Ethanol-which story to believe??

4dsc · Tar Sands Joined: Apr 03, 2005 Posts: 31

I have read two article about ethanol that seem to contradict each other. Which should I believe??

http://www.greenbiz.com/news/news_third.cfm?NewsID=27864 Latest Study Shows Ethanol Generates More Energy Than It Takes to Produce

Or http://www.energybulletin.net/5062.html Ethanol Production Consumes Six Units Of Energy To Produce Just One

Cool

MonteQuest · Posted: Sat May 14, 2005 7:25 am Post subject:

It seems to come down to exactly what you include in your evaluation. Like gasoline, there seems to be "external costs" that are not included in many studies that are included in the UCLA study. Depends whether the study paramenters have an ecological paradigm thrust to them. This quote from the energy bulletin article may be the best answer.

killJOY · Fission Joined: Feb 21, 2005 Posts: 2481 Location: ^NNE^

4dsc · Tar Sands Joined: Apr 03, 2005 Posts: 31

I guess I'm looking for whether or not a gallon ethanol is equal to a gallon of gas in the amount of energy given off when used.. I believe this is probably a different subject than what is being discussed in both articles..

MonteQuest · Posted: Sat May 14, 2005 8:23 am Post subject: Re: I guess I'm looking for

Pops · Posted: Sat May 14, 2005 8:30 am Post subject:

That stinking USDA report had some really convoluted language. But Monte is right it was based on BTU’s not gallons which doesn’t really matter much I think. Of course bang/buck depends on the respective buck/gal.

Gasoline, being comprised entirely of fossil fuels will necessarily have an output of less the 1 since some fossil fuel is used in it’s manufacture and transport.

But I don’t think they added btu’s for solar energy. The “contribution of solar energy” bit is simply an explanation of why ethanol has a net positive after subtracting all fossil fuel input. It seems to go without saying there is a contribution from solar energy, how the heck do you grow corn without “solar energy”?

The quote from energybulliten is misleading to me as well; since the study seems to be based on btu’s - I can’t figure out how “hidden subsidies” can affect btu’s.
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MonteQuest · Posted: Sat May 14, 2005 8:45 am Post subject:

Pops · Posted: Sat May 14, 2005 9:03 am Post subject:

Gallon per gallon that’s true, but FWIW, here in the Midwest I’ve seen mid-grade straight gasoline and premium grade 10% ethanol blend at the same price. Don’t know how that works out on the BTU/Buck scale though.

It seems btu-wise it’s positive, so 100 gallons of ethanol effectively makes 100 gallons of oil go some percentage further – plus keeps some of that money at home.

But when it comes to unraveling the “hidden subsidies” of ethanol vs. petroleum, it’s gonna take a bigger brain than mine!
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Pops · Posted: Sat May 14, 2005 9:26 am Post subject:

One think I forgot to mention regarding many of these studies, most find a positive return, but those showing the highest returns include the “embodied energy” of “distillers grains” which are the byproducts of distillation valuable as animal feed.

Not a trivial item especially when talk turns to the world starving to death in order to make ethanol.
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mididoctors · Posted: Sat May 14, 2005 11:01 am Post subject:

4dsc · Tar Sands Joined: Apr 03, 2005 Posts: 31

again I have two report that seem to contradict each other.

http://nature.gardenweb.com/forums/load/sustain/msg0113331712037.html

RickTaylor · Tar Sands Joined: Apr 05, 2005 Posts: 35

Correct me if I'm wrong, but isn't the fundamental problem with all the proposals that involve growing and then harvesting living matter for fuel is that they are all a form of solar energy, one that's even more inefficient than photovoltaics? Dr. David Goodstein said that about one tenth of one percent of the sunlight is actually converted to chemical energy when using biomass.

Of course using oil and gas is a similar use of solar energy, but in this case we're using deposits that accumulated over millions of years. Using biomass in whatever form will inevitably be limited by the land we have available for planting, the energy from the sun upon that land, and the efficiency of the organisms involved in converting that energy into fuel. Biofuels may have a role to play, but it is inconceivable that they will somehow replace fossil fuels in transportation. At least that's how I understand it.

--Rick

aahala · Intermediate Crude Joined: Feb 03, 2005 Posts: 954

Caoimhan · Intermediate Crude Joined: May 10, 2005 Posts: 562

I wish people would stop complicating threads such as these with discussions of (monetary) price. The issue of price adds in a whole lot of other factors that are not germaine to the argument of whether or not ethanol is a net energy gain or loss.

Also, the reasons why solar energy is not considered an input into the equation, is that:
1) it's a "free" input... the sun is going to shine no matter what we do.
2) we're comparing it to the energy stored in the petroleum, which, if we believe that petroleum is truly "fossil fuel", then it's also just stored solar energy, too. To make a fair comparison, we have to make the solar energy stored in the chemical bonds in both of these fuels a non-factor in the equation.

That said, we need to agree on how to define the energy inputs.

For gasoline: drilling, pumping, transportation, and refining are all fair to calculate.
For biofuels: cultivation, harvesting, pressing/fermenting, transportation, and refining are fair to calculate.

Take a million BTUs of gasoline and a million BTUs of ethanol and find out how much of each fuel makes up that million BTUs.

Then find out how much energy is used by the production processes above to produce those amounts of fuel.

Divide that number by one million, and you'll have your ratio.

While the process to produce gasoline from petroleum is pretty well established and mature, and therefore, pretty stable and predictable, processes are still being improved on ethanol production.

Pops · Posted: Sun May 15, 2005 9:01 am Post subject:

4dsc, I don’t think there IS any alternative to oil in the amounts consumed now, it’s just too dense in energy and varied in uses. I will speculate that where suitable crops can be grown (and of course all the other alternatives) there is a possibility to ease down to a more sustainable level. But the time it takes to ease down and how far down is, is more speculation than I care to make.

As for Pimentel, he has been cited over and over, if you look at his figures on page 5 of the report you can see he uses the lowest corn yield figures, the highest fertilizer rates, and the largest energy inputs for conversion. Granted his study was done 15 years ago and things have improved both on the farm and in the conversion process. The reason ethanol is not used to make ethanol however is that ethanol is worth more than coal or natural gas (well, for a while anyway). At any rate of 5 studies the USDA cite indicating ethanol is a net loser Pimentel did 3 – 10 others showed a gain.
Argonne Study

I agree that comparing gasoline or diesel return to ethanol or biodiesel does make the simple question of whether there is a net gain with biofuels unnecessarily complicated.

Either they produce a net gain or they don’t.

If they do produce a gain then they can make oil and particularly natural gas go further and keep some farmers in business in the bargain.

Although Borris, I can’t figure how 4 BTUs of gasoline only uses up 1 BTU of fossil fuel…

BTW there was another discussion of this recently if you haven't seen it; http://www.peakoil.com/fortopic6540.html
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