[LINK] Solar cells

[Stewart Fist]

Glen writes:
> 
> I'm not so sure about that. Large solar panels are expensive. But
> I'm increasingly impressed by the small ones -- the sort of thing
> that runs your garden lights or changes your phone.  I think
> solar is now at the stage where its superceeded technology is
> itself efficient enough to be useful.

Glen's Big vs, Little point is important

We can also ask, are they:

Useful?      Definitely Yes.
Cheap?       Probably No
Efficient?   Definitely not
Fragile?     I haven't been able to find any useful information.
Long-lasting?  No one really knows, and it must depend on the type.


The last time I looked the combined 'energy cost' of manufacturing
large-panel solar cells and the electrical storage unit to make them useful,
was marginally higher (according to some sources) than the energy they would
generate over a life-time.  Other sources said it was lower.

Either way, the margin is not too great if you are considering solar as an
alternative to conventional energy sources -- unless you've got no
alternative.

If you can bring in a power-cable from some distant grid, for a reasonable
multiple of the cost of a solar unit, it will probably be justified very
quickly.

Of course, it also depends on what the solar cell promoters mean by a
lifetime.  Are large panels of solar cells able to withstand the occasional
heavy hailstorm?  

Most sites just ignore this question, although one promotional site says:

"Most are tested for hail damage, but the reality is that hail tends to
glance off the module¹s surface because of the angle that most arrays are
installed at. However, given a strong enough impact, modules could break. If
a module is shattered or punctured, it would eventually fail due to water
getting into the solar cells and causing corrosion. "

After seeing the damage to tiled roofs in Sydney a few years ago, I don't
find that reassuring, and even less so when it comes to costing the energy
efficiency.

The collector-type systems which use curved metal mirrors to bounce the
energy back to smaller high-temperature silicon cells are protected against
hail but they require motors, etc. to track the sun.  Then they require
technicians on hand.

The claim that a solar panel can last 25 years, is also one that I'd take
with a grain of salt.  And, if we really are seeing rapid advancements in
the technology, then most installed today would be obsolete long before
this.

Has anyone got any trustworthy figures on costs, returns, etc in terms of
energy as well as money?



-- 
Stewart Fist, writer, journalist, film-maker
70 Middle Harbour Road, LINDFIELD, 2070, NSW, Australia
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