🚀 go-pugleaf

In article <1992Aug5.163953.4087@sei.cmu.edu>, firth@sei.cmu.edu (Robert Firth) writes:

|> And, when you consider how much cheaper and more efficient a leaf is
|> than any man-made solar collector, the idea of replacing the one by
|> the other is a delicious irony.  Crazy Eddie engineering at its finest.

Cheaper, but hardly more efficient.  Photosynthesis, in the real world,
has an efficiency at most on the order of a few percent.  Most of the
energy is either of the wrong wavelengths, lost to inefficiencies in
the photosynthetic chain or in keeping the plant alive.  Then converting
the biomass to electricity loses 60+% of the energy.  PV cells are
much more efficient.

Consider:  a person needs only 150 watts of food (on average) to
live.  To collect this much solar energy would require an area less
than 1 m^2 (with diurnal and weather effects included).  Yet agriculture
requires > 1000 m^2 per person, even in the most land-efficient countries
(like China).

	Paul F. Dietz
	dietz@cs.rochester.edu