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From: amirza@silver.ucs.indiana.edu (anmar mirza)
Newsgroups: sci.energy,sci.electronics,sci.physics
Subject: Re: solar cells
Message-ID: <1990Dec31.171413.18138@bronze.ucs.indiana.edu>
Date: 31 Dec 90 17:14:13 GMT
References: <1990Dec17.190857.16559@engin.umich.edu> <1990Dec28.210436.10601@zoo.toronto.edu> <939@venice.SEDD.TRW.COM>
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In article <939@venice.SEDD.TRW.COM> ries@venice.sedd.trw.com (Marc Ries) writes:
>In article <1990Dec28.210436.10601@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
>->(1) Solar cells are expensive to make and don't last forever.  (Also, the
>->	production processes are not particularly "clean" and the more
>->	advanced cells are often hazardous wastes when they are retired.)
>   Yet, the prices are falling as we speak.  There is no reason why the pure
>      silicon-based PVs can not last "forever" -- there is nothing to break 
>      down within the cell itself.  It's true that creating PVs are not
This is true, the polycrystalline cells themselves do not degrade, and
it has been almost 40 years since they were first made. The amorphous
cells will degrade over time, but their manufacturing process is so
much simpler and cheaper to replace them every 10-20 years. Depends on
what you are trying to power. Also, amorphous cells are a lot less
energy intensive, and less polluting to make than polycrystalline
cells.
Coal burning plants, nuclear, wind, hydro, oil, none of our power
sources last forever, or even more than a generation, without some
type of overhaul.

>->(2) Extensive energy storage or extensive long-range power transmission --
>->	difficult and expensive either way -- is needed to cope with
>->	outages due to night and cloud.
These can all be overcome, there is no new technology needed to do
this, and with improvements on existing technologies efficiency goes
up. If a new technology comes along that is better, great.

>->(3) Solar energy is thinly spread and very large collecting areas
are needed
Well, since most areas on earth get at least 500 watts per meter
squared during peak, and we can easily tap 14% of that with photovoltaics,
and much much more (the exact percentage of efficiency of the La Luz
plants escapes me), I would say there is a flaw with your reasoning.
What is great about solar energy is that *everyone* can get some,
even if only to a limited degree, and don't knock it bub, you are 
powered by energy from the sun, where do you think your food comes
from?

>      PVs work in Alaska... Very large collecting surfaces are only needed for
>       the production of very high amounts of energy.  A typical home could be
>       powered by PVs covering the roof area alone.
As is true of most of the world. 
 
>->(4) Large-scale solar power seriously changes the heat balance of the
>->	surrounding area, so it is not completely clean.  In particular,
>->	desert areas normally reflect most sunlight back out into space,
>->	but when paved with solar cells, most of the energy is released
>->	as heat into the biosphere instead.
Where does the energy from your rooftop go? I would wager that should
solar become a very well utilized form of power, it would disrupt the
total biosphere less than any other form of energy, where do you think
your oil came from? The problem is not with the power source, but the
number of consumers of that power. Even nuclear would be safe if we
only had to have one small plant to satisfy the energy demands of the
entire world.


I like Marc's response to your post, he is saying that he is willing to
try this seemingly less harmful source of power before trying others that
are known to have deletarious effects.

Your post is common of the attitude many of the peoples of this
country. You already having it fail even before you have tried to make
it work. I am glad that there are some people who are working with it,
and having success.




--
Anmar Mirza   # If a product is good, # I speak only my   # Space, humans next
EMT-A         # they will stop making # opinions on these # goal in the race 
N9ISY (tech)  # it. Unless it is      # subjects, IU has  # for immortality.
Networks Tech.# designed to kill.     # it's own.         # --- me