Xref: utzoo talk.politics.misc:8569 sci.misc:1157 Path: utzoo!mnetor!uunet!husc6!think!bloom-beacon!athena.mit.edu!jfc From: jfc@athena.mit.edu (John F Carr) Newsgroups: talk.politics.misc,sci.misc Subject: Re: greenhouse effect Message-ID: <4056@bloom-beacon.MIT.EDU> Date: 26 Mar 88 03:10:21 GMT References: <34557@kestrel.ARPA> <2430@umd5.umd.edu> <2116@mit-amt.MEDIA.MIT.EDU> <22089@bbn.COM> <35092@kestrel.ARPA> <22285@bbn.COM> Sender: root@bloom-beacon.MIT.EDU Reply-To: jfc@athena.mit.edu (John F Carr) Distribution: na Organization: Massachusetts Institute of Technology Lines: 44 In article <22285@bbn.COM> eli@BBN.COM (Steve Elias) writes: :In article <35092@kestrel.ARPA> king@kestrel.ARPA (Dick King) writes: ::In article <22089@bbn.COM>, eli@bbn.com (Steve Elias) writes: :: : and solar power satellites would be even bigger thermal :: : offenders than solar cells on the ground. :: Actually no becuase the waste heat would be dissipated in space. : actually yes: waste heat would be dissipated both : in the atmosphere and on the ground. (microwave transmission). But the initial thermodynamic inefficiencies would be in space; there would be inefficiencies on the ground, but these would be far less than the 60-70% waste of thermal plants now (and large solar power generators are thermal, not photoelectric). : extrapolate if you like. my point stands: there are energy sources : which do not upset the thermal balance of the planet. that's it. But these are just interesting footnotes to the main problem, unless it can be demonstrated that they can provide for a large part of future energy consumption. : i'm talking about the greenhouse effect, not whatever your : darling power source might be. that particular example, : biomass, also has the benefit of using as much CO2 in the biomass : process as is produced when the natural gas burns. closed cycle. : (get some good chemistry dirt to tear this one apart, if you can:) Assume that various biomass methods are used their greatest extent. Excerpts from a book which I recently posted figure biomass to be capable of providing about 2% of our energy needs. So, at great cost we reduce CO2 production by 2%. (Plants also have an oxidation cycle, which they use at night to burn the stored up sugars produced by photosynthesis; but I doubt this is important.) On the other hand if we replace coal with nuclear we reduce CO2 by about 20% (since much of the energy produced by fossil-fuels is not used for electricity, but by vehicles). A 2% change to man-made CO2 is not a lot; a 20% change is. John Carr "No one wants to make a terrible choice jfc@athena.mit.edu On the price of being free" -- Neil Peart