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jonk
Deinonychus
Joined: Nov 18, 2007
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 Posted: Sun Feb 17, 2008 5:04 pm Post subject: |
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| Alexey wrote: | | May be it is possible to ... invent a catalyst which will allow to conduct nuclear fission at room temperature. |
I think you mean fusion, as in cold fusion. Fission works just fine at room temperatures.
I've been closely following cold fusion discussions from a physicist point of view. The important physical laws and how they might apply to cold fusion are pretty well understood and, to be honest, were pretty well understood by the end of the 1950's. Nothing new has arrived that I'm aware of that changes the possibilities here. Not even suggestions of spin-2 bosons in superconductivity. It simply isn't in our near future -- near enough to make any difference at all in what lies ahead.
Physicists never bought into the idea, even at the beginning. The idea of cold fusion was cold dead in the physics community for a long time. Cold fusion caught the attention of chemists who, I have to say, would be pretty happy as a group to see the physics community with a bit of a bloodied nose. If you have any question about that emotional desire, just nine months after the announcement from Fleischmann and Pons, and in preparation for the annual meeting of the ACS, the physicists were actually barred from presenting there. The chemist community had come together on this subject and didn't want to hear dissenting voices, most especially _informed_ dissenting opinions.
Nothing much of real consequence has happened since to change the predictions about this. And in no way is it going to happen in time to make any difference, even if I'm wrong about the possibilities.
Jon
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Say what you will about the sweet mystery of unquestioning faith. I consider a capacity for it terrifying. [Kurt Vonnegut, Jr.]
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jonk
Deinonychus
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| Posted: Sun Feb 17, 2008 5:15 pm Post subject: |
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| Alexey wrote: | | It is very hard to have liquid hydrogen in a car - it is extremly cold and volatile. Compressed hydrogen is too penetrative and flammable. May be, some hydrides will help. |
The last column in the following chart represents the H2 portion of the available energy. Obviously, for hydrogen, the last two columns are identical since 100% of hydrogen's energy is hydrogen. In the case of the carbon based fuels, hydrogen is only one part of the total energy from burning with O2.
| Code: | Fuel Energy Comparison
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MJ/kg Total MJ/liter H2 MJ/liter
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H2, 20K cryogenic 120 8.4 8.4
H2, 150K cryogenic 120 3.5 3.5
H2, 5000 psi, ambient 120 2.75 2.75
H2, 3600 psi, ambient 120 2.0 2.0
Methane 50 21.0 12.6
Ethane 47.5 23.7 12.0
Propane 46.4 22.8 10.6
Gasoline 44.4 31.1 13.2
Ethanol 26.8 21.2 12.3
Methanol 19.9 15.8 11.9 |
This chart below is also interesting:
| Code: | Energy Density Chart
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MJ/kg MJ/liter
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Batteries 1 1
Pressurized H2 2 2
Hydrides 5 4
Liquid/20K-cryo-H2 8 8
Gasoline 38 27 |
It shows clearly the difficulty we face in replacing gasoline for vehicles. Carbon is very effective at helping to pack hydrogen into smaller containers and it provides its own source of energy, as well. It is tough to beat.
I don't have much hope, for the above reasons, plus all the reasons I've mentioned earlier about the massive changes we'd need to make in terms of just producing H2, that hydrogen will be of any material help to us. The production of hydrogen will cost us dearly in releasing CO2 (steam reforming) or else dearly in proliferating nukes around the world. The USE of hydrogen is every bit as problematic, as well. As the above charts show.
| Alexey wrote: | Another good variant is ethanol but it is expensive and drinkable  . |
The way it is being produced in the US is by diverting a food product that is already required en masse to feed our livestock for meat as well as for human consumption towards fuel production. And it is not ever going to be done on a scale that will make a serious difference. Do the calculations. It doesn't pan. In the US, it's all just politics and money and no reality.
Jon
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Say what you will about the sweet mystery of unquestioning faith. I consider a capacity for it terrifying. [Kurt Vonnegut, Jr.]
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ouinon
chemical reaction
Joined: Jul 11, 2007
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| Posted: Sun Feb 17, 2008 5:50 pm Post subject: |
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Wasn't there some idea of setting up solar panels/"batteries/energy captors in orbit around earth, with some kind of fuel-cheap "lift"/system for transferring the solar energy to earth. That is to say i read it in some supposedly reasonably researched sci-fi a couple of years ago.
Re; apparently total disaster facing us, people have been predicting the catastrophic end of the world for thousands of years now, and every time it turns out they were wrong, AND that they completely failed to imagine/include the most important developments of the next hundred years of their time.
It does look like space colonisation would be a good idea while still can, to spread "eggs", that is to say should do it now. Though if THAT is feasible, i don't see why can't be done on earth like space ship. 
I read that to stop, or even significantly limit use of fossil fuels at this point, with nuclear ( and green) so inefficient and small scale, is a bad idea, as it might destabilise economic systems to point of collapse, whereas fossil fuels allow a certain level of technology which may enable/encourage the kind of inventivity in science and technology which is required to come up with original solutions, rather than cut-backs which would concentrate ( inevitably) on short term goals.
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jonk
Deinonychus
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| Posted: Sun Feb 17, 2008 7:09 pm Post subject: |
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| ouinon wrote: | | Re; apparently total disaster facing us, people have been predicting the catastrophic end of the world for thousands of years now, and every time it turns out they were wrong, AND that they completely failed to imagine/include the most important developments of the next hundred years of their time. |
First off, this is a subject (global warming) that I've been involved in for more than 20 years now. I am a reviewer on climate science papers, as well. I know the subject a bit.
If you would care to cite specifics, rather than just hand wave about prognosticators, I'll deal with each in turn and explain why it doesn't apply here. But hand-waving ignorance doesn't cut it with me. I've been quite specific above. Deal with the facts if you wish to challenge.
Jon
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Say what you will about the sweet mystery of unquestioning faith. I consider a capacity for it terrifying. [Kurt Vonnegut, Jr.]
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Alexey
Blue Jay
Joined: Jan 25, 2008
Posts: 82
Location: Moscow, Russia
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| Posted: Mon Feb 18, 2008 2:46 am Post subject: |
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| jonk wrote: | | I think you mean fusion, as in cold fusion. Fission works just fine at room temperatures. |
Of course, I mean cold fusion (aka "cold thermonuclear synthesis").
| Quote: | | I've been closely following cold fusion discussions from a physicist point of view. The important physical laws and how they might apply to cold fusion are pretty well understood and, to be honest, were pretty well understood by the end of the 1950's. |
Laws of quantum mechanics were discovered more than 70 years ago, but chemistry still develops and definetly using empirical ways of searching new catalysts. I see nothing wrong in searching catalysts for decreasing the activation energy of nuclear fusion process.
| Quote: | | Cold fusion caught the attention of chemists who, I have to say, would be pretty happy as a group to see the physics community with a bit of a bloodied nose. |
But a lot of research fields of physics are the parts of chemistry too: e.g. thermodynamics, quantum mechanics, statistical physics. Physics now are often going into metaphysics, e.g. with general relativity theory, quarks and strings theory, which are hardly applicable. |
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jonk
Deinonychus
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| Posted: Mon Feb 18, 2008 2:54 am Post subject: |
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| Alexey wrote: | | jonk wrote: | | I think you mean fusion, as in cold fusion. Fission works just fine at room temperatures. |
Of course, I mean cold fusion |
Understood. I saw fission and figured out what was probably meant.
So far, no more than another "polywater" disaster for chemists. That was yet another time a physicist had to come in from the outside and point out the obvious to chemists.
I've periodically gone back to check up to see if anything notable has happened since. Nothing, yet. Can you point me to at least two recent peer-reviewed papers that would indicate otherwise?
Jon
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Say what you will about the sweet mystery of unquestioning faith. I consider a capacity for it terrifying. [Kurt Vonnegut, Jr.]
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Alexey
Blue Jay
Joined: Jan 25, 2008
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Location: Moscow, Russia
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| Posted: Mon Feb 18, 2008 5:36 am Post subject: |
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| jonk wrote: | | So far, no more than another "polywater" disaster for chemists. That was yet another time a physicist had to come in from the outside and point out the obvious to chemists. |
I agree that current messages about cold fusion are not reliable. But the idea of catalyst is right - e.g. fusion in the core of Sun is catalytic process using 12-C as catalyst; of course, temperature and pressures are too high for reproduction in the lab. May be, we will have to combine magnetic traps and catalysts for building fusion reactor.
| jonk wrote: | | The production of hydrogen will cost us dearly in releasing CO2 (steam reforming) or else dearly in proliferating nukes around the world. The USE of hydrogen is every bit as problematic, as well. As the above charts show. |
I agree, that hydrocarbon fuels are hard to replace and know that now hydrogen=hydrocarbons. that I think, that mass hydrogen car is not very realistic thing. So, more obvious is another way - use ethanol or gasoline cars for little towns and Soviet type mass transit systems for big cities. May be, electrocars will be nice thing too. |
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jonk
Deinonychus
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| Posted: Mon Feb 18, 2008 6:28 am Post subject: |
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| Alexey wrote: | | jonk wrote: | | The production of hydrogen will cost us dearly in releasing CO2 (steam reforming) or else dearly in proliferating nukes around the world. The USE of hydrogen is every bit as problematic, as well. As the above charts show. |
I agree, that hydrocarbon fuels are hard to replace and know that now hydrogen=hydrocarbons. that I think, that mass hydrogen car is not very realistic thing. So, more obvious is another way - use ethanol or gasoline cars for little towns and Soviet type mass transit systems for big cities. May be, electrocars will be nice thing too. |
I haven't taken the time to gain a comprehensive view by performing the necessary surveys, reading and understanding the fuller details, and then deducing and applying the equations necessary to compute accurate estimates. I will, because this is too common a political issue. But the narrower view I have right now informs me that ethanol isn't even close to a possible answer for cars now and I don't even think it is likely to be a very effective _part_ of a collection of actions.
The nub of the problem I see comes down to plant respiration and I do NOT see how it can be overcome, but I need to study more about ethanol production options to know for sure. What I do know about respiration issues seems to fatally injure the idea as a solution, but it is possible that someone has considered it and disposed of the problem in some way I cannot now see. So I'll have to reserve final judgment until I get some time to fill in details I lack. But I'm not at all convinced by the mere suggestion of it, that's for sure.
Electrocars are no solution, at all. That's a subject I'm more positive about. I've already written a little about two completely different and very large problems in earlier posts on this thread, but you need to fully appreciate what I wrote there to get the picture clearly in mind. There are other problems which are probably just as large, too, that I didn't mention. Electrocars are not, nor will they ever be viable on a civilization wide basis nor will they be a part of the solution to the central problems we face. In fact, they would make it far worse than ever before, if we actually did use them in any significant way.
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Some things that will help will be if people will stop importing and learn how to live with the nearby resources they have and, if they don't have enough, move permanently and forever away from there. I live in an area where oranges cannot grow. I should not eat oranges, as they must be imported from at least 1000 miles away or more. Apples are everywhere. I should eat those. Etc. Import as little as possible and if that can't be brought down to a small percent of what is used in practice, then change the practices or move.
Not to brag, because it's only that I'm too lucky for my own good and not because I'm smart, I produce almost everything I need on my property to live here. I already get all my water requirements from the land -- no imported water, even from a small pipe. Almost all the food I need is grown here. I chop wood from the land for heat, when needed, and have learned to enjoy a home with the temperature in the mid 50's F to save my poor back some excess pain. I have chickens which eat the insects here and lay eggs, fruit trees and nut trees, etc. I import electricity/energy and I'm considering how I might alter that, too, in a sustainable way. I'm sure I will continue to import things like nails, hammers, replacement parts and so on. But I think I can learn to keep my consumption to a minimum and can exchange excess supplies I have, for them. A single goat or two is a tremendous boon (don't have one, yet) in providing milk, cheese, and butter. This is the kind of thing I'm talking about in terms of thinking local -- almost down to the home itself. But in reality, it will have to be small community efforts for most folks who aren't as lucky as I've accidentally been.
Jon
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Say what you will about the sweet mystery of unquestioning faith. I consider a capacity for it terrifying. [Kurt Vonnegut, Jr.]
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ouinon
chemical reaction
Joined: Jul 11, 2007
Posts: 3122
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| Posted: Mon Feb 18, 2008 7:45 am Post subject: |
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| jonk wrote: | | ouinon wrote: | | Re; apparently total disaster facing us, people have been predicting the catastrophic end of the world for thousands of years now, and every time it turns out they were wrong, AND that they completely failed to imagine/include the most important developments of the next hundred years of their time. |
First off, this is a subject (global warming) that I've been involved in for more than 20 years now. I am a reviewer on climate science papers, as well. I know the subject a bit. If you would care to cite specifics, rather than just hand wave about prognosticators, I'll deal with each in turn and explain why it doesn't apply here. But hand-waving ignorance doesn't cut it with me. I've been quite specific above. Deal with the facts if you wish to challenge. |
The reason i posted that particular remark was not intended as an attack on your figures, which i don't, as you pointed out, know anything about, so much as in an effort to overcome the kind of fear which more often than not follows on from that kind of presentation of "facts", which more often than not leads to more destructive behaviour, more paralysis of will, more "i don't care anyway"reactions, more feelings of hopelessness and despair which are far from being the best ways to approach the future or find solutions.
Fear very often produces even more of the behaviour which caused the problem in the first place. I think it is important, VERY important, to remember that NOONE has so far been right about the end of the world/disaster/catastrophe. That is all.
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jonk
Deinonychus
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| Posted: Mon Feb 18, 2008 3:12 pm Post subject: |
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| ouinon wrote: | | jonk wrote: | | ouinon wrote: | | Re; apparently total disaster facing us, people have been predicting the catastrophic end of the world for thousands of years now, and every time it turns out they were wrong, AND that they completely failed to imagine/include the most important developments of the next hundred years of their time. |
First off, this is a subject (global warming) that I've been involved in for more than 20 years now. I am a reviewer on climate science papers, as well. I know the subject a bit. If you would care to cite specifics, rather than just hand wave about prognosticators, I'll deal with each in turn and explain why it doesn't apply here. But hand-waving ignorance doesn't cut it with me. I've been quite specific above. Deal with the facts if you wish to challenge. |
The reason i posted that particular remark was not intended as an attack on your figures, which i don't, as you pointed out, know anything about, |
I didn't mean to point out that you didn't know anything, because I cannot know what you might now until you say so, but instead to challenge you to present what you know. Comments as you made can be taken in several ways, but I couldn't see any value at all in writing the way you did.
| Quote: | | so much as in an effort to overcome the kind of fear which more often than not follows on from that kind of presentation of "facts", which more often than not leads to more destructive behaviour, more paralysis of will, more "i don't care anyway"reactions, more feelings of hopelessness and despair which are far from being the best ways to approach the future or find solutions. |
That is a very good point and I should have said something towards it, earlier, so I'm glad you now bring it up. But even reading it now, and reading what you wrote earlier, it seems to me that the earlier statement could not have possibly had the effect you now say you desired. Worse, what you said before casts such terrible disrespect, without cause, towards modern science which has instead been so very successful and consistently incremental in producing tentative knowledge about the world. But I will drop it and focus here on our agreement on this point.
There are two directions of profound changes that might take place in someone who is informed about the difficulties ahead and able to consider them in their totality can take the situation we face. One is towards action. One is towards inaction, by just giving up. The latter is a sure path to disaster.
I used to fly 1000 miles round trip every week. I'd leave Monday and come back Thursday. I did this for almost two years, while I was working on submarine tracking for a military contractor. In getting to the airport in time for my flight (I flew down with someone else), I would too often wake up very late. The drive was long, the airport busy, etc. If I didn't have X time, I could not get there in time. I would wake up late on these times, see the time and get moving fast. Becky would tell me, "No way, Jon. You are going to have to take a later flight." I would say, "No. I have to at least try make it. No matter what."
I never missed a flight. Not once. I did have the experience on several occasions of getting to the airport, dropping my car into the closest (most expensive) spot, literally running as fast as I could to the waiting area for the flight, see no one there waiting and the airplane just beginning to break the walkway to it to start moving on the tarmac, and yell as I ran by to the attendant to let the pilot know I was coming down the gangway as I flew by towards the plane. I would get that close to missing the plane. But I never missed a flight.
Because I tried and didn't give up.
I have no control over the reaction of others. But what I think is important is that people become informed about the situation, as accurately as is possible. What they do with that information must be their own business, as I have no powers over them and I'm no dictator of the world and cannot hold a gun to their heads. But what I can work to do is to inform and to show how one can learn how to develop the skills necessary to start making informed decisions of their own without relying upon the authority of others. I want informed disagreement. In fact, since I currently don't see any easy way out and since I think, sadly, that people on a large scale are basically lazy unless their pants are on fire, I want folks who are informed to smash me in the nose about some really good solutions I can't see and make me feel stupid for not seeing them. I want that, badly.
For me, it just motivates me all the harder to become more broadly informed, and in more detail. I've studied everything from stratospheric chemistry to biological island effects to plant respiration to our cryosphere, because of that drive to get a fuller picture so that I can see more clearly what the situation really is, for myself. 20 years of working at this, so far, and I spend time on it most every single day. And there is so much more out there I cannot keep up with. I'm looking for the path. But no, in no way do I ever feel like giving up. (By the way, I started out with this because I was asked to design a cheaper yet accurate Dobson meter. Later, as I became more informed, I found myself interested in learning more details just because I like to learn, not driven by worry of any kind. My opinion was that there was not going to be any real problems for many centuries at that time and that people would have plenty of time to come to grips.)
| Quote: | | Fear very often produces even more of the behaviour which caused the problem in the first place. I think it is important, VERY important, to remember that NOONE has so far been right about the end of the world/disaster/catastrophe. That is all. |
Well, there you go again. I say stay focused on becoming informed. And I take it quite personally the lumping of scientists with sandwich sign wearers in public streets. There is quite a difference you are not granting.
Jon
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Say what you will about the sweet mystery of unquestioning faith. I consider a capacity for it terrifying. [Kurt Vonnegut, Jr.]
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ouinon
chemical reaction
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| Posted: Mon Feb 18, 2008 7:28 pm Post subject: |
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jonk, i'm trying to post a reply to this but every time i try for real it won't post. will try again later. seems to be to do with how long i spend on reply!!
umm; was to say that i used to believe wholeheartedly in the organic walking etc thing. but am bit disabused, like an ex catholic to organised religion, as learned about the sandwich boarding going on, fear fueling sales of million dollar disaster containment schemes etc.
lomberg is my frame of ref; is that foolish?
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pbcoll
Phoenix
Joined: Feb 15, 2007
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Location: England
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| Posted: Mon Feb 18, 2008 7:57 pm Post subject: |
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Excellent posts, jonk, it's always good to read a rational discussion of issues that tend to degenerate into mindless slogans.
I don't think that, given the rising costs of fossil fuels, there is a realistic alternative to increased use of nuclear fission. 'Green' energies are either clearly insufficient (solar, wind, tidal) or a total con (ethanol, which is just corporate welfare for US agribusiness). Fusion is a completely pie-in-the-sky option right now (to quote a lecturer of mine, 'it's the energy source of the future and always will be'). Hydrogen has, among other problems, that since it is a highly explosive gas there is as of now no practical way of it replacing gasoline, even if it could be produced cheaply in sufficient amounts.
Someone asked about the difference between fusion and fission: fission is breaking apart uranium or plutonium atoms, fusion is fusing hydrogen atoms together to produce helium atoms. Both processes release energy, but fusion requires conditions such that using it as an energy source is currently beyond our technical capabilities, and will remain so for the foreseeable future.
What really annoys me are biofuels - you know, it doesn't seem exactly brilliant to me to cut down the rainforest and starve the world's poor to produce fuels that do not, in fact, reduce CO2 emissions.
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I am the steppenwolf that never learned to dance. (Sedaka) |
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jonk
Deinonychus
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Posts: 329
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| Posted: Mon Feb 18, 2008 8:32 pm Post subject: |
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| ouinon wrote: | | jonk, i'm trying to post a reply to this but every time i try for real it won't post. |
I have problems, too. Different, some of them, due to the stupid laptop's "mouse pad" which is a disaster to even have present. (I like the IBM 'stick' lots better.) I just brush even ever so gently as I type and the mouse cursor takes me somewhere else and if I then type "backspace" the whole post goes "boom!" and often cannot be recovered. Lost hours of typing, in that way. Nasty. Doesn't happen on the desktop because when I type my mouse is 12" away from my hands!
| ouinon wrote: | | will try again later. |
I'm just so sorry it happened, at all. I hate it when it happens to me and I can definitely sympathize with you.
| ouinon wrote: | | seems to be to do with how long i spend on reply!! |
Murphy's law? 
| ouinon wrote: | | umm; was to say that i used to believe wholeheartedly in the organic walking etc thing. |
I just think we need to start learning how to de-globalize some of what we do. I mean, shipping raw materials half way 'round the globe to have value added by labor, then half way back 'round the globe to be 'consumed', with all of the associated packing and unpacking and storage and various transportation systems used throughout the process (shipping, air, truck, train, you name it...), well there is a LOT of energy packed up into even the simplest items that way.
Some, we pretty much need. Nails and screws, for example, though some things we could learn to "peg" together, instead. Some, we pretty much want desperately as a convenience. Toilet paper comes to mind, there! And perhaps the mass production of toilet paper at a central site makes more sense, coupled to distribution costs, than does distributing the manufacturing sites and having less distribution involved. (I've not tried to do the calcs on that.) And even that may depend on geographies of local areas. So it's not always the same decision everywhere.
Some, we could learn to live without. Oranges is my stock example for that. I like them a lot. Limes, too. But they don't grow here and I would definitely suggest that people in my local area learn to live without them. They are not needed to live. And we shouldn't, except perhaps in rare celebrations of some kind or for some very specific medical conditions that I cannot imagine exist right now, import them. Too much energy, too little return for it.
| ouinon wrote: | but am bit disabused, like an ex catholic to organised religion, as learned about the sandwich boarding going on, fear fueling sales of million dollar disaster containment schemes etc.
lomberg is my frame of ref; is that foolish? |
Yes, it is quite foolish. Bjørn Lomborg (I think you mispelled the name) is no panacea for your information on the subject of global warming. No one person is, and this most particularly goes for Lomborg. There is a saying you might as well learn like a mantra -- 'If you are willing to be selective about the facts you consider, you could quite reasonably conclude that the world is flat.' Memorize this, tatoo it to your arm, burn it into your flesh.
Best thing for you to do is select your questions carefully, the ones you believe make the most sense to you in making your points. I will understand that you haven't researched these things and that you are just bringing up points to see if there is something I can add to provide a fuller view for you. And I will try and do that, where I can, or refer you to the work of others where that is appropriate. I know some things well enough to do calculations that will pan out accurately in terms of prediction as well as explanation. The physics of radiation and absorption, molecular vibration modes, and so on, in particular. I often know where to go for some good summaries. I also can contact lead scientists on any subject area and get their responses for you, if that will help, too.
Of course, that will mean you have to work for your opinion. If all you want to do is pre-select someone you wish to be your sole guru on this subject and just claim they are right about everything, knowing nothing yourself, then all we are going to do is make each other angry. Might as well avoid all that and just stop here.
Jon
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Say what you will about the sweet mystery of unquestioning faith. I consider a capacity for it terrifying. [Kurt Vonnegut, Jr.]
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jonk
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| Posted: Mon Feb 18, 2008 9:31 pm Post subject: |
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| pbcoll wrote: | | Excellent posts, jonk, it's always good to read a rational discussion of issues that tend to degenerate into mindless slogans. |
Thanks.
| pbcoll wrote: | | I don't think that, given the rising costs of fossil fuels, there is a realistic alternative to increased use of nuclear fission. 'Green' energies are either clearly insufficient (solar, wind, tidal) or a total con (ethanol, which is just corporate welfare for US agribusiness). Fusion is a completely pie-in-the-sky option right now (to quote a lecturer of mine, 'it's the energy source of the future and always will be'). Hydrogen has, among other problems, that since it is a highly explosive gas there is as of now no practical way of it replacing gasoline, even if it could be produced cheaply in sufficient amounts. |
It's gong to be tough to go that way, too, though. Fission, while it is doable right now and can indeed be fielded on a much wider scale if we choose to, it has problems. One is that I believe the designs _must_ be completely and publicly disclosed, so that informed scientists and engineers can meaningfully criticize the designs and thereby move us towards much safer resulting practical designs. Proprietary behavior, I think, can no longer be treated as acceptable. (There are some designs that are fundamentally safe, by physics and not by safety engineering, and can even allow a terrorist to intentionally blow out the safeties without melting down. These are self-moderating designs we could discuss.) Also, we need to understand that quite a lot of plutonium is produced in the process of most designs and that it is rather easily separated out, chemically. If the world decides that fission is the way to go, we cannot then say to North Korea, for example, "No, we are going to all use fission but you are not allowed to." Everyone will have permission, in effect. And that means that plutonium will be quite widely and cheaply available. How that is handled, I don't know. But there it is. And, of course, there is the waste disposal problem which will only get far, far worse if fission is implemented on a sweeping, global scale.
Also, fission generates electricity (well, it generates heat, but I don't know of any case where someone uses that heat directly to warm their homes.) As I indicated earlier, 3 watts are generated to get 1 watt delivered. On the global scale, we are consuming some 400 quads of energy. Most of that, though, is NOT electricity. It's vehicles, heat, etc. But if we decided to switch over to all-electric methods of heating, vehicle motion, etc, then we would probably require something closer to 1100 quads of electrical energy production in order to deliver the existing 400 quads (of which electricity is perhaps 15%) we currently need. (400*85%*3+400*15%) That's a serious problem. That is just a quick estimate, though, and I'd need to incorporate differences in conversion efficiencies for electric motors in cars, for example, versus current gasoline (28%, roughly) and diesel (40-45% roughly?), etc, to get better numbers for all this. But that gets us somewhere in the vicinity. It means we need to not just replace, but we need to nearly triple our expectations on top of that, to handle all the conversion and distribution losses. Maybe a little more, or less, but somewhere in that ballpark.
All of that is converted to heat, eventually. In the big picture, compared to what the sun provides Earth, it's not all that much. But just to see, lets do some calcs using Stefan-Boltzmann's (integral of Planck) radiation law. For absorbed solar flux on earth and insolation, NOAA has figures which amount to this:
| Code: | total incoming 342 W/m^2
- reflected 107 W/m^2 (ice and cloud albedo, and the rest)
------------result------------
outgoing longwave 235 W/m^2 (can treat similar to blackbody radiation) |
(Solar insolation in space, above the earth, is measured at 1366-1367 W/m^2. But the earth is a curved surface and only half of it is exposed at all, so you already know that it will be substantially less than 1/2 this figure. The above numbers put precise values to an average over all of the earth's surface, including dark and glancing surfaces.)
What is required to produce a one degree Kelvin change? We can choose to simplify the problem, without terribly distorting the results, by assuming that the earth is a black body (I don't mean "black" as a color, but as in emissivity and Planck's law) and use Stefan-Boltzmann's law. Taking the 235 W/m^2 figure and using the law to get the apparent mean temperature: 4th root of (235 W/m^2)/(5.67E-8 W/m^2/K^4) = 253.73 Kelvin. Using the law again, now calculate what things would be at 254.73 Kelvin -- one degree higher -- and this comes up to 238.73 W/m^2. So, from the difference (238.73 - 235), I arrive at this figure: 1 degree Kelvin change is about 3.73 W/m^2 change, as a nearby slope at our current apparent temperature on Earth. That's the linearized slope approximation at our current equilibrium state.
The earth's total surface area is roughly taken to be 1.97*10^8 miles^2, so this 1-Kelvin change is equivalent to a change of about 1.9*10^15 Watts. Over a year's time, this amounts to about 6.01*10^22 Joules. Total world energy consumption is around 400 quads. But we are now talking about producing, say, 1100 quads right away to completely switch over to electric power. (Well, this is a hypothetical, granted.) This works out to about 1.16*10^21 Joules. All of which is converted to heat at some point during or at the end of its use. This is only about 0.03% of the Earth's insolation, but we get a lot of energy from the sun and to have a number that is even looks that close is worrisome. In terms of modifying the temperature of the Earth, it represents about 20 milliKelvins (0.04 F) change. All by itself!!
Simplified. But something on the rough order of things. Interesting.
| pbcoll wrote: | Someone asked about the difference between fusion and fission: fission is breaking apart uranium or plutonium atoms, fusion is fusing hydrogen atoms together to produce helium atoms. Both processes release energy, but fusion requires conditions such that using it as an energy source is currently beyond our technical capabilities, and will remain so for the foreseeable future.
What really annoys me are biofuels - you know, it doesn't seem exactly brilliant to me to cut down the rainforest and starve the world's poor to produce fuels that do not, in fact, reduce CO2 emissions. |
Yes. In fact, this all gets back to the respiration problem I indicated earlier. No escaping it, from what I see.
This is a difficult issue to grapple with.
Jon
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Say what you will about the sweet mystery of unquestioning faith. I consider a capacity for it terrifying. [Kurt Vonnegut, Jr.]
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jonk
Deinonychus
Joined: Nov 18, 2007
Posts: 329
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| Posted: Tue Feb 19, 2008 1:51 pm Post subject: |
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I see no one is quite ready or interested to engage these issues in more detail.
Which brings me to another question. Is there anyone interested in a thread that either helps to teach what we know about global climate science, today, as a dialog (not lecturing, except as needed?) Is it even interesting enough to try and learn about it?
Jon
_________________
Say what you will about the sweet mystery of unquestioning faith. I consider a capacity for it terrifying. [Kurt Vonnegut, Jr.]
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