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From: lindsay@gandalf.cs.cmu.edu (Donald Lindsay)
Newsgroups: sci.energy,sci.electronics,sci.physics
Subject: Re: solar cells
Message-ID: <11515@pt.cs.cmu.edu>
Date: 4 Jan 91 16:53:46 GMT
References: <1991Jan3.072059.20842@loop.uucp>
Organization: Carnegie-Mellon University, CS/RI
Lines: 29

In article <1991Jan3.072059.20842@loop.uucp> keithl@loop.uucp 
	(Keith Lofstrom;;;628-3645) writes:
>Most solar cells are made with processes that are similar to those
>used to make integrated circuits.  A big IC fab turns out on the
>order of a million wafers a year, and turns out tens of thousands of
>gallons of liquid toxic waste and hundreds of thousands of cubic feet
>of gaseous waste in the process.  

>Scaled to nuclear plant size, that's millions of
>gallons of waste per year for the same amount of power.

I detect a humongous assumption, namely, that cell fab and chip fab
use the same amount of processing per area.

Some ICs are built with more than 20 processing steps (ie layers).  I
can't imagine how a mass-market solar cell could be that intricate or
various.  Chips also have about three orders of magnitude more
pins/area. Chips also require the highest purity of materials, and
their yield depends on very stringent definitions of "working". Even
a reject solar cell is likely to worth using.

You are also making the big, fat assumption that those "most" solar
cells have anything to do with the way we will make things in the
future. Glad to hear you have such faith in technological progress.
The US government agreed with you: that's why they axed the solar R&D
funding, a decade-odd ago. I can't express politely what I think of
their foresight. Am I to think better of yours?
-- 
Don		D.C.Lindsay .. temporarily at Carnegie Mellon Robotics