Xref: utzoo talk.politics.misc:8774 sci.misc:1266 Path: utzoo!mnetor!uunet!husc6!bloom-beacon!mit-eddie!uw-beaver!cornell!rochester!udel!gatech!mcnc!rti!xyzzy!throopw From: throopw@xyzzy.UUCP (Wayne A. Throop) Newsgroups: talk.politics.misc,sci.misc Subject: Re: efficiency / greenhouse effect / solar power satellites Message-ID: <747@xyzzy.UUCP> Date: 5 Apr 88 19:48:06 GMT References: <22678@bbn.COM> <5564@well.UUCP> <761@spdcc.COM> <4195@bloom-beacon.MIT.EDU> <763@spdcc.COM> <2997@sfsup.UUCP> <768@spdcc.COM> <774@spdcc.COM> Organization: Data General, RTP NC. Lines: 35 > eli@spdcc.COM (Steve Elias) > my contention is that to meet a large increase in power demands with solar > power satellites will add something on the order of one percent or so to > the total energy flux that the earth receives. This is true iff the "increase in power demands" itself is about a percent of the total solar flux reaching earth. My personal feeling is that by the time people demand that much power to maintain their lifestyles, they had better be using that power primarily in space, and not on the earth. If not, I'd guess that earth would soon become an untenable place to live for anything much more complicated than lichen, whether or not thermal effects of that much power use are considered. Looking in tables and such I think that the current energy use by humans on earth is something like 6x10^18 cal/yr. The current solar flux reaching earth is something like 1x10^24 cal/yr. That is, if human energy consumption was totally supported by SPS, and doubles every 10 years, and none of this consumption moves to space, we would see 1 percent of solar flux delivered to earth from our SPS system in about 150 years. And in thinking about this, it is well to remember that the sun is, itself, about 3% variable, so that a small hicup in solar activity could swamp this effect for another 300 years at least. And, as I said to start out, we would have far, far more serious problems than thermal pollution if we had 100,000 times our current industrial activity, and if it (and we) were still confined to the earth. -- You can lead a yak to water but you can't teach an old dog to make a silk purse out of a pig in a poke. --- Opus -- Wayne Throop !mcnc!rti!xyzzy!throopw