Path: utzoo!mnetor!uunet!husc6!spdcc!eli
From: eli@spdcc.COM (Steve Elias)
Newsgroups: sci.misc
Subject: Re: efficiency / greenhouse effect / solar power satellites
Message-ID: <806@spdcc.COM>
Date: 8 Apr 88 15:29:56 GMT
References: <789@spdcc.COM> <758@xyzzy.UUCP>
Reply-To: eli@spdcc.COM (Steve Elias)
Organization: S.P. Dyer Computer Consulting, Cambridge MA
Lines: 66

In article <758@xyzzy.UUCP> throopw@xyzzy.UUCP (Wayne A. Throop) writes:
>>, >>> eli@spdcc.COM (Steve Elias)

>But the fact that SPS is more efficent thermally puts the figure back up
>quite a lot.  But I'm sure we can agree that we are talking at least a
>thousand times, and probably closer to ten thousand times, the current
>industrial activity.  And again, this much industrial activity will
>totally destroy the biosphere long before thermal effects become
>important.

	although it has been demonstrated that it would take thousands
	of times our present industrial activity to create power needs
	that equal the solar flux -- i believe that thermal considerations
	will become important long before that point; at a level !only!
	hundreds of times where we are now...  clearly, needs equal to 
	the solar flux would be disastrous.  i suspect we would see some
	major negative environmental effects before then.

>But again, thermal pollution is a very small factor in this, not
>particulary significant in the face of the other effects, and further,
>SPS would be a smaller thermal polluter than almost any alternative.

	thanks for all that info on biosphere feedback effects !
	perhaps SPS is less of a thermal polluter than some of the
	more 'conventional' power generation schemes.

	there seem to be a couple of arguments against my points about
	thermal pollution, especially with regards to SPS.

	1 -- thermal pollution is not important since power needs will never
	     approach levels of hundreds or of times present needs.  i 
	     understand that even hundreds of times present needs would not
	     be more than a few percent of solar flux.  i claim that such 
	     power needs are forseeable, if we manage to stick around.
	     (perhaps folks here would like to see me take a one way trip
	      to rec.arts.sf-lovers...)

	2 -- SPS is not as much of a thermal offender as some other power
	     sources.  perhaps i am being unfairly harsh on SPS -- most
	     current power sources could put us in a rather toasty boat
	     if we expanded them to hundreds of times their present capacity,
	     even those which don't produce CO2.  i think that SPS would be
	     a poor way to spend R&D $$.  lots should go towards generation
	     schemes which produce no CO2 and no thermal imbalance.

	     humankind has got to learn to leave less of a footprint on the
	     planet, as we continue to grow -- or we'll squish the earth one
	     way or another.

>> 	i still hope to locate Frank Drake's notes on this subject.
>
>I would be very, very interested.  I still don't beleive that thermal
>pollution is the most troublesome effect, and even if I did, I don't
>beleive that SPS is worse than, for example, ground-based solar power.
>So why Drake might single out SPS as environmentally dangerous is a
>mystery to me, one I'm currious to see a little more about.
	
	a friend has located the notes...  apparently there aren't any
	handy factors of ten to bolster my prejudice against SPS.  i'll
	see the notes myself this weekend, and will summarize interesting
	sections.  the notes are from a class i took in 1983...

	i don't think that Drake or myself would contend that SPS is thermally
	worse than ground based solar power...  

	bye!