I wonder if you had in mind a Stirling Cycle engine (in addition to electric motors)?
A Stirling engine is just an external-combustion heat engine, like a steam engine. It has every disadvantage of external combustion engines, including the fact that some of its parts have to run hotter than the working fluid ever gets. Since the efficiency of a heat engine is limited by how hot the high side can be, and high-temperature materials are expensive, this is a problem.
The main advantage of the Stirling engine is that it can operate from anything which can supply heat at the required temperature. This can be a flame, a solar concentrator, or a nuclear reactor. It can also be very smoothly balanced and has no pulsating intake or exhaust, making it very quiet. This makes it great for some applications, but if it was going to beat the Otto or Diesel engine in any major respect you'd be seeing lots of them out there. You don't, which ought to tell you something. --
The government isn't going to make it easy for EV's because they earn too much in petrol tax's...
My libertarian streak says that this offers a way to sell them: they are tax avoidance, a way to remove one of the government's screws from your bum.
a) we should produce vehicles that have better range/performance than the current IC vehicles
Better range is easy, look at the Insight. Better performance will probably be obtained with something other than batteries, like compressed-air energy storage for regenerative braking and acceleration (you can dump air through an air motor really fast). Heat your stored air with the engine exhaust and watch how far that little tank goes (and how much higher your efficiency goes).
But you've fallen prey to a hoax:
why not tranmit the power to the car when it's in the garage. That would make it _more_ convenient than petrol.
Energy is conserved. If you are going to convert 60 Hz electricity to RF, you will have losses. If you radiate it around the garage, some of it will leak. Not only will you be paying for more power just to get the same amount to your car, you will be radiating RF around the neighborhood (which may be illegal without the proper transmitting licenses) and subjecting yourself, your family and your neighbors to EMF's much higher than you'd otherwise have (with unknown effects). Plus, it'll probably screw up a fair fraction of the electronic stuff in your house.
99% of the Tesla-related stuff on the Net is total bunk. Just remember TANSTAAFL. --
I believe that considering that a carburator existed in 1955 that got 50 miles to the gallon
Your belief is founded on the "miracle carburetor" hoax. That belief is false. When you consider the engine technology of the time (which often included side-valve "L-head" engines, with their huge surface areas and large thermal losses) it is patently obvious that no possible carburetor could have improved the efficiency of the engine to the point where the vehicle could achieve 50 MPG at highway cruising speeds. Carburetors have long been eclipsed by modern fuel injection systems, and those don't break 50 MPG by much even in a Geo Metro.
A carburetor is just a gadget for generating a more or less consistent fuel/air mixture. Unless you are grossly away from stoichiometric or running a really bad imbalance between cylinders, you are not going to lose more than perhaps 10% to 20% from having a bad carburetor versus the best. 20% is nothing to sneeze at, but it won't take a 20 MPG car and make it a 50 MPG car either. --
One last point on the nuclear fuel issue is that we should not only be allocating money for fusion research, but also for research into how we will clean up the mess we have created with fission technology [1]. Currently we still have not agreed on how to dispose of nuclear waste [2].
[1] That's easy. The key is isolating the fission products, which can be done by electrolysis of spent oxide fuel in a bath of molten salts. The uranium and transuranics are plated out, the fuel cladding is recovered more or less as-is, and the fission products remain in salt solution. The salt is adsorbed in the pores of a zeolite (creating an insoluble mixture) and hot-pressed into solid chunks in stainless steel cans. These cans can then be embedded in glass or ceramic and buried. They will be about 98% gone in 200 years, essentially cold in 1000 years.
[2] That's politics, not engineering. The greenies have as one of their express goals the closure of all nuclear powerplants. They have tried to force this by preventing plants from sending their spent fuel to the US Government for disposal, even though the USG is mandated by law and by contract to take it. Since the USG has welshed on their agreement (prompted by the greenies), the plants have moved some of their cooler fuel from ponds to dry-cask storage. This has really pissed off the greenies: they couldn't shut down the plants directly, they failed to shut them down indirectly, and now they'll have to either come up with a new idea (difficult for brains trained to dogma) or give up. --
Oh, on the second resource you listed from gaia.org that was comparing solar heating of water to heating with electricity. But they put everything in units of kWh to give the impression they were measuring electric power, very sneaky to method to waylay the layman. Electricity is a very low entropy type of energy while heat is very high in entropy.
When you consider the number of people in the Sun Belt who heat their domestic hot water with electricity using resistance heaters (not even heat pumps), it should suddenly click for you. Until then, I guess you'll have to invent conspiracy theories. --
We've been trying to do nuclear right for almost 40 years and we still can't solve problems like the fact that the waste products are among the most toxic substances known to man
Consider the toxicity per unit energy. Unlike coal ash, there's almost none of the stuff, and unlike chemical toxins, radioisotopes decay. Most of the problem isotopes have half-lives of 30 years or less, so in 1000 years they are down by a factor of 10 billion to one. Fact: of all the fission products in existence when I was born, well over half of them are already decayed, gone, safe.
and also contribute to fears of nuclear proliferation
The simple fact of the matter is that you can make bombs with RMBK's and CANDU's (the former were designed for that purpose), but the spent fuel from pressurized-water reactors is essentially proliferation-proof. The thing needs to run a couple of years between fuellings to be economical, and by then the fuel has been so irradiated that the plutonium is crammed with higher-order isotopes (Pu-240, Pu-241) and useless for making bombs. The uranium was never concentrated enough to make a bomb, and is even more hopeless in the spent fuel. What proliferation threat? It's all FUD.
as far as more advanced, safer designs for fission reactors, where's the research being done? It's almost nonexistent.
You can thank Congress for cutting off the money for the IFR for that. A proliferation-proof breeder reactor that yields its waste glassified and ready for burial, and they kill it. --
You could beam the energy down via microwave, but don't let Austin Powers (or Peter Sellers) get ahold of it, or he'll fry a major city. Microwaved people, anyone?
The original Glaser (and later O'Neill) power satellites had beam-power densities of about 70 watts/m^2 maximum, limited by the diameter of the transmitting antenna. Even if some baddie could divert a beam (and existing technology could make it extremely difficult), nothing would fry beneath it. Sunlight on a typical summer day is ten times as powerful, and you could escape the beam by crawling underneath anything metallic (including aluminum foil). Most office buildings have metal roofs and the floors are concrete poured over corrugated steel; those would be absolutely proof against such a baddie. It would be a lot of work to do about nothing (except take the plant off-line, which could be done by taking down the transmission towers).
I'm afraid that the "zapped city" idea is a hoax, and you bought it. --
the two best (most efficient) methods of collecting solar power right now are through farming
Sorry to burst your bubble, but it is probably the least efficient. Plants grown for seed convert sunlight to seed with an efficiency of around 1%. A cheesy solar-steam engine can easily do 5%, solar cells 15%, good steam engines 20+%.
An acre is 43,560 square feet, or about 4000 square meters. If you average 400 W/m^2 of sunlight on a field for 10 hours a day for 2 months, that's about 880 megajoules per square meter or 3.5 terajoules per acre. A gallon of gasoline is about 119,000 BTU or 126 megajoules, so the energy falling on that acre of land is equivalent to about 28000 gallons of gasoline. It doesn't take any analysis to see that the energy yield from the corn grown on that land is only a very small fraction of the total solar input.
While growing corn may not be the most efficient plant to farm fuel alcohol, it IS sustainable.
Current practice uses petroleum-based insecticides and herbicides, natural-gas-derived nitrate fertilizers and diesel fuel for planting, cultivation and harvest. This isn't sustainable in the least, and the yield from corn looks pretty bad if you count those inputs against the fuel production.
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What I don't understand is why car makers skipped over hybrids to electric cars (like the EV1) and then came back to hybrids.
It is a completely artificial reason. It came about because the California Air Resources Board (CARB) insisted that some fraction of all cars sold in California have absolutely zero emissions (ZEV's), and hybrids did not qualify under their rules. The fact that battery technology was woefully inadequate despite a century of electric vehicles didn't bother them; they thought they could overcome the difficulties of physics and electrochemistry by bureaucratic fiat.
Needless to say, it didn't work. I was saying so ten years ago, and now I get to say "I told ya so."
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I read the article, and it sounds like snake oil to me. The claim is the transmission of 1 bit/symbol (1 BPS/baud), but the bandwidth is minuscule. This is contradictory. Further, what I was able to glean from the article seems to claim that the keying is done by tiny phase-shifts in the outgoing signal which affect the timing of the zero crossing. A tiny phase shift would be easily masked by noise, causing a timing error and decoding of the wrong bit. This contradicts the claim of high noise immunity.
It's possible that EDN got this all wrong, and someone has actually found an end-run around a whole lot of difficult stuff in conventional signalling theory. But I wouldn't bet on it, and if you're smart, you won't either. This may be some scheme to get investment money out of a bunch of suckers, and it behooves you to not be one of them. --
Many "highland" regions use water and pumps to "store" spare energy, by simply pumping the water up into the hills in large tubes and then when needed let it come back down and through turbines to (re-)create energy. A siple and VERY efficient battery. I challenge You to find a better large scale storage method of energy.
This is not useful unless you have a large supply of water close to a much higher area you can use for an upper reservoir. If you don't have the necessary geography, you can't use pumped storage.
This is not something that coexists well with other uses. Fish tend not to fare well when they go through the pumps.
The net efficiency is only about 80% at best.
The systems must be huge to be effective. To store 6 gigawatt-hours (to replace one major powerplant's output during the afternoon hours) with a 200 foot rise takes (6e9 * 3.6e3 / 9.8e3 / 61 ) = 36 million cubic meters of water. That's an area of 2900 acres covered to a depth of ten feet. It can't be used for wildlife habitat or fish or much of anything else because it's always being filled and drained. Here are links to sites for the Ludington MI pumped-storage plant, and one for the Mount Elbert plant. (Note that the Mt. Elbert plant claims a capacity factor of 15% of its rated 200 MW, and that is probably when running on a daily cycle. If it had to even out multi-day variations in supply from e.g. wind, it would be far lower.)
Storage is the killer for alternative energy applications. Chemical fuels have storage built in, all you need is a tank. When alternative energy technology comes to a point where it can be transformed into, or generated directly as, a form of energy which is easily stored and transmitted, that will address some of the biggest issues immediately.
I never said it was CHEAP, I merely said it was possible.
Long before the limits of possibility are reached, cost has forced everyone to do something else. Currently, PV with battery storage has a delivered cost of about $.90/KWH. That kind of cost makes the most gold-plated nuclear plant look cheap by comparison.
I never said that nuclear power was obsolete. I merely pointed out that it was not a NESSESITY as we have alternatives,
Ummm, no. An alternative must satisfy the same need. There is potential for alternative systems which incorporate work-arounds to achieve the "where needed, when needed" parts, but this requires re-thinking the system from end to end. In general the alternative advocates have done a lousy job of this.
I was refering to CARS
So was I. Hybrids kill pure electrics, because they carry chemical fuel. However, the storage problem is not specific to vehicles.
But look at the operating costs of fossil fuel powerplants, and You WILL see that they are obsolete. first of, the sheer cost of rawmeterials WILL increase as the availability of materials decrease (law of supply and demand).
The price of crude oil has been falling in real terms for many years. So has the price of coal. The technology for extracting the raw materials has been improving as well, and in some cases faster than the difficulty of finding new reserves.
Second look at the environmental impact. The cost of cleaning up the environmnt, reversing the greenhouse effect etc.
After looking at that, nuclear may still be the preferred alternative. It's far easier to isolate a few tons of fission products for a thousand years than it is to store and cycle millions of tons of chemicals, especially when those chemicals include ions of toxic heavy metals. For alternative energy to get away from the problem of toxic releases, it will have to move to materials which are made entirely of carbon, hydrogen and oxygen. These include hydrocarbons and alcohols. Interestingly enough, hydrocarbons are a lot like fats, and sugars are alcohols...
Reversing the greenhouse warming (we need the greenhouse effect or the earth freezes solid) needs further tricks. One that I like involves taking the methane clathrate deposits on the continental shelves (which are threatening to decompose to gas, and CH4 is about 200 times as good a greenhouse gas as CO2) and mining them for fuel. Crack the CH4 into H2 and carbon soot, then bury the soot (old coal mines seem appropriate). Burn the H2 in whatever is convenient.
However, MANY countries are right now doing fine wihtout nuclear power, MANY countries (including a lot of US states) are suppling a larger and larger part of their electrical energy from "environmentally safe" powersources
With a few exceptions, those countries are generally producing their electricity from fossil fuel and exacerbating greenhouse warming something awful. China is a huge offender in this regard.
In this DOE table you'll see that the total nameplate capacity of non-hydropower renewable energy generators in the country for 1999 was a whole 2000 megawatts. That is out of a total generating capacity of nearly 700,000 megawatts. The entire nameplate generating capacity would barely replace 2 nuclear plants, and probably have about 1/3 the capacity factor. If it's going to really be an alternative, it has a hell of a long way to go. --
In fact, the fission cross section of Pu-239 is high, so it is quite difficult to make weapons out of plutonium.
That's a non-sequitur. A high fission cross-section is good (gives a smaller critical mass); the problem is the very high rate of spontaneous fission, which can initiate a chain reaction before the mass is properly assembled in a prompt-supercritical configuration.
This is why plutonium bombs are all implosion designs; a gun can't get a mass of plutonium into the right shape fast enough. The chain reaction starts prematurely, the bomb comes apart before more than a tiny fraction of the Pu has fissioned, and you get a "fizzle". This is the reason that it is nearly impossible to use recovered plutonium from power reactors to make bombs. Power reactor fuel spends years in a heavy neutron flux, and it is chock-full of higher isotopes of Pu (like Pu-240, Pu-241 and Pu-242) which have far higher spontaneous-fission rates than Pu-239. You'd need a bomb design made from scratch to use this stuff if you could use it at all. ISTR reading that the Russians had actually done isotope separation on their already-weapons-grade Pu to get rid of some of the higher Pu isotopes and make their weapons more reliable. If you're going to need gas-centrifuge gear anyway, you might as well go with uranium. Your chances of success are far better that way. --
Dam bursts have killed more people in this century than every nuclear accident outside of Russia. Hundreds of times as many people, as a matter of fact.
Hydropower is also being opposed by the greenies because
it destroys runs of migratory fish
it creates emissions of greenhouse gases (methane) from the decay of submerged organic material
it displaces people from their traditional lands and obliterates the archaeological record of an area.
I'm not saying I agree with all these charges, but if you are going to claim hydro is so great it is up to you to rebut the counterclaims. --
Using uranium in a fission reactor produces plutonium which then needs to be disposed of. The problem is just that, what do you do with all this radioactive waste?
Plutonium isn't waste, it's fuel. If your system is designed properly (like the Integral Fast Reactor) you can recycle it and burn it. The only real wastes are fission products. Most fission products have half-lives of 30 years or less, so in 1000 years there will be less than 1 billionth of them remaining. You don't have to bury them, you can build a pyramid out of them and they'll be history in 1/5 the lifespan of the ones in Egypt. Removed from its solvents and whatnot, all the high-level nuclear waste in the world wouldn't make a decent sized hill; it is quite literally a very small problem. --
Chernobyl was caused by incompetant people trying to run an imperfectly built reactor at over 115% capacity...
Not true. Chernobyl was caused by incompetent people trying to run a reactor with a positive reactivity coefficient and a large inventory of poisons (such as xenon) off-line with the safeties disconnected. They were doing an unauthorized experiment at power levels far below what they should. The chain reaction apparently stopped, and when the operators pulled out the control rods to restart it they got into the strongly positive section of the reactivity curve (where the reaction efficiency goes up with increasing power level). The power surged to several hundred or thousand times rated power, causing a steam explosion. The explosion blew the lid off the reactor core and scattered white-hot fuel pellets among graphite (carbon) blocks. The result was the world's largest radioactive hibachi.
The point is threefold:
The design of the RMBK reactors used at Chernobyl was grossly unsafe. This is only a flaw in that design, it does not apply to PWR's, BWR's or HTGR's.
Even so, the reactor wasn't a problem until it was operated in a patently unsafe manner.
There still wouldn't have been a problem if the reactor had a proper containment building around it.
With US-style safeguards, nuclear power is safer by far than coal, and even safer than wind (working on towers is dangerous). There are more people killed every year in chemical plant explosions than could possibly ever die from all US nuclear accidents from Three Mile Island onward, and most years there are more bystanders killed by chemical plants than could ever die from nuke accidents from TMI on up. Funny, where's the greenie hype about chemical plants? Looks like selective blindness to me. --
Now terrorist factions like Hamas and general crime rings like the Russian Mafia have a new window for getting HEU.
They do? How? The fuel for pressurized-water reactors is not HEU, it is low-enriched uranium (3% or so U-235, not 80+%). You're assuming that Hamas could turn LEU reactor fuel into HEU bomb-grade material, but couldn't turn natural uranium into bomb-grade material given the same technical resources. There's a little flaw in the reasoning there.
As others have noted, the big threat is that Russian warheads will wind up with "FOR SALE" signs. Reactor fuel (raw, spent or re-refined) is not a proliferation threat. --
By your definition, no "proper" breeder reactor could have been built, because the weapons-grade Pu to fuel it has to be made in a breeder reactor. Check on the history of the Hanford N reactor to see where you went wrong. --
All one has to do is drop a few pounds of powdered Uranium, way up-stream in the Mississippi, and we're all in for a world of hurt.
That would be a really expensive way to accomplish not very much. Uranium is one of the more reactive metals (it's used in anti-tank ammo because it bursts into flame when it pierces armor plate; metals like uranium are called "pyrophoric"). Uranium powder in water would oxidize rather quickly. Guess what? Uranium oxide is not terribly soluble in water, so it goes down into the sediments and stays there. The biggest threat is from heavy-metal poisoning (not radioactivity) and even then the threat would be tiny. Ion exchange resins could remove any uranium which got into the treatment plants. The biggest problem would be that a few miles of the river might not be all that safe if you wanted to eat the fish. --
IIRC, South Africa's bomb tests showed that they could get a couple kilotons yield out of 80% U-235. This is still a hell of a long way from the 3% U-235 mix used for light-water reactor fuel. --
In this case, you don't burn anything. The final exhaust stream is room temperature (ambient environment, actually, but close enough),
Not even close. If you are heating the gas all the way up to ambient temperature before the final expansion, it will still lose temperature in that expansion. That exhaust is going to be chilly. (It sounds just like what the sun-baked freeways of Los Angeles need on those hot summer evening traffic jams!)
so you don't need to heat anything up. As for storage, it doesn't require any energy to store; you just stick it in a container when it's cold, cap it really tight, and it stays liquid because it can't expand into a gas.
Again, not even close. The density of liquid nitrogen at atmospheric pressure is a lot higher than the density of nitrogen gas at room temperature and 3000 psi. If you capped a container of LN2 and let it heat up to room temperature, you would have gas at many thousands of PSI on your hands. This takes a very strong, heavy, expensive tank to hold it. It is also an extreme explosion risk in a collision.
The way it'll be done is to have a super-insulated tank of LN2 or liquid air at more or less atmospheric pressure; no pressure container, no explosion risk. A pump draws liquid from the tank and pressurizes it to several thousand PSI. This liquid goes through the evaporator where it becomes high-pressure gas, which in turn operates the expander to produce power. This limits the high-pressure sections of the system to a few tubes instead of the entire fuel supply, and cuts weight and expense. A system designed for efficiency will have several expansion stages with a re-heat in between. --
The problem with hydrogen is where you get it from: as it is not produced by any biological process...
Not true, or at least not any longer. Researchers at NREL and some university discovered an alga which has an interesting metabolic pathway; when held in a sulfur-deficient medium in the dark without oxygen (and thus dependent on anaerobic metabolism, like glycolysis) they switch to a mode where one of the products of the metabolism is H2. So long as you put them back in the light before they burn all their energy reserves and starve to death, they can be cycled from growing to H2 production and back every few days. The interesting thing is that this alga wasn't engineered, the alternate pathway is something that just evolved.
One more response for the day before the limit kicks in.... have to decide priorities. <sigh> --
The point is that the people with money can't corner the market on biofuels, so they don't invest in the development of engines to run off it.
So what you're saying is that nobody invests in diesel engines (which are easily run on methyl esters of fatty acids, which are in turn easily produced from vegetable oils, methanol and sodium hydroxide). Excuse me while I laugh.
Nearly every biofuel engine I have ever heard of has been produced by universities&colleges and not major companies, likely for this very reason.
More likely for the reason that vegetable oils cost a dollar or more per gallon, while crude oil is still about US$0.60/gallon. Biodiesel is easy if you are willing to pay the price, but the price of the raw material makes it uneconomical. Besides, would you want to contribute to the kind of subsidies which have made Archer Daniels Midland such a huge company (off of the US taxpayer, in no small part)? How about the environmental damage from using more pesticides and fertilizer, not to mention erosion from cultivation? Biofuels aren't a panacea.
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We've got one, as I understand, at Douneray in Scotland.
No, what you have at Douneray is a chemical reprocessing plant for oxide fuel. The IFR has an on-site electro-refining plant for metallic fuel. The Douneray scheme yields aqueous solutions of liquid wastes which are hell to package for disposal, the IFR yields waste as molten salts which can be immobilized with zeolites and are almost ready for disposal as-is.
Then, as with all things Nuclear, the decommisioning cost when it finally has to go is phenomenal.
Funny, when the Shippingport reactor was decommissioned the costs were well within reason. Or is this just a British thing? --
It doesn't matter what you measure the temperature in; you could use degrees Rankine, which are Farhenheit-sized degrees with the 0 at absolute zero. The only requirement is that the scale has to have its zero point at absolute 0.
Everybody uses Kelvin these days, but you get exactly the same results with Rankine or any other absolute scale. You can prove this to yourself by multiplying the numerator and denominator of your equation by any non-zero factor. The result does not change. --
Actually, renewable energy sources (ie. NOT fossil and NOT Nuclear) CAN supply the world with the energy it needs.
How about where needed, when needed? You left that part out. When you add in the cost of storage (even without the implied environmental impact of that cost), the current scheme for renewables can't supply what we need at anything like what we can afford to pay.
I'm waiting for systems which use cheap materials for storage to get around that. Something like a photosynthetic rooftop which converts CO2 and water into methanol (CH3OH) and oxygen would fit this bill, because the cost of storing a liquid like MeOH is minuscule compared to the cost of a battery or even the tanks for holding H2.
And THAT'S why the world "needs" fossil and nuclear fuel. Technologically the fossil fuel was obsoleted more than 50 years ago.
The energy density (both per volume and per mass) of mere hydrocarbon chemical fuels leaves every battery ever invented in the dirt. Don't even get me started with nuclear (you measure the output of a reactor fuel load in the tens of thousands of megawatt-days per ton).... There are many applications for which the need to carry your energy supply with you leads to a serious degradation in system performance when you try using renewables. Hydrocarbons and nuclear are not obsolete, quite the opposite. They are the gold standard that keeps renewables from gaining acceptance, because the systems for storing and delivering renewable energy fall so far short. --
Slashdot Mirror
The main advantage of the Stirling engine is that it can operate from anything which can supply heat at the required temperature. This can be a flame, a solar concentrator, or a nuclear reactor. It can also be very smoothly balanced and has no pulsating intake or exhaust, making it very quiet. This makes it great for some applications, but if it was going to beat the Otto or Diesel engine in any major respect you'd be seeing lots of them out there. You don't, which ought to tell you something.
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But you've fallen prey to a hoax:
Energy is conserved. If you are going to convert 60 Hz electricity to RF, you will have losses. If you radiate it around the garage, some of it will leak. Not only will you be paying for more power just to get the same amount to your car, you will be radiating RF around the neighborhood (which may be illegal without the proper transmitting licenses) and subjecting yourself, your family and your neighbors to EMF's much higher than you'd otherwise have (with unknown effects). Plus, it'll probably screw up a fair fraction of the electronic stuff in your house.99% of the Tesla-related stuff on the Net is total bunk. Just remember TANSTAAFL.
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Your belief is founded on the "miracle carburetor" hoax. That belief is false. When you consider the engine technology of the time (which often included side-valve "L-head" engines, with their huge surface areas and large thermal losses) it is patently obvious that no possible carburetor could have improved the efficiency of the engine to the point where the vehicle could achieve 50 MPG at highway cruising speeds. Carburetors have long been eclipsed by modern fuel injection systems, and those don't break 50 MPG by much even in a Geo Metro.
A carburetor is just a gadget for generating a more or less consistent fuel/air mixture. Unless you are grossly away from stoichiometric or running a really bad imbalance between cylinders, you are not going to lose more than perhaps 10% to 20% from having a bad carburetor versus the best. 20% is nothing to sneeze at, but it won't take a 20 MPG car and make it a 50 MPG car either.
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[2] That's politics, not engineering. The greenies have as one of their express goals the closure of all nuclear powerplants. They have tried to force this by preventing plants from sending their spent fuel to the US Government for disposal, even though the USG is mandated by law and by contract to take it. Since the USG has welshed on their agreement (prompted by the greenies), the plants have moved some of their cooler fuel from ponds to dry-cask storage. This has really pissed off the greenies: they couldn't shut down the plants directly, they failed to shut them down indirectly, and now they'll have to either come up with a new idea (difficult for brains trained to dogma) or give up.
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I'm afraid that the "zapped city" idea is a hoax, and you bought it.
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An acre is 43,560 square feet, or about 4000 square meters. If you average 400 W/m^2 of sunlight on a field for 10 hours a day for 2 months, that's about 880 megajoules per square meter or 3.5 terajoules per acre. A gallon of gasoline is about 119,000 BTU or 126 megajoules, so the energy falling on that acre of land is equivalent to about 28000 gallons of gasoline. It doesn't take any analysis to see that the energy yield from the corn grown on that land is only a very small fraction of the total solar input.
Current practice uses petroleum-based insecticides and herbicides, natural-gas-derived nitrate fertilizers and diesel fuel for planting, cultivation and harvest. This isn't sustainable in the least, and the yield from corn looks pretty bad if you count those inputs against the fuel production.--
Needless to say, it didn't work. I was saying so ten years ago, and now I get to say "I told ya so."
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It's possible that EDN got this all wrong, and someone has actually found an end-run around a whole lot of difficult stuff in conventional signalling theory. But I wouldn't bet on it, and if you're smart, you won't either. This may be some scheme to get investment money out of a bunch of suckers, and it behooves you to not be one of them.
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- This is not useful unless you have a large supply of water close to a much higher area you can use for an upper reservoir. If you don't have the necessary geography, you can't use pumped storage.
- This is not something that coexists well with other uses. Fish tend not to fare well when they go through the pumps.
- The net efficiency is only about 80% at best.
- The systems must be huge to be effective. To store 6 gigawatt-hours (to replace one major powerplant's output during the afternoon hours) with a 200 foot rise takes (6e9 * 3.6e3 / 9.8e3 / 61 ) = 36 million cubic meters of water. That's an area of 2900 acres covered to a depth of ten feet. It can't be used for wildlife habitat or fish or much of anything else because it's always being filled and drained. Here are links to sites for the Ludington MI pumped-storage plant, and one for the Mount Elbert plant. (Note that the Mt. Elbert plant claims a capacity factor of 15% of its rated 200 MW, and that is probably when running on a daily cycle. If it had to even out multi-day variations in supply from e.g. wind, it would be far lower.)
Storage is the killer for alternative energy applications. Chemical fuels have storage built in, all you need is a tank. When alternative energy technology comes to a point where it can be transformed into, or generated directly as, a form of energy which is easily stored and transmitted, that will address some of the biggest issues immediately. Long before the limits of possibility are reached, cost has forced everyone to do something else. Currently, PV with battery storage has a delivered cost of about $.90/KWH. That kind of cost makes the most gold-plated nuclear plant look cheap by comparison. Ummm, no. An alternative must satisfy the same need. There is potential for alternative systems which incorporate work-arounds to achieve the "where needed, when needed" parts, but this requires re-thinking the system from end to end. In general the alternative advocates have done a lousy job of this. So was I. Hybrids kill pure electrics, because they carry chemical fuel. However, the storage problem is not specific to vehicles. The price of crude oil has been falling in real terms for many years. So has the price of coal. The technology for extracting the raw materials has been improving as well, and in some cases faster than the difficulty of finding new reserves. After looking at that, nuclear may still be the preferred alternative. It's far easier to isolate a few tons of fission products for a thousand years than it is to store and cycle millions of tons of chemicals, especially when those chemicals include ions of toxic heavy metals. For alternative energy to get away from the problem of toxic releases, it will have to move to materials which are made entirely of carbon, hydrogen and oxygen. These include hydrocarbons and alcohols. Interestingly enough, hydrocarbons are a lot like fats, and sugars are alcohols...Reversing the greenhouse warming (we need the greenhouse effect or the earth freezes solid) needs further tricks. One that I like involves taking the methane clathrate deposits on the continental shelves (which are threatening to decompose to gas, and CH4 is about 200 times as good a greenhouse gas as CO2) and mining them for fuel. Crack the CH4 into H2 and carbon soot, then bury the soot (old coal mines seem appropriate). Burn the H2 in whatever is convenient.
With a few exceptions, those countries are generally producing their electricity from fossil fuel and exacerbating greenhouse warming something awful. China is a huge offender in this regard.In this DOE table you'll see that the total nameplate capacity of non-hydropower renewable energy generators in the country for 1999 was a whole 2000 megawatts. That is out of a total generating capacity of nearly 700,000 megawatts. The entire nameplate generating capacity would barely replace 2 nuclear plants, and probably have about 1/3 the capacity factor. If it's going to really be an alternative, it has a hell of a long way to go.
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This is why plutonium bombs are all implosion designs; a gun can't get a mass of plutonium into the right shape fast enough. The chain reaction starts prematurely, the bomb comes apart before more than a tiny fraction of the Pu has fissioned, and you get a "fizzle". This is the reason that it is nearly impossible to use recovered plutonium from power reactors to make bombs. Power reactor fuel spends years in a heavy neutron flux, and it is chock-full of higher isotopes of Pu (like Pu-240, Pu-241 and Pu-242) which have far higher spontaneous-fission rates than Pu-239. You'd need a bomb design made from scratch to use this stuff if you could use it at all. ISTR reading that the Russians had actually done isotope separation on their already-weapons-grade Pu to get rid of some of the higher Pu isotopes and make their weapons more reliable. If you're going to need gas-centrifuge gear anyway, you might as well go with uranium. Your chances of success are far better that way.
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Hydropower is also being opposed by the greenies because
- it destroys runs of migratory fish
- it creates emissions of greenhouse gases (methane) from the decay of submerged organic material
- it displaces people from their traditional lands and obliterates the archaeological record of an area.
I'm not saying I agree with all these charges, but if you are going to claim hydro is so great it is up to you to rebut the counterclaims.--
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The point is threefold:
- The design of the RMBK reactors used at Chernobyl was grossly unsafe. This is only a flaw in that design, it does not apply to PWR's, BWR's or HTGR's.
- Even so, the reactor wasn't a problem until it was operated in a patently unsafe manner.
- There still wouldn't have been a problem if the reactor had a proper containment building around it.
With US-style safeguards, nuclear power is safer by far than coal, and even safer than wind (working on towers is dangerous). There are more people killed every year in chemical plant explosions than could possibly ever die from all US nuclear accidents from Three Mile Island onward, and most years there are more bystanders killed by chemical plants than could ever die from nuke accidents from TMI on up. Funny, where's the greenie hype about chemical plants? Looks like selective blindness to me.--
As others have noted, the big threat is that Russian warheads will wind up with "FOR SALE" signs. Reactor fuel (raw, spent or re-refined) is not a proliferation threat.
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By your definition, no "proper" breeder reactor could have been built, because the weapons-grade Pu to fuel it has to be made in a breeder reactor. Check on the history of the Hanford N reactor to see where you went wrong.
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IIRC, South Africa's bomb tests showed that they could get a couple kilotons yield out of 80% U-235. This is still a hell of a long way from the 3% U-235 mix used for light-water reactor fuel.
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The way it'll be done is to have a super-insulated tank of LN2 or liquid air at more or less atmospheric pressure; no pressure container, no explosion risk. A pump draws liquid from the tank and pressurizes it to several thousand PSI. This liquid goes through the evaporator where it becomes high-pressure gas, which in turn operates the expander to produce power. This limits the high-pressure sections of the system to a few tubes instead of the entire fuel supply, and cuts weight and expense. A system designed for efficiency will have several expansion stages with a re-heat in between.
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One more response for the day before the limit kicks in.... have to decide priorities. <sigh>
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Everybody uses Kelvin these days, but you get exactly the same results with Rankine or any other absolute scale. You can prove this to yourself by multiplying the numerator and denominator of your equation by any non-zero factor. The result does not change.
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I'm waiting for systems which use cheap materials for storage to get around that. Something like a photosynthetic rooftop which converts CO2 and water into methanol (CH3OH) and oxygen would fit this bill, because the cost of storing a liquid like MeOH is minuscule compared to the cost of a battery or even the tanks for holding H2.
The energy density (both per volume and per mass) of mere hydrocarbon chemical fuels leaves every battery ever invented in the dirt. Don't even get me started with nuclear (you measure the output of a reactor fuel load in the tens of thousands of megawatt-days per ton).... There are many applications for which the need to carry your energy supply with you leads to a serious degradation in system performance when you try using renewables. Hydrocarbons and nuclear are not obsolete, quite the opposite. They are the gold standard that keeps renewables from gaining acceptance, because the systems for storing and delivering renewable energy fall so far short.--