Wednesday, August 01, 2007

David Pimentel and Tad Patzek

Critics of ethanol-as-fuel often point to studies done by these two prolific, vocal, and zealous anti-ethanol crusaders. If you see any report or article or blog post that cites either Pimentel or Patzek, whether directly or indirectly, you need to turn on your bullshit detector.

It's not that they don't put a lot of work into their work, they do, but some of it's fuzzy, some of it's poorly reasoned, and some of it's downright controversial.

A f'rinstance. They calculate the "oil equivalent" of the labor that goes into farming corn [and other ethanol-producing crops]. They figure up how many calories of food a farm laborer eats and how many gallons of gasoline a farm laborer uses to get from home to the fields and back, and then set this equivalent to X number of liters of oil and add this to the total energy put into producing the resulting ethanol [8000 liters/year/hectare here].

That's all fine and dandy, I like thorough analyses as well as the next number-cruncher [and maybe more], but they never once do any such figuration on producing an equivalent amount of gasoline. Oops. In fact, I've spent the last two years, ever since Slate lauded their anti-ethanol ethos here, trying to find out how much energy goes into producing the gasoline you use.

This is the best I've found so far [and it's not great, so remember your grain of salt]:

  • It takes 0.74 BTU of fossil energy [coal + natural gas + petroleum] to produce produce and deliver to the gas pump 1 BTU of ethanol from corn.

  • It takes 1.23 BTU of fossil energy [coal + natural gas + petroleum] to produce produce and deliver to the gas pump 1 BTU of gasoline from petroleum.

NB: As far as I can tell, nobody's found a link between Pimentel and Big Oil, but Patzek has ties.

Just sayin'.


Keifus said...

Oh Christ, it's been years since they tried to teach me this, but I think the power required to operate a gas plant (or whatever plant where the feedstock is also power, I think the class example was cracking ethylene), then it's not counted in the output. There's an efficiency, so much raw material in per product out, and that's where the cost of burning the fuel is sunk.

Refinery efficiency may be something well understood, by the way. May even have a section on it in my Perry's (not that I have time to look today).

This Wang feller has the right idea in any case, in counting fossil in per energy out. He should show his work though, or supply references. (No time for this either.)

I remember PhilfromCalifornia, my favorite codger from teh old moneybox Fray, bitching about Pimental. I had a pdf file on my desktop that of his (Pim.'s) paper, procrastinated the reading for a year, until I changed computers.


uhwwbp: uh, what would bp do?

hipparchia said...

refinery efficiency = 40-60%, if i remember rightly, but that was just one paper i found [can't find it now] and i'm going on notoriously unreliable memory here.

i read two of pimentel's papers [and my head slmost exploded]. let me save you -- don't bother trying to read anything he writes if you value your sanity.

yes, it would have been much better if wang had shown his work, and i'll keep looking for a more thorough analysis.

i've lost a bunch of my bookmarks in a computer crash too. among them something else [more substantial, i think] by wang and some stuff on refinery efficiency. it's been a while, so i didn't want to try to paraphrase either of them from memory.

refinery information [the kind i want] is kinda hard to come by on the web. or it could just be that i'm not looking in the right places. i'll let you know if i need to borrow your class notes.

phil is one of my favorite codgers there too. now that i know his opinion of pimentel, i like him even better.

Keifus said...

I don't think highly of my sanity, but (quality) free time is one thing, and if there's no outlet for the outrage, it can be bad for the spleen.

Maybe I'll mine the ancient archives next week. I threw a lot of 'em out recently (but kept the books).


kmtoj: karmic tables of justice

hipparchia said...

pimento! oooh, good one.

don't bother excavating in the archives, i'm pretty sure i can google up enough on the subject.

[unless you really really want to. i'd welcome input from a smart, sane engineer any day, even if you end proving me wrong on any of this. i'm all about opinions, but we really need to start fixing some of these problems, even if some of the fixes are less than optimal.]

Steve Bates said...

I should learn to read your blog from oldest to newest. Here is an interview with former Sierra Club president Robbie Cox that has some info about Pimentel's participation in Richard Mellon Scaife's attempted "hostile takeover" of the Sierra Club in about 2004. It's not exactly a connection with Big Oil, but it's not savory, either. See my comment on your downstream post.

[pmtzpj - Pimentel, zero pajamas]

hipparchia said...

no pajamas for pimentel! [zing]

thanks for the link.

Anonymous said...

You just don't get it. The argument isn't that ethanol is worse than fossil fuels. That's idiotic. The argument is that ethanol is a TERRIBLE form of renewable energy, and should not be pursued when so many other options (take a look at methanol, which isn't even close to optimal either) with superior potential are out there.

By the way, I don't like patzek at all. He was my teacher for introduction to MATLAB and it was the worst class I've ever taken. Ever. So you can probably take this is a VERY objective analysis.