Problems with ethanol as a fuel


in Daily updates

Biofuels are quite a hot topic at the moment. There is an ongoing debate about subsidies for corn ethanol in the United States, and a more general discussion about the overall merits and shortfalls of the biofuel approach. One compound that features prominently in the debate is ethanol: the two-carbon molecule familiar to martini drinkers everywhere.

Unfortunately, ethanol has a number of properties that make it unappealing as a fuel:

  1. While oil and water are famously difficult to mix, water mixes easily with ethanol. This makes it more difficult and expensive to store and transport. Pipelines are especially afflicted by this issue. Ethanol that has been blended with gasoline can seperate when it comes into contact with water.
  2. Moving through pipelines and sloshing around in storage tanks, ethanol is also prone to collect various sorts of crud and impurities. These must then be filtered out at a later stage.
  3. Ethanol is corrosive to both metals and rubber compounds. As such, it can increase the level of maintenance required in all of the machinery that comes into contact with it, as well as diminishing the lifetime of that equipment.
  4. Ethanol has a lower energy density than conventional liquid fossil fuels. That means less distance travelled for any particular volume, as well as a larger ratio of fuel weight to total weight for vehicles with a particular range.
  5. The volatility of ethanol is also problematic. The fact that it turns to gas easily (and has high vapour pressure) can be problematic in hot environments.
  6. Finally, ethanol is made in ways that have both direct and indirect negative consequences. The direct production of ethanol from corn raises food prices (affecting the poor, in particular). Corn agriculture also uses fertilizers (causing eutrophication of rivers) and pesticides. Large increases in land use for bioethanol production may also lead to deforestation, as crops that can be grown in areas presently forested (like soya in the Amazon) get displaced from existing agricultural lands.

None of this is to say that ethanol is without advantages – nor that it will have no role in the future energy mix. I am simply laying out some of the problems that need to be overcome, or that will otherwise limit the adoption of bioethanol as fuel.

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{ 31 comments… read them below or add one }

Milan October 30, 2007 at 4:20 pm
tristan October 30, 2007 at 6:25 pm

I don’t think 3 is a problem. There needn’t be any rubber coming in contact with fuel. This is only any issue for trying to run ethanol in gasoline powered engines. GM is able to sell cars that will not be corroded by ethanol for only a few hundred dollars more.

Also, you neglect to mention that ethanol has a temperature flash point. The upshot of this is that smaller engines can be used to produce the same power. Smaller engines – less parts to move around, less wasted energy. The increase in power per engine size is dramatic, like 20 to 30 percent. Smaller engines are also cheaper to produce, using less energy.

Milan October 30, 2007 at 7:39 pm


The third issue could be a problem in refining and fuel transport. At least, that is an issue I have frequently seen mentioned in relation to ethanol.

Does the flash point issue require all-ethanol engines, or can they use gasoline blends? Almost nobody is considering pure ethanol fuel. 85% is as high as I think it goes commercially.

tdot October 31, 2007 at 10:21 am

Indy cars have used 100% ethanol for years. Using an 85% blend lets engines be tuned for 25% more power. Of course, when you run the same engine on regular fuel, you lose the power advantage.

However, its not as simple as that. It is, in that you can advance the timing significantly when you run the E85, and then scale it back when you don’t (happens in the computer, you don’t actually do anything). But the really big power advantage (the big numbers, like 20%), comes with using a higher compression ratio. For example, the Koenigzeg, when its set up for regular petrol produces 800 hp, when you buy it only to run on E85, it produces 1000hp. Similarly, the Lotus exige S, when you buy it to run on regular gas, produces around 210hp, when you buy it specifically to run on E85 only, it produces 265 hp.

Of course, rather than increasing the HP numbers, my point is the engines could be made smaller.

The real efficiency, however, would be for the state to limit the power-to-weight ratios of cars. Less powerful engines are more efficient (and actually, even producing some given power, X, a smaller engine isn’t neccesarily more efficient than a bigger one; a 400 hp corvette with a 6 Liter displacement engine is better (alot) on fuel than an mitsbishi EVO q400, with the same 400hp, and its lighter, but the engine is only 2 liters rather than 6.

anyway, the issues are complex. The real solution is transit.

I’m wondering why you havn’t posted about air-powered cars yet?

. October 31, 2007 at 2:04 pm

Bush touts cellulosic fuel as remedy for high corn prices

President Bush touted federal support for renewable energy development today as a possible cure for high food prices fueled by the corn-ethanol boom.

Energy Harvest: Power From the Farm — An E&E Special Report

Bush told the Grocery Manufacturers Association meeting in Washington that the government is supporting “new technologies” to make fuel from wood chips, switchgrass and other sources.

“It is in the nation’s interest to expand investments in alternative energy sources, ” Bush said.

He also announced intentions to name a new Agriculture secretary this afternoon to replace Mike Johanns, who left the administration to seek a U.S. Senate seat in Nebraska. The Associated Press reported that Bush would nominate Edward Schafer, a former two-term Republican governor from North Dakota (see related story).

Bush acknowledged that food and feed companies have felt the downside of the ethanol boom in paying for higher corn prices.

“I understand that folks out there are concerned about the price of corn,” Bush said. “I’ve heard about it from my hog-raising buddies.”

He said investment in new technologies for cellulosic ethanol would help relieve the demand on corn and “deal with significant problems.”

. October 31, 2007 at 2:06 pm

I’m wondering why you havn’t posted about air-powered cars yet?

Compressed air for mobile energy storage
* March 20th, 2007

. October 31, 2007 at 2:13 pm
Sarah October 31, 2007 at 5:23 pm

As far as I’m aware, the trendiness of Ethanol has at least as much to do with electoral incentives in the US (ie. pandering to the interests of the Corn Belt) as it has to do with the real advantages and disadvantages of the fuel. However, if the Americans are going to push it as a solution I suppose it makes sense to have a clear understanding of the associated problems.
Speaking of which, why so much recent debate on American issues? How about some posts on Alberta oilfield expansion? Or the problems for Northern communities due to the melting permafrost? Or about how the most highly-polluting vehicles for the US market are manufactured in Canada (where the so-called leftwing fights for the continuation of that manufacturing & its jobs in Ontario)? Or does working for the government restrict your freedom to discuss those things? (I don’t mean this last as an accusation of bias; it’s a genuine question.)

Milan October 31, 2007 at 7:34 pm

the trendiness of Ethanol has at least as much to do with electoral incentives in the US (ie. pandering to the interests of the Corn Belt) as it has to do with the real advantages and disadvantages of the fuel.

True, though ethanol is not entirely without promise. Done properly, ethanol use in transport can be largely carbon-neutral.

Why so much recent debate on American issues?

More is happening there at the moment and they get much more media coverage. I will try to mention Canada more in the next while.

Milan October 31, 2007 at 11:20 pm

Biofuel rush harmful, Oxfam warns

The rush to cash in on EU biofuel demands could destroy the livelihoods of farmers in developing countries, the charity says.

. November 2, 2007 at 11:04 am

Biodiesel: King of Alternative Fuels

“Biodiesel has a much greater energy content than ethanol, and diesel engines are more efficient than spark ignition engines. The energy return for biodiesel is over double that of ethanol. One the downside, most of us don’t drive vehicles with diesel engines, and there is a technical problem (minor, in my opinion) that biodiesel will solidify in cold weather. But the most amazing thing is that biodiesel can be produced from algae that have been used to reduce carbon emissions from the exhaust of power plants, in yields as high as 15,000 gallons per acre. This is 2 orders of magnitude higher than biofuel yields from crops. Biodiesel produced from algae is the only theoretically feasible alternative energy solution that could actually replace our current fuel demand. Combined with an aggressive conservation program, success in large scale biodiesel production from algae could ultimately lead to energy sustainability. The one thing we lack here is a good analysis of the energy balance. The group at UNH reports that the EROI is likely to higher than the 3.2 reported for soybeans, but I would still like to see a rigorous analysis.”

. November 4, 2007 at 11:52 am

Water is another problem

Heavily subsidized and absurdly inefficient, corn-based ethanol has already driven up food prices. But the Senate’s plan to increase production to 36 billion gallons by 2022, from less than seven billion today, will place even greater pressure on farm-belt aquifers.

Ethanol plants consume roughly four gallons of water to produce each gallon of fuel, but that’s only a fraction of ethanol’s total water habit. Cornell ecology professor David Pimentel says that when you count the water needed to grow the corn, one gallon of ethanol requires a staggering 1,700 gallons of H2O. Backers of the Senate bill say that less-thirsty technologies are just around the corner, which is what we’ve been hearing for years.

. November 7, 2007 at 3:56 pm

George Monbiot’s latest article in the Guardian

… the superior purchasing power of drivers in the rich world means that they will snatch food from people’s mouths. Run your car on virgin biofuel, and other people will starve.

Even the International Monetary Fund, always ready to immolate the poor on the altar of business, now warns that using food to produce biofuels “might further strain already tight supplies of arable land and water all over the world, thereby pushing food prices up even further” …

If you count only the immediate carbon costs of planting and processing biofuels, they appear to reduce greenhouse gases. When you look at the total impacts, you find they cause more warming than petroleum …

You could, for example, ban palm oil from new plantations. This is the most destructive kind of biofuel, driving deforestation in Malaysia and Indonesia. But the ban would change nothing. As Carl Bek-Nielsen, vice chairman of Malaysia’s United Plantations Berhad, remarked: “Even if it is another oil that goes into biodiesel, that other oil then needs to be replaced. Either way, there’s going to be a vacuum and palm oil can fill that vacuum …

Yes, it can grow on poor land and be cultivated by smallholders. But it can also grow on fertile land and be cultivated by largeholders. If there is one blindingly obvious fact about biofuel, it’s that it is not a smallholder crop. It is an internationally traded commodity that travels well and can be stored indefinitely, with no premium for local or organic produce. Already the Indian government is planning 14m hectares of jatropha plantations. In August, the first riots took place among the peasant farmers being driven off the land to make way for them.

. November 7, 2007 at 3:57 pm

“In principle, burning biofuels merely releases the carbon the crops accumulated when growing. Even when you take into account the energy costs of harvesting, refining and transporting the fuel, they produce less net carbon than petroleum products. The law the British government passed a fortnight ago – by 2010, 5% of our road transport fuel must come from crops – will, it claims, save between 700,000 and 800,000 tonnes of carbon a year. It derives this figure by framing the question carefully. If you count only the immediate carbon costs of planting and processing biofuels, they appear to reduce greenhouse gases. When you look at the total impacts, you find they cause more warming than petroleum.

A recent study by the Nobel laureate Paul Crutzen shows that the official estimates have ignored the contribution of nitrogen fertilisers. They generate a greenhouse gas – nitrous oxide – that is 296 times as powerful as CO2. These emissions alone ensure that ethanol from maize causes between 0.9 and 1.5 times as much warming as petrol, while rapeseed oil (the source of more than 80% of the world’s biodiesel) generates 1-1.7 times the impact of diesel. This is before you account for the changes in land use.

A paper published in the journal Science three months ago suggests that protecting uncultivated land saves, over 30 years, between two and nine times the carbon emissions you might avoid by ploughing it and planting biofuels. Last year the research group LMC International estimated that if the British and European target of a 5% contribution from biofuels were to be adopted by the rest of the world, the global acreage of cultivated land would expand by 15%. That means the end of most tropical forests. It might also cause runaway climate change.”

. November 7, 2007 at 3:58 pm

“If the governments promoting biofuels do not reverse their policies, the humanitarian impact will be greater than that of the Iraq war. Millions will be displaced, hundreds of millions more could go hungry. This crime against humanity is a complex one, but that neither lessens nor excuses it. If people starve because of biofuels, Ruth Kelly and her peers will have killed them. Like all such crimes, it is perpetrated by cowards, attacking the weak to avoid confronting the strong.”

. November 8, 2007 at 9:46 am

Ricardo Haussman is bullish on biofuels

By Tyler Cowen on Economics

He writes in the FT:

…technology is bound to deliver a biofuel that will be competitive with fossil energy at something like current prices. It probably already has. Brazil has been exporting ethanol to the US at an average delivery price of $1.45 for an amount with the energy equivalence of a gallon of petrol. It is doing so profitably and in increasing amounts, in spite of a 54 cents a gallon tariff to protect American maize-based ethanol producers. Many countries are following suit.

But ethanol is an inconvenient chemical compound that is corrosive and soluble in water, thus limiting its immediate market to that of a gasoline additive. However, this is just the Betamax phase of the industry. There is plenty of private venture capital money being poured into finding more efficient ways of extracting energy from biomass and delivering it to transport and power systems. Over time, the technology will also become more flexible, allowing more crops to be used as feedstock, not just the current choice of sugarcane, maize and palm oil…the world is full of under-utilised land that can grow the biomass that the new technology will require.

It shocked me to read this, though not for any good cognitive reason. Perhaps I too quickly assume that the trendy will not pan out. My not well informed mental model has been that our energy future lies with (relatively) clean coal, not so clean coal, nuclear, oil shale, and tar sands, all of which can in fact produce lots of power.

. November 8, 2007 at 9:55 am

Who are you calling sensible, punk?

By David Roberts

Over the years, Hillary Clinton has voted against subsidies and mandates for corn ethanol in the Senate a number of times. If you know anything about corn ethanol, you know that’s a good thing.

When Clinton released her (otherwise excellent) energy plan this week, it contained a whole boatload of … subsidies and mandates for corn ethanol. That is, conversely, a bad thing.

Obama’s campaign took the opportunity to bash Clinton for it — not for switching from a sensible position to a more politically convenient but substantively wrong position, but for … having the sensible position in the first place. How can we trust that she’s truly committed to this awful position? they asked.

This prompted an explanation from Clinton that is nothing short of tortured:

This is what we’ve come to in the strange world of ethanol politics: a presidential candidate furiously trying to explain away her previous good sense. Sigh. I can’t wait until the Iowa primary is over.

Milan November 13, 2007 at 10:29 am

R-Squared on ethanol

My objection is that I think the way we make ethanol in the U.S. is a big mistake, and we will recognize this eventually. It may happen following a drought in the Midwest that causes corn crops to fail. That may be what it takes before we recognize that recycling natural gas into ethanol via food was a terribly bad and short-sighted idea.

I also dislike the incredible hype associated with cellulosic ethanol. Promising too much lulls the public into thinking we have a solution ready to go in case of an energy crisis. Not so. But underneath that hype is a lot of potential. I don’t think cellulosic success will come from an expensive hydrolysis/biological process. This is simply too inefficient, and requires very high fossil fuel inputs. Rather, I think success will come from a thermochemical process.

. November 20, 2007 at 1:29 pm

Ethanol is 2007’s worst investment, market experts say

Ethanol has become 2007’s worst investment after the price of the corn-based fuel fell this year for a variety of reasons, driving crop prices to a 10-year high, market experts said this week.

The Bush administration energy plan triggered a growth in ethanol production by mandating increased uses of all biofuels. The White House also proposed raising biofuels output in the next 10 years to five times the current target amount for 2012.

The Senate approved the increase and lengthened the time frame to 2022. The federal government has 20 separate laws and incentives to boost ethanol use, and 49 states offer additional subsidies and supports, according to the Energy Department.

But, as a result of these policy decisions, the market price of ethanol fell 57 percent this year from last year’s record of $4.33 per gallon due to a production glut financed by investment bank Morgan Stanley, hedge fund firm D.E. Shaw & Co. and venture capitalist Vinod Khosla.

Corn has risen to $3.795 per bushel on the Chicago Board of Trade from less than $2.50 in September 2006, and ethanol on the exchange is little changed at $1.865 per gallon after falling from the $4.33 peak.

Ethanol markets are so depressed that distilleries from Iowa to Germany are shutting down. If an investor put $10 million into ethanol on Dec. 31, 2006, the investment is now worth only $7.5 million. Also, Florida and Georgia banned ethanol sales during the summer because of concerns that the fuel may evaporate and create smog.

Archer Daniels Midland Co., the largest producer of ethanol, may resort to exporting ethanol.

“I don’t anticipate any sort of immediate rebound,” Center Ethanol LLC President Barry Frazier said. “It’s going to take 12 to 24 months before the market is able to absorb the large amount of new capacity.”

“Ethanol companies are near break-even at best,” Broadpoint Capital Inc. principal Ron Oster said. “That’s not a good recipe when you have $100 oil” (Carroll/Parker, Bloomberg, Nov. 18).

. December 7, 2007 at 1:02 pm

Ethanol: A Worthy Subject for Debate
7 Dec 07

In the wake my post yesterday, lauding an anti-corn-ethanol report posted on a website generally associated with any lobbyist willing to pony up support funding, the thoughtful and articulate John Mashey threw this counterpunch. Lots of interesting issues here in a subject very worthy of more debate. Thank you, John:

. December 18, 2007 at 11:52 am

Corn Kills Fish
Category: What the…?

Dead Zone Widens. Thank You Ethanol!

Demand for ethanol is rising (dumb) and with it, an increased production of corn and use of nitrogen-based fertilizers. All those fertilizers in the corn belt make their way into the Mississippi River and out to the Gulf of Mexico, creating a dead zone where nothing can live.

Anon December 20, 2007 at 11:48 pm

According to IFPRI, the expansion of ethanol and other biofuels could reduce calorie intake by another 4-8% in Africa and 2-5% in Asia by 2020. For some countries, such as Afghanistan and Nigeria, which are only just above subsistence levels, such a fall in living standards could be catastrophic.


. January 3, 2008 at 1:33 pm

On one hand, the ethanol hype ramped up to dizzying new heights this year, driven by subsidy-hungry agribiz, agribiz-friendly Midwest legislators, and, lamentably, credulous environmentalists. It crescendoed with the passage of the energy bill in December, which mandates 36 billion gallons of ethanol by 2022, much like a little boy might close his eyes, furrow his brow, and mandate a rocketship for Christmas. On the other hand, the ethanol backlash gained momentum, as new research and skeptical greens revealed the limitations and unintended consequences of feeding our carbon sinks to our cars. Expect this to be the cat fight of 2008.

. January 23, 2008 at 10:43 am

The Handy-Dandy Khosla Refuter

Ethanol: A Few Myths Debunked

To be honest, there are so many misconceptions and myths in the article that a better name for it would have been Ethanol: A Few Myths Repeated. I think all of these “myths” have been covered at one time or another in this blog, but he does quote Vinod Khosla at length. So, this might be a good time to re-debunk Khosla, given that he has repeated this claims many times since the first debunking.

So, once again, here are Vinod Khosla’s claims, repeated from the above article, dissected and debunked.

. March 31, 2008 at 10:44 am

How Corn Ethanol Destroys Rain Forests

In Brazil, for instance, only a tiny portion of the Amazon is being torn down to grow the sugarcane that fuels most Brazilian cars. More deforestation results from a chain reaction so vast it’s subtle: U.S. farmers are selling one-fifth of their corn to ethanol production, so U.S. soybean farmers are switching to corn, so Brazilian soybean farmers are expanding into cattle pastures, so Brazilian cattlemen are displaced to the Amazon. It’s the remorseless economics of commodities markets.

. January 21, 2009 at 11:53 am

But ethanol has one particularly compelling argument: Ethanol has a high octane rating (103), which means it does not easily pre-ignite. This means higher engine efficiencies could be obtained than can be achieved with gasoline.

. May 9, 2009 at 3:12 pm

Bioelectricity Promises More ‘Miles Per Acre’ Than Ethanol


STANFORD, CA – Biofuels such as ethanol offer an alternative to petroleum for powering our cars, but growing energy crops to produce them can compete with food crops for farmland, and clearing forests to expand farmland will aggravate the climate change problem. How can we maximize our “miles per acre” from biomass? Researchers writing in the online edition of the May 7 Science magazine say the best bet is to convert the biomass to electricity, rather than ethanol. They calculate that, compared to ethanol used for internal combustion engines, bioelectricity used for battery-powered vehicles would deliver an average of 80% more miles of transportation per acre of crops, while also providing double the greenhouse gas offsets to mitigate climate change.

. August 12, 2009 at 5:23 pm

Maized and confused
Aug 10th 2009
From The Economist print edition
Does ethanol in Iowa cause deforestation in Brazil?

HOW green is ethanol? The Renewable Fuels Association (RFA), an American lobby for the stuff, obviously wants voters and politicians to think it is very green indeed. The association’s cool-coloured website plays down claims that ethanol may actually harm the environment. The biggest target of those claims these days is that growing maize to make ethanol causes indirect changes in land use by altering the incentives of other, often foreign, farmers.
Adding ethanol to the traditional markets for maize (food and fodder) inevitably pushes the price up. That encourages farmers, including those in poor countries, to boost production. If some of those farmers plough up savannah or cut down forest to grow the extra crops, the carbon dioxide released from the plants destroyed and soil ploughed up reduce the benefits of substituting the ethanol produced for petrol. If forests that are still growing are cleared, the environment loses the effect of their future uptake of carbon dioxide, too.

The benchmark paper on this, published in Science in February 2008, argues that, if such changes in land use are taken into account, ethanol is twice as carbon-intensive as petrol in the short run. Making ethanol and burning it in a car (without land changes) emits 20% less carbon dioxide than refining and burning petrol. But planting a hectare of ethanol causes someone to clear land for food crops elsewhere. That ethanol crop must provide that modest 20% reduction for 167 years to achieve a net carbon reduction. By then, of course, it is far too late to mitigate climate change.

. April 7, 2010 at 11:43 am

“The EPA has been forced to slash its 2010 mandate for the most widely touted of the non-corn biofuels, cellulosic ethanol, from 100m gallons to just 6.5m, less than a thousandth of the 11 billion gallons produced from corn in 2009.

The fact that corn-ethanol production has continued to grow, despite the failure of a number of firms in late 2008 and early 2009, points to the efficacy of the various protections and subsidies it enjoys (falling maize prices helped too), though it says nothing about their efficiency or wisdom. Ethanol, which is used mainly as an additive to petrol, is not a particularly good fuel: it offers only about two-thirds as much energy as petrol and can corrode pipelines and car engines. By 2014 or earlier, ethanol production is expected to reach 10% of America’s total fuel demand, and thus to hit a “blend wall”, since the EPA does not at present allow blends of more than 10% for mainstream use.”

Matt April 8, 2010 at 1:43 pm

I was reading recently that many US states have laws that don’t require stations to advertise if there is ethanol in fuel provided it is less than 10%. This poses a problem for small aircraft owners who use automobile gasoline in their planes, as the STC (supplemental type certificate, a document that legally allows them to use the alternative fuel) specifically prohibits ethanol blended fuels. The reason the fuel can’t be used is because of unreliable range planning (the lower energy content of the fuel means the plane consumes more than ‘book’ value to fly any given distance) and problems with vapour-lock due to a lower boiling point.

The reason it may be desirable to use car gas in a small plane is
A) cost
B) reduced problems that come with using unleaded gas (fouled spark plugs).

. April 23, 2011 at 5:59 pm

IT IS bad enough that Republicans and Democrats are so divided on how much to spend and tax. But if you want to feel really gloomy about America’s ability to tackle its deficit, consider the ideological, almost theological, arguments about tax that are taking place within the Republican camp itself. In the past few weeks these have been revealed in all their dreadful clarity by an esoteric debate about the tax break for ethanol.

To balance the budget you can spend less or tax more. The Republicans are allergic to tax increases, and since their capture of the House of Representatives in November’s mid-term elections have succeeded in focusing the debate almost exclusively on what should be cut. One bit of spending that has caught the eye of Tom Coburn, the Republican senator for Oklahoma, is the $6 billion a year the government doles out in tax breaks to refiners who blend ethanol into their petrol. By general consent, this is not money well spent. Farmers may relish receiving taxpayers’ money to grow the corn that goes into ethanol, but corn-based ethanol is not the green fuel it is cracked up to be. Almost as much energy is used to make it as when it is burned. Here, you would think, is one subsidy that any Republican fiscal conservative in his right mind would want to get rid of.

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