i have seen this debate and concluded that pimental and padzyck were being misleading, though the 1->1.3 gain isn't much. but now i'm confused again. what is the relevant metric?
it would seem one asks how many barrels of oil does it take to produce gasoline (or equivalent) directly, versus via ethanol. the standard view is you get a 30% gain via corn ethanol. I guess this ignores the fact that ethanol production may not involve just oil, but rather natural gas and coal too (so then may be the gain is better, since all fuels don't have the same use). is it only by considering the various other fuel inputs that one gets the .8 versus 1.3 comparison?
also it would seem that if one produced corn fuel starting with oil, eventually you could then use part of the corn fuel to run the operation, so then it would not use any oil (assuming no coal or natural gas is required). (or more simply people could just run their cars on wood, like the old days.)
most corn i think is used for beef and sugar production; so if the corn crop were diverted instead to fuel, this also seems to be a common sense solution, though at odds with american consumerism.
the reason this idea may be worth considering is simply as an excercize in calculation, logical reasoning, critical thinking, and cost/benefit analyses. its possible many of today's current problems exist because people don't know how to do these, or simply prefer not to do them because of either current 'social programming' (education, media, information overload) or 'rational irrationality' (biologically based cognitive biases).
of course it may also be possible that the 'status quo' is optimal or neccesary (voltaire's candide) and more rational rationality actuallly would lead to stifling boredom and calcification. (but then maybe future generations could use that as fuel.)
--- On Thu, 8/28/08, Jim West <[log in to unmask]>
From: Jim West <[log in to unmask]>
Subject: Re: Bio-Diesel, vastly better [BTU Efficiency]
To: [log in to unmask]
Date: Thursday, August 28, 2008, 2:21 PM
I too was surprised by the claim the gasoline and alcohol are similarly
inefficient in terms of BTU efficiency. Yet the claim is not uncommon, as
found here, for example, at www.theoildrum.com/story/2006/8/25/221617/881
Some say ethanol production is more efficient, others that gasoline is more
efficient. The differences are small compared to algae-oil, which is highly
efficient, and much safer and sustenable.
It seems to me that the simplest (i.e. ignoring infrastrcture cost, water
use, soil damage, etc) relevant metric from a peak oil perspective is the
ratio of fossil fuel inputs to useable energy outputs.
gasoline: 1 BTU (petroleum) input -> 0.8 BTU output
ethanol: 1 BTU (mix hydrocarbon) input -> 1.3 BTU output
In this context, inputs are just inputs; they may be, but are not
necessarily, consumed. It seems inappropriate to ignore the "input"
that becomes gasoline, just because it isn't literally consumed (i.e.
burned) in the process. You still have to put it in the front end, in order
to get product out the back end.
Calculated this way, ethanol does beat gasoline. Fine, so be it. But it's
a very simplified metric, and the net benefit, while positive, is small.
I think that this entire arguement is really a distraction from the bigger
question of appropriate energy policy. The detractors of corn ethanol are
wasting their time splitting hairs over the definition of efficiency or
EROIE, at least in the context of public debate. The points that need to be
made, loudly and clearly to the public, are these:
1. If you're concerned about peak oil, ethanol is no solution. It's
positive, but it's not positive enough to offset rising demand coupled with
declines in production.
2. If you're not concerned with peak oil, but just want to reduce oil
(e.g. for national security reasons), then ethanol is still a waste of time.
The externalities are very high, and the return on investment is low
compared to energy efficiency measures.
The pro-ethanol lobby has completely bollixed those who are interested in
actual sane, sustainable energy policy by focusing excessive attention on
the energy return question. And the ethanol detractors have, for the most
part, fallen for it. We need to stop dancing to their tune, and talking
from their frame. Instead, accept their arguements as being "close
to correct, and demonstrate why those arguements are not sufficient to
support a national move towards ethanol.
Disclaimer: all the above statements are specifically about corn ethanol.
On Wed, 27 Aug 2008 11:29:32 -0400, Eric Entemann <[log in to unmask]>
>"Both gasoline and ethanol utilize nearly as much energy to
>As regards gasoline, this statement is prima facie nonsense.
> Date: Wed, 27 Aug 2008 11:12:31 -0400> From: [log in to unmask]>
Bio-Diesel, vastly better than ethanol and gasoline> To:
[log in to unmask]> > An impressive documentary
"FIELDS OF FUEL" has won many awards.> > The film eloquently
approximately 600 articles published in> major media to bash bio-diesel. It
reviews petrochemical's political history.> > Don't confuse this
Ethanol.> > Biodiesel certainly seems to be one of the best alternative
power sources> available. Algae farms are now producing bio-oils from which
fuel, food,> and plastic can be derived. Mere cold-pressing can extract oil
which is a> main component of algae, by weight, 50%. It is now being offered
at fuel> stations througout Europe.> > Bio-diesel oil tops the BTU
efficiency studies. Both gasoline and ethanol> utilize nearly as much energy
to manufacturer as they provide. Yet, bio-oil> produces a multiple of the
energy required to create it.> > Bio-diesel exhaust is much less
then petroleum fuel exhausts. It> smells like french fries, rather than
carcinogenic hell. Newer diesel> engines are highly efficient and clean. The
first diesel engine was> introduced to the world in the late 19th c. running
on peanut oil. Not> surprisingly, the wealthy and successful Rudolf Diesel
died an early death> under suspicious circumstances.> > Algae grows in
seawater, and duplicates its mass every 24 hours. It can use> wastewater. It
is a completely renewable resource. Algae farms extract> carbon dioxide from
the air and produce oxygen, protein, fiber and oil.> > Oil can be
from algae by cold-press, harmless CO2 process, or> conventional hexane
solvent process. > > The process is completely independent of
industry, though the> existing pipeline grid would be useful.> > Under
pessimistic scenarios, bio-diesel shines brightly in terms of the>
environment and economics.> > Here are optimistic scenarios that I've
calculated. Please confirm and> critique.> > Using the optimistic
the algae farmers (see below), then if> biodiesel hybrids (generated or
plug-in) replaced gasoline cars and if> engine efficiencies are doubled,
then a city of 1 million people could> replace all of its gasoline usage
with an algae farm of 3.65 square miles,> or 1.35 miles on each side of a
square representing that farm.> > A village of 5,000 could replace its
gasoline requirements, accordingly,> with an algae farm of 25,000 square
feet (500 ft per side). > > For more info:> >
> Here are
statments from a company that is currently going into production.> >
> a) "Microalgae... can produce 30-100 times the oil yield of soybeans
marginal land and in brackish water. The biomass left-over from
oil-pressing> can either be fed to cattle as a protein supplement, or
fermented into> ethanol." > > b)"The current algae farm
consists of 1,100
acres of saltwater ponds that> the Company projects will produce a minimum
of 4.4 million gallons of algal> oil and 110 million pounds of biomass on an
annual basis." > > Jim West> www.geocities.com/noxot
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