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From: ries@venice.SEDD.TRW.COM (Marc Ries)
Newsgroups: sci.energy,sci.electronics,sci.physics
Subject: Re: solar cells
Message-ID: <939@venice.SEDD.TRW.COM>
Date: 29 Dec 90 02:39:06 GMT
References: <1990Dec17.190857.16559@engin.umich.edu> <1990Dec28.210436.10601@zoo.toronto.edu>
Reply-To: ries@venice.sedd.trw.com (Marc Ries)
Organization: TRW Systems Engineering & Development Division, Redondo Beach, CA
Lines: 43

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
      100% "clean", but then neither is any power generation source, from
      "hydro to nuclear."  It takes alot of "dirty" manufacturing to make
      computers -- will you stop using them?
->
->(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.
     New battery storage technologies are being made, along with other methods
       holding energy over time -- underground storage, etc.  There are even
       experimental "reverse" PVs that store energy during daylight and release
       it at night.
->
->(3) Solar energy is thinly spread and very large collecting areas are needed.
->
      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.
 
->(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.
      I would guess that there are very few deserts in the world *today* which
        are being threatened by reverse-desertification.  Beside, you don't
        have to cover the *whole* desert to power America: the stats have been
        hashed in this group previously.  

      The real question is that the sun provides the earth, via sun-light and
      invisible energy, many more times the amount of energy then the earth's
      population uses: what is the most benign, inherently-sane, way to process
      this incredible "free" energy?  Solar power in general is one of the
      "cleanest" ways to do that.  A passive solar house is a good example:
      No PV's, no Solar hot water, just sun-light....

      - Marc Ries