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Energy Solutions

Ethanol Under Fire

Producing ethanol from corn yields a poor energy return on investment and has negative impacts on ecosystems in the Midwest

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Because of the U.S. mandate requiring ethanol to be blended with gasoline, Midwestern farmers have dramatically increased the number of acres devoted to corn.
Image Credit: Lynn Betts, USDA-NRCS
Because of the U.S. mandate requiring ethanol to be blended with gasoline, Midwestern farmers have dramatically increased the number of acres devoted to corn.
Image Credit: Lynn Betts, USDA-NRCS
Corn production is energy-intensive and results in significant nutrient pollution.
Image Credit: USDA-NRCS

In my book, corn-based ethanol as a vehicle fuel has never been a good idea. But an in-depth investigation by Dina Cappiello and Matt Apuzzo of The Associated Press, published last week, outlines a lot of other reasons why we should finally kill this particular farm subsidy.

Before explaining why corn-based ethanol production is a bad idea, it’s worth noting why we’ve been promoting it. The U.S. is one of the most agriculturally rich nations in the world, and we’re also one of the world’s largest fossil fuel importers. It makes sense on some levels to convert some motor fuel to bio-based sources, such as ethanol and biodiesel — because we can produce it ourselves, helping to wean our dependence on oil from the Middle East and other politically unstable or unfriendly places.

Also, in theory, biofuels should help to reduce greenhouse gas emissions, since the raw materials (corn in the case of ethanol) is produced, in part, using solar energy via photosynthesis. The Obama Administration, like the George W. Bush Administration before, touted ethanol as a strategy for reducing our nation’s greenhouse gas emissions.

Energy return on investment

I’ve written here in the past about the energy return on investment (EROI) with ethanol. Depending on whose study you believe, it either takes a little more or a little less energy to produce corn-based ethanol than that end-product contains. That EROI ratio ranges from 0.8:1 to 1.5:1, depending on the study.

Any time the EROI is less than 1:1, it takes more energy to produce the fuel than the fuel contains. Even giving the ethanol industry the benefit of the doubt by assuming the actual EROI is 1.5:1, that means to produce a gallon of the fuel takes two-thirds of a gallon (equivalent) of fuel — diesel for tractors and combines on the farm, natural gas to produce nitrogen fertilizer, natural gas and electricity at the ethanol plant, and energy to ship that fuel around the country.

By comparison, the ethanol produced from sugar cane in Brazil has an EROI closer to 8:1 — for every gallon (equivalent) invested you get about eight gallons back out.

No matter whose numbers you believe, from an energy standpoint turning corn into ethanol to fuel our cars makes little sense.

Land conversion to corn production

Even more troubling than the dubious energy balance of ethanol is the land conversions that have occurred as demand for corn has increased in recent years. Just since 2008, according to the AP investigation, more than 5 million acres of land that had been set aside as part of the Conservation Reserve Program have been converted to corn production — an area greater than Yellowstone, Yosemite, and the Everglades National Parks combined.

Since 2006, some 1.2 million acres in Nebraska and the Dakotas that had never been tilled have been converted to corn and soybean production. This is even worse than converting conservation acreage into tilled farmland — since much of the conservation land had once been tilled. When virgin prairie is converted to farmland, along with losing the biodiversity on that land, a significant amount of carbon that was stored as organic matter in the soil is released into the atmosphere — contributing to greenhouse gas emissions.

Increased fertilizer use

The dramatic increase in corn production in recent years has also dramatically increased fertilizer use. Between 2005 and 2010, according to the AP investigation, nitrogen fertilizer use increased by 1 billion pounds, with another billion-pound increase likely having occurred since 2010.

Along with requiring a lot of natural gas to produce all that fertilizer, the runoff from that farmland is a huge pollution problem and contributes directly to the “dead zone” that occurs each year in the Gulf of Mexico.

Corn for energy vs. food

As demand for corn increased to meet increasing mandates for ethanol in U.S. gasoline, the price of corn increased (commodity pricing is driven by supply and demand). In our increasingly global markets, this affected food prices in developing countries that rely heavily on corn. Corn prices climbed to $7 per bushel in the U.S., double what they had been a few years earlier, and this dramatically increased food prices in Mexico, leading in some places to food riots.

Prices of corn have since dropped somewhat and record harvests are expected this year, but prices are still above where they were ten years ago.

Reevaluating our ethanol policy

The AP report came out just as the Obama Administration is reconsidering the ethanol mandates that have fueled the dramatic increase in corn production. The U.S. Environmental Protection Agency has proposed scaling back on the biofuel mandates in the Renewable Fuel Standard. Legislation passed in 2007 called for increasing the production of biofuels each year, with production reaching 16.55 billion gallons this year (2013) and rising to 36 billion gallons by 2022.

But when that legislation was passed, the consumption of gasoline was expected to continue rising, so the quota could have been achieved without increasing the percentage of ethanol in gasoline beyond the 10% that car makers are comfortable with. More ethanol in gasoline can cause corrosion in engines. With cars and light trucks becoming more fuel efficient, the numbers weren’t working.

EPA has proposed scaling back the ethanol mandate in 2014 to 15.21 billion gallons, down 14% from where it would be under the Renewable Fuel Standard — and just under 10% of the motor fuel sold in the country. An unusual coalition of oil companies and environmentalists is proposing going further and eliminating the biofuel mandates altogether.

The road ahead

I, like many others, have been hoping that “cellulostic ethanol” (made from agricultural residue like corn stalks rather than high-value corn) would advance more quickly than it has. So, along with proposing a reduction in the overall biofuel mandate, EPA last week proposed cutting the target for so-called “advanced biofuels” from 2.75 billion gallons this year to 2.2 billion gallons next year.

In the coming weeks, during the 50-day comment period for the new EPA rules, expect to see a barrage of dueling television ads on this issue.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.


  1. user-723121 | | #1

    King Corn
    Nice summary, Alex

    Growing up on a farm and being landowners, we have watched the ethanol industry and debate for many years. The byproduct of ethanol production is distillers grain and this is fed to livestock. How much has the use of corn for ethanol raised the price of corn over the years is an interesting debate. The price of corn took a big jump in 2012 due to the drought in the midwest, supply and demand drove the market.

    The sad result of the last couple of years is the great loss of virgin prairie, time will tell what the impact will be. Biodiversity on the farm these days is far fetched concept, seldom talked about and rarely practiced. The loss of pollinator species is one area that is garnering attention, a move towards providing habitat may be the start of reconnecting landowners with the natural systems.

    I do not begrudge the farmer for planting corn, he or she is only hoping for profitability. Putting all of your money on one crop is a Las Vegas style gamble and may be the downfall of some. The price of corn today is below the cost of production and the view from the country is one of concern. I see in agriculture what happened to the housing market in the last downturn, the cost of inputs is driving the cost of production to an unsustainable level. Low interest rates seem to be the driving force at play for both the housing bubble and the much higher production costs for farm commodities.

  2. Expert Member
    Dana Dorsett | | #2

    The EROI of any biofuel prospects...
    ...are tepid at best. Standard efficiency silicon photovoltaics installed in roof-top residential does as well or better than the 8.0 EROI mentioned for Brazilian cane-ethanol. Utility scale ground mounted PV beats it with margin, and utility scale wind beats it by more than 2x, almost 3x.

    Then when you take that energy-expensive low EROI liquid fuel and burn it in a 20-25% efficiency Rankine-cycle heat engine (like a piston-driven gas or diesel) it's pretty much wasted. If you take the comparable EROI rooftop PV and charged a plug-in car with it you'll be north of 75% from PV panel to where the rubber meets the road, compared to 20-25%. If the EROI is measured from input energy to the end-used energy it's no-contest- the rooftop PV is 300-400% more energy efficient than the BEST CASE biofuel in this example.

    Spending huge money on biofuels just to support the business-as-usual installed base of transportation infrastructure is extremely short sighted. You'll save more oil-imports and gain more carbon reduction by using that corn ethanol subsidy money to ramp up the plug-in car sales, and maybe a hint more (it doesn't need much) for cost-reducing the "rest of system" costs of PV (the panels are cheap compared to the racking & installation costs at 2013 system component pricing.) Electrifying personal transportation in some US markets would see a short term increase in the carbon rate, but the cost of distributed PV is crashing so fast (it's $2/watt, installed in Germany right now, compared to $5/watt in the US, but sub-$2 is anticipated in some parts of TX next year). Smart-chargers and car batteries would actually help manage the variable input of PV onto the grid, and allow the grid operator to run the other generating assets at or near maximum efficiency (more use of 55% efficiency combined cycle gas, less 35% efficiency gas-fired peaker power.)

    Any significant penetration of plug-in cars would make a difference, and plug-ins are on a much faster launch trajectory than when the first gas/electric hybrids hit the market a decade or so ago. This is a grid-control problem at the local-grid level that needs to be managed, but it IS a managable problem, and done right makes both the grid and any renewable grid sources more efficient.

    From a policy point of view the corn ethanol fuel approach conceived of in the 1980s really has run it's course- it's toast, the world has moved on, and it's time to wake up and smell the toast burning. It's becoming the moral equivalent of a steam locomotive technology or horse fodder subsidy. It made some sense for Brazil, but it never really added up for the US economy. Electric cars are coming, in one form or another (hydrogen fuel cell cars are electric cars, with a fuel cell instead of a storage battery, but are currently net-energy efficient than grid-to-battery cars.)

  3. GBA Editor
    Martin Holladay | | #3

    Response to Dana Dorsett
    The idea of hydrogen-fueled cars is fundamentally flawed.

    If anyone thinks that we will be using electricity from renewable sources in the future to produce hydrogen by electrolysis, then physics tells us that battery-powered electric cars will always be more efficient than hydrogen cars.

  4. Expert Member
    Dana Dorsett | | #4

    No kidding!! (response to Martin)
    Even on a cost-basis the estimation is that for gasoline-equivalent-miles-driven is on the order $3/gallon-gasoline-transport equivalent (before road taxes, etc.) which makes it more that 2x the cost of grid-powered electricity at the full residential retail rate. Hydrongen fuel cells may have some transportation applications, but personal transport probably isn't one of them. The only advantages over grid-charged battery are range, and refueling speed. But for the vast majority of personal car use the range isn't much of an issue for the day-to-day stuff, and the plug-it-in-at-home convenience beats the side trip to the hydrogen station.

    Don't discount the ability the coming tsunami of way sub-$2 PV to bring the cost of generating the hydrogen way down too, but the quality and convenience factors of plug-in hybrids and straight-ahead electric cars is at a pretty-good price point now, and improving. The prospects of dramatically reducing the infrastructure costs of hydrogen fueling down just aren't very promising, but nearly everybody ('ceptin' maybe Martin Holladay :-) ) has a grid-connection at the house, and don't need 5 minute refueling/recharging times. Unless you really need the range and short refueling time of a hydrogen fuel cell, and you're willing to spend 2-4x as much for those features, an electric car is going to continue to have a very big economy & convenience advantage.

    Even putting more non-plug-in hybrids on the road can put a far bigger dent in the fossil-fuel burn rate than any amount of corn ethanol subsidy, for the dollars invested. I won't rule out cellulosic ethanol just yet, but I'm not holding my breath. You'll get far more driving miles out of covering your marginal acres with PV than with switchgrass, not that I'm advocating covering agricultural land or virgin prairie with PV. There are still literally millions of acres of suitable rooftop and parking lot to farm for photons, located much closer to where the output can be used. Parking the electric car under the PV awning/charging-station at work is already a reality for some, a dead-obvious application in an already competitive market:

    The Chevy Spark EV (currently only available in CA & OR, where the road-trip charging infrastructure is better developed) would be a GREAT little commuter car for a lot of folks. It has a comparable size & performance to the recently released electric Beemer, but at 1/3 the sticker price. (In CA after subsidy they're about $20K) They're made in Korea, and the Asian market for them is pretty hot- maybe TOO hot to expect it to show up on the right-coast of the US any time soon. The Nissan Leaf has been out for a few years now and a pretty good history- nobody wants to sell their used ones just yet. But this is the thin edge of the wedge- plug-ins are likely to become dominant eventually, and given the synergy you get with low-priced and getting ever cheaper distributed PV it's seems almost inevitable to become the new paradigm for personal transportation in the coming couple of decades, even if we're already past "peak car", as many analysts believe. (I'm less certain of the peak car argument- the high price of gasoline and low growth in wages seems to be the primary inhibitors for buying cars. Cheaper electric cars & cheaper electricity may transform that too.)

  5. Brent_Eubanks | | #5

    on the topic of biofuels
    On this topic, particularly on the prospects of the "next generation" biofuels approach, I would recommend the writings of Robert Rapier. He is a chemical engineer formerly of the oil industry who now works for a startup that is working on a pryolysis-based biofuel path. He's pretty negative on the prospects for cellulosic and algal ethanol, for what seem to be very good technical and logistical reasons (long-distance transportation of low-energy-density biomass makes getting a decent EROEI challenging).
    Sorry I don't have time to review/recommend particular articles right now, but if you search on "Robert Rapier" and biofuels or ethanol, you'll get many relevant hits.

  6. 3daves | | #6

    Electric cars are coming...
    As mentioned by earlier posters, I see electric cars as the solution. Here's one reason why:

    Ethanol from corn is simply solar energy by a different name. The path from sun to car in the "ethanol cycle": Sun to corn plant (with additional fossil fuel external energy inputs from farm equipment, transport, fertilizers, etc.). Harvest corn, transport it to silos, then on to processing plant (more fossil fuel input). Processing, followed by by extraction of the ethanol (more fossil fuel input), Transport of ethanol to fuel processing faclity, then on to gas stations (more fossil fuel input), then burn in an internal combustion engine at roughly 20% efficiency.

    Compare that to the solar powered electric car:
    Sun to PV panel, conversion to electricity (roughly 15% of sun's energy converted to electricity, and hopefully this will improve with time). Delivery to car's battery system (with charging losses, of course). "Burn" energy in the elctric motor in the 90% efficiency range.

    The latter option makes a whole lot more sense to me, especially if we can include development of standardized "swappable battery systems" that could be a value added feature for existing gas stations (Better Place tried this, but failed for fiancial reasons, I hear).

    And consider this for around town driving - no more trips to the gas station!!!! Imagine how this would upset the Koch Brothers and their ilk (all the more reason to FIGHT for this scenario!).

    Finally, imagine how much simpler cars will be when we eliminate the complex I.C. engine, the radiator/coolant system, the gas tank/fuel system, all of the sensors that are constantly going bad, etc. A lot of parts suppliers will go out of business, but...

  7. GBA Editor
    Martin Holladay | | #7

    Response to David Congour
    "Eliminating the radiator/coolant system," which you list as a plus, is bad news for those of us who live in cold climates. It's hard for an electric car to have a heater -- and when it's 0 degrees F, the way it is today in Vermont, a heater is handy.

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