Ethanol and Burning Corn 31 comments
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Ethanol is a popular biolfuel because it is the main crop of Iowa, the key primary state in presidential politics. A big debate is whether the energy used to grow the corn and then process it is greater than the amount of fuel produced. David Pimentel of Cornell states that ethanol from corn in the US needs 25,000 kcals of energy to create 19,400 kcals of energy, for a net cost of 29% in BTUs (it takes 1.29 BTUs to generate 1 BTU of ethanol). In contrast, Bruce Dale of Michigan State stated this metric was irrelevant, and besides, applied to oil would generate a net cost of 45% and (coal was 240%). Slate notes that Pimental calculates gas as being a benefit of 527%, so they disagree profoundly on a very basic fact. Dale seems wrong intuitively - it can't cost more energy to generate oil and coal because otherwise we wouldn't have any oil and coal--if we lose more of it trying to get it we wouldn't have as much as we do--where does the energy then come from?
The debate seemed at an impasse of technical details, but I think we have a definitive answer. Recent research suggests it would be more efficient to actually burn the corn, rather than process it and use it as fuel. From Bloomberg:
Burning sugar cane or corn to make electricity for powering cars may be smarter than refining the crops into biofuels.
Clearly we are defining biofuels down if they are now best used like dung in some African village. By the transitive property, if burning corn is better than turning it into ethanol and burning it, oil or gas is more efficient than ethanol.
The new DOE chief, Nobel prize winning scientist Steven Chu has noted that ethanol is probably not the way to go. Too bad we put in this massive infrastructure to process corn as a fuel, including multi-year mandates, subsidies and tax credits. One big problem with government solutions, is that like the education quagmire, the solution is always more money.
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This article has 31 comments:
ethical problem with corn ethanol is that corn really should be used to feed people who are starving all over the world.
> jack
The important point made by the recent study referred to, is that there is an opportunity cost to diverting the bio-energy in corn to liquid fuels as opposed to heat -- either for direct heating purposes (e.g., home stoves) or electricity. A lot of us have been trying to make this point for some time, but it is nice to see somebody finally do it in a scientifically rigorous manner.
Please provide the link to both studies so that I can study the assumptions each used
corn is voracious consumer of nitrogen fertilizer which is made from natural gas (could be made from coal, this has been done by TVA).
potash comes from saskatchewan, phosphate comes from florida.
tractors could be run on home-grown ethanol, henry ford advocated this in the 1920's, he hated the major oil companies with a passion.
> jack
We may find the solution was there all along, let Chrysler resurrect the Stanley Steamer.
Or if we want to go "Deep Green" feed the corn directly to the horse!.
But NEVER--NEVER consult or emulate Brazil which has had a successful ethanol program for over 10 years. That would violate the "Kickback" rule-above. Better to place tacos beyond a starving Mexicans reach so he has to come here to eat.
Given enough crayons a class of second graders could figure this one out!!.
In this case Bruce Dale is correct, to the extent that there is a net loss in energy yield for gasoline production. The truth is, according to the United States Department of Agriculture (see link below), for every unit of energy expended in the production of gasoline, there is a net loss of 19% in energy yield. According to the same source, from production to utilization, ethanol is 81% more energy efficient than gasoline.
Unfortunately, arguments for and against biofuels and renewable energy have been so impassioned that sentiments often override technical evidence.
In my personal blog, htttp://7xreferences.b... l have tried to correct myths and outright falsehoods on energy that are propagated perhaps innocently without proper analyses.
The link for the energy balance tests is: www.mda.state.mn.us/re...
Sometimes our intuition may be flawed by subliminal biases. We all, have at one time or the other been guilty of such.
In this case Bruce Dale is correct, to the extent that there is a net loss in energy yield for gasoline production. The truth is, according to the United States Department of Agriculture (see link below), for every unit of energy expended in the production of gasoline, there is a net loss of 19% in energy yield. According to the same source, from production to utilization, ethanol is 81% more energy efficient than gasoline.
Unfortunately, arguments for and against biofuels and renewable energy have been so impassioned that sentiments often override technical evidence.
In my personal blog, 7xreferences.blogspot.com, l have tried to correct myths and outright falsehoods on energy that are propagated perhaps innocently without proper analyses.
The link for the energy balance tests is: www.mda.state.mn.us/re...
On May 13 09:02 AM SubsidyEye wrote:
> Well, Peabody, I guess you haven't noticed that there has been a
> considerable investment in local roads in places like Iowa to handle
> the extra heavy-truck traffic; new investments in rail spurs and
> in special tanker cars to carry the ethanol. And the industry is
> now looking for government-backed loans to build a multi-billion
> dollar dedicated ethanol pipeline. On the consumption side, there
> have been generous subsidies to help install E85 pumps. And then,
> of course, there are all the subsidies that have been poured into
> building ethanol plants themselves. And, by the way, ethanol does
> not utlizes ONLY existing crop land. Some grasslands in the Dakotas
> have been plowed up to grow corn for ethaol, and in the east former
> apple orchids have been converted to increase the supply of corn.
WJS
That debate was settled years ago. It persists as an internet rumor, which can be hard to kill.
The energy balance for corn ethanol went from next to nothing to positive overnight when someone a came up with the idea of energy credits. This is where you account for the energy saved by feeding cattle the waste product from ethanol called distiller's grains. In 2006 a study in Science by Farrell et al looked at six energy balance studies and concluded that 5 to 26% of corn ethanol was indeed renewable if you give energy credit to distillers grains:
www.sciencemag.org/cgi... (sub required)
In other words, a corn ethanol refinery essentially converts fossil fuels (coal, natural gas, petroleum, and diesel) into ethanol adding a small amount of solar energy captured by the plants into the final product. For every 1.25 gallons of ethanol, one gallon is made from fossil fuels (mostly natural gas) and one quart from plants.
www.biodiversivist.com
Unfortunately, the original article is no longer on line. Whether one is talking about new spur roads or upgrading, there is still investment going on to handle new traffic created by ethanol plants.
Dennis U.Atuanya: You again make the same mistake that Eric Falkenstein does in his article: you conlate "energy" with "fossil fuels". When one converts ANY energy source from one form to another (crude to refined products, solids to liquids, solids to electricity) there is a loss of energy. For gasoline, one starts with 1.2 units of energy, one gets 1 unit out. For ethanol, one starts with 1.6 units of energy (in the form of corn starch, natural gas or coal, diesel), one gets 1 unit. Conclusion: producing ethanol is less ENERGY efficient than gasoline. Look at the published life-cycle analyses (like GREET or GHGenius) if you don't believe me.
However, if one wants to talk about FOSSIL FUELS, then the ratio is still 1.2 : 1 for gasoline but 0.75 : 1 (approximately) for ethanol when a credit for co-products is taken.
If you want to talk about myths and falsehoods, there is no better place to start than the web pages of the Renewable Fuels Association. As the Global Subsidies Initiative has shown, the RFA routinely vastly exaggerates -- by more than double -- the amount and the value of imported crude oil displaced by ethanol:
globalsubsidies.org/en...
If we want to be technical, energy is never really lost ;it only changes form. For example part of the energy supplied to a light bulb in the form of electricity is used to light the bulb (light energy), the rest is released as heat energy. For purely lighting purposes therefore, the heat energy in this case is a loss.
If we were mixing up "energy" with "fossil fuels" we would not be talking about bioethanol which is not a fossil fuel.
What the tests by the United States Department of Agriculture says is that for every 1 unit of energy expended in making gasoline, only 0.81 of it is useable. For ethanol the value is 1.34, making ethanol more energy efficient. The United States Department of Agriculture is certainly not a propaganda machine.
Gasoline has a higher calorific value than bioethanol just like Mr. A weighing 300kg and being able to bench press 250kg may be stronger than Mr. B weighing 100 kg but who can bench press 180kg. Mr. B who presses 80% more than his mass, is more efficient than Mr. A who only presses 16% less than his.
You may not think it necessary to make the distinction between "energy" and "fossil fuels", but the scientists who do life-cycle analysis do. By failing to maintain the distinction, you sow confusion. But perhaps that's your intention?
Again, the point of this article (and other studies looking at how much USABLE energy can be obtained per acre) is that converting the energy in corn to electricity (and then using the electricity to power a car) is more energy-efficient than converting the corn to a liquid fuel.
Is that the whole story? Of course not. What should matter in the end is which is more cost-effective, taking into account externalities.
But, to repeat: corn ethanol is NOT more energy-efficient than gasoline. It has a better ratio of fossil energy inputs to usable energy outputs, which is a different thing.
If there were no difference between "energy" and "fossil fuels" then the whole test by the USDA would be meaningless. Unless of course that is what you are saying. If not then the result stands that from production to utilization, ethanol is 81% more ENERGY efficient than gasoline. From production to utilization! Does that not sound like life cycle?
The electricity-powered engine is INHERENTLY more efficient than the internal combustion engine whether the latter runs on ethanol or gasoline. Even the authors of the original report concede this. About the intention to confuse, does that cap not fit you just well?
As l have just posted to my blog, it is worth considering the use of synergies inherent in lignocellulosic biomass-to-energy programs in current energy policy solutions. Brazil, the global model for bioethanol excellence for example uses sugarcane for feedstock. After milling for ethanol, the residue called bagasse is used for auxiliary power generation (just like the authors of the said report did). For most milling plants, the power so-generated is often in excess of production requirements. The excess is sold to utilities with proceeds in the millions of US dollars.
The same crop of say switchgrass can therefore be used to first mill for ethanol (for blending with gasoline in traditional internal combustion engines) and the residue burnt to generate electricity (for battery-powered engines). This delivers on the two key tenets of current energy policy thrust, cleaner burning and more efficient fuel especially in the transportation sector.
This is also a less traumatic transition to other-powered vehicles.
When other countries were improving on automotive fuel efficiency and emissions standards, the US was slow to latch on. Today's US automobile industry lessons may be hard ones.
It would be impossible to address all the misinformation and faulty assumptions without writing a book. But to hit some of the high points.
Making ethanol from corn is burning food, causes starvation etc. etc.------the truth is, the final product of ethanol production from corn is animal feed. The final product is DDG, high protein animal feed. What the corn was grown for in the first place. DDG contains about 20 to 30% protein vs. about 2-4% for dent corn. Humans can not eat dent corn. The yeast culture that produces the ethanol as and end product of anaerobic metabolism is itself the the protein source. DDG is a cheaper replacement for Soy meal because you can raise about three times the amount of corn per acre than you can soy beans. The ethanol is a bonus. You have to remove the ethanol before you feed it to cattle or pigs so you don't have a herd of drunk cattle or pigs on your hands. Ethanol produced from corn produces both food AND fuel.
Energy balance. To say that corn produces less energy than some other plant is misleading. Corn produces less ethanol per acre than sugar cane, but not less energy. There is still a considerable amount of energy(calories) in the DDG. This is passed down the line and used by the cattle(for instance) to which the DDG is fed to maintain metabolism ---- and passed on further as energy in the form of meat, dairy products, or any other food derived from animals to which it is fed, like eggs. There is even energy left in the form of manure. Put cattle manure in a big pile and it generates heat due to bacterial action----and if you enclose the manure pile you can capture the heat and even more energy in the form of methane given off by the bacteria.
Ethanol can be produced from any plant source whatever. We can produce ethanol from wood, and have been able to for over 100 years. Ethanol was produced in commercial quantities from wood in both the US and Germany from the 1890's to after WW1. This used the Scholler process, also used in the US in WW2 at a facility in Wisconsin to produce ethanol for butadeine, artificial rubber to make tires for the war effort. There were at least 20 factories in Germany, 3 in Italy and one each in Japan, Korea and Manchuria that were known to military intelligence using the same process mentioned in the letter of proposal to build the US plant to the War Production Board in 1942.
Germany produced almost all of its fuel needs using Fischer-Tropsch process after the loss of North Africa and the Allied bombing of Ploesti left them with virtually no petroleum at all. They powered everything from submarines, to panzer tanks, V1 and V2 rockets--even the Me-262 Swallow, the world's first operational jet fighter. Range Fuels is just completing construction of a plant in Soperton GA to produce 100 million gal/yr of ethanol from wood waste from logging and milling operations, using F-T process. South Africa has produced jet and diesel fuel using F-T since 1980.
Ethanol is an important biofuel, but it is not the only biofuel.
There is also methanol, butanol and other alcohols.
Gasoline can be made from plant sources.
There is also biodiesel made from plant oils---algae are the most promising and productive source of plant lipids.
Biomass---can be burned directly as a heat source, wood would be an example. Biomass can be pelletized to uniform shape, size and weight to give more reliable combustion properties.
Biomethane---exactly the same methane as in natural gas chemically, the only difference is where it comes from. Biomethane can be produced from composting and sewage treatment. We need to treat sewage anyway. Biomethane can do anything that natural gas can do---and can be mixed in any proportion with no loss of performance. Biomethane can be the base raw material for thousands of other products from plastics to fertilizer----just the same as natural gas, the two are completely interchangable.
flwetdog@hotmail.com
This means that ethanol has a much lower tendency to pre-ignite and cause cylinder knock, explode at the wrong time in the power cycle. This can destroy an engine.
This means that it is possible to build engines with much higher compression ratios using ethanol as a fuel than gasoline. Compression ratio determines how efficient an engine is, the higher the compression ratio, the greater the amount of work comes out at the wheels compared to the amount of fuel(in BTUs) put into the tank. Ethanol can achieve compression ratios of 18-24 : 1, compared to gasoline that can only get 9-11 : 1 before you start to encounter problems with preignition.
Typical gasoline engines get about 20% thermal efficiency, about 1/5 of the energy put in comes out as work. Ethanol engines can get up to 45% thermal efficiency. More work, and more power from smaller engines.
That is why the fastest, most advanced race cars in the world all run on 100% ethanol. The Indy Racing League Circuit. Ethanol is just a better fuel than gasoline, and it is much safer to use---an ethanol fire can be put out with plain water. Indy League race cars can produce about 1200-1600 bhp from a 3L V8 engine, (smaller than most passenger cars on the road)---but more horsepower than three 18 wheel diesel rigs. That is why they use ethanol.