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352 comments on DrumBeat: July 19, 2006

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Don Sailorman on July 19, 2006 - 1:41pm Permalink | Subthread | Parent | Comments top
They have been economically efficient in Brazil for forty years, often with minimal or no subsidies at all.

Brazil is a large country with a lot of smart people in it. Maybe we could learn some things from them.

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tate423 on July 19, 2006 - 1:53pm Permalink | Subthread | Parent | Comments top
Great side step...you gonna move forward now?
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odograph on July 19, 2006 - 2:31pm Permalink | Subthread | Parent | Comments top
For air travel it comes down to power per weight, rather than the more conventional power per volume.  The numbers I've seen are:

Kerosene: 45.9 MJ/kg
Ethanol:  29.7 MJ/kg

So there's basically a 50% higher weight penalty carrying ethanol for fuel.

I was actually more hopeful until I had those numbers driven home for me:

http://ergosphere.blogspot.com/2005/06/post-oil-airliners.html

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Don Sailorman on July 19, 2006 - 6:11pm Permalink | Subthread | Parent | Comments top
Would you like to see some two dozen scientifically reputable peer-reviewed articles listed in accepted referance form?

Or do you prefer to go on with meaningless handwaving, snide remarks and armchair theorizing?

In other words, do you want to genuinely learn something of value?

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odograph on July 19, 2006 - 6:56pm Permalink | Subthread | Parent | Comments top
I think I've given the source for every number I've provided as a URL.  I think that's pretty much standard form on TOD.

If you have better data, ideally with a URL to provide easy access to all of us, that would be great.

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Don Sailorman on July 19, 2006 - 10:29pm Permalink | Subthread | Parent | Comments top
My sad experience has been that about 98% of URLs are unreliable and most are worse than useless. What we often have on the Internet is a Reign of Error.

Indeed, my opinion is that excess posting of links tends to make people stupid.

I am extremely selective in what I choose to study. Most of my secondary research is done in libraries and with the aid of reference librarians. That is why I have so much accurate information and so little garbage in my memory.

By the way, I have been home brewing ethanol from the age of fourteen and have been doing small-scale replications of some of the key research papers for decades.

Expertly written and edited books and peer-reviewed reputable scientific publications is the way to get an increaingly accurate and complete world view, in my opinion.

I rarely post links, for the reasons indicated above. I presume you pay taxes: Some of this goes for libraries. Why not use them. Librarians are some of my favorite people; they know where the good stuff is and are delighted to help you find it. And who knows, you might meet somebody interesting and intelligent in a library--happens to me more than once a month.

BTW, I keep in touch with chemists who have advanced degrees and who keep up in their fields. How many chemists do you know well enough to call by their first names?

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WinterIsComing on July 20, 2006 - 1:34am Permalink | Subthread | Parent | Comments top
"Expertly written and edited books" at least have ISBNs. Care to share a list?
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Don Sailorman on July 20, 2006 - 12:10pm Permalink | Subthread | Parent | Comments top
Thank you. List posted below on this thread.
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AlanfromBigEasy on July 20, 2006 - 6:55am Permalink | Subthread | Parent | Comments top
I keep in touch with chemists who have advanced degrees and who keep up in their fields. How many chemists do you know well enough to call by their first names?

Chemical engineers rather than chemists have much of the knowledge needed to analyze the EROEI of ethanol.  RR is one (graduate level research in ethanol at the second best ChemE department in Texas).  (I was in the best ChemE Department in Texas and transfered to BioMedE, then my tenured professor & I resigned to chase a dream; a liquid membrane blood oxygenator using liquid perfluorocarbons).

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odograph on July 20, 2006 - 8:36am Permalink | Subthread | Parent | Comments top
Don, you've made an interesting line of defense, but unfortunately one that indicts not only me, but TOD, and everyone who has ever published a number here.

I am really loathe to get into a credentials battle, in an obvious logical fallacy (an appeal to authority) but since everyone else is doing it ;-), I'll mention that I have a chem degree myself.

Ultimately the value of the web is created and reinforced when we can point, and link with URLs, to things we find which are true.  That builds value (and google rank) for those that come after us.  It is a community process.

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odograph on July 20, 2006 - 9:11am Permalink | Subthread | Parent | Comments top
And of course, science itself is moving on-line:

http://www.plos.org/

Scientists themselves coverse with URLs.

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JN2 on July 20, 2006 - 3:15am Permalink | Subthread | Parent | Comments top
Odo, yes, etahnol's specific energy may be down, but what about the efficiency? If ethanol aircraft engines are, say, 35% efficient and kerosene 23% then fuel consumption would be the same, no?
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Jack on July 20, 2006 - 5:43am Permalink | Subthread | Parent | Comments top
The track record does seem to show, in cars at least, that ethanol gets 25-30% worse mileage. In Brazil, ethanol has traditional sold at a discount of a bit more than 30% to gasoline, based on the % of ethanol in fuel. If a fuel contains 20% ethanol, it should sell at a 6% discount.

Unfortunately, this seems to be an unavoidable barrier and ethanol will have to be economically viable at a discount of 30% of gasoline. I do think that ethanol from sugar cane can meet this criteria, once sugar markets adjust. Right now, growing ethanol use, combined with other factors, has driven sugar prices up.

My calculations have a breakeven point below 70% of current gas prices, although at this level it remains more profitable to produce sugar. A price of 80-85% is required to be better than sugar. It is almost always more profitable to produce ethanol than molasses, which is about 30% of a sugar refineries output.

The additional weight/volume issue is not a death blow for cars, but may well be for airplanes. I would guess it will always, make sense to use petroleum-based fuel and increase ethanol in vehicles.

 

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odograph on July 20, 2006 - 9:20am Permalink | Subthread | Parent | Comments top
"say, 35% efficient and kerosene 23%"

Sure, that would do it.  My assumption is that a turbine has relatively equal efficiency ...

For what it's worth a raft of papers on ethanol in aviation are here:

http://www.baylor.edu/bias/index.php?id=5302

In a fast pass it looks like ethanol is used in piston craft and biodiesel has been tested in turbines?  Anyone feel free to investigate and correct me.  A chem degree is not required ;-)

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odograph on July 20, 2006 - 9:54am Permalink | Subthread | Parent | Comments top
I had some time and scanned this paper:

http://www.baylor.edu/bias/publications/avgasethanolETBE.pdf

It gives similar MJ/kg numbers to the ones I gave above:

avgas - 44.2 MJ/kg
ethanol - 27.2 MJ/kg

Interestingly, flight tests show a smaller penalty:

Although not shown, the full-power, full-rich Brake Specific Fuel Consumption (BSFC) of ETBE and avgas was essentially identical, while that of ethanol was measured at only about 15% more.  (Compare these actual data with expectations of 23% and 62% more consumption based on the heating value ratio.)  This is consistent with previous results both in flight and during tests performed on other test stands.  Flight test data has shown a 10 to 15% reduction in range operating on neat ethanol compared with range on avgas.

So there, I think that shows how you do it.  It confirms both that my earlier number was correct, shares my "expectations of 23% and 62% more consumption based on the heating value ratio" ...  and finally shows that it is possible to add to our knowledge with a URL. ;-)

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Don Sailorman on July 20, 2006 - 2:43pm Permalink | Subthread | Parent | Comments top
Thank you!
When you're right, you're right.

And that is usually the case.

What bothers me is that people sometimes think that just because I disagree with maybe 2% of a person's posts that I do not like or respect them.

Anybody who agrees with me always should be committed to a locked ward of a state hospital.

I change my mind whenever I get new evidence that suggests my previous view was incomplete or incorrect.

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odograph on July 20, 2006 - 10:57am Permalink | Subthread | Parent | Comments top
Hey, here's an interesting one.  It's a presentation by Boeing on "alternate fueled aircraft"

http://www.trbav030.org/pdf2006/265_Dagget.pdf

I'm not sure if it was clear to the reader above, but I'm more optimistic about piston aircraft running ethanol.  This paper addresses large commerical passenger aircraft, and from page 8 says such an ethanol aircraft requires:

  • 50% Larger Engines (needed for extra weight of fuel and wing)

  • 25% Larger Wing (needed to carry more fuel since it contains less energy*)

  • 35% Heavier Takeoff Weight (20% OEW Increase)

Energy demands:

  • 15% More energy use on 500 nmi mission

  • 26% more on 3K nmi mission
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ThatsItImout on July 21, 2006 - 3:06am Permalink | Subthread | Parent | Comments top

Imagine my astonishment when the folks who are normally preaching to me that it will be impossible to save autos are on here designing post peak airplanes!  :-)

Be the oddity of that as it may, it gave me pause to remember one of the single great "beautiful items" ever designed by human folk, inspired by the last time we were at peak, or at least were sure we were...

http://www.rps3.com/images/Pages/Starship/Starship%20page/star1385%2012x9%20lg.jpg

http://www.rps3.com/Pages/Starship%20Resources.htm

http://www.starshipdiaries.com/Images/16.jpg

What we found out then is that efficiencies can be improved by staggering degrees with aerodynamic and structural  development.  

The price of fuel crashed in the early 1980's against everyone's bet and sadly, the plane failed terribly as a commercial venture.  But a few are still around, and the models and photos, to prove it can be done.  Due to it's efficiency, it of course would change all calculations of needed fuel and needed power to weight ratio.

Whether something he actually said or not, in the movie "Tucker", the car designer Preston Tucker is attributed the words, on finding out that his venture is not going to make it, and the handful he has built is all there will ever be.....
"Son, you don't understand, it's not how many you built, even if it's just ONE, It's the IDEA that matters, just so that get's built...."

With the Beechcraft Starship, it did.

Roger Conner  known to you as ThatsItImout

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odograph on July 20, 2006 - 11:07am Permalink | Subthread | Parent | Comments top
As I wake up I notice the correlation between the two above papers, one for piston and one for jet aircraft.

That is:

  1. the agreement on lower MJ/kg
  2. the cited 15% reduction in range

I think it's pretty clear, based on the MJ/kg data, and reinforced by Boeing's numbers, that the range reduction is not a flat percentage, but based on distance of travel.  The further the (loaded) distance, the greater the penalty.

So ethanol looks good for shorter flights in piston or jet aircraft, but a flight from Los Angeles to Tokyo may be problematic.

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tate423 on July 20, 2006 - 2:04pm Permalink | Subthread | Parent | Comments top
Great work...I think it's settled then.
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peakearl on July 20, 2006 - 3:20pm Permalink | Subthread | Parent | Comments top
Couple other quick points I got from reviewing info on ethanol fueled aircraft. One is that currently most piston GA aircraft use 100LL gas, which is leaded. One concern in GA is what to do if leaded gas is outlawed for aircraft. With some modifications, ethanol has a high enough octane to use with GA engines. Second, due to the fact it burns cleaner, it can yield greater time between overhauls (TBO). This is more meaningful in aircraft than in automobiles.

I am staying out of the range/power debate till I see specific results of real world tests. With aircraft, any reduction in maximum power output significantly changes performance and safety in a variety of situations.

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