[SGVLUG] Especially for Tom & his Prius....

[David Lawyer]

On Tue, Jul 11, 2006 at 10:27:09AM -0700, Dustin Laurence wrote:
[snip]
> with.  From corn it doesn't so much because you get so little net energy
> production (some say negative, but I think it's modestly positive, like
> 1.3 or something).

More likely negative.  It was once estimated that for every calorie in
food, it takes about 10 calories of fossil fuels to create it.  This
claim was repeated in the recent video "End of Suburbia".  The people
that claim it's positive ignore the energy required to manufacture
farm machinery, etc.  To estimate this you need an input-output matrix
for the world economy.  

An example column of such a matrix (Leontief): What are the inputs for
say a ton of steel in terms of coke (from coal), electricity,
chromium, computers, etc.  An interesting question: Since it takes
human energy to make something, should that be counted too?  If a
person works at a steel mill (as I once did), does all the energy it
takes to keep that employee healthy and working count as input energy
to the production of steel?  What about that person's recreation and
vacation energy use?

This is really becoming OT!  I've thought about the above situation,
but don't have time right now to go into it.  Also, IO matrices are
fine but nobody has the data for them and such data depends on the
technology used which varies a with location and time.  I've seen
attempts at this in the 1970's and that was only because the US Gov't
paid for the research.  A few years ago I couldn't find any recent
research.  The math is easy but finding data is not so easy.

Newsweek claims that one saves energy by riding a bicycle but I'm not
so sure since the human engine is not as efficient as the internal
combustion one.  But I would like to find some estimates on the energy
ratio for food other than the 10:1 which is obviously a guesstimate.
Of course meat will be a lot higher that grains.

			David Lawyer