[FoRK] peak coal

Aaron Burt aaron at bavariati.org
Tue Oct 27 18:49:43 PDT 2009

On Tue, Oct 27, 2009 at 04:52:57PM -0700, Ken Ganshirt @ Yahoo wrote:

> It's interesting that even using horsey power has environmental overhead
> issues. Using draft horses requires that the production from about 40% of
> the tilled acreage be used for fuelling the horses.

Tha Wife is the expert on horse and cow nutrition - we have the books at
home, but that sounds a bit high.  Also depends on whether you can use
marginal land as pasture, and whether you count manure as fertilizer.

> (Would you guess that's about the same as you would need if you were
> going to use biofuel in the tractor?? Or are horses more efficient?
> Anyone know of a source for such figures?) 

I've seen (biased) studies that put horses and tractors even, or put horses
ahead, depending on how you count energy, which field->fuel technologies
are used and whose production figures you believe.  But as Eugen points
out, photosynthesis is not terribly efficient.

> One of the reasons oxen were so popular for early transportation of goods
> is that they can work with only grass for feed. Horses can live on grass
> but if you are going to work them they need grain (higher energy
> concentration).

Feed rationing is complicated.  But yes, oxen are great.  Simpler harness,
too - no big leather collar, no hames to bonk you in the head.

If we get to the point of producing PV arrays and high-capacity batteries
using renewable energy, we'll be home free.  "Plan B" does make for a great
hobby, though.

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