[LINK] Solar cells

Karl Auer kauer at biplane.com.au
Sat Jan 20 15:55:54 AEDT 2007

> Fragile?     I haven't been able to find any useful information.

Solar panels are not fragile. They are not indestructible, but they are
certainly not fragile.

> Long-lasting?  No one really knows, and it must depend on the type.

BP Solar guarantee theirs for 25 years for power production,  3 years
for workmanship. Dunno what happens if workmanship problems stp them
producing power :-)

> 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.

This is a vexed question. I've found no conclusive answer, and both
sides of the argument make some very big assumptions.

> 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.

It costs about 15K per pole to get the grid on, and a decent solar power
system costs 30-50K. In many areas the grid is unreliable, noisy and
dirty. All (yes, all) the stories I've heard from people who don't like
their solar power systems boil down to the same basic problem: They
installed a system that was too small or too complicated.

> 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?  

Mostly yes. Depends on the angle of the panels and the heaviness of the
storm. Economically it is an insurance question, or as Glen suggested,
simple protective measures will reduce the chance of damage. Nothing is
proof positive against all eventualities - solar panels are bloody
tough, but heavy enough wind will take the panels and hard enough hail
will break them. Lightning striking the wrong spot will fry them.
Vandalism is also an issue for some sites.

The same sorts of arguments can be applied to any technology that is not
completely case hardened. Do we factor the risk of accident into the
"cost" of, say, a hybrid car? Probably we should. The Swiss were trying
for geothermal energy in Basel - and setting off earth tremors *3.5R!).
They've stopped trying now :-)

When people hear how much we paid for solar, they just shake their
heads, but the fundamental point is that when you factor all the costs
of other energy sources (pollution, global warming, whatever),
electrical energy is just way too cheap. Which breeds a culture where
energy is not valued, a culture that spends energy like, er, water :-)
Our solar panels etc don't make economic sense - but they do, we think,
make a different kind of sense.

Regards, K.

Karl Auer (kauer at biplane.com.au)                   +61-2-64957160 (h)
http://www.biplane.com.au/~kauer/                  +61-428-957160 (mob)

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