> A couple of interesting points: Brazil already has 3.6 million
pure
> ethanol driven vehicles on the road...
And they're turning the Amazon Basin into a wasteland at an alarming
rate. Maybe Jay has the figures to do the accounting on this.
Enough
"cellulosic biomass" -- typically, that means trees -- to generate
enough ethanol to replace a significant fraction of fuel protroleum
use is how many trees? I live in a generally woodland area of what
the industry would consider second-rate trees for any use but pulp.
And we're already seeing ecologically unsustainable clearcutting by
hungry small woodlot owners to feed megacorp buyers. A tree is
marketable if a semiautomated mill can cut a single grade C 2x4 out
of
it.
Most Ethanal is manufactured from agricultural crops such as sugar
cane, corn and wheat starch. Ethanol can be produced from trees but the
production costs are very high and have only been experimental. Brazil uses
sugar cane to produce most of its ethanol. Recent studies in Australia
suggest that ethanol would only be a viable option as a blend with
petroleum. Even so there are a number of issues that would need to be
resolved before general use. Firstly there are technical problems with
mixing ethanol and petroleum, secondly ethanol and ethanol blends lead to
less efficiency in current vehicles, however can be more efficient in
vehicles designed to operate only on pure ethanol fuels.
While there is a reduction in carbon monoxide and hydrocarbons from
vehicle emissions from cars using ethanol, as the original story points out,
there is a significant increase in other pollutants such as nitrogen oxides
(this leads to smog), and volatile organic compounds (some of which are
toxic).
I would expect an ethanol industry to promote massive clear cutting
of
"over-mature" and "inefficient" woodlands (read healthy, diverse
biome) with monoculture replanting of fast-growing plantation
species.
Feh.
Anybody have the numbers on acres of woods per supertanker-load of
crude equivalence?
Estimates in Australia on the total land that could support crops
suitable for ethanol production (crops based on wheat, sugar cane,
artichokes, cassava and sugar beat) have been put at 21 506 thousand
hectares. This would yield 22.05 million tonnes per year of raw material or
5 700 Megalites of Ethanol. Enough to supply 20% of Australia's fuel supply.
I've seen figures that suggest only 15% of current US consumption could be
supplied by Ethanol (based on agricultural crops).
This does not take into account other demands on land such as
competition from sheep and cattle farming, droughts, land fertility
problems, land degradation, etc.
Estimates costs in 1994 prices put the cost of ethanol production at
50 to 70 cents per litre. For ethanol to be profitable it has been
estimated by the Australian Institute of Petroleum that the cost of a barrel
of oil would have to be in the range of US$50-70.
At present oil prices it basically ain't a goer.
It would be fare better to concentrate on improving city design to
reduce the need for cars and trucks, and on improving engine design to
improve efficiency.
<<...>>
- Mike
--
Michael Spencer Nova Scotia, Canada
[EMAIL PROTECTED]
URL: http://www.mit.edu:8001/people/mspencer/home.html
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