[Diy_efi] Is E85 worth it?

Klaus Allmendinger klaus
Fri Aug 25 21:57:53 UTC 2006

I have done some research recently into ethanol as fuel. From the various studies and test results the conclusion I came to is that ethanol is a superior fuel for engines compared to gasoline, PROVIDED the engines are designed around ethanol fuel.
1. Production efficiency
To produce (and transport) 1 BTU of ethanol energy requires the expenditure of ~0.6 BTU in input energy. About half of that is in other fuels like fossil fuel. The other half comes from electrical energy, which can be nuclear, water, wind and also fossil. 1 BTU of gasoline requires ~0.2 BTU in drilling, transportation and refining. The difference is that gasoline puts out a total of 1.2BTU worth of greenhouse gases vs. Ethanol at 0.6 BTU (well to wheel). The CO2 from burning ethanol is taken up by the plants in next years crop and therefore doesn't contribute to atmospheric CO2 total. The 0.6 BTU is with todays technology producing from corn. Within 3-5 years, the yield producing ethanol from other biomass and using newer distillation technologies the expected expenditure is predicted to drop to about 0.2-0.3 BTU. This is comparable to gasoline. Gasoline prices are expected to rise in the future because it is a finite resource. Ethanol prices will continue to fall in the future because the cost is a function of technical efficiency, not of scarcity.
2. Engine efficiency
Gasoline engines convert about 25 to 30% of the energy contained in the fuel into available power. With the superior combustion properties of ethanol, used right, 40-42% efficiency can be achieved. This requires high level turbocharging, cooled EGR and direct injection. These techniques are not used today in production automobiles to the required extent because they can't be done "flex", only with ethanol or methanol. See here:
http://lfee.mit.edu/public/LFEE%202006-01%20RP.pdf  and here:
3. Production feedstock availability
Some recent breakthroughs in custom enzymes allow the production of ethanol from other biomass, like perennial switchgrass. This allows to use much more available biomass than just corn kernels, sugarcane or sugar beets. In fact a large amount of biomass that currently goes into land-fills can be used for ethanol production. Once cellulose is broken down with these enzymes it is more efficient to produce ethanol than higher alcohols (higher BTU yield).
4. Greenhouse gas production
The higher hydrogen/carbon ratio of ethanol or methanol means that a lot of the energy is produced from the combustion of hydrogen vs carbon. This lowers the tailpipe emissions of CO2 and CO dramatically for the same energy unit. Also a comparison based purely on BTU (thermal) content as a basis for milage prediction is unfair to these lower alcohols. As mentioned before, they produce more gas molecules as combustion product and therefore higher cylinder pressure with lower BTU input. After all, we are running internal combustion engines, not steam engines, where a BTU comparison would be fair. The lower flame-front temperatures of burning alcohol means also that less nitrous oxides are produced.
5. Pipeline compatibility
It is not a matter of ethanol corroding the pipelines, but because ethanol is hygroscopic, it can take up water pockets and crud that has accumulated over time in those pipelines. This means running ethanol through them would clean them out, but the ethanol at the other side won't be usable until the line is clean.
6. Tax subsidies
The oil companies have gotten over the years far more in indirect and direct tax subsidies (exploration writeoffs for example) than has been put total into agriculture. Despite that, of every dollar you spend at the gas pump a large percentage goes to places that use that money to try to kill us. I don't think that is money wisely spent by us. I'd rather spend that money so that it goes back into the US economy.
7. Propanol, Butanol and other higher alcohols
Yes, butanol, partly because of its lower hydrogen/carbon ratio, behaves much closer to gasoline in an engine. But also, because of that it also does not have the additional advantages that the lower alcohols have in raising engine efficiency.
Just my $0.02 worth.


From: diy_efi-bounces at diy-efi.org on behalf of Daniel Nicoson
Sent: Fri 8/25/2006 12:39 PM
To: diy_efi at diy-efi.org
Subject: RE: [Diy_efi] Is E85 worth it?

Ethanol absorbs too much water and ends up being pretty corrosive in
pipelines.  If you read up on what the ethanol camp has to say, they claim
to have improved the energy exchange in production so that it is a positive

Personally I think ethanol is a transitional fuel and will eventually be
replaced by butanol as the long term replacement for a percentage of
gasoline.  There is a modified fermentation process being finalized by
several research groups that can make butanol from biomas as opposed to
needing high cost grain.  BP & Dupont are pursuing this technology in the
UK.  The beauty of butanol is that it has very similar characteristics to
typical gasoline; doesn't absorb much water, about 90% the energy content
per gallon as gasoline, high octane rating (I think 94 or so?) and can be
used within the existing pipeline-tank infrastructure without modification.
Currently only available as an industrial solvent derived from oil, butanol
will have to be made from any of the various biomass sources to be viable.

Whatever wins long term market acceptance I would rather make some
Midwestern farmer and his agro-industry marketing chain wealthy than keep
supplying oil dollars to nations and people that don't like us.

I don't think we will ever get away from oil entirely in our lifetime but we
can certainly change how much we get from where by using some of these

Bottom line, the market will determine...

Dan Nicoson

-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]On
Behalf Of Frederick Trient
Sent: Friday, August 25, 2006 2:26 PM
To: diy_efi at diy-efi.org
Subject: Re: [Diy_efi] Is E85 worth it?

This "pipeline" factor is new to me. Why can't ethanol be piped?
Could it be if pre-mixed with petro?

I don't see much mention in this thread of the geo-political
ramifications of using greater and greater amounts of ethanol. For
me, on balance, the upside is that less and less $ goes to petro
producing countries that turn around and funnel some of that wealth
into Islamic extremist organizations. Saudi Arabia and Iran are prime


On Aug 25, 2006, at 7:28 AM, Steve Ravet wrote
> Farming is petroleum intensive work, with diesel fuel for equipment,
> petroleum based fertilizers and pesticides.  Then add the fact that
> ethanol can't go in a pipeline and has to be hauled everywhere by
> truck.
> If you have to burn a gallon of diesel to make and transport a
> gallon of
> ethanol then it's not very "hydrocarbon effective" either.  E85 is
> about
> corporate welfare, and farming welfare queens.
> --steve

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