Is Ethanol Too Corrosive?

Politicians love to fall all over themselves to promote the ethanol use. In 1990, this resulted in Clean Air Act provisions that compromised the effectivenes of fuel content requirements and led to widespread MTBE water pollution. (While MTBE was the pollutant, the provision that led to widespread MTBE use was pushed by the ethanol lobby.)

The New York Times reports on another potential problem with E85 ethanol fuels: their corrosivity.

E85, a blend of 85 percent corn-based ethanol and 15 percent gasoline, could be eating away at metal and plastic parts in pumps being used to dispense the fuel at gasoline stations, Underwriters Laboratories, the private product-safety testing group, said this month. . . .

Underwriters Laboratories, which certifies the safety of everything from toasters to televisions, has temporarily withdrawn authorization for the U.L.-approved label on parts used in E85 dispensers. Those dispensers, it turns out, were modified from regular gasoline dispensers and were certified only for a maximum of 15 percent ethanol concentration; U.L. said it had never certified any E85-specific pumps.

The reversal has heightened concerns among some oil companies about the safety of E85 pumps on the market and threatens to slow the proliferation of the fuel, which automakers, President Bush and Midwest lawmakers are pushing as a homegrown alternative to gasoline.

As a resident of Indiana, I am outraged by this attempt to slander a safe, clean, and very profitable industry.

If we ban E-85, the terrorists have already won.
10.27.2006 9:51am
This is pretty silly. Before the latest E85 push, auto makers, gas pump manufacturers, etc. had to create products that could handle "gasohol" of at most 15% ethanol. Faced with that task, the obvious engineering response was to totally eliminate materials that are corroded by ethanol, not to design to the limit or push the envelope by trying to manufacture something that could just barely tolerate a 15% concentration of ethanol but no more. The fact that these products were only certified to handle the 15% ethanol fuel does not mean that they are incapable of handling E85 -- it just means that they need to be officially re-tested and re-certified to handle what the engineers will tell you that they already can.
10.27.2006 10:25am
Jack S. (mail) (www):
What's the point of this post? What does TOO Corrosive mean? Corrosion, oxidation, etc. occur because one compound reacts with another, or one liquid acts as a solvent to another. Not all compounds behave the same with each other. Biodiesel has a a problem with dissolving natural rubber, but less so with various synthetic rubbers (therefore A solution). Bicycles have the same problem with Ti and Al components reacting and creaking enough to drive a rider crazy. But these problems all have relatively simple solutions.

Maybe we should just go with Homer Simpson's philosophy. "Trying is the first step towards failure." and just forget about it.
10.27.2006 10:26am
Grant Gould (mail):
If I recall correctly, the big corrosion problem with 15% ethanol was impurities -- pumps and pipes could handle the ethanol just fine, but trace quantities of methanol and other impurities (or even stabilizers added intentionally) played havoc with the plumbing. Does E85 have this same problem?
10.27.2006 10:30am
keypusher (mail):
Ethanol, global warming, Moyers, habeas: you're really covering a lot of ground, Professor! Thanks for all the interesting posts.
10.27.2006 10:44am
Houston Lawyer:
Since ethanol has been included in the gas I buy, my mileage has gone from 17 to 15. Has anyone conducted a study on how much extra gasoline we are burning to support the ethanol lobby?
10.27.2006 11:14am
Mark H.:
I'm not worried in the least about reduced life of gas pumps. It's the fuel train in my car and the inside of my engine that concern me. I should be saddled with expensive repair bills to subsidize the ethanol lobby?
10.27.2006 11:23am
Are there any other flex-fuel drivers out there? I get lousy mileage (mostly because I only drive around town and it takes me 2 months to get through a tank of gas), and of course it is marginally worse with E85. But my husband swears that if we run a tank of E85, and then fill with a tank of E10, we get WAY better mileage on that E10 tank than if we just stick to E10. I think he's delusional -- does anybody else have any experience where you have noticed such an effect?

Also, if those pumps are only rated to E15 then Minnesota has a problem. Their gas is all E20.

There are actually two very separate corrosion problems. The first is worrying about the alcohol dissolving plastic parts. The other one is that over the years gasoline storage tanks collect a layer of crud that settles out of the gas. A lot of that crud is ethonol soluble, and so even E10 or E15 will pick up the stuff and then deposit it in your engine.
10.27.2006 11:24am
Richard Aubrey (mail):
You complainers just hate the starving family farmers.

Alternatively, you hate the big ag corporations who get all the tax breaks.

Hate. That's all there is here. Hate.
10.27.2006 11:30am
Before we get too excited about planting a lot of corn, the availability of sufficient water should be considered. The Ogallala aquifier is the world's largest aquifier, stretching from S. Dakota to Texas and providing irrigation for 20 percent of all US crop land. Due to mismanagement and overuse, in the past 40 years, the level of the aquifier has dropped 100 feet. There is more to look at when considering biofuels than just throwing seed on the ground.
10.27.2006 11:36am
Houston Lawyer: I'll do a study for you right here: Since your gas milage only dropped 11%, you're actually burning less gasoline with a 15% ethanol fuel than you were with 100% gasoline (25% less gasoline, to be exact: (17mpg on 100% gas - (15 mpg on 85/15 blend*0.85 gallons gas per gallon 85/15 blend))/17mpg on 100% gas). You are burning more total fuel, though.

The better question is how much money are we wasting to support the non-cane-sugar derived ethanol lobby? Clearly you have burn more gallons of total fuel when ethanol is mixed with gasoline due to the lower energy density, but if ethanol were cheaper enough than gasoline, this should be a net gain both in dollars and sustainability. Another good question then is why are we wasting money on more expensive corn-derived ethanol from the US midwest when the Brazilians could produce and ship sugar-cane derived ethanol here for $0.90 less per gallon without our ~$0.58/gal import tariff? Their ethanol is already cheaper than ours, leading to significant increases in its importation in the last few years, but it's not clearly cheap enough yet (though it would be sans protectionism) to make up for the loss in enerygy density.
10.27.2006 11:45am
Thanks, billb--The Brazilians have done a brilliant job with biofuels. We don't have the right climate to grow the required amount of sugar. But I'd trade a lot of DoD funds if we could jumpstart research for an enzyme that can convert switchgrass of willows to fuel.

Where is the Bush administration on this? The Democrats? Is Lula the only leader who sees the value of energy independence?
10.27.2006 12:10pm
Joe7 (mail):
One of my annoyances with the current obsession with ethanol (besides the fact that it's currently economically feasible only because of heavy government subsidies) is that it's distracting everyone from doing research with a much more viable alternative; butanol.

(Good article on butanol at Wikipedia;
10.27.2006 12:37pm
Houston Lawyer,

When I calculate the gas saved using E85 that gets 15 mpg versus 100% gasoline that gets 17 mpg, I show a 3.8% reduction in gasoline used, not 25%:

(15 / .85) / 17 - 1 = .038
10.27.2006 12:43pm
Looked at another way, you're using 85% as much gas to go 88.2% as far (15/17).
10.27.2006 12:44pm
Houston Lawyer:
I don't think any of your calculations take into account the amount of hydrocarbons that must be burned to make ethanol. I understand that the net energy gained from ethanol is quite low.
10.27.2006 1:07pm
Waldensian (mail):
There's another interesting problem with ethanol. Many owners of piston engine airplanes have gone to extra expense to have them approved for use with automotive gas ("mogas") rather than the much more expensive, and MUCH MUCH less environmentally friendly, leaded aviation gasoline ("avgas").

Avgas is generally dyed blue and is known as 100LL, for 100 octane "low lead," although it actually has quite a bit of very nasty tetraethyl lead in it. Hot rodders know it as "blue racing gas."

Anyway, it turns out that ethanol is bad for airplanes. Apparently in addition to deleterious effects on seals and fuel lines, its presence in gasoline increases the risk of vapor lock, which is a really big problem when you are sucking gas into a hot engine at high altitude.

And now it's become impossible, in some areas, to find mogas without ethanol in it. Major bummer.
10.27.2006 1:26pm
Sigivald (mail):
McGuffin: I don't think the obvious engineering response is that at all.

Faced with a requirement of handling 15% ethanol, it's very likely that handling that by using parts that can take 15% ethanol for the expected life of the product is cheaper and easier than making ones that can handle 85% for that timespan.

Unless they expected a change to 85%, there'd be no reason to spend extra time and money supporting that case.

A product need not be "just barely" able to handle 15% ethanol for years of running life to be likely to fail early if used at 85%.

An over 5-times increase in chemical concentration is a significant change, not a minor one, in my experience.
10.27.2006 1:58pm
Houston Lawyer,

Sorry, my previous comments should have been addressed to billb, not you. I just wanted to point out that the 25% gas savings was inaccurate.

I agree with you that my analysis only focused on gasoline used after the fuel is pumped into the car.
10.27.2006 1:59pm
Jack S. (mail) (www):

Since ethanol has been included in the gas I buy, my mileage has gone from 17 to 15. Has anyone conducted a study on how much extra gasoline we are burning to support the ethanol lobby?

Don't know. Did we find out if there was a study on how much extra gas we are burning to support the oil and car manufacturer lobbies to continue producing gasoline powered cars that get 17mpg? Don't know if you're in a truck/SUV or sports car, but if truck/SUV, should've been designed with a diesel engine. Gas inherently sucks at heavy loads.
10.27.2006 2:00pm
Faced with a requirement of handling 15% ethanol, it's very likely that handling that by using parts that can take 15% ethanol for the expected life of the product is cheaper and easier than making ones that can handle 85% for that timespan.

The point is that it is not cheaper and easier to do so, therefore the switch to materials fully capable of handling E85 when the 15% ethanol requirement came about.
10.27.2006 2:11pm
Since Ethanol has about 20% less BTU heat energy per unit volume you will get less mileage. Plus the ethanol has been a scam from git go due to it taking more energy to make than it produces. From fuel/tires for tractors, trucks to market, distillation and transport to market/ huge water issues etc. Corrosion in the entire pipeline system. Subsidized by 50 cents a gallon etc.

The entire US would have to be plowed from LA to NYT to grow the amoung needed just for fuel.

And the statements about Brazil being self sufficient is not phrased properly. They may be self sufficient in Total energy but not in ethanol. The get 20% from Ethanol...the other 80% comes from their OWN oil mostly from offshore in Brazil.

We dont even want to think about Hydrogen since it is not a primary a storage method. There are no Hydrogen deposits to mine or drill. You have MAKE it. From water electrolysis or steaming of methane or other hydrocarbon. If we can get pebble bed nukes to do it or more efficient solar...then maybe work. But transporting it is a booger.

And it is even more detrimental to the pipeline system due to "hydrogen embrittlement" Hydrogen molecules are so small they pass into the crystalline structure of steel. This causes the metal to become porous, brittle and break like glass. Not good with a gas that is flammable from about a 4% to 70% concentration.
10.27.2006 2:31pm
Jack S. (mail) (www):

Plus the ethanol has been a scam from git go due to it taking more energy to make than it produces. From fuel/tires for tractors, trucks to market, distillation and transport to market/ huge water issues etc. Corrosion in the entire pipeline system. Subsidized by 50 cents a gallon etc.

It does? This study from the DOE seems to suggest otherwise. I clearly states that all calculations and estimates were done without any tax credits or subsidies. The process also has two by-products, 1) excess electricity produced by steam turbine and sold back to the grid and 2) animal feedstock (DDG credit in tables).

The price of corn that they are buying at already has the tires and tractors built in. So, if there's subsidies at the farm level keeping the price of corn artificially low then there may be some hidden margin here.

Also as stated by most promoters of ethanol or other alternative fuels, few are relying on corn as a long term solution. There's no doubt with its current yields that it is viable as a major source of fuel. But that in itself doesn't support the argument that ethanol taking more than it gives.

Agree as well that ETOH has fewer BTU's, but do you have a reliable report that supports the claim that real cost of producing ETOH > true market rate?
10.27.2006 2:56pm
DRWN, yep. You're absolutely right. I forgot to invert my mpg to get gallons/mile before using the 85%. Makes all the difference in the world. I get 3.6% less gas with 85/15 gas/ethanol blend and a 17/15 mpg difference now. I shouldn't have done math before I got any stimulants in my system. :)

BTW, DRWN, you're method isn't quite right, I believe the appropriate formula should be:

fraction change in gas used = (1/17 gal gas/mile - (1/15 gal blend/mile *.85 gal gas/gal blend))/(1/17 gal gas/mile))

To everyone bringing up the petro used to make ethanol: I'd like to point out that neither do any of these numbers take into account the petro use to get petro out of the ground and refine it. In any case, my above point was about price and consumer consumption of gasoline not the net effect on carbon emissions. No matter what, there's one thing that's guaranteed, taking petro out of the ground and burining it takes carbon out the the ground and puts it into the atmosphere. With ethanol, at least some of the carbon comes out of the atmosphere before being converted to ethanol and burned. As the ratio of ethanol to petro products used in fuel blends (used in tractors and ethanol refineries) goes up, the net effect should eventually work out. The remaining hurdle to this is finding plant products that can be used to make ethanol more efficiently than we can make it from corn or killing the import tariff between us and Brazil.
10.27.2006 4:36pm
DerMensch (mail):
To put it in Jim Chen's words: Tomorrow people will look back at Ethanol as an embarassing lie that was propagated by corn lobby pimps and their congressional whores. I am ashamed that all hints of good science and common sense have been thrown off to the wilds of irrational enviro-nuttiness. And my wife comes from a far western island where corn monsters eat children at night. Argh.
10.27.2006 4:43pm
JonBuck (mail):
May I suggest butanol instead? Higher energy density, very similar combustion characteristics to gasoline, and thus can be used as a total replacement.

Information here.
10.27.2006 4:45pm
hey (mail):
McGuffin demonstrates how a little (very, very little) knowledge is a dangerous thing. To go from the fact that every design incorporates a safety factor, a measure designed to allow for the differences between theoretical calculations and reality, the variability of conditions, the imprecise nature of all models, and the sheer inventiveness of humans and nature to produce conditions that simply shouldn't be possible, to then assume that one can take advantage of this overengineering to totally change conditions is not exactly the wisest idea in the world.

Introducing ethanol into gasoline has two major problems: it is a much less pure substance, thanks to the way that it is produced as compared to the methods used to produce petrochemicals (biological processes producing very similar chemicals versus fairly straight forward catalysed reactions that produce much more easily discernable products) and it is hydrophillic unlike industrial petrochemical hydrocarbons.

So you have to deal with a more variable product with interesting corrosive and polluting characteristics (gasohol products can produce some truly horrible crud and sludge, especially in marine environments, as very many boat owners have learned... which is especially horrible if you can't get the engine and fuel pump out of the boat without a chainsaw).

Then there is the introduction of water into all parts of the engine and fuel system. With straight gasoline, water isn't introduced from the gas tank as it stays physically separate from the fuel and the engine instantly shuts down when any is introduced. The alcohol water mix goes all the way through the system, with diminished combustibility and drastic corrosion. For fuel pumps at a station, they will always have a water air bath attacking its workings, as well as the gas and alcohol trying to corrode it.

Designing tanks and pump systems for these four types of chemicals is very challening and expensive, especially when you have dramatically increased the very corrosive elements (alcohol and water) while reducing the relatively inert ones (petrochemicals). That is going to throw your safety factor right out the window and light it on fire, which is also something that is likely to happen to the unfortunate gas stations and customers when these tanks and pumps start to fail spectacularly.

All of these problems are yet more examples of why you don't let liberal arts grads, especially hippy liberal arts grads, write technical legislative mandates. People that can't even explain what happens in a gas tank using words, never mind do the math or understand the chemical differences between similar organic compounds (and no that term does not refer to related communes in Vermont!) should not have any say in the operation or composition of our transportation system. For when they do, you get these idiotic things, where not only are insanely expensive mandates imposed on the public and gas stations (which said innumerate hippies then use to attack the oil companies for conspiring to raise prices) but they end up being physically impossible and many times more expensive thanks to the damage to infrastructure and the crash development projects required to save it. Reminds me of Ralph Nader's murderous impact on car design, and it isn't exactly shocking to see him and his organisations leading the charge to wound America all over again.
10.27.2006 5:19pm
Hey demonstrates how bloviating presumption conjoined with clich├ęd obsession is an amusing thing.
10.27.2006 6:29pm
TJIT (mail):

Do you have an engineering or other type of rational reply to hey's comment?

Or are you just going to use snark to cover up your apparent lack of

1. Design knowledge

2. Ability to reply to hey's comments on the problems ethanol causes in the fuel stream

3. Ability to reply to hey's comments on the difficulty in engineerging components to deal with ethanol.
10.27.2006 9:58pm
TJIT (mail):
As they say in engineering school yesterday I couldn't even spell engineer now I are one.

In comment above engineerging should have been engineering.
10.27.2006 10:13pm
Jack S. (mail) (www):
I actually haven't seen anyone actually state what their degree or background is to support their arguments, nor cite to an objective source to do the same.

What I have seen is attacks on what is a commenter's perceived background.

The E85 rollout has been hasty, and looks very political in light of recent events. Nothing signficant has been done in 20 years or more to come up with a better solution. Now some hacks are rushing in to try and fill the gap and save face. Example of trying to plug holes, an Escalade running E85 is still a crap design for a large car engine. Sparking engine technology does not scale well under heavy loads.

That said, dimissing alternative fuels without proposing a solution other than stay the course or suggesting that it's hippy liberal arts grads writing the legislation is hardly productive. Is the non hippy side of the political fence full of engineers in its ranks? Doubt it.
10.27.2006 11:31pm
Mark H.:

That said, dimissing alternative fuels without proposing a solution other than stay the course or suggesting that it's hippy liberal arts grads writing the legislation is hardly productive. Is the non hippy side of the political fence full of engineers in its ranks? Doubt it.

I think you've hit on the problem, perhaps unintentionally Jack S., it boils down to the inefficiency of having the government dictate (and, unfortunately, subsidize) what fuel we're going to power our current/future transportation methods with.

Market forces will (would have) take(n) care of things just fine thank you, but they cannot take hold with the current manipulation by the government. Their efforts merely delay progress while transferring the current status quo, partially, from oil to corn.

When I was a kid I was admonished to clean my plate because people were starving in China, now we're growing corn to burn up in our cars, while people still starve around the world -- there's something wrong with this picture, isn't there?
10.28.2006 2:37am

My comments before hey's decent into the ad hominem were rational and entirely based upon the engineering. Whatever else is "apparent" to you doesn't change that.
10.28.2006 9:25am
karl (mail):

When comparing us to Brazil and their sugarcane derived fuel, you must take into account the species of cane grown there is a perennial. They get as many as 10 harvests from a single planting. American cane is an annual, it must be replanted every year. That's expensive.
10.28.2006 11:27am
Bottomfish (mail):
Here is an interesting summary of corrosion issues regarding E85, coming from the National Ethanol Vehicle Coalition(

"Small NEVC conversion grants: On a limited basis, the NEVC may have small grants available to retailers that install or convert equipment to dispense E85. Typically, retailers must agree to sell E85 for a minimum of 24 months to qualify for this assistance. The grants generally cover the cost of professional cleaning and testing of fueling system as well as minor upgrades to alcohol-compatible hoses, steel or plated nozzles and 1-micron dispenser filters. In addition to the financial assistance, the NEVC provides a basic station kit of dispenser decals, pump toppers, nozzle covers and in-store materials for its retailer partners. Please note these grants are conducted on a case-by-case basis and are limited by the availability of NEVC funding. The NEVC reserve the right to decline stations that may not meet technical or operational requirements."

The NEVC adds that the program has now been suspended due to lack of funds. I wonder how many gas station operators would be willing to convert to E85 without having their costs defrayed.
10.28.2006 11:08pm
Harry Eagar (mail):
10 ratoon crops of cane would be very unusual. 2 or occasionally 3 would be the most any farmer would try, since yield declines with each harvest.

Hawaiian sugar cane is grown for around 24 months, which is optimal for sugar production. Sugar varieties are not necessarily the best for making fuel.

However, if molasses is used to make fuel, most of the objections about net energy yield disappear. So eat more granulated sugar.

Brazilian ethanol is cheap (though not in Brazil, where ethanol fuel sells for $5 or $6/gal, depending on location) because it is manufactured without any noticeable environmental controls. The vinesse (the leftover liquor from the distillation) is just dumped on the fields. This is not bad for the soil but it smells awful.
10.29.2006 2:43am