[SGVLUG] OT Re: Should we use biofuels? Was ...Tom & his Prius....

[David Lawyer]

On Tue, Jul 25, 2006 at 12:20:56AM -0700, David Lawyer wrote:
> I searched for Pimentel and Leontief matrices and found nothing
> appropriate.  So I suspect that Pimentel hasn't done it right either
> and that his results may understate the energy content of ethanol.

I found a very relevant article which tried to estimate the error of
failure to use Leontief matrices for Photo-Voltaics.  It doesn't
mention "Leontief" but just calls it input-output analysis.  The
authors point to examples where just tracing the energy inputs back
one level (as has been done for ethanol) results in erroneous fossil
fuel energies that need to be increased by about 50%.

The article concludes that we don't know if photo-voltaics generate
any net energy or not.  It suggests that a way to roughly estimate the
embedded energy of a good would be to assume that it is directly
proportional to it's price.  I was about to suggest this method but others
came up with the same proposal  Using price (unsubsidized) results in
hybrids and bio-fuels failing to produce any net energy savings since
they cost (unsubsidized) more.

See the article on photo-voltaics by someone who teaches at the Naval
Postgraduate School at Monterey, CA.  It needs some polishing but I
think the gist of it is correct.

http://72.14.203.104/search?q=cache:bY84rPgOPNYJ:www.nps.navy.mil/drmi/WorkingPapers/DRMI%2520Working%2520Paper%252006-02.pdf+%22embodied+energy%22+united+states+bea&hl=en&gl=us&ct=clnk&cd=1&ie=UTF-8

			David Lawyer