pokey@well.UUCP (Jef Poskanzer) (03/30/88)
Steve Elias is, as Jerry Pournelle put it, "not merely uninformed but
aggressively misinformed." This thermal pollution bullshit seems to recur
every few years. Here's an excerpt from a message of mine way back in 1983:
The Earth is currently receiving sunlight at the rate of 1.1e24 ergs/sec.
That is ten million gigaWatts. One million rectennas. As far as I know,
no-one is planning to build that many in the near future. Let's look at
a more reasonable number, say a thousand ten gigaWatt rectennas. How
much would this heat up the planet? To raise the temperature of the
world's oceans by one degree C takes 5.71e31 ergs. If you consider the
atmosphere alone, it takes about a thousand times less: 5.26e28 ergs.
In one year, a thousand rectennas would receive 3.15e23 ergs (plus a
bit because they are only 90% efficient). Thus in the long run, the
temperature of the oceans would rise by about 0.00000001 degrees per
year; in the short run, the atmosphere would heat up by 0.00001 degrees
per year. Are you still worried?
Complete with spelling errors, no extra charge. But that's only part of the
reason Steve is full of shit. As John Carr and others mentioned, most of the
inefficiencies in SPSs are off-planet. The conversion from microwaves to
electricity is extremely efficient. (Yes, 90%. Not 80%. Not 50%.) And the
physical structure of a rectenna is a coarse mesh -- it doesn't affect the
albedo (proportion of light reflected) of the land.
Now contrast that with ground-based solar, which Steve appears quite fond
of. The collectors are only 15%-20% efficient, but they have albedos of
close to 0 -- they are black. They absorb *all* the sunlight, turn 20%
into electricity, and emit the rest as heat. Since large-scale ground-based
solar would be built in the desert, it's even worse: the land it would
cover up is extremely light, with an albedo of around 0.8, so the 80%
of the sunlight that would otherwise have been reflected back into space
is instead absorbed.
So the question is: for a given electrical capacity X, how much extra energy
gets absorbed by the Earth? For SPS, the answer is simple: 1.1 X -- X itself
gets absorbed (eventually), and the 10% inefficiency in the collector gets
absorbed. For ground-based solar, you absorb X, you absorb 4 X for the
collector inefficiencies, and you get to discount X because that's how much
was previously being absorbed by the desert before you covered it over.
The result, for those of you who are arithmetic-impaired, is 4 X.
So, if you insist on being utterly paranoid and worrying about the thermal
balance of the Earth, you should be out there campaigning hard for SPS,
since by your own criteria it's 3.6 times better! DO YOU GET IT YET STEVE?
YOU'RE WRONG! YOU'RE A MORON! SHUT THE FUCK UP!
For the few reasonable people out there: the CO2-induced "greenhouse effect"
is very very different, and is indeed a serious problem. But of course
SPS wins there too.
---
Jef
Jef Poskanzer jef@lbl-rtsg.arpa ...well!pokey
Most people on this network wouldn't recognize
subtlety if it hit them on the head.eli@spdcc.COM (Steve Elias) (03/31/88)
In article <5564@well.UUCP> pokey@well.UUCP (Jef Poskanzer) writes: >Steve Elias is, as Jerry Pournelle put it, "not merely uninformed but >aggressively misinformed." This thermal pollution bullshit seems to recur speak for yourself, Jef. we don't need bullshit comments like this. it figures that you would quote Pournelle. you are both assholes. >reason Steve is full of shit. As John Carr and others mentioned, most of the >inefficiencies in SPSs are off-planet. The conversion from microwaves to >electricity is extremely efficient. (Yes, 90%. Not 80%. Not 50%.) And the efficiency has nothing to do with the problem of thermal pollution. >Now contrast that with ground-based solar, which Steve appears quite fond >of. i am fond of this? thanks for letting me know. be sure to keep me up to date on my beliefs. >So the question is: for a given electrical capacity X, how much extra energy >gets absorbed by the Earth? For SPS, the answer is simple: 1.1 X -- X itself snore >So, if you insist on being utterly paranoid and worrying about the thermal >balance of the Earth, you should be out there campaigning hard for SPS, >since by your own criteria it's 3.6 times better! DO YOU GET IT YET STEVE? >YOU'RE WRONG! YOU'RE A MORON! SHUT THE FUCK UP! i didn't come up with the theory myself, you unmitigated asshole. Frank Drake is not a moron. (i'm not either, Jefy). your obnoxious comments are not relevant to the debate. all energy produced by solar power satellites would not otherwise enter the earth/atmosphere system. so your silly arithmetic is pointless. if you had done your silly calculations properly, you would see that solar satellites are infinitely worse than most other energy sources. >For the few reasonable people out there: the CO2-induced "greenhouse effect" >is very very different, and is indeed a serious problem. But of course >SPS wins there too. jef -- you misunderstand my point completely. jfc and others out there apparently do not. and they are capable of civil discussion. get lost. take your silly arithmetic and silly 'one-f' and go eat some microwaves.
jfc@athena.mit.edu (John F Carr) (03/31/88)
In article <761@spdcc.COM> eli@spdcc.COM (Steve Elias) writes: >In article <5564@well.UUCP> pokey@well.UUCP (Jef Poskanzer) writes: ::Steve Elias is, as Jerry Pournelle put it, "not merely uninformed but ::aggressively misinformed." This thermal pollution bullshit seems to recur : : speak for yourself, Jef. we don't need bullshit comments like this. : it figures that you would quote Pournelle. you are both assholes. Would it be possible to save the name-calling for private email? Pournelle is an informed, intelligent source who supports such accusations as quoted above with facts. ::reason Steve is full of shit. As John Carr and others mentioned, most of the ::inefficiencies in SPSs are off-planet. The conversion from microwaves to ::electricity is extremely efficient. (Yes, 90%. Not 80%. Not 50%.) And the : : efficiency has nothing to do with the problem of thermal pollution. Efficiency has everything to do with thermal pollution. For a fixed power consumption, efficiency determines the amount of heat generated relative to useful power. A system with a 50% efficient converter would produce twice as much heat as a 90% converter (including the rest of the system, and the consumer). ::So the question is: for a given electrical capacity X, how much extra energy ::gets absorbed by the Earth? For SPS, the answer is simple: 1.1 X -- X itself : snore No wonder you have missed my point: you slept through it. As you have not argued for zero growth in consumption, I must assume that you think certain power sources are worse than others producing the same useful power. The only factor determining the waste heat produced by a system is its efficiency. SPS are among the most efficient power generation systems (counting the earth-based parts, which are the only ones relevant to thermal pollution). ::So, if you insist on being utterly paranoid and worrying about the thermal ::balance of the Earth, you should be out there campaigning hard for SPS, ::since by your own criteria it's 3.6 times better! DO YOU GET IT YET STEVE? ::YOU'RE WRONG! YOU'RE A MORON! SHUT THE FUCK UP! : : i didn't come up with the theory myself, you unmitigated asshole. : Frank Drake is not a moron. (i'm not either, Jefy). : your obnoxious comments are not relevant to the debate. all energy : produced by solar power satellites would not otherwise enter the : earth/atmosphere system. so your silly arithmetic is pointless. : if you had done your silly calculations properly, you would see that : solar satellites are infinitely worse than most other energy sources. If you are arguing that SPS are worse than earth-based systems capable of generating the same power you are wrong. If you are arguing against increasing our generating capacity you should say so. ::For the few reasonable people out there: the CO2-induced "greenhouse effect" ::is very very different, and is indeed a serious problem. But of course ::SPS wins there too. : : jef -- you misunderstand my point completely. jfc and others out : there apparently do not. and they are capable of civil discussion. For sources on the greenhouse effect I recommend the Feb 88 issue of Scientific American and an article in the science section of Tuesday's New York Times. My conclusions from these: the earth reacts to thermal pollution on a very short timescale (days to weeks). The timescale of the feedback by which an increase in temperature produces a runaway greenhouse effect is millions of years. On the other hand, the timescale for CO2 pollution to produce a greenhouse effect is very short. Adding heat will not raise the temperature noticeably until the rate of addition approaches the solar flux on the earth. Adding CO2 has already warmed the earth (the articles have numbers). John Carr "No one wants to make a terrible choice jfc@athena.mit.edu On the price of being free" -- Neil Peart
jwm@stdc.jhuapl.edu (James W. Meritt) (03/31/88)
In article <761@spdcc.COM> eli@spdcc.COM (Steve Elias) writes: >In article <5564@well.UUCP> pokey@well.UUCP (Jef Poskanzer) writes: >>reason Steve is full of shit. As John Carr and others mentioned, most of the >>inefficiencies in SPSs are off-planet. The conversion from microwaves to >>electricity is extremely efficient. (Yes, 90%. Not 80%. Not 50%.) And the > efficiency has nothing to do with the problem of thermal pollution. To the contrary, efficiency has a great deal to do with it, if you are talking about the heat produced where. As I recall from the original posting, one of the primary "efficiencies" discussed involved the absorption of the light in the first place. Everything absorbed will become heat, eventually, so that is not really an issue. The percent absorbed in the first place, however, IS. As given in the example, sand reflects light and solar panels do not (mostly). The reflected LIGHT goes back into space. Thus, solar panels trap energy into the earth/atmosphere system that would ordinarilly be immediately returned into space. This occurs no matter their ELECTRICAL efficiency ... in fact, it happens even if they are merely black painted wood. > all energy > produced by solar power satellites would not otherwise enter the > earth/atmosphere system. so your _____ arithmetic is pointless. > if you had done your _____ calculations properly, you would see that > solar satellites are infinitely worse than most other energy sources. Initial statement concerning energy entering the earth/atmosphere system is correct, unless it is running only while eclipsing the earth. The arithmetic, however, is not pointless. It demonstrated that: 1. We are very unlikely to produce sufficient energy to significantly directly increase the overall average temperature of the earth/sea/ atmosphere system. 2. Importing electrical energy directly (in the form of microwaves? skyhook-type LLLLOOOOOOONNNNNNNNNNNNGGGGGGGG extension cord?) would provide energy without the indirect thermal problems associated with on-site generation by any means. The waste heat associated with the generation of electricity by any means at any efficiency produces waste heat. SPS will produce this waste heat outside of the e/o/a system, other methods produce it inside the system. If you want the electricity (and I notice you are not willing to do without simply by the fact that you are reading this) you gotta do something about the inefficiencies of electrical generation. >>For the few reasonable people out there: the CO2-induced "greenhouse effect" >>is very very different, and is indeed a serious problem. But of course >>SPS wins there too. > jef -- you misunderstand my point completely. jfc and others out > there apparently do not. and they are capable of civil discussion. > get lost. take your silly arithmetic and silly 'one-f' and go > eat some microwaves. If the point is "thermal pollution is a problem", I concur that it is an interesting problem. As the arithmetic displays, however, it is not a hazardous problem except to those in the immediate vicinity of the power sites. (or an advantage, depending. There are some tropical fish and reptiles living in New York: seems they wound up in a power plant cooling pond, which was warmed up to tropical temperatures by the power plant. If it goes, they go.) Now for my major gripe with the general trend of this discussion. flaming, while it may satisfy your ego, does not advance your ideas. And you have a tendency to discredit yourself by an hominem (sp?) attacks. I really expected more. Do you notice something odd about the sentence containing "civil discussion" followed by the phrase "get lost", both followed by one containing the self-evaluated "silly" twice and an absurd suggestion? As a question, what do you estimate the electrical requirements of a planet to be that would produce a thermal problem to fit within the "dangerous" (which is?) region? Disclaimer: Individuals have opinions, organizations have policy. Therefore, these opinions are mine and not any organizations! Q.E.D. jwm@aplvax.jhuapl.edu 128.244.65.5
chris@mimsy.UUCP (Chris Torek) (04/11/88)
>In article <5564@well.UUCP> pokey@well.UUCP (Jef Poskanzer) writes: >>Steve Elias is, as Jerry Pournelle put it, "not merely uninformed but >>aggressively misinformed." This thermal pollution bullshit seems to recur In article <761@spdcc.COM> eli@spdcc.COM (Steve Elias) writes: > speak for yourself, Jef. we don't need bullshit comments like this. > it figures that you would quote Pournelle. you are both assholes. Sorry Steve, but Jef is right, even if he is offensive about it (and even if he does sharpen his incisors every morning :-) ). > efficiency has nothing to do with the problem of thermal pollution. Efficiency has *everything* to do with it---total system efficiency and thermodynamical equilibrium (if you prefer big words). >>So, if you insist on being utterly paranoid and worrying about the thermal >>balance of the Earth, you should be out there campaigning hard for SPS, >>since by your own criteria it's 3.6 times better! [namecalling deleted] > i didn't come up with the theory myself ... [more namecalling deleted] > [implication that] Frank Drake [first proposed it] ... all energy > produced by solar power satellites would not otherwise enter the > earth/atmosphere system. Not exactly, but close enough. The reason Jef is right and you are wrong, however, is that not all enegry that enters the earth/atmosphere system stays there. > so your silly arithmetic is pointless. Not so. Replacing a rainforest with a desert raises the albedo (reflectivity) of the region. This means that more of the energy that enters the earth/atmosphere system is reflected back out of earth/atmosphere system. In the same manner, replacing a desert with a solar collector array reduces the albedo of the region, meaning that more of the energy that enters the earth/atmosphere system stays there. In other words, we have various choices for producing more energy (assuming that we intend to produce more energy: this is a different argument altogether and is worthy of a separate flame war for me to mediate :-) ). In one of them (SPS), we throw more energy at the ecosystem from outside; in other (local solar power), we increase the energy retained within the ecosystem from that which already touches it. If you work out the numbers, one scheme results in approximately 1.1 joules retained for every joule we get to use; the other results in about 4 joules retained for every joule we get to use. There are no schemes that result in less than 1 joule retained per joule used, although there may be schemes that result in <1.1. -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163) Domain: chris@mimsy.umd.edu Path: uunet!mimsy!chris