Re: Cellulosic Ethanol

From: daestrom (daestrom_at_NO_SPAM_HEREtwcny.rr.com)
Date: 08/23/04 

Date: Mon, 23 Aug 2004 15:14:20 GMT

"Robert" <RB@..> wrote in message
news:542ji051371677jjl2b2755g7cp7nq1eta@4ax.com...
> On Sun, 22 Aug 2004 18:51:29 -0500, "Stephen Sprunk" <stephen@sprunk.org>
> wrote:
>
> >"Robert" <RB@..> wrote in message
> >news:0b9ii0tirk9kfgmk8782n3defct2gda651@4ax.com...
> >> On 22 Aug 2004 06:01:38 -0700, bri1600bv@hotmail.com (brianb) wrote:
> >>>http://news.uns.purdue.edu/html4ever/2004/040628.Ho.ethanol.html
> >>
> >> This sounds very promising but until we know the overall amount of
> >> energy used in the manufactuiring process, it is hard to really
> >> comment quantitatively.
> >
> >According to ANL and the USDA, current ethanol production yields about
35%
> >more energy than it consumes. This process should improve that to 89%.
> >Assuming the new yeast strain adds no significant costs to the refining
> >process, that means ethanol pump prices should drop 40% or so --
approaching
> >the price of unleaded.
> >
> >Also, since this new strain can process "waste" crops that existing
yeasts
> >cannot, that should logically contribute to lower source fuel prices and
> >correspondingly lower refined ethanol prices. I have no clue where to
get
> >data to support this, however.
> >
> >> Even with such high yields, when one takes into account the amount of
> >> solar energy used in producing usable agricultural waste, the total
area
> >> of land needed to replace oil is quite prohibitive.
> >
> >How much land area do we waste by paying farmers not to work or by
throwing
> >out crops that don't get to market before they perish? How much land
area
> >is completely idled because it would cost more to farm it than the
possible
> >revenue?
> >
> >1 acre produces about 137 bushels (3.8t) of corn, which can be refined
into
> >383.6 gallons (9.13bbl) of Ethanol. We currently import about 4.4
billion
> >barrels of oil per year; about 45% of that goes to motor fuels. Doing
the
> >math, we'd need 217 million acres (339,000sqmi) of source crops to
replace
> >gasoline as a motor fuel using current ethanol refining methods. That
drops
> >to 155 million acres (242,000sqmi) with the new yeasts, and presumably
will
> >continue to decrease as more effective techniques are found.
>
> I think you are being over optimistic here.
> You would certainly need a great deal of fertilizer and water to get
yields
> anything like that generally.
>
> There is also a problem in that the 'waste' that will converted to ethanol
> would normanlly plat\y a large part in maintaining soil fertility.
>
> I think your scheme will end up in large scale desert.
>

So, a question. When producing ethanol in this manner, what is currently
being done with the leftover 'mash'? Seems like the remaining matter would
be rich in nutrients from the incoming feed stock and could be recycled back
out onto the fields. After all, the only real thing we need to remove
permanently from the field is ethanol which is just carbon, hydrogen and
oxygen. Plants get that from CO2 and H2O and sunshine.

Unlike food products that remove a variety of nutrients from the land that
have to be replenished with crop-rotation and/or expensive fertilizers, it
seems to me that ethanol crops could be sustained indefinitely just using
the byproducts of the ethanol production.

daestrom

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