roll out the EVs and plug-in hybrids that can use them:

    I'm betting it'll be a pretty hot EV market by 2020- (especially after friends let friends test drive theirs!)

    E30 is not a flex fuel- you can't run it in the existing fleet with reasonable efficiency (maybe not at all in some cases). It will only run efficiently in higher compression engines specifically designed for E30, which means only new cars will be able to use it. The hit in mpg you get with E10 fuel relative to gasoline will go away with E30- specific engines, since the efficiency will be higher than engines designed for gasoline when burning E10, which is the basis of the advocates' higher mpg claim. That higher mpg claim is true, but only if you read the fine print (fine print not found in this blog piece, mind you.)

    In the meantime, plug-in hybrids are now being described as the "gateway drug" to the pure EV driving addiction. :-) A car that has reasonable range, great off the line torque, that never needs an oil change that can be charged at home (or lots of places, with infrastructure policy support) will be very competitive over a clunky E30 pure internal combustion engine car. An E30 fuel plug in hybrid might be interesting to some who need the extended range, but if the Chevy Volt and other plug-in hybrids are iany guide (and I think it is), the E30 would be the least aspect of the carbon & oil use reductions. I talked to a Volt driver a few weeks ago who fills up the tank every 2 to 4 months, usually just before going on a longer weekend road trip. When batteries are cheap enough for longer all electric range (150+ miles) for cars in all price ranges it's surely going to cut into plug in hybrid sales.

  17. AlanB4 | | #17

    @ Dana
    I completely forgot about this thread and it just came back to me so i apologize for the late reply
    Its odd that we keep disagreeing because fundamentally we are on the same side, i completely agree that electric cars are the future, and that ethanol is a bad idea, and we need to move on climate change much faster then we have been.
    I would very much like to see mostly electric in 15 years, and you are correct that the demand is there, but keep in mind the automakers are not selling 10-15 million electric cars annually (outdated US sales number, no idea what the current number is) and won't suddenly do so. If Tesla sells 500k a year after a ramp up period of years and their competitors even match that its still a fraction of the annual worldwide car sales.
    Hence i still believe we have decades left of ICE cars. I would be very happy to be wrong, and i completely support incentives and other supports to make ICE engines obsolete ASAP

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