Re: Solar-Thermal vs Photo-electric

From: daestrom (daestrom_at_NO_SPAM_HEREtwcny.rr.com)
Date: 09/02/04 

Date: Thu, 02 Sep 2004 00:23:36 GMT

"Rob Eldred" <nsmontassoc@yahoo.com> wrote in message
news:DjaZc.13945$ll6.3975@newssvr27.news.prodigy.com...
>
> "sanman" <manofsan@yahoo.com> wrote in message
> news:f144e162.0408311028.1bc4b170@posting.google.com...
> > Here's an interesting article:
> >
> > http://www.businessweek.com/magazine/content/04_36/b3898119_mz018.htm
> >
> > Photo-electric seems to lose a lot of the light energy sent its way,
> > which then becomes wasted heat. But solar-thermal seeks to convert
> > sunlight into heat in the first place, and provides double the
> > conversion efficiency.
> >
> > So is solar-thermal the better candidate for making solar power a
> > bigger part of our energy-production infrastructure?
> >
> > Should we focus more on solutions that convert heat into electricity,
> > since heat seems to be the universal raw garbage slop form of energy?
>
> Unfortunately this is all future think and many pieces need to fall into
> place before it becomes reality, if it ever does. Notice the many future
> tense comments in the article, "predicts that"," for that to happen",
"soon
> compete", "should get"," materials for the future", etc. By my
calculations,
> the 25KW power number is peak power at maximum sun. The average power for
> the 150 sq meter collector is about 9.5KW, remember the sun doesn't shine
at
> night or when cloudy. This number is based on an average insolation of
5KWH
> per day per sq. meter which is typical for the mid US and includes 30%
> efficiency. The per-watt projected prices for solar must include the fact
> that the sun is not available 100% of the time thus the peak power numbers
> are often very misleading and give a false impression of the true costs
and
> returns.

Using $/watt without a projected availability is ludicrous. And trying to
'average' a 25KW plant's cost as the equivalent of a 9.5KW plant is almost
as bad.

The $/watt, plant life *and* the projected availability *must* be known
before any sane economic analysis can be made. All too often some reporter,
or arm-chair analyst will focus on the cost per watt as if it *proves* some
great economic breakthrough in a form of energy production.

Without knowing the total up-front construction costs ($/watt), projected
availability (kwh/watt per year), the ongoing O&M costs, the fuel cost
(granted $0.00 for solar) and the design lifetime of the system, it is all
just nonsense. A production facility that costs $5/watt can be economically
viable if it can run 24/7. Or one that costs $0.75/watt might not be viable
if it runs only 700hours/year with a staff of 50 full-time engineering
people.

daestrom

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