Do you mean electrodynamic space tethers? Cool stuff!
Yes, they do work. They tested one on the space shuttle but the cable broke.
Contrary to first hypothesis, it didn't break because it wasn't strong enough. It broke because the electricity flowing through the wire caused it to burn through.
(3,500V @ 1-2A, IIRC)
There was air trapped between the layers of insulation on the wire and there were pinholes in the insulation, as well. The electrons passed through the pinholes, ionized the air and turned it into a heated plasma which, in turn, burned the wire through.
If they could have manufactured the cable in space, this might not have happened.
Geothermal is cool, as well, but don't forget that it's still not 100% reliable. Geysers, volcanoes, thermal vents and what-have-you are known to go extinct without warning. Nobody is 100% sure why geothermal vents go extinct but it wouldn't be very cost effective to build a geothermal generation plant then have the thing go extinct a year after it is built.
Any I've ever seen was pretty darn hot!
Originally Posted by Worker 11811
I do use a digital device in my photographic pursuits when necessary.
When someone rags on me for using film, I use a middle digit, upraised.
Note that most of the power forms are actually solar! Hydro, wind, biomass/biofuel, etc., they are all solar. They all just include natural mechanisms to A) store that energy, B) to convert it to a suitable form.
If more efficient direct solar panels and batteries are invented, then they will prevail. If not, those indirect are already doing very well; they will be used anyway during the transition.
As for the chemical batteries, I think Diapositivo nailed down some of the current problems. These problems are not completely impossible to overcome even now; but some development will turn the tables quite quickly, so we are actually quite near to the point. As for the current technology, lithium cells do not use as toxic chemicals as the former batteries; Lead and Cadmium are history. Current materials include lithium, iron, phosphates, sulfur etc. If they want to run a pilot now, it certainly won't be very effective or cost-efficient as of now, but some experimentation is needed. If we compare to nuclear power generation, just enormous amounts of money have been put in breeder reactor development for decades in hope of a future solution, still with no practical outcome. But we need to try all kind of stuff.
The rest of the post is a bit lengthy, sorry for OT! I've been playing around with these thoughts in my head for a year but never written about them (especially not in English...) But as I can't catch sleep right now, I started writing and here goes... I really hope it gives some ideas to think about . And now as this thread is already completely off topic, I hope it doesn't matter anymore .
Athiril's post sounded SO familiar that I felt nostalgic; it was like going back to March last year. I thought those arguments stopped when we learned how serious the Fukushima indeed was after a month or so, but as the mainstream media was quite quiet about it, maybe everyone didn't catch that.
Actually, in the first days, when I saw the pictures of a fossil fuel plant burning, I was already giving arguments that this will surely cause more cancers than the problems at Fukushima.
Then, when I had screamed that "if we don't use nuclear, we NEED to use coal, and it generates MORE radioactivity, and not using nuclear kills more than using it" mantra for a few weeks after Fukushima, I started tracing down for the sources of those calculations and claims, shown in many blogs and even mainstream media, to strengthen my argument pro nuclear. I ended up finding either nothing or completely bogus or very weakly referenced research. This got me to a realization that in order to really understand what's going on and make my own decision, I need to:
1) find some research, opinions etc. from third parties who are not pro- nor antinuclear, but writing from a different perspective, not even thinking about the nuclear debate. To give you an example: medical research on X-ray radiation effects on human health. This gives you some kind of "touch" how those "millisieverts" translate to real effects, as the information given by pro- or antinuclear people could differ by factors from 1000 upwards!
2) do logical thinking, trying to stay calm and objective. This can be quite effective, but you have to use either completely third-party statistics or numbers both "sides" agree on.
3) Go through the points given carefully, sentence by sentence, word by word, number by number, suspecting everything from every side. You will find most of the arguments are complete lies (the person saying them is not probably the liar, but just trusting his source, who just trusted his source, etc.), numbers may be off by many decades, etc. This goes for both sides and all arguments, and this makes this all really difficult! Everyone seem to have a strong opinion that is more important than the truth.
What I found out is that, naturally, anti-nuclear side has some of the most colossal exaggerations. But, this is simply because you can exaggerate without almost any limit ("the whole World and our universe will be destroyed"), whereas there is a lower limit in downplaying ("it was nothing.")
I had read dozens of times the same quotes (mostly without sources) of how many killed per megawatt of electricity generated in different ways. Of course, the nuclear was SOOO safe, even the solar is more deathly because there have been some accidents where the electrician has fell down. Analyzing these statistics a bit, there are a multitude of simple yet effective propagandistic tricks.
For example, it is very easy to come up with an error (or concealment) by a factor of 100 like this:
Exaggerate the particulate emission (incl. those radioactive elements) of the coal power by a factor of ten by simply using old statistics (the plants have developed, installed filters etc.) This is still almost of the correct magnitude, not a big deal at all.
Then, downplay the emission from nuclear accidents by taking the LOWEST POSSIBLE estimation of Chernobyl effects, and ignoring all the others, by factor of ten.
Still no big deal; there is no "true" numbers, they are all ranges. We are just picking the numbers we use from the opposite ends of the ranges, but not actually forging them.
But combined, the factor becomes 100. The more we have so called starting conditions, numbers that model the reality, the more we can adjust the results by just fine-tuning these parameters.
There are actually many more clever propaganda methods here. For example, nuclear is actively compared to only coal power, while it is not a realistic at all. But the coal happens to be the dirties method. Even if nuclear were to completely replaced with something else right now, that would be a combination of different energy sources; oil and natural gas as the two other large fossil fuels that are AFAIK less dirty than coal for particulate emissions, and of course some part would be from renewables. In addition, they would need to build some NEW coal power plants, and they probably would have better burners and better filtration. Altogether, these tricks can give an another factor of 10, bringing the total "misleading" factor to whopping 1000!
This is exactly why they say: "Never trust statistics".
Then we have the mostly undiscussed fact that we really know VERY little of the effects of ionizing radiation on human health and environment. We cannot simulate the living tissue too well, so this is something we can only know by real experiments. And, we have had just few of those unwanted "experiments".
The first one were the atomic bombings. Unfortunately, in that kind of situation, not much research could be made on the effects. Furthermore, the amount of internal exposure was low compared to that of direct external radiation. The amount of hot particles was around 100 times or so less than from Fukushima. It was practically nothing, so even if we would have conducted enough research, it would have been from a completely different type of subject.
Then, there was the Three Mile Island accident. Now, this was the first large-scale nuclear accident in human history. They had practically NO knowledge on the effects at the time; still, the authorities insisted that it was theoretically impossible for that radiation to cause any effects, even though they even didn't have proper radiation monitoring. A book called "Three Mile Island: The People’s Testament", by Aileen M. Smith, gives a collective view of dozens of locals, and even though there were some clearly mass-hysterical psychological effects going on too (probably post-traumatic), there still are many of those very level-headed and even quite objective testimonies (for example, dental X-ray films fogged on those very days at a local clinic; something not happened before or ever since) there that clearly contradict with the official information.
And, that very accident have been popping up again in the last few years. There have been some evidence of increased cancer death rates, even when carefully compensated for possible other factors. It is very unclear how much is was downplayed, but it clearly was at some level.
That gets us back to the point of studying the effects of radiation--- while we didn't learn enough from atomic bombings, then, did we learn from the TMI? Did we learn how the human body reacts in this kind of still relatively "small" accident? No we didn't, because we aggressively decided not to even try to learn. We decided that there was zero effect, even when some opposite evidence was there. Even if you would disagree with that evidence, this would still have been a great chance to try to really learn how ionizing radiation affects human health.
This (finally) lead us to my point; the Chernobyl accident in 1986 was actually the VERY FIRST opportunity to take a close look on health effects of the type ionizing radiation caused by a nuclear accident. The radiation as well as the isotope footprint was finally measured, and human health really monitored for the first time. There probably were HUGE shortcomings in health monitoring, but still it gave us more material than anything before.
We have now had 25 years to analyze this data --- 25 years itself is not enough yet for all cancers and other health problems to come up! --- and research this very complex area of human health. This is next to nothing; we are just taking our first steps on the subject. How can anyone make claims about the relative safety of radiation when we have actually pretty strong evidence of real dangers? They give us an argument: "this has not been proved well enough!" Surely true, but in 25 years, it has been just impossible to prove anything to the typical scientific standard. As we NEED to make decisions now (for example, how much to evacuate in case of an accident), we need to practice precautionary principle as much as practically possible.
In the last decades, there have been new research but for some reason, it hasn't got very much attention. After it was noticed in the Great Britain that leukemia rates are higher near the operating nuclear power plants, a large systematic research was launched by the German authorities (a link: http://www.bfs.de/en/kerntechnik/kinderkrebs/kikk.html ). The results are somewhat groundbreaking. While they do not show that operating nuclear power would be especially dangerous (as stated before, burning fossil fuel agreeably causes cancers), they still contradict with the very strong claims of no effect at all. Also, it has been studied in a large meta analysis that the nuclear workers have somewhat increased cancer rates. IIRC, it was something around 10-20% more or so. This doesn't change the fact that in the world of no accidents, nuclear power is still quite green in it's lifetime, even though not with zero effect.
However, as accidents happen, these findings open up completely new questions for low-level extra radiation exposure, such as that encountered in further away areas of Fukushima (such as Tokyo), or even the West coast of the USA, or large parts of Europe (including my country) due to Chernobyl.
In any case, I feel that it's a bit weak argumentation to say that "nuclear is green if accidents don't happen", when they, in reality, happen "all the time" (compared to the severity of these accidents). We should just search for the facts instead of reading directly the downplayed view of the industry and even downplaying it more by ourselves(!!). We should also understand that the current "safety" level of a major accident happening every decade of two, is not bad luck but a clearly calculated risk. Those who took it, were hoping for good luck, but we just have had "average" luck. Fukushima could have been VERY much worse even with exactly the same technical standpoint; the direction of the wind was almost as optimal as it could be.
Thanks for reading, sorry for flooding! :-).
Last edited by hrst; 05-18-2012 at 11:35 PM. Click to view previous post history.
Originally Posted by Photo Engineer
Biomass does not produce new CO2 in principle.
During burning, just like during natural decomposition, CO2 is freed in the atmosphera.
You have C + 02 = CO2 + heat.
But this CO2 will be used by plants, trees, etc. to make new wood, through the chlorophyllian photosynthesis, which uses again that CO2 in the atmosphera to create C + 02 anew (where "C" is the plant, and "02" is the oxygen which is freed during the process).
So you have a circle which is in equilibrium: biomasses are a great accumulator of solar energy, burning it will only put in the environment some CO2 which will then become again biomass thanks to solar energy, and the cycle will begin again. Think of CO2 as a "vector" of solar energy
That's why biomass is the fuel of the future. It doesn't alter the CO2 equilibrium of the atmosphera (no greenhouse effect), and it doesn't alter the thermal equilibrium of the Earth because that same process (liberation of CO2 and heat) is what would naturally happen through decomposition.
Said in the words of the producer of my wood stove: The quantity of CO2 produced by the combustion or decomposition of a plant corresponds to the quantity of CO2 that the same plant is able to take from the environment and to transform in oxygen during its life cycle.
In the case of fossil fuels enormous quantities of CO2 which were accumulated in millions of years underground are suddenly released into the atmosphera, which alters the CO2 equilibrium.
PS It should be noted that, for this reason, a bit all over the world biomass production and consumption is encouraged. When I installed my wood and woodpellet stove I got a fiscal rebate of 40% of the cost diluted in 10 years.
By the same token, wood surface is continuously increasing in countries where wood burning is encouraged. Switzerland, which was a pioneer in this policy, saw its wood surface increase in the last decades, after a continuous depletion in the previous centuries. Italy is now also increasing its wood surface.
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What HRST writes is very interesting and I do agree, especially, that in this field lies run freely from every source, even the most "reputable" ones.
I am a convinced antinuclearist, but in the 1987 referendum in Italy I voted in favour of nuclear energy. I changed my mind later, when I understood that the arguments given to me in favour of nuclear were mostly lies.
The idea behind the nuclear, that "if there are no accident it is safe", is intrinsically a nonsense. Shit happens in whichever human endeavour. There is no field of human activity which is free of errors. However small the probability of a catastrophe, it's not inexistent and, in my view, it's not tiny, but even if it were tiny, it would not be acceptable. Any time there is a new nuclear accident, people say "it happened there, but it couldn't have happened here" or "it couldn't have happened with last generations reactors". They forget to say that "here" other kinds of accidents might happen, that most reactors are not last generation, and that reactors which have problems now are those which were deemed secure one day.
Besides, when the catastrophe happens it's too late to admit "I was wrong".
This reminds me the Pascal paradox of probabilities. You can reason about how likely it is that God and Hell exist, or not. You might decide that there is only 1 probability on 1000 that God exists. So you might decide "not to believe". But you should also ask yourself: what if that 1 probability over 1000 is verified? Then you might go to Hell for ever... So "believe", even if the probabilities are tiny, because consequences can be awful. The "weighted probabilities" (weighted with the consequences) are more important than the probabilities themselves.
There are also persons, within the scientific community, who are prejudicially pro-nuclear as they feel that antinuclearist positions are somehow "against progress" and they confuse antinuclearists, more or less, with creationists and other kinds of fools.
That really is a prejudice. It's like being "anti-film" in photography just because digital photography came later
Last edited by Diapositivo; 05-19-2012 at 08:31 AM. Click to view previous post history.
A few points here:
1. Sorry, I was thinking space elevator with energy pumping and not the tether concept. My bad.
2. Stainless steel is non-magnetic if it is good Stainless.
3. Many materials we wish to use for construction of geothermal systems melt at the temperature of the vent. That is why geothermal would actually use rather mild temperature differences between the surface and underground areas, not active volcanos. And, these differences are rather permanent and do not vanish abruptly.
4. Biomass is, as stated, a "recycling" of materials, but as we cut more wood, there is less plant life left to use the CO2. That is one problem today. More CO2 is produced than can be used and thus CO2 is going up. Also, the reaction is not pure carbon + oxygen. It is sugars and cellulose + oxygen which produces CO2 and H2O, two greenhouse gasses. It also produces some byproducts that are not very nice just like all combustion.
In any event, there is no easy way through this maze. What we need is a smaller human footprint on the earth.
Welcome my "sun", welcome to the machine.
There are some long and turgid posts here, so I have not read them all. The subject seems to have shifted to safety of energy production.
The U.S. uses about a fifth of worldwide energy consumption, yet has 5% of the population. Maybe it's time to start conserving? It's the only answer.
Biomass really relies on that principle of growing new mass at the same rate as burned. The biggest problem here is that this is too great opportunity to cheat, given the human nature. Just sell some biofuel without growing new material!
I think that in order to really work, they need to have some bacterium that can use up CO2 at very high rates and low costs. Area efficiency is the key point.