8/26/07 – Added section on environmental benefits.
8/5/07 – Added to section on the petroleum displacement claims. Building the section on Brazil.
8/4/07 – Updated section on the ethanol subsidy, and who it benefits. Also updated section on ethanol and job creation. Updated section on land requirements.
8/3/07 – Updated section on energy balance, and whether it matters.
I am starting to get a lot of traffic and e-mails off of this Rolling Stone article. A lot of the same questions/criticisms come up again and again, so I am finally being prompted to do something I have been meaning to do for a long time: Write a FAQ, where my position is summed up concisely, and is understandable by anyone. This is a work in progress, so if you can think of something that should be addressed, please speak up. I am going to throw them out there as I do them, and I will clean them up later. I hope to put up one or two new items a day, and if you find errors, I will certainly correct them. This will not be an opinion piece. It is going to be based on facts and numbers.
This one is where opponents tend to go when they are lazy, or have no better arguments to offer. But not only is it an ad hominem argument, it is wrong on 2 counts. First, I have a long track record of being supportive of alternative fuels, I did my graduate school thesis on the subject, and in fact I have done a lot of work in this field. Many people who read this blog can attest to the fact that I have done a lot of pro bono work, on a lot of projects: From biodiesel to biobutanol, right through cellulosic ethanol and yes, even corn ethanol. Furthermore, I am currently involved in a cellulosic ethanol project.
But the second reason that this argument is invalid is that the corn ethanol industry is heavily dependent upon fossil fuels for the entire production process. These fossil fuels include gasoline and diesel, but are primarily natural gas embedded in the fertilizer for the corn, and for the distillation energy. Guess who produces this natural gas? Big Oil, and my company in particular, produces a tremendous amount of it. The tripling of natural gas prices since 2002 happened just as we had a dramatic increase in ethanol production. Coincidence? No. And this has been a windfall for Big Oil.
Don’t take my word for it. Here’s the view from Ethanol Producer Magazine:
One source tells EPM that when ethanol production reaches 7.5 billion gallons (assuming all of that capacity was fueled by natural gas) demand from the industry could represent a 1.2 percent increase in total U.S. demand for natural gas. That’s a significant rise when you consider that the total increase in natural gas consumption from 2004 to 2005 was only about 1.4 percent. What happens if the ethanol industry goes to the apparent next production plateau at 12 billion gallons per year? Ultimately, increased natural gas use resulting from the ethanol industry’s expansion affects total U.S. demand of fossil energy, helping to keep supplies tight and prices elevated.
That’s right: Corn ethanol is a boon to Big Oil, because it has helped tighten up fossil fuel supplies, which has helped with the price increases – while displacing little to no fossil fuel itself. And I can tell you that a lot of people in the oil industry recognize the irony. A number of oil companies, including my own, have come out and endorsed ethanol. So my arguments against corn ethanol are actually contrary to the official position of my company.
There are many claims around these theme. From the Renewable Fuels Association’s (RFA) “Energy Facts”:
FACT: In 2006, the production and use of ethanol in the U.S. reduced oil imports by 170 million barrels, saving $11 billion from being sent to foreign and often hostile countries.
The RFA’s page on industry statistics shows that ethanol production in 2006 was 4.86 billion gallons. This is 116 million barrels. Oil has a BTU value of 138,000 BTUs/gal, versus 76,000 BTUs/gal for ethanol; therefore 116 million barrels of ethanol contain the BTU equivalent of 64 million barrels of oil. (Source: ORNL). The claim then is that 64 million barrels of oil equivalent (BOE) displaced 170 million barrels of oil.
The production of nearly five billion gallons of ethanol means that the U.S. needed to import 206 million fewer barrels of oil in 2006, valued at $11.2 billion. This is money that stayed in the American economy.
Source: Contribution of the Ethanol Industry to the Economy of the United States in 2006 (PDF download)
While you might expect to find such claims from the ethanol industry, even grander claims are being made by the U.S. Government. From DOE Assistant Secretary Alexander Karsner’s keynote address to the RFA’s National Ethanol Conference in Tucson, Arizona:
Last year, we contributed something on the order of a displacing 500 million barrels of oil, oil that we didn’t have to import from regimes that are hostile to our interest or might leverage energy economics over our future.
Over 6 billion gallons of ethanol were produced in the United States last year, and we have an additional 5 billion gallons of refining capacity under construction.
That effort means 500 million fewer barrels of oil that we have to import from the Middle East.
That’s from the U.S. Department of Energy. That is the department of the U.S. government that is charged with formulating and carrying out U.S. energy policy. How on earth are people coming up with these numbers? Can 64 million barrels of oil equivalent displace 170 million, 206 million, or even 500 million barrels of oil? And recognize that we haven’t even touched upon the fact that the 64 million barrels is the gross output, and not the net. To get a true displacement number (for just petroleum), we have to subtract out all of the petroleum inputs that went into making those barrels of ethanol.
The way they are coming up with such unreasonable numbers is because they are making some invalid assumptions. They are assuming that since only 1/6th or so of the BTUs embedded in a BTU of ethanol come from oil (the rest are from natural gas or coal), that a barrel of ethanol can actually displace more than 1 barrel of oil. The higher estimates are also completely ignoring the fact that the half of the barrel of oil that doesn’t provide gasoline goes into diesel, jet fuel, heating oil, etc. In these analyses, those are simply unaccounted for. So when that barrel is “displaced”, we just lost a lot of fuel.
But consider this for a moment. Consider if only 1/100th of the inputs into ethanol were from oil. In this case your multiplier is 100 (instead of 6). Do you believe that a barrel of ethanol then displaces 100 barrels of oil? Consider that 1/1,000,000 of the inputs into ethanol were petroleum, and you quickly start to see the sleight of hand employed.
So how much oil can ethanol really displace? No more than the BTUs that are contained in the ethanol. A 1 to 1 BTU replacement is is the best you could get even if the ethanol was free of any energy inputs, and just available for pumping out of a well. That is the maximum theoretical displacement.
Since ethanol is a gasoline replacement, the displacement should be most pronounced if we look at the gasoline demand curve. As ethanol has ramped up exponentially since 2000, one might expect to see this in the gasoline demand curve. Yet there is no obvious inflection on the gasoline demand curve. As shown in the link, as ethanol has ramped up since 2000, not only has gasoline demand increased by 10 billion barrels per year, but there isn’t even any obvious effect from ethanol on the gasoline growth curve. Even as ethanol has ramped up, the data indicate that we have become more dependent upon petroleum.
U.S. dependence on foreign oil is a demand-side problem. It is not going to be fixed by producing more ethanol – false claims about the amount of displacement notwithstanding. And it is not going to be fixed unless we confront the reality of the situation instead of the political spin.
The EROEI, (Energy Returned on Energy Invested), EROI, and energy return all refer to the same idea. It is the ratio of usable energy returned from a process divided by the energy expended (consumed) in the production process. Or, simply put, if I expend a total of 1 BTU of energy in a process that yields 5 BTUs of energy, the EROEI is 5/1.
This is an area rife with misunderstand and garbled definitions. Depending on where the system boundaries are drawn, one can come up with very different definitions.
No, and this is a big source of confusion. The process efficiency refers to the percentage of net energy yielded in the process. In the above example, 1 BTU was expended to produce 5 BTUs. The net energy is then 4 BTUs, and the efficiency of the process is (4/5), which is 0.8 or 80%. An EROEI can be greater than or less than 1. A process efficiency is always going to be less than 1 (i.e., you are always going to use up some of the energy value in the process).
I think most people are starting to accept this as a debunked myth. But let’s review the history, because I do still hear this claim occasionally. A few years ago, Michael Wang from Argonne National Labs invented a metric, which was fossil fuel inputs into both the ethanol and gasoline production processes. This metric was neither an EROEI nor an efficiency, it was a hybrid, and has led to a lot of apples and oranges comparisons between gasoline and ethanol.
I have dealt with this claim several times in this blog. I addressed it here in response to a claim from the Minnesota Department of Agriculture (which they seem to have since removed):
In summary, the finished liquid fuel energy yield for fossil fuel dedicated to the production of ethanol is 1.34 but only 0.74 for gasoline. In other words the energy yield of ethanol is (1.34/0.74) or 81 percent greater than the comparable yield for gasoline.
I addressed it here, in response to a letter from a reader in which Michael Wang and Vinod Khosla were both copied, and both got involved in the debate:
If your assessment of the ethanol fuel cycle energy balance (and its comparison with the petroleum fuel cycle energy balance) is right, then not only is Vinod Khosla wrong, but many others of us in the energy community — including the U.S. Department of Energy and Argonne National Laboratory (see attached summary) must also be wrong.
Now I will address it here for the last time. What’s the issue? For Wang’s metric, the inputs aren’t considered in a consistent manner. For instance, the fossil fuel inputs into the ethanol process are burned. Gone. The fossil fuel inputs he is considering for gasoline production includes the barrel of oil that gets turned into liquid fuels. So, he is including only expended fossil fuels in the ethanol case (which is what you want to do for an EROEI) but in the case of gasoline he is also including fossil fuels that were not consumed and are still available as fuel. What Wang has done, by defining his metric as he has, is to measure the EROEI of ethanol – at 1.3, versus the efficiency of gasoline, which according to Wang’s most recent modeling, is 0.8 (from crude in the ground to gasoline in your gas tank). And I can tell you that this is reasonably accurate. But to compare the two different metrics causes the kind of confusion that you might expect.
So, let’s compare EROEI to EROEI and efficiency to efficiency. At an ethanol EROEI of 1.3, that means that burning 1 BTU to produce 1.3 BTUs only results in a net of 0.3. Therefore, the efficiency is 0.3/1.3, or 23%, versus Wang’s estimate of 80% for gasoline. Comparing EROEIs, an 80% efficiency for gasoline means that to produce 1 BTU consumed 0.2 BTUs, for a net of 0.8. The EROEI for gasoline then – the energy return over energy invested – is 1 BTU/0.2 BTUs, or 5/1. This was the source of the claim to that effect in the Rolling Stone article.
EROEI of producing ethanol – 1.3/1
EROEI of producing gasoline – 5/1
Efficiency of producing ethanol – 23%
Efficiency of producing gasoline – 80%
It depends. A society that operates with a high average EROEI is going to look quite a bit different from a society that doesn’t. In the former, a relatively small proportion of the overall economy can be involved in the production of energy which drives the rest of society. But as the EROEI of a society decreases, the energy production of the society must increase. Society becomes more dependent upon energy production. For instance, the world uses 85 million barrels of oil a day. If the EROEI of society is 10/1, then 8.5 million of those barrel equivalents were used to produce the oil. For the sake of this exercise, let’s assume that oil was used to make oil. That leaves us with a net of 76.5 million barrels.
Now, drop the energy return of that same society to a biofuel range of 1.3 to 1. We have to solve two equations here: Net Energy = Energy out – Energy in, and Energy return = Energy out/Energy in. Solving these two equations for a net of 76.5 million barrels of oil means we have to produce a total of 255 million barrels of oil equivalent. In the fossil fuel society, it takes 85 million barrels of total production to sustain it. In the low energy return society that approximates today’s biofuels, it takes 255 million barrels per day to sustain it. That means that if we tried to run the world on low energy return biofuels, we would need to triple the overall energy output over what we produce today.
But what if, in the second case, we could use biomass as our energy source (but not for the first case)? Or what if, in the first case there are lots of other negative externalities that go along with the energy source? Or what if the second case utilizes a very cheap energy source to make a fuel that sells for a much higher value? In reality, EROEI is a part of the overall evaluation, but by itself does not tell you much.
Consider that your goal is merely to make money. You may be able to make lots of money with a process having an EROEI of less than 1. You can take a BTU of coal and use it in an ethanol process to make less than a BTU of ethanol. Considering only your energy inputs, you have increased the $ value of your BTUs by a factor of 10. So, even if you take 1 BTU of coal and convert that into 0.7 BTUs of ethanol, there may be plenty of economic incentive to do it, despite the energy returns.
EROEI matters. Sometimes. And as a part of the overall context.
Here’s Vinod Khosla from a story in Wired, Six Ethanol Myths:
Yes, ethanol producers and blenders share in a 51-cent-a-gallon federal credit that costs taxpayers about $2 billion a year. The majority of that accrues to oil companies, not farmers.
Before pondering this too much, consider for a moment just who has lobbied to keep the credit intact. Has it been oil companies? No. Has it been politicians from oil states like Texas and Alaska? No. The groups always arguing in favor of the ethanol tax credit have historically been farm state politicians, ethanol lobbying groups, and corn lobbying groups.
Last year I documented the reaction of Brian Jennings, the executive vice president of the American Coalition for Ethanol, when ExxonMobil (XOM) CEO Rex Tillerson called for an end to the subsidies. Jennings said “it is outrageous for an executive for big oil to actually suggest getting rid of the tax credit for ethanol.” That’s very odd behavior if Big Oil is actually the beneficiary.
But of course as you might guess, Jennings isn’t making the case for Big Oil, because Big Oil isn’t the actual beneficiary. Here’s what’s going on. The blender’s credit does in fact accrue to the purchaser of the ethanol. That’s because the wholesale price of ethanol, at only 67% the energy content of gasoline, historically has been more higher than that of gasoline. (At times ethanol has traded cheaper than gasoline, but never on an average annual basis in the past 27 years. See the chart in this essay). So, without the incentive, it would not be economical for oil companies to purchase ethanol for blending. The blender’s credit has resulted in an artificial inflation of the price that ethanol producers can get for their product, which is why they are defensive about keeping it.
However, I have noted a change in attitude from oil companies lately with respect to this credit. Whereas they were once strongly against it, I think the fact that ethanol is now mandated has some of them changing their tune.Even the American Petroleum Institute has changed their tune. I recently posed the question to API president Red Cavaney on the API’s stance on the subsidy, and he stated that they are agnostic on the issue.
Why the change? Because now, with ethanol mandated, eliminating the credit would mean that oil companies would be forced to pay the true price for ethanol without getting a credit, meaning they will have to pass these costs on. This would result in an increase in the cost of gasoline (consider that this would cause the price of E85, for instance, to rise by 85% of the value of the subsidy – $0.43/gal). This would likely reduce overall product demand. So oil companies may be realizing that with mandated ethanol, they are better off with the credit in place – even if the primary beneficiaries are ethanol interests.
Of course it does. But how are jobs created? If we mandated that everyone had to consume a pound of potatoes or a pineapple each week, it would also create jobs and revitalize communities. So why don’t we do this?
We don’t do this because the jobs are created by flowing money out of one region of the country into another. If job creation had no impact on jobs in other regions, we could just enact one mandate after another, forcing us to buy various products until everyone was happily employed. But the economy doesn’t work that way. The jobs that are created in Iowa are a result of money flowing out of the rest of the country.
Paul Rogers, a reporter for the San Jose Mercury News, gives the following account in which he asked Iowa governor Tom Vilsack why the rest of the country should be forced to use ethanol:
“Because it helps farmers from my state expand their markets, Vilsack explained. ‘So I guess you’d support a new federal law to require everybody in Des Moines to buy a computer, to help people in Silicon Valley expand their markets?’ I asked. He didn’t concur.”
That’s a pretty good example of why job creation isn’t free. Forcing people in Iowa to buy computers would result in less money to spend on other things. It is just less obvious with ethanol, because the money is extracted in smaller increments.
Again, Vinod Khosla from Wired, Six Ethanol Myths, addressing the “myth” that the U.S. doesn’t have the available land:
Former secretary of state George Schultz and ex-CIA director R. James Woolsey estimate that 30 million acres can replace half our gasoline. I estimate that 40 million to 60 million acres can replace our gasoline needs. By taking land now used to grow export crops and instead planting energy crops, it’s feasible to eliminate our need to import oil for gasoline.
Let’s think about that for a minute. Presume that gasoline demand doesn’t grow at all from today’s 140 billion gallons. Now consider that, because ethanol only contains 67% of the energy of gasoline, it’s going to take 210 billion gallons of ethanol. In Khosla’s “worst case”, he would have 210 billion gallons of ethanol being produced on 60 million acres. This would require an ethanol yield of 3500 gallons per acre, around 10 times the current per acre ethanol yields. While you will sometimes hear of ethanol yields of 500 gallons per acre of corn, the nationwide average yield is around 350 gallons per acre.
So, we require an improvement in yields by a factor of 10 if we use corn, or we need something that has a better ethanol yield per acre than corn. But let’s assume for a second that it can be done. Now, here is where the EROEI issue becomes important. That 210 billion gallons of ethanol is the gross amount of ethanol required. But, how much energy is required to produce that much ethanol? At the current EROEI of 1.3 (with animal feed byproducts included), it would take the BTU equivalent of 210 billion/1.3, or 162 billion gallons worth of ethanol just to drive the process. In reality, we are treating animal feed by-products as BTUs that can be burned for transportation. If we were only considering fossil fuel inputs in and ethanol BTUs out, it would take pretty close to 200 billion gallons of ethanol equivalent to drive the process.
So with the generous assumption on by-products, the actual energy production required in this scenario is 210 billion gallons of ethanol, plus 162 billion gallons worth of BTUs to drive the process for a total of 372 billion gallons. Furthermore, you would end up with more animal feed by-product than you know what to do with.
Clearly, it is a stretch to presume we could supply U.S. demand by using corn, which means another biomass source will be required. That technology is not presently commercially available. Furthermore, if/when such a technology does become available, unless the EROEI is much improved we will find ourselves in the position of having to produce almost twice as much energy as we do now, just to have the same amount of net energy at the end of the process.
First off, let me state that I think sugarcane ethanol is a good solution for Brazil. Brazil is located in the tropics, and receives far more solar insolation than temperate locations like the U.S. Furthermore, a study commissioned by The Netherlands Agency for Sustainable Development and Innovation concluded that sugarcane ethanol production in Brazil is sustainable. I wrote an essay addressing that situation:
So, if Brazil can do it, why can’t the U.S.? I have heard the claim many times that Brazil has shown us the way to a bio-fueled future. I have also addressed the fallacy of these arguments in the following essays:
For the purpose of this FAQ, I will briefly summarize the issues. First, Brazil still relies on oil for 90% of their transportation needs. Ethanol in fact only serves 10% of the market there. Their “energy independence miracle”, as Mr. Khosla has referred to it, actually happened as a result of a major oil find by Petrobras. The following short report shows the stark contrast between the amount of oil Brazil produces, and the amount of ethanol Brazil produces:
So that’s the first issue: The contribution of ethanol has been exaggerated. The second issue is that the per capita oil consumption in Brazil is about 4 barrels per person per year. In the U.S., per capita consumption is about 27 barrels per person per year. Given that Brazil produces a little over 3 barrels per person per year, they have a very small gap to close, and sugarcane ethanol helps close that gap. In the U.S., we produce a lot more oil than does Brazil – around 11 barrels per person per year – but we then have a gap of 16 barrels per person per year to close. In other words, we would need to close a gap of more than 16 times that of Brazil, and do so in a temperate climate.
So, the answer to the question of why the U.S. can’t do “it” just depends on the definition of “it.” If “it” means cutting our oil consumption down to the level of Brazil’s, or for that matter even just cutting it in half (which would still be triple that of Brazil’s), then the U.S. could do “it.” But if “it” simply refers to growing our way to energy independence – as many biofuels proponents have suggested, then Brazil can’t serve as the model for what we wish to do in the U.S. If a dramatic cut in oil consumption is not part of the equation, then the U.S. and Brazil are apples and oranges.
What works well for Brazil does not necessarily scale to the rest of the world. As shown in the previous section, Brazil has much lower per capita energy consumption than the U.S. (and the European Union). Scaling up to supply the world with biofuels is already having some undesirable consequences:
The issue is not, as some have suggested, that Brazil is cutting down rain forest to make way for sugarcane plantations. It is a bit more complicated than that.
In the past four decades, more than half of the Cerrado has been transformed by the encroachment of cattle ranchers and soybean farmers. And now another demand is quickly eating into the landscape: sugarcane, the raw material for Brazilian ethanol.
The roots of this transformation lie in the worldwide demand for ethanol, recently boosted by a U.S. Senate bill that would mandate the use of 36 billion gallons of ethanol by 2022, more than six times the capacity of the United States’ 115 ethanol refineries.
In addition, as use of corn-based ethanol grows in the United States, rising prices are influencing American soybean farmers to switch to corn. And as the United States, the world’s largest soybean producer, cuts soybean plantings, buyers are looking to Brazil, the No. 2 soy producer, to expand its production. Brazilian soybean production is already at record levels and is predicted to increase another 4.5 percent this year, according to Abiove, an industry association.
To summarize, the issue is that land in the Cerrado, a tropical savanna with a great deal of biodiversity, is being deforested at a much faster rate than is the Amazon. The expansion of ethanol into the Cerrado is pushing cattle ranchers and soy farmers into unspoiled regions of the Cerrado, and in the case of soy it is pushing soy farmers into the Amazon:
Soy farming is having a huge impact in the Amazon right now, for three reasons. First, industrial soy farmers are themselves clearing a lot of forest. Second, soy farmers are buying up large expanses of cleared land from slash-and-burn farmers and cattle ranchers, and the displaced farmers and ranchers often just move further out into the forest, maintaining a lot of pressure on frontier areas. Finally, the soy farmers are a very powerful political lobby that is pushing for major expansion of roads, highways, river-channelization projects, and other transportation that will criss-cross large expanses of the Amazon. This infrastructure is acting like Pandora’s box–it is opening up the frontier to spontaneous, unplanned colonization and exploitation by ranchers, farmers, hunters, and illegal gold miners.
Brazil already exports ethanol to other parts of the world. In the case of the U.S., this comes despite a $0.54/gallon tariff in place to protect U.S. corn ethanol producers. So, whether or not Brazil can supply more biofuels to the rest of the world is not the key question. In my mind, the key question is “Given the potential for deforestation, do we want them to?”
There are environmental benefits, but also negative environmental consequences from using ethanol as fuel. If the ethanol is produced from industrial corn farms, more negative environmental consequences can be added.
Because of ethanol’s marginal energy balance, there is a marginal reduction in greenhouse gas emissions per distance driven. Researchers have also found that ethanol produces less carbon monoxide when it is burned in an internal combustion engine.
On the other hand, ethanol raises the vapor pressure when blended with gasoline, which causes an increase in smog. In an August 1, 2007 article in the Houston Chronicle (now archived, but available at the following link):
Q: We’re already using more ethanol in our fuel now, because of the outcry over the fuel component methyl tertiary butyl ether or MTBE and its propensity to foul groundwater. You had warned that replacing MTBE with ethanol could hamper efforts in cities like Houston to improve air quality because of these problems with volatile organic compounds and nitrogen oxides. So has that actually happened?
A: Yes, it has happened. Los Angeles is the cleanest example. They began switching from MTBE to ethanol in 2001. But when they made their major switch in 2003, there was a significant decrease in air quality. They basically stopped making progress toward attainment on EPA’s ozone standards when they switched to ethanol. When using MTBE, with the cars getting cleaner each year, coupled with a very clean fuel, Los Angeles was on a straight-line path toward attaining EPA’s air standards by about 2002 or 2003. Now that they have switched to ethanol, the trend line indicates nonattainment for many years to come.
A 2007 research paper by Stanford University professor Mark Jacobson echoes that claim:
In this paper, Professor Jacobson studied the potential impact to air quality as more E85 vehicles hit the roads, and he concluded:
“In sum, due to its similar cancer risk but enhanced ozone health risk in the base emission case, a future fleet of E85 may cause a greater health risk than gasoline. However, because of the uncertainty in future emission regulations, E85 can only be concluded with confidence to cause at least as much damage as future gasoline vehicles.
Because both gasoline and E85 emission controls are likely to improve, it is unclear whether one could provide significantly more emission reduction than the other. In the case of E85, unburned ethanol emissions may provide a regional and global source of acetaldehyde larger than that of direct emissions.”
In addition to the mixed environmental impact of directly burning ethanol as fuel, industrial corn farming has significant negative environmental impacts. From a 2006 paper that evaluated ethanol and biodiesel:
Both corn and soybean production have negative environmental impacts through movement of agrichemicals, especially nitrogen (N), phosphorus (P), and pesticides from farms to other habitats and aquifers (9). Agricultural N and P are transported by leaching and surface flow to surface, ground, and coastal waters causing eutrophication, loss of biodiversity, and elevated nitrate and nitrite in drinking-water wells. Pesticides can move by similar processes.
The markedly greater releases of N, P, and pesticides from corn, per unit of energy gain, have substantial environmental consequences, including being a major source of the N inputs leading to the ‘‘dead zone’’ in the Gulf of Mexico (11) and to nitrate, nitrite, and pesticide residues in well water. Moreover, pesticides used in corn production tend to be more environmentally harmful and persistent than those used to grow soybeans.
Two additional factors not discussed in the article are 1). Industrial corn farming depletes the topsoil, putting future generations at risk:
Row crops such as corn and soy cause 50 times more soil erosion than sod crops [e.g., hay] or more, because the soil between the rows can wash or blow away. If corn is planted with last year’s corn stalks left on the ground (no-till), erosion is less of a problem, but only about 20% of corn is grown no-till. Soy is usually grown no-till, but insignificant residues to harvest for fuel.
2). Corn farming and subsequent conversion to ethanol consume enormous amounts of fresh water:
In this article, David Pimentel is the pessimistic expert who claims that when you add in the water required to grow the corn, it takes 1,700 gallons of water per gallon of ethanol produced. The “optimist” in the article, Derrel Martin, an irrigation and water resources engineer, said:
Martin said the question of whether increased corn production and the irrigation it requires will overburden the state’s water supply is an important one that does not yet have a clear answer.
Additional research has been reported by two Colorado researchers:
In late June, two Colorado scientists, Jan F. Kreider, an engineering professor at the University of Colorado, and Peter S. Curtiss, a Boulder-based engineering consultant, presented their peer-reviewed report, “Comprehensive Evaluation of Impacts from Potential, Future Automotive Fuel Replacements” at a conference sponsored by the American Society of Mechanical Engineers. The two found that producing one gallon of corn ethanol requires the consumption of 170 gallons of water. That figure includes the amount needed for all irrigation and distillation. For comparison, the two scientists estimated that each gallon of gasoline requires just 5 gallons of water. If Kreider and Curtiss are right, the 5 billion gallons of corn ethanol produced in America in 2006 required more water than production of the 140 billion gallons of gasoline the U.S. consumed that year.
Ethanol proponents have largely downplayed the negative environmental impacts of increased ethanol production, while emphasizing the positive impacts. But by ignoring the negatives, all of us, and future generations, are being put at risk.