In article ,
David Hansen writes:
On 27 Jan 2008 13:29:58 GMT someone who may be
(Andrew Gabriel) wrote this:-

For a few
people, energy payback might be a consideration, but photo-
voltaics really struggle to produce more energy during their
lifetime than they consume in manufacture,

It is a common claim, but still an incorrect one. It may have been
true in the 1970s, but that was a long time ago and engineering has
moved on since then.

Not much. In spite of much research, their efficiency has
only doubled in the ~50 years since they were invented, and
almost none of that was recently. Research now is tending to
look for alternative materials as no further headway was being
made with silicon. There are a few, but a big problem (literally)
is that you tend to need a lot of material to make large receptors.
Whilst silicon is cheap and in plentyful supply, it's just the
processing of it into sufficient purity which is expensive. For
anything else that turns out to work well, it's unlikely there
will be the volumes of raw materials available in the first place,
making them more expensive before you even start with the
processing of it into sufficient purity.

It is some sort of step function improvement in efficiency or
reduction production cost which is needed to make photovoltaics
more viable, but that's just not shown up yet, although there is
much research looking for it.

--
Andrew Gabriel
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