Re: impediments to gasohol

From: Uncle Al (UncleAl0_at_hate.spam.net)
Date: 06/14/04 

Date: Mon, 14 Jun 2004 10:50:00 -0700

"Wendy E. McCaughrin" wrote:
>
> What are the impediments to enriching the ethanol/gasoline mixture
> beyond the 10% mix called "gasohol"? Why can't the conventional
> internal-combustion engine burn a 50% mix -- or can it?

Thermodynamics says gasohol is bull***, and thermodynamics has the
only vote that counts.

http://www.news.cornell.edu/releases/Aug01/corn-basedethanol.hrs.html

Prof. David Pimentel of Cornell University calculated energy consumed
in growing corn, processing the grain, and distilling ethanol versus
the energy generated by its combustion. It requires 131,000 British
thermal units (Btus) to produce one gallon of ethanol, which yields
77,000 Btus of fuel energy. That's a 70% net energy *loss.* The
federal government paid tens of $billions of tax credits and subsidies
to ethanol producers like agri-giant Archer-Daniels-Midland.

Photosynthesis is very optimistically equivalent to producing 15
bbl/day-mile^2 of diesel fuel and ignoring all energy inputs.

http://www.hort.purdue.edu/newcrop/duke_energy/Saccharum_officinarum.html

Fat is so cheap that it makes biodiesel only costing two or three
times as much as the real thing. If there were any demand for fat as
fuel the price would skyrocket, as waste fat is well used as it is.

The most efficient uses of bio-fuel burn corn in a stove designed to
burn wood pellets. Heating with corn at $2.50 a bushel is the same as
using $(US)0.64/gallon propane. The best deal is to burn the anhydrous
ammonia fertilizer and not bother planting the corn. You must have a
way to condense the exhaust and store the nitric acid for resale, and
you have to keep it burning so it produces nitric acid and not merely
nitrogen oxides. That one makes money

Fuel cells convert about 50% of the Gibb's free energy of hydrogen
plus oxygen to water into electrical energy. Consider the losses in
both electricity conversion and electric-motor efficiency, around 20%,
to 'shaft energy' to move the car. The overall efficiency is 40%,
modestly better than gasoline or diesel engines. We would need to
generate around 370,000 tonnes of hydrogen daily, enough in liquid
form to fill 3500 Space Scuttles or as gas to fill 21,000 Hindenburg
airships each day.

About 640 gigawatts of continuously available electric power
generation must be added to the grid, more than doubling the total US
national average power capacity. The number of new power plants based
on present technologies is roughly 1300 natural gas fired
combined-cycle units generating 500 megawatts, or 800 800-megawatt
coal-fired units, 320 Hoover Dams (two gigawatts each), or 160
French-type nuclear clusters (four reactors, about one gigawatt each).

The average capital cost of building an electric power plant is
$1000/kilowatt, or an overall new investment exceeding $400 billion
(5% of the US gross domestic product). Distribution costs are extra.

Earth surface area required to produce 640 gigawatts would be 210,000
km^2 for wind and 32,000 km^2 for solar technologies. The former is
almost double the area of New York State, the latter about the size of
Denmark.

About 15% of US land area is under cultivation. Annual biomass energy
equivalent of crops is roughly 23 million gigawatt-hours, or about
2600 gigawatts of continuous power production. To add ananother 640
gigawatts of electrical power to produce hydrogen for transport would
require another 5% of overall land to undergo cultivation, an area
half again the area of Nevada. 

-- 
Uncle Al
http://www.mazepath.com/uncleal/
 (Toxic URL! Unsafe for children and most mammals)
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