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Fuel Cell Powered Japanese Trains on Trial in July
ScorpFromHell writes "As per this yahoo! news item, "East Japan Railway Co. is to conduct a test run of the world's first fuel-cell-powered train in July.
The fuel cells, which generate power from a chemical reaction between hydrogen and oxygen, will help reduce environmental pollution compared to the existing electric and diesel engines, the company said."
But I wonder how much energy did it consume to produce those huge amounts of Hydrogen & Oxygen? Will it be lesser than the power generated by the reaction between them?
In other words, can this technology be used by countries with not so deep pockets as Japan?"
Will it be lesser than the power generated by the reaction between them?
Of course it will... heard of Newton?
The fuel cells, which generate power from a chemical reaction between hydrogen and oxygen
That doesn't sound right. Usually "chemical reaction" infers that new molecules will be formed. As I understand it, in the case of most fuel cells, the electron is stripped from the hydrogen to produce electricity. If these cells were utilizing the combustion of H2 and O to form H2O, wouldn't that make them a powerplant rather than fuel cells?
Or am I totally off base here? (Feel free to mod me down if that proves to be the case.)
Javascript + Nintendo DSi = DSiCade
Fuel cells are an energy storage medium, not an energy source.
Centralizing power generation should be more efficient than millions of smaller generators all over the place.
Now, it's just a matter of finding out if generating, transporting, and storing the required hydrogen is environmentally/economically better than diesel or gasoline.
"In other words, can this technology be used by countries with not so deep pockets as Japan?"
I think a better question would be "Why isn't the U.S. doing more to be in the forefront of promoting alternative fuel sources?
Steve,
http://tail-f.net/
" I wonder how much energy did it consume to produce those huge amounts of Hydrogen & Oxygen? Will it be lesser than the power generated by the reaction between them? " But of course! Now you take the energy generated and then produce more Hydrogen and Oxygen, then put it back in the cells and generate yet even more energy. The world's energy problems are solved at last! And who would have thought -- by a Japanese train and an observant Slashdotter.
It's a lot closer to the way a battery works than it is to combustion. The hydrogen and oxygen react in the presence of a catalyst. Not much heat is generated. The energy that is released is in the form of an electron which is stripped, travels through your circuit releasing that energy as useful work and returns to complete the water molecule.
Seriously, what can be possibly better than electric trains? Unless your electricity comes from coal, in which case replacing the power station to something else, say nuclear, would make more sense.
.. sheesh!
Fuel cells are useful for energy storage. Perfect to, say, drive a car for a few hours, then dump some more into your energy storage, and drive back, in any direction. Also, they're good to bring energy to remote location. Setup a quick electricity generator in the middle of nowhere. But for trains? They go on tracks, so installing a few wires isn't too expensive or difficult, making the electricity transportation far more efficient trought wires than fitting fuel cells on every locomotive, and then carrying all that hydrogen and
Really, i see this as the wrong match of a technology to a need.
Hydrogen is best buddies with nuclear power. That's how it SHOULD be done too. The greenies can have their wind, and I shall watch them beg for my nuclear power. THAT'S satisfaction.
hold on a sec.... Electric train engines produce pollution? How is that possible?
Granted, a fair amount of power is lost in the transmission lines, but given that they're run at such a high voltage to begin with, that shouldn't be a huge issue (P=I^2*R). Is more power lost in the transmission process than the process necessary to manufacture and produce all this hydrogen and oxygen?
Fuel Cells are nifty as an energy storage medium, but for trains, they seem wholly inappropriate, especially when electric trains eliminate the need for a storage medium at all (and in a country as densly populated as Japan, this shouldn't be an issue at all)
-- If you try to fail and succeed, which have you done? - Uli's moose
Combustion is a chemical reaction.
The way a fuel cell works is the same as burning straight Hydrogen. 4 Hydrogen atoms combine with 2 Oxygen atoms to form 2 Water molecules. When you burn Hydrogen, it happens all at once in one big pop (or bang!). In a fuel cell, the atoms dissolve into the water at the electrodes and combine in solution. The reaction is much more controled and generates an electric potential at the electrodes.
As far as efficiency is concerned, the seperation of Hydrogen and Oxygen (by electrolosis) from water and the subsequent recombination in a fuel cell (creating electrical energy) is over 95% efficient. That compares to around 30% for a good diesel engine.
In high school, I actully built a rudementary fuel cell as a science project.
I would have though conventional railway electrification would be a better, more cost effective solution. You can make use of regenerative braking this way, as you've got a load sink to return your kinetic energy to.
Of course I haven't read the article, but I can't imagine where you'd send your regenerative braking power in this application. I'd guess that it would go the same way as a diesel-electric locomotive - dissipated as heat through a resistor load bank. What a waste.
Summarized this is a test vehicle being used on a non-electrified line in a mountainous region. The advantages are less local pollution (which can be a significant issue in mountainous regions where diesel exhaust can linger or even concentrate in valleys) and no large capitol investment in line electrification & maintenance. A side benefit is the advantages of an electrical train without power lines intruding into the landscape.
As a regular user of urban commuter rail service this sounds like an interesting development. The cost of electrifying a rail line is prohibitive yet the all-electric engines are quieter and less polluting, a big sell in expanding service in urban & ex-urban areas. Technology like this could certainly quiet the complaints of many neighbors as well as improve the air quality near central stations.
I don't read ACs: If a post isn't worth so much as a nom de plume to its author then I wont bother either.
Editors - how about feeding us some articles with some real info in them? There just might be some technical people in this crowd who'd read them.
Never shake hands with a man you meet in a fertility clinic.
Alright, everyone's going to jump down the guy's throat for:
/.er out there with some nice statistics for us all.
But I wonder how much energy did it consume to produce those huge amounts of Hydrogen & Oxygen? Will it be lesser than the power generated by the reaction between them?
However, I think we should question the efficiency of this. If it takes X amount of energy to run a normal train, but 4X to produce the fuel cell, then is that really a good thing? It's like people saying that electric cars are so much better for the environment. Instead of burning gasoline, you burn coal (or whatever) in the power plants. Is the efficiency of a power plant really so much better than your car?
I don't know the answer to that, but I'm sure there's a
Wer mit Ungeheuern kämpft, mag zusehn, dass er nicht dabei zum Ungeheuer wird. --Nietzsche
You need to look into how that hydrogen is being produced. The only large scale production of hydrogen that I know of makes hydrogen from natural gas, a fossil fuel. And it is amazingly wasteful and inefficent, and as dirty as burning natural gas or gasoline in a motor veichle. Although it does allow one to relocate the polution from a given area, it contributes even more to global warming than older technologies.
I'm an American. I love this country and the freedoms that we used to have.
Well, sir, there's nothing on earth ...
Like a genuine,
Bona fide,
Electrified,
Six-car
Monorail!
Proof by very large bribes. QED.
I gotta call BS on this 95% number; where are you getting it, because it is way off from the numbers I have seen.
--
WHO ATE MY BREAKFAST PANTS?
Having spent a lot of time analyzing the hydrogen economy in terms of generation, this topic is near and dear to my heart.
Hydrogen is a method of TRANSPORTING and STORING energy. It is not a solution to energy generation. As a storage and transport method, IMSO (S=Scientific), it is not particularly cost effective, and has as much potential for unforseen concequenses as any other untested energy method.
That said, I am highly in favor of fuel cells in general, and am happy to see them adopted more often.
In relation to the question asked about poorer countries, I would also hasten to point out that the fuel cells themselves are expensive, as they require (I believe) a platinum catalyst.
That is all.
hmmmm?
There is no system where there is no loss, but I think he was trying to lump coal-generated electricity into that statement. The reality is that the electricity to produce the hydrogen probably came from a coal fired plant anyway. Though I would venture a guess that there is less power loss by creating H2 at a factory and piping it to wherever you need it rather than pushing electricity over lines. Total energy cost is harder to predict though and most people rarely take into account needing to truck the stuff around, the extra energy required to carry the fuel, etc. etc. There's no way you're going to get that much info out of a short news clip.
Wow...pop? dissolve?
"As far as efficiency is concerned, the seperation of Hydrogen and Oxygen (by electrolysis) from water and the subsequent recombination in a fuel cell (creating electrical energy) is over 95% efficient."
Whoa! Sure that's the efficiency of electrolysis but then you have to compress and store the hydrogen (hydrogen storage is a whole thing in itself), then you have to feed it to a fuel cell that has an efficiency much less than 95%...usually less than 50% system efficiency. Overall, the total efficiency of hydrogen fuel cells is comparable to a diesel fueled vehicle, maybe even a bit less.
Of course, that's if you make the hydrogen by electrolysis. Most hydrogen comes from natural gas at the moment, which is less efficient and produces CO2.
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Although the article doesn't say, I think these will be used for trains that run in remote or mountainous areas (e.g., the Koumi Line) which aren't so easy to electrify.
While I'm all for fuel cells and cleaner use of energy, if it's one thing that most Japanese people want from their trains is NOT for them to use cleaner energy, but for the damn things to be BIGGER.
Nobody wants to get crushed in the morning by hundreds of alcohol reeking salary men storming onto the morning rush hour train every day. Nobody should have to put up with being fondled and "fart in the elevator" scenarios either, simply because the train is too small to handle the number of people it attempts to daily.
READY.
PRINT ""+-0
But I wonder how much energy did it consume to produce those huge amounts of Hydrogen & Oxygen?
Here in Canada, there's a lot of potential power that is let go through our hydro-electric dams at night due to the less demand at that time of the day. Instead of "wasting" that energy, you could produce quite a bit hydrogen that could be used for fuel cells or hydrogen driven cars.
Then there's always the sun, nuclear power, wind power etc.
The efficiency of electrolysis is very high, 95% is actually possible. BUT, electrolysis has nothing to do with generating power, electrolysis is how you separate water into H2 and O2. A fuel cell is actually less than 50% efficient, and the overall efficiency of hydrogen fuel cells is comparable or a little less than diesel fueled cars.
If you're burning oil or coal, you're definitely getting a dose of pollution, just not where you're using the electricity. Given the inefficiencies in generation and transmission, you're actually getting more pollution, only in a (perhaps) less visible and more centralised fashion.
The same holds true for nuclear energy, but if you're catching lightning in a bottle or using interns or hamsters to power your generators, you're probably OK.
"But I wonder how much energy did it consume to produce those huge amounts of Hydrogen & Oxygen? Will it be lesser than the power generated by the reaction between them?"
First law of thermodynamics says . . . NO!
And as Homer Simpson put it, "In this house we obey the laws of thermodynamics!"
It is absolutely meaningless to contemplate any feasible fuel alternative to gasoline as anything other than an energy transport mechanism, if you want it to be renewable. By very definition, you can't get more energy out of a system than is put in. Our fossil fuels represent millions of years of stored solar power, for example, and we just don't have millions of years to let potential fuels develop.
So.. for hydrogen as fuel, there's going to be more energy consumed in its making, than would be available to be extracted by the car. And, there are many studies that indicate that ethanol has a similar problem.
The only near term way either works is either by using coal plants or nuclear plants to produce it. Thus far, nuclear seems to be the preferred alternative, because, even if you take into account a periodic chernobyl sized disaster, nuclear power remains safer than fossil fuels when you correctly factor in the true costs of fossil fuels - greenhouse gasses, their own radioactive releases, mercury, etc. Natural gas is not an option, because, we are running out of that too. So really, to understand the cars of the future, you can't ask how the economics work versus gasoline, you have to ask, how do the economics work with other energy transport mechanisms, such as batteries, and have to accept that our energy portfolio needs to be nuclear, unless, barring some minor miracle, ITER actually works and we can start building fusion plants down the road.
This is my sig.
As far as efficiency is concerned, the seperation of Hydrogen and Oxygen (by electrolosis) from water and the subsequent recombination in a fuel cell (creating electrical energy) is over 95% efficient. That compares to around 30% for a good diesel engine.
WTF? But the diesel from the diesel engine is pumped out of the ground. There an energy potential in the oil. With the fuel cell, you have to use energy from somewhere (probably diesel) to make the energy potential (hydrogen). It wouldn't matter if the conversion from the hydrogen/oxygen to electricity was 100% efficient instead of 95%.
But that's largely irrellevant if the energy to produce them was derived from an energy source that is not exausted by use, such as solar, hydro, or geothermal sources.
File under 'M' for 'Manic ranting'
You gotta give the Japan people props about their notorious trains, because they're not trains, they're, I don't know, space ships.
How many G does a passenger feel as the "train" accelerates? I mean, some of them look up side down I wonder if the seats are on the roofs?
Also most of them don't actually touch the rails they fly on a magnetic fields or something, right?
Do passengers have to pass a special training to ride on one of those trains?
Has it happened that a Japanese train can't take a corner and just flies off never to be seen anymore?
Anyhow, I bet they are really proud of their trains, and they have to. Good luck with hydrogen bomb ones as well!
I mean hydrogen fuel cell, sorry.
Then there's the problem of many railway lines not being secured along their length like the systems you're referring to. It'd be rather ugly the first time some person or other large animal crossed a 3rd rail, at a grade crossing or otherwise...
I don't read ACs: If a post isn't worth so much as a nom de plume to its author then I wont bother either.
http://www.visionengineer.com/env/fc_efficiency.ph p
A nice graph of fuel cell efficiency.
Practical fuel cell efficiency is around 50% (it is temperature dependent), less if you are using methanol instead of pure hydrogen.
What, rich people should do things that are economically stupid?
It's not about this being stupidly inefficient, yet Japan can afford to do it anyway because they're rich. The question is, which is a more efficient use of electricity (or, more generally,. resources), running an electric train, or running a hydrogen/oxygen fuel cell train? Whether you're rich or poor, you should still use the technology that works best for you.
I think it might have occurred to someone in Japan to check and see if this is better than running a conventional electric train in otherwise similar conditions before building it. Although it's quite possible they didn't care. It could be like ethanol in the US, which is used for political reasons, not because it's an efficient way to improve the environment. Depending on who's counting, it generates between .7 and 1.5 times as much power as it consumes to make. We could reduce pollution (including carbon emissions) much more by spending the money we spend on ethanol on nuclear power, solar arrays, or wind power. Ethanol fuel, in it's present state, is government graft to benefit corn farmers and ease the conscience of environmentalists who don't understand it.
I am interested to know if this train really is about a great new technology for saving the environment, or a political ambition.
Can anyone tell me how to set my sig on Slashdot?
Does that take into account digging up and converting petroleum? And how much efficiency do we piss into the wind via our dependence on arab oil, and all the meddling we needs do to protect it?
Send lawyers, guns, and money!
Pop (as in boom), I guess you missed that science class. Very similar to the way methane burns (quickly and explosively).
As for dissolve... The atoms ionize at the electrodes (H gives up an electron to one electrode and O takes one from the other electrode) and dissolve into the electrolyte (which does not actually have to be liquid... It's usually some sort of gel in practical fuel cells). The electron given up by the O travels through the circuit from one electrode to the other, driving your load (i.e. doing the work).
Practically the efficiency is much less (i.e. if you actually want to do something with it). But if your load is close to zero, the temperature is low enough and you use the best materials possible (platinum infused teflon electrodes and highly concentrated KOH electrolyte, if memory serves correctly) you can get into the 95% range for efficiency. This is not practical, just possible.
Electric wires. Everywhere. Even at the most beautiful temples. Even in front of tremendous viewpoints.
Good lord, bring on the fuel cells.
Btw, if you are wondering about the first two, they are 1: Japanese men are sexist pigs and 2: The "$"#"#$ last train runs around 11:30 pm!
Yes, the initial energy does have to come from somewhere. In the end, it all comes from the sun (diesel is just rotten and compressed plant matter from a long time ago).
Direct solar energy is the ideal source of the energy to separate the water into hydrogen and oxygen.
Nuclear wants to be the one true energy monoculture - which is stupid when most of the installed plants are 1950's style economic white elephants and the newer designs like pebble bed lose the thermal energy economy of scale by having small safer units. It's a pity that the nuclear debate ranges between bare faced lies (too cheap to meter) and utter horror with little in between and so few agencies giving out real information. Find a real research reactor (clue - reasearch reactors in places like Indonesia, Pakistan, India, Israel, Nth Korea etc have a military bias) and listen to stuff that comes out of those places - they keep coming up with solutions to major problems that snake-oil salesmen trying to sell nuclear power pretend don't exist in the first place. A reasonable solution for waste storage has been worked out for a tiny fraction of the amount that was spent on advertising that nuclear power is "clean" and the stupid premise that if ash heaps at coal fired plants have traces of radioactivity then it's OK for nuclear power to spread radioactive waste about instead of constructively dealing with the problem.
Fuel Cell Powered Japanese Trains on Trial in July
What are they on trial for?
Huh? Ohhhhhh....
my pet machine
A pure Fuel cells system is in the order of 70-80% Combined with an average 80% motor, you have 50-60% efficiency.
OTH, if use a reformer rather than a regular storage system, you lose the bulk of the efficiency (lowers you to 30-40%). Combine that with the 80% motor, and you are in the 24-32% efficiency.
Sadly, an autmobile is around 20% efficiency. And that is only from the Gas forward. It does not include the previous inefficiencies.
Basically, we are using one of the worse systems possible. It just got developed and marketed first.
I prefer the "u" in honour as it seems to be missing these days.
I think it also needs to be pointed out that when comparing the relative efficiencies of engines, you need to decide on what kind of output power you're going to use as the standard. I.e., is your end-product going to be mechanical motion or electricity? Because the fuel cell will always have a bit of an advantage over a diesel engine at producing electricity, because to get electricity from a diesel engine requires a generator; conversely deriving mechanical energy from a fuel cell requires a motor.
So if we're talking about trains/buses/cars, you also have to factor in the loss in the motor and its associated equipment. (Alternators, because they don't run on DC usually; speed controls, etc.)
And of course, there's the ever-present problem of where you're getting the energy from that goes into a fuel cell's fuel in the first place. If you're going to split them from water, that's a very energy-intensive process, as is cracking natural gas. Unless you're planning to tap some sort of very green and otherwise-surplus energy to create the fuel, this should really be part of the whole comparison. Since only a few countries seem to have any plan that eliminates a dependence on fossil fuel for electricity generation (France with its nuclear plants, Iceland has geothermal, feel free to add to this list), it seems likely that petroleum or natural gas will be the ultimate energy source here. And that requires adding electric-distribution losses in, and comparing it to the energy investment in the transportation and distribution of liquid fuels.
I'd really be interested in seeing a rigorous, "well to wheels" (or 'well to rails,' in the case of a train) analysis, showing what the advantage was in terms of fuel consumption for a fuel cell vehicle that's ultimately powered by a fossil-fuel energy source, and a well-designed hybrid internal-combustion/electric system. I have a feeling that a well-built diesel-electric may win out; but I'd like to see a fair comparison. I'd also like to see an economic analysis of how much each one costs right now in terms of variable input costs, and under what conditions one would become preferable to each other. (If the diesel-electric is cheaper now, would there ever be a point where petroleum gets so expensive that fuel cells are preferred? If so, when?)
I salute the Japanese for experimenting with this technology (and also on investing in a rail system that doesn't suck, which is more than I can say for the US), but I just wonder if the science and economics behind it work out.
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But going from electricity to hydrogen you've already paid the carnot-cycle efficiency penalty. You used a power plant which (being big and stationary) can run a bit more efficiently than a portable plant like a diesel, but not all THAT more efficiently - just a few percent better. THEN you paid ANOTHER penalty, almost as steep, to make the hydrogen and run it through a fuel cell.
The one big advangage of fuel cells is that the cycle is essentially the same as a storage battery, not a heat engine. It doesn't have to pay the carnot cycle tax again. In principle fuel cells COULD get very efficient - eventually.
In practice the hydrogen-to-electricity part of the fuel cell cycle is already far ahead of anything a heat engine could ever do. So if you're already committed to using hydrogen to run your train, to avoid discharging pollution in an urban area, you're MUCH more energy efficient using fuel cells than if you use a heat engine to run a generator.
But you're farther ahead to use a trolley wire.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Indeed. Japan could use any of a number of environmentally friendly but nonmobile methods (large arrays of solar cells, wind power from offshore windmills, etc.) to generate the hydrogen and oxygen, then use the fuel cells to make use of the stored energy from the hydrogen and oxygen in the train where the solar cells or windmills would be infeasible.
There's better ways to store hydrogen than compressing it like you would propane or CO2.
1 2070501.asp
http://www.rsc.org/chemistryworld/News/2005/July/
I think you'd like that short article. And maybe an article saying "screw using fossil fuels for everyfreakingthing"... at least that's my motto.
http://www.zetatalk.com/energy/tengy14r.htm
That train is nothing. The Japanese have totally been schooled by Greenpiece. Haven't you seen their wind-powered train? It gets more power the windier it gets!
Canada announced today that they're going fully environmental and will power their trains with weasels. "We realize that we're the first to tap the weasel energy source. Canada is a great country and we got plenty of weasels." Henry Smith said with a wide smile on his lips. "If you just put them inside a wheel connected to a generator, and then get them to run in the same direction, you can easily tap enough power to travel from Ottawa to Toronto on one load of weasels." When asked about the inhumane working conditions for the weasels, Mr Smith answered "Well, Canadians can beat the crap out of cute little seals without any iinternational sanctions, so who would care about a couple of hundred thousands of weasels?" The fact is that weasels are environmentally friendly, and once they've been used up, there's always the market for their furs. Canada is once again showing their ingenuity.
Infeasible? On the train sounds like the perfect place to install a "windmill". I mean there's always gonna be a 100km/hr wind around when it's in use.
Somewhat off topic, but anyway:
Where I live (Sweden) there are seemingly lots of just-starting-up ethanol production plants along with lots and lots of ethanol buses in our towns. And the number of "green" cars is steadily rising, many of which run on the stuff. (Tax breaks and exemption from congestion charges being the main incentives.)
I realize it's a poor argument, but if there was something fundamentally wrong with using ethanol as a medium- or large-scale alternative to fossil fuels I think someone would have pointed it out by now. There is the occasional criticism; it's are mostly "but will it be competitive with ethanol made in Brazil from sugar canes?", though.
On the other hand, I bet it's a lot more expensive than refining the black stuff that comes out of the ground. Fortunately for us, our ~= 200% taxes has prepared us for that...
Hm, Jeroen Tel's excellent tune "Alternative Fuel" is coming up on Kohina as I'm typing this. Coincidence? Of course not. I guess I'll have to post this now.
The issue with ethanol is twofold:
(a) what is the net carbon effect on the atmosphere. Ethanol produced from cane gets its carbon from the atmosphere, so it is not going to contribute to increases in CO2, shown to be a primary driver for global climate change.
(b) what does it cost to produce? *if* it's carbon neutral, all that matters is the cost. It doesn't matter how inefficient it is.
You know about the ethanol economy in Brazil? I think there is just far too much misinformation about ethanol going around.
Uhmm, oxidation by any means in this case what amounts to a catalyst IS a chemical reaction the byproducts being H2O and electron's molecules created and as a bonus electricity it even fits the parent post definition of chemistry (however flawed a definition it may be...). What, were all the chemistry geeks asleep?
It is absurd to run trains on power generated by a fuel cell when the train can be powered by electric motors
which receive power from overhead electric lines.
If the Apollo spacecraft could have tapped into electric power along the way, it wouldn't have used fuel cells either.
Why not just get it over with and change the name of Slashdot to "Buzzword-dot" ?
In other words, can this technology be used by countries with not so deep pockets as Japan?
Yeah, I can't think of another single country that could possibly have pockets as deep as Japan's. Nope. Not a single one. *Especially* countries that use lots and lots of oil, and could benefit from using less of it. I mean, Japan is so huge. And their industrial might is second to none. How could anyone possibly catch up?
"No problem. I have the capacity to do infinite work so long as you don't mind that my quality approaches zero."-Dilbert
Direct solar energy is the ideal source of the energy to separate the water into hydrogen and oxygen.
Okay, I'll bite here. Has anyone ever done the math to see how much electrical energy would be required to produce enough hydrogen and oxygen to power a number of fuel cell vehicles that's anywhere close to our current transportation needs? And then gone and multiplied that number by the energy output of the best solar panels? I haven't done the calculation, but I have this feeling that the area would just be prohibitively large.
I have heard, though, that the energy that we use for transportation, in the form of liquid petroleum fuels, is actually greater than the amount of electricity we use.[1] So to have direct solar energy be a feasible power source for transportation would actually be a BIGGER undertaking than replacing every current power plant.
[1] Just some back-of-the-envelope calculations:
US Oil Consumption: 20 M bbl. oil / day * 158.984 liters / bbl = 3.18 B liters oil / day * 0.873 kg / liter = 2.78 B kg oil / day
2.78 B kg oil / day * 45MJ / kg = 1.25 × 10^17 J / day == 1.44576042 × 10^12 W = 1.45 TW
Transportation believed to account for ~50% of oil consumption, so transportation is 725 GW.
According to Wikipedia, the average total electrical power consumption of the entire world is around 1.7 TW, on average, the US is 424.3 GW (2001).
So conservatively, the amount of new, green generating capacity we'd need to create in order to replace oil for transportation fuel, would be (assuming roughly equal efficiencies) 170% of what we have in use today (also assuming we want to have the same excess generating capacity as we do now). I think the only way that direct solar would be feasible is if there was some huge step forward in the technology; but if we're placing bets on giant technological breakthroughs, why not just pray for fusion? (Or Tesla's magical Free Energy apparatus?)
Obviously this is a very rough calculation, but I think it's helpful to go through, if only to remind us yet again of the sheer size and scope of the energies that are being talked about in proposing solutions for the transportation problem.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
if only people who actually understood, say, chemistry or electricity or, or, or _English_ were allowed to post on news items? I mean, come on, "lesser than"?!
And yes, a fuel cell strips electrons from H2 in the process of creating H2O from H2 and O2 - a chemical reaction - and no, it does not take "lesser" energy to create the gases than is generated! But it sure generates less smog and polution than diesel, and is arguably as effecient as transmitting high-voltage electricity over long distances.
-- Let him who is without spelling error ignite the first flame --
If the system efficiency is near 50% it's a lot better than diesel. Only the most efficient diesel reaches 50% efficiency and it's the size of a house, it's in a container ship. Last I checked it was the most efficient internal combustion engine on the planet. Granted, a turbo diesel is the most efficient internal combustion powerplant for automotive use, but that's not saying much since last I looked it up, the really efficient gasoline engines were hitting around 26%. Not sure where the automotive engines are but they're not any 50%. (It would be interesting to know what the efficiency of the VW TDI engines is.) If the hydrogen is indeed produced through electrolysis (not altogether unlikely in Japan) then this is much more efficient than diesel. The engines used in trains should be somewhere in between an automotive engine and the best case, depending on the size.
This train is specifically using the hydrogen fuel cell system instead of diesel-electric, which involves running the diesel to a generator, and then using the resulting power generation to run electric motors. The generator and motors are each, best case, probably around 90% efficient. That's a 19% loss in efficiency, unless I'm doing the math totally wrong - but it's not great no matter how you look at it. The diesels themselves, as above, will be less than 50% efficient. Using a manual gearbox would provide something like 10% loss in efficiency, which would be less than using a diesel-electric system, but then you'd be shredding gearboxes and clutches all the time, so that's no solution either.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Electricity - consumption: 3.656 trillion kWh (2003)
/ us.html
http://www.cia.gov/cia/publications/factbook/geos
My vote is for fusion too.
But I wonder how much energy did it consume to produce those huge amounts of Hydrogen & Oxygen? Will it be lesser than the power generated by the reaction between them?
Even if it takes about the same energy to produce the chemicals, this is ok. Don't think of a fuel cell as an energy producer, it's an energy storage device. This is like a battery. When you charge a battery, you don't get a net increase in energy. You are merely moving electricity that is produced in an electric plant into the battery. The train is the same idea. With something the same size as a train, I can't see any reason not to just use a battery. In fact, you could potentially have a batery car or something like that to store the energy and it would be cheaper than fuel cells. Fuel cells are mainly interesting in automobile applications because their energy storage density is greater than Lithium batteries. Still it's good to see work being done on the fuel cell front.
No Sigs!
My understanding is that it's possible for ethanol production from corn stocks to be energy-positive but it takes expensive equipment. However, it's pretty well-known that there are other stocks from which ethanol can be generated that are more easily energy-positive. You're quite right about the fact that ethanol production from corn stocks in the US is currently just another farm subsidy, though.
Of course, if you're really going to be doing biofuel, you're better off doing biodiesel, which is definitely energy-positive, and which has significantly higher energy density than either ethanol or veggie oil - just thought I'd throw the veg in there to cover all the bases.
However, in any case, topsoil-based fuels are the completely wrong way to go. If we're going to do biofuel, we need to be growing the fuel stocks hydroponically. All farming leads to the depletion of topsoil one way or another, whether it's blowing away because it's not covered by the native grasses that protected it and let it get to where it was, or because of depletion due to a lack of rotation which I can see being a huge potential problem if you're growing crops so you can turn them into fuel. Topsoil is less than 40% mineral... Hell, IIRC, it's significantly less.
In my opinion, if you can't get the power from substantially low-impact sources like wind, solar, or tidal, then it should be nuclear, and breeder reactors should be used, because depending on who you believe, they reduce waste (or improve efficiency, however you want to look at it) by something between two and three orders of magnitude. Then the real issue is how to store and transfer that power. Hydrogen is a reasonable way to accomplish that, especially using fuel cells, provided you can keep the energy consumption and pollution down in the manufacturing process.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
More people die every year due to accidents in coal mining and accidents at coal-burning power plants than have died due to all the nuclear accidents put together.
More nuclear material is released into the atmosphere every year due to the burning of coal for electrical power alone (not counting heating) than has been released by all the nuclear accidents that have ever occurred. In 2000, the US alone released around 1250 metric tons of uranium and 5000 metric tons of thorium. Want another fucked up statistic about coal power? If we could extract the nuclear material from the coal, and burn it in nuclear reactors, it would produce more power than burning the coal it's contained in does.
Moving to using breeder reactors to refine fuel for reuse would, IIRC, reduce the amount of nuclear fuel necessary to produce our current output by three orders of magnitude.
On the other hand, solar has already surpassed nuclear for power generation, although maybe that's just in the US or something, not sure if it's a worldwide statistic or not, and wind is well on its way. The solution might be to build more solar and wind power generation facilities. Solar mostly produces power during the day, which is when we need it the most. Wind produces (or doesn't produce, depending on wind) power both during the day and at night. If we used electrolysis to produce hydrogen, and had a highly efficient way to convert it back to electrical energy (like a fuel cell... but they're not cheap to make, which says to me that they probably produce significant pollution and require a lot of energy to put together) it might be a reasonable means of storing excess electrical power, to provide more constant production.
I do believe, however, that we will probably always need nuclear power (fission today, perhaps fusion "tomorrow") for producing industrial power, at least unless we build solar power satellites, or tap the vacuum energy, probably leading to the premature collapse of the universe or something. TANSTAAFL, after all.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Maybe we'd have several working ITER like plants if my gov't (the US, I'd say "our" but I'm not certain where you are) would spend more than a minuscule amount on it. $50M on ITER, "Fossil Energy Research's department budget of $491.5M", and another $200M efforts to clean up the pollution after burning coal. It's a joke. The DOEn doesn't get near enough money, and that they do get isn't well spent. There's also about $200M in "renewable energy in the form of bioenergy and bioproducts". I think these are 2005 Budget numbers I pulled out of a blog I wrote last October.
CH4 + O2 + Energy --> CH3 + H02 (Chain initiation)
(I'll skip the rest of heavy organic chemistry lecture. The short form is here but be ready to consult an organic chemistry and and a combustion theory book for the nitty gritty details.)
From there you have a series of other chemical reactions where energy is released as the compounds break down into CO2 and H20 (Carbon Dioxide and Water).
The amount of energy released is fixed by the amount of methane burned. (I am assuming an idealized stoichiometric reaction with no left overs or pollutants) The method of capturing and using the energy released is what is important.
If you burn the fuel you get: heat and pressure. From there you can use it to generate steam power, electrical power, etc etc etc. The current efficiencies on gasoline engines (in your car) is running around 30%. Most of the waste energy goes out the tail pipe or the radiator. If you are planning on producing electrical energy or driving a vehicle from the power of the engine, you also have to start considering drive train losses.
In a fuel cell: energy is provided to strip chemical bonds that hold methane together, then hydrogen is seperated and then allowed to recombine with the oxygen to make water, the carbon forms carbon dioxide. The second two reactions produce energy. The trick to the fuel cell is that less of the energy is wasted in lost heat, pressure, etc. Efficiencies in fuel cells easily run over forty percent, are quieter and have less drive train losses. The electrical power drives the motor directly with no transmission or gear losses.
Architectural plans are like computer source code with a couple of differences: You only compile once.
Crazy Japanese, first the exoskeleton, and now this...
mk
Also I have heard that GE has a coal gassification turbine that runs in the area of 60% efficient. And that is with the waste and pollution controls factored into the energy cost.
Architectural plans are like computer source code with a couple of differences: You only compile once.
AFAIK, nearly all of Japan's trains are powered by electricity. And they already have the distribution system set up with overhead wires! What advantage are fuel cells going to offer besides the powerloss when hydrogen is converted to electricity in the cell!
Also I have heard that GE has a coal gassification turbine that runs in the area of 60% efficient.
Sorry, those numbers aren't possible for a heat engine operating at reasonable temperatures (i.e. below plasma on the hot end and above cryogenic on the cold) You don't GET half the energy from heat into work - you gotta burn the fuel at some sane temperature and dump the heat in a cooler place, and there's a limit to both how hot you can run your combustion and how cool a heatsink you can dump gigawatts of heat into on the planet's surface.
(That's why running fuel cells directly on fossil fuels - rather than on hydrogen generated by using post-carnot-cycle energy to crack water - is so attractive. Fuel cells are NOT heat engines and don't have a carnot cycle limit. They're batteries and can approach 100%.)
I'd suspect they're talking about percentage of perfect carnot cycle efficiency, rather than fraction of heat energy turned into work or electricity. But in that case they sound a tad low.
Perhaps they're talking about a plant that uses the "waste heat" for something else useful (like process steam for a manufacturing plant)?
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Did the studies of ethanol include free energy such as the sun?
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The current debate on nuclear reactors at least here is not so much reactors themselves as where and how to store the waste securely for how many hundred years?
Your electrician dad will love them... ;-)
The greenies won't get their wind. The Chinese government who would most likely do nasty things to vocal greenies will be getting wind instead.
Except that the article is talking about Japan. You know, a little independent nation just east of China.
On the other hand, solar has already surpassed nuclear for power generation, although maybe that's just in the US or something, not sure if it's a worldwide statistic or not, and wind is well on its way
Solar power is not even close to passing nuclear for power generation, and neither is wind.
This is my sig.
No other energy source offer the same energy per volume efficiency, energy per weight efficiency and power burst.
Nuclear energy does, and even with a huge margin on all accounts. It's a bit impractical to use for driving a car forward, though.
I have a really elegant proof for Fermat's last theorem. If this sig was only a bit longer...
There are extensive tests and research into various algae that produce hydrogen from water in sunlight. (Think vast fields of the stuff in the UAE when the oil runs out :-)
http://www.green-trust.org/2000/algaehydrogen.htm
I wonder if that train will be named the "Apollo 13". Megatokyo, we have a problem!
The solution is electrified railways with overhead wire and nuclear powerstations to feed them. The russians have recently finished electrocuting the entire 11.000 kilometers of their Transsiberian Line. it is only the yankee who have polluting all-diesel locomotive fleets. Civilized countries have electric locomotives everywhere.
When they give a %-efficient, they are, indeed, talking thermodynamic efficiency, not fraction
of carnot efficiency. All turbine-style power generation techniques are limited by the
carnot efficiency, but modern turbines operate at such enormous pressures and temperatures
that high thermodynamic efficiences are possible.
Modern power plants can and do get 60+ percent thermodynamic efficiency by using gas turbines
as the primary generation step and then reclaiming the waste heat to drive a steam turbine.
Google for "combined cycle" and see what you can come up with.
Replacing the gas turbines with industrial fuel cells will improve this even further.
*sigh* back to work...
Gotta call BS on that one. No engine that relies on thermal expansion and contraction to produce movement can ever be more than 50% efficient. That is a limitation of the Laws of Physics, and won't be overcome by invention. You can try to capture more of the heat and KE remaining in the exhaust, but you'll never get it all: the second law of thermodynamics is against you. The Victorians were building steam engines where the exhaust from one cylinder powered another cylinder and sometimes even a third, but this cannot be continued indefinitely: diminishing returns set in because the cylinders need to get bigger as the pressure decreases, increasing the friction between piston and cylinder. A double expansion engine gives a slight efficiency boost, a triple expansion engine more so, but a quadruple expansion engine is barely better than a triple.
..... they also need electricity, and perhaps compressed air. The engine can run a compressor directly, cutting some inefficiency.
OTOH, if you actually want heat, you can get apparently higher efficiency at turning fuel into something else besides heat. Suppose you have a generating plant that burns some fuel and gets 25% of the energy stored in the fuel to come out as electricity. That means 75% of the energy stored in the fuel is coming out as heat. Now, big buildings such as office blocks and factories need heating
Now suppose that instead of installing an ordinary boiler that will turn fuel into heat, you install a generator set with a water-cooled engine that will turn the same fuel into heat and electricity. You put in 4 units of fuel and get out 3 units of heat {which you needed anyway, to keep the factory warm; workers go on strike if it's too cold, and machinery seizes up when the grease solidifies} plus 1 unit of electricity. A simple boiler would have needed only 3 units of fuel to get the same 3 units of heat; but that extra one unit of fuel is not wasted. You have just turned it into one whole unit of electricity! Since this is a factory, the electricity can be used on site.
Even if this arrangement does not provide the factory's entire electrical or compressed air requirements {and it almost certainly won't}, you will still get a whole unit of electricity for the price of just one unit of heating fuel.
Je fume. Tu fumes. Nous fûmes!
Sorry, those numbers aren't possible for a heat engine operating at reasonable temperatures (i.e. below plasma on the hot end and above cryogenic on the cold)
So, tell me: what's the carnot limit on the efficiency of a system operating at a combustion temperature of 1800 K, dumping waste heat at 400 K? Bit higher than the 60% figure he mentioned, isn't it?
There are existing, operating natural gas combined cycle plants with efficiencies close to 60%, and they're constantly finding new ways to improve the designs (for example, use closed cycle steam instead of bleed air to cool the turbine blades, or use a Kalina cycle for bottoming.)
Hmmm. I'm thinking "hair removal"...
THAT's a lot of hair removal to power that train... It'll stink all the way down the line. Like a rolling hair dryer with a head stuck in it, ignored by the attendant yacking with another customer whose hair is ALSO about to let catch fire...
But, I suppose an electrolysis-driven train speeding like a Shinkansen would be ummm... a "hair-raising" experience....
So, what's gonna be that, umm... "train's gender"? (pun intended)
Hmmm... image word: "petting"
Previously: "Linux... Toward the Sunrise..." Now: "Linux... Toward the-- No, now, part of Every Sunrise"
It occurs to me that trains are a great place to try out fuel cells and their related infrastructure. I mean that equipment right now is pretty hefty and large, but in a train that doesn't matter that much (when compared to a bus or a normal car) --- in the worst case you create a large locomotive that you cram with tech. So maybe a train is just a great test bed for this kind of new technology. Just guessing though.
"If the system efficiency is near 50% it's a lot better than diesel."
The fuel cell system efficiency is close to 50%. Accounting for the well to wheel which includes generating and storing hydrogen, then the total efficiency is near the well-to-wheel efficiency of a diesel car.
I'd rather call the "pop" a combuston reaction and the "dissolve" an electrochemical reaction. There is no dissolution, hydrogen is oxidized, oxygen is reduced, the resulting potential difference causes electron and ion flow.
There is absolutely no way a fuel cell can do anything at 95% efficiency, other than perhaps slowly charge a battery. You're right in saying that at low currents, efficiency is higher, but you can't drive a car at low currents...Electrolysis can afford to be slow though because typically the hydrogen is produced over night, and so the efficiency of an electrolyzer can reach 95%.
You also must realize though that this is 95% of it's theroretical maximum efficiency, which is not 100% for an electrochemical reaction, it's close to around 85% at room temperature and goes down as temperature increases.
But I wonder how much energy did it consume to produce those huge amounts of Hydrogen & Oxygen? Will it be lesser than the power generated by the reaction between them?
Short answer. NO.
Long answer. NO, because it would violate the rules of thermodynamics.
What you're asking is can you get more energy out of a battery than you put into it.
LK
"Hi. This is my friend, Jack Shit, and you don't know him." - Lord Kano
In the name of "saving the environment" I envision hundreds of millions of vehicles powered by fuel cells emitting tons of water vapor in exchange for hydrocarbon pollutants. The problem is that water vapor has a huge greenhouse effect-- Just look at Venus and its heat which is incompatible with human life. So catastrophic climate changes and the end of mankind is brought about by excessive water vapor emmissions.
Save the world... Drive a big SUV which is powered by less toxic liquified dinosaur juice and can carry 8 passengers and thus is more efficient since it has a higher miles per gallon per passenger ratio.
First: what are we comparing here? combustion engine vs fuel-cell based engine.
Now, the *environmental* issue is not: which uses more energy? The environmental issue is: which *pollutes* most? It boils down to the fact that the fuel cell can be refilled by electricity taken from the grid (hydrogen and oxigin can be generated by performing electrolysis on water, therefor, net result: the fuel cell is refilled by electricity from the grid). Electricity on the grid can be generated in many ways and as environment-friendly as possible (set up wind-turbines and you have near-zero pollution). The combustion engine is polluting, end of line, no two ways about it. So, *can* the environment win with this solution? Yes!
The economical issue: Fossil fuel is running out and becoming more and more expensive. Prices can fluctuate, so it's a bad thing for the stability of the cash-flow of your business. Since electricity from the grid can be produced in many ways, it's easy to switch your electricity provider, so prices will remain reasonable. So, *can* a business win with this solution? Yes!
Conclusion: fuel cells are a good thing when used in a rational way. Choosing for fossil fuel is a political or biased choice rather than a rational choice.
And what if there's nothing behind the door until it is being opened?
heh.
I wonder what they're planning on doing about the used-up PEMs [Proton Exchange Membranes]that they'll have to replace every 6 months, or so [google.com]. Those things aren't cheap, nor are they exactly environmentally friendly.
You failed to confirm you are a human. Please double-check the image and make sure you typed in what it says..
funny thing is... that word [as obscured as it is] looks a lot like "failed"
Iceland is ramping up to use geothermal to split seawater for use in fuel cells:
http://news.bbc.co.uk/2/hi/science/nature/1727312
So, they're using hot water to split cold water into fuel that emits warm water. Where's the pollution? Hell, about the worst that could come from it is a catastrophic accident prodicing massive quantities of NaOH, resulting in a bumper season for lutefisk. Talk of toxic waste...
I hope they have a good lawyer
The problems with any hydrogen/oxygen storage mediums are: 1) Even liquid hydrogen has low densities 2) The potential for a devastating explosion with a hydrogen leak is a serious danger. And since hydrogen is colorless and odorless, one may not detect the leak until it's too late.
If you have to burn one gallon of ethanol (or equivalent energy) to make .7 gallons of ethanol, then it doesn't matter how inefficient it is?
If you get the "extra" power you sink into the process from, say, solar, wind, or nuclear, then it's still carbon neutral. But it's still incredibly stupid if the whole process serves only to waste power and subsidize corn farming. So yes, it is about the efficiency.
Even doing something that's marginally really cheap, but losses money every time you do it, is still a stupid thing to do. So cost doesn't matter at all, it's all about the efficiency.
Can anyone tell me how to set my sig on Slashdot?
FTS (From the summary): But I wonder how much energy did it consume to produce those huge amounts of Hydrogen & Oxygen?
Consider this... Japan has to import all its oil. There is hardly a drop they can get from their own land. They are more dependant than the United States since we still have the Gulf Coast and Alaska. It might cost them less to produce fuel cells with nuclear power than to import more oil.
"I am the king of the Romans, and am superior to rules of grammar!"
-Sigismund, Holy Roman Emperor (1368-1437)
Looking at this National Debt by % of GDP Japan has a much higher percentage of debt than the United States: 170% vs. 64.7%.
And if you cross reference those numbers with the GDP by Country they actually have more debt in terms of dollars also.
Kinda scary.
Claimer: IAACHE (I am a Chemical Engineer)
I did undergraduate research at the University of Texas on a way to separate ethane from ethene (ethylene) without using expensive cryogenic distillation. The idea was for the mixture of gases to pass over a liquid phase that would selectively absorb ethylene at certain pressure, which could be released by a simple pressure swing, after the liquid was saturated with gas. I'm not sure how that turned out, but gas separation has progressed tremendously in the past 10 or so years.
Just this week I saw an ad for nitrogen and hydrogen gas generators: http://www.parker.com/ags The technique uses hollow microfibers that are selectively permeable. Just put compressed air in, and get out pure nitrogen while separating the oxygen, water, and other trace gases. Also back at UT, I had a different professor who wanted to make windows out of these semi-permeable membranes, which would basically serve as air purifiers--oxygen diffuses in, carbon dioxide diffuses out.
Some bastard at Parker posted info about the hydrogen gas separation in a freaking MSWord doc, so here's an excerpt for those who don't have Word:
There's nothing new about using hydrolysis to make hydrogen from water, but being able to easily separate that hydrogen is very important if you don't want to foul your fuel-cell catalyst with contaminants.Si la vida me da palo, yo la voy a soportar Si la vida me da palo, yo la voy a espabilar
You're making a false distinction here: almost all chemical reactions are ruled by electronics. All reactive and physical properties of elements and molecules are governed by the distribution of electrons (although the distribution of electrons is determined by the number of protons in the nucleus, of course). Polar means that the electrons in a molecule are unevenly distributed. Nonpolar means they're evenly distributed. Reactivity is determined exclusively by how badly a molecule "wants" to give or receive electrons.
Anyway, if it helps you to make sense of it, think of a fuel cell as a very slow, controlled combustion that produces little heat. Generating H2 and O2 from water is a separation of charge (and therefore consumes energy). Recombining those charges generates current. Normally that requires a high activation energy (ignition with a spark) and is very rapid, very exothermic. The fuel cell catalyst lowers the activation energy of the combustion process, and the fuel cell system regulates the overall reaction rate. But guess what? This process is exactly how plants photosynthesize. The electron transport chain uses solar energy to split water, then stores that energy, from the charge separation, as sugar. Then via respiration (aerobic metabolism), the plants turn the sugar back into energy. All life, whether aerobic or anaerobic, depends on the ability to separate and recombine charge.
What we really need to do is figure out how to make a fuel cell powered by glucose.
The point I'm getting at is that the article feels incredibly imprecise. There is an electrochemical reaction occurring that produces power output, but the actual chemical reaction is not harnessed. Or at least, that's the one way of looking at it. You do still end up with a recombination of the electrons, protons, and oxygen to produce water in the end so I guess I can't entirely fault the article.
Actually, I would argue that you can entirely fault the article. It was a worthless stub, and was indeed incredibly imprecise. All the useful information was already given in the /. writeup.
Si la vida me da palo, yo la voy a soportar Si la vida me da palo, yo la voy a espabilar
you're way off base with your heat engine. there is no law that requires efficiency to be less than 50%. only that efficiency of any heat engine can never be 100%.
the theoretical limit is
1- (Tc/Th) where
Tc is the temperature of your exhaust(cold resevoir)
and
Th is the temeprature of your hot resevoir(basically, how hot you get the material)
If your cold resevoir is at absolute 0, you can have 100% efficency(impossible) but let's look at other options:
a gas engine , given some compression ratio, has a max efficiency of:
1-s^(f-1) where
s: inverse of the compression ratio
f: f is approximately 7/5 for air
so if you can get your compression ratio extremely high, you can be efficient.
btw, its probably a bad idea to make up physics on slashdot.
all these numbers are from : Thermal Physics by Schroeder
7/9 or ~78%.
much, but I didn't know they could get the working material up to 1800 K ever. I've only heard of numbers in the 800 to 900 range. Anyways, carnot is not a good engine to compare to because it takes infinite time to do a carnot cycle. its probably the stirling engine would give better numbers though i don't remmeber its efficiency formula. I think its along the lines of 1-sqrt[(tc/th)]
Centralized power generation would seem to be (in some cases) better because the efficiency of the generator increases. But there are losses in transmission that also come into play. I don't know exactly how great these are, but common sense says that getting the power from the generator to the user is less and less efficient the further way the user is.
:-)
Of course, there's a "transmission cost" for fossil fuels that includes piping it from wells to the gulf, sending it across the ocean in a tanker, piping it to the refinery and trucking it to the stations.
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I have to agree, but I'm not giving it back!
The ways of the mods are mysterious (and mostly idiotic).
It's not offtopic, dumbass. It's orthogonal.
At the time of this posting, the parent is modded troll. But it's actually pretty funny. Admittedly, It took me a while to understand what the poster was trying to say, though. And I am a Japanese.
chp is ok when you need quite a bit of low quality heat (e.g. heating buildings) and some power would be nice too and as you say for true chp you need localised generation.
but i see several major issues with it
1: what do you do in midsummer? (assuming you aren't somewhere cold enough to use heating all year round) i can't imagine chp plant will be very efficiant when its being used as pure power plant
2: you are probablly going to control the chp plant for its heat output so you get the same issues as renewables, namely what do you do with excess leccy (this is actually somewhere where hydrogen electrolosis for vehicle fuel could help as it could be easilly controlled based on the power demand of the grid)?
3: most people wouldn't wan't to be fagged with loading up solid fuel and the control systems would be tricky. Deisel and petrol are very expensive fuels. That just leaves natural gas which is very awkward to transport and the first world is running out of local supplies of.
note: i'm known as plugwash most places but i screwd up registering that here somehow in the past and now can't register
much, but I didn't know they could get the working material up to 1800 K ever.
The temperature of the working fluid in a combustion turbine is higher than the temperature of the solid materials that make up the turbine. This is one of the advantages of an internal combustion system -- you don't need to transfer the heat through a solid/fluid interface.
In turbines, the blades (which are traveling at high speed through the hot gas) are the high tech parts. They are often made of directionally crystallized superalloys, are coated with refractory thermal barriers, and are designed to have cooling channels run through them so they stay cool enough to avoid creep from centrifugal stress. Some fraction of the air from the compressor is directed through the blades for cooling or (more recently) steam is routed through the blades before being sent on to the steam turbine bottoming cycle.
Rocket engines, btw, often have thermal efficiencies in excess of 90%. The temperature of the gas in the thrust chamber is usually higher than the melting/sublimation point of any material.
But I wonder how much energy did it consume to produce those huge amounts of Hydrogen & Oxygen? Will it be lesser than the power generated by the reaction between them?
Fuel cells and hydrogen are not a power generation technology. They are a power *storage* and *transportation* technology. This has been said time and time again. Get over it. You're not being clever. You are not poking holes in the hydrogen economy. You are simply missing the point. Please educate yourself, because you people are really starting to irritate me.
Just to be clear, fuel cells aren't a power generation mechanism. They're a power /storage/ mechanism, like batteries. The reason they're an environmental savings is that the generation of the hydrogen can be done in large-scale standing power plants, which can work with much larger economies of scale and have far more effective pollution control systems than can an engine car. This is not terribly different than electric cars - we're just centralizing the power generation into a facility far better equipped to handle the downsides than we can do with a small moving vehicle.
StoneCypher is Full of BS
and also on investing in a rail system that doesn't suck, which is more than I can say for the US
The problem with the US rail system is the same as other mass transit. Our average population density is so much less than other countries that it's hard to achieve the necessary number of people traveling the same route for it to be practical.
Still, I agree with the investment of technology.
I don't read AC A human right
Agreed; however there's no reason why it ought to suck so much on city-to-city routes and in the Northeast Corridor. Although I understand the population density differences preclude too much Europe/US comparisons, if you look at something like the German DB "ICE" or Inter-City Express network, I think we could easily have something like that here in the Northeast.
Despite normally considering myself a basically small-government Conservative, I think we've put ourselves into a bad situation by giving what is in effect a giant taxpayer subsidy to the trucking industry (in the form of the Interstate Highway system), while crippling the railroads' ability to compete by forcing them to pay for their own infrastructure, and also pay into an obsolete and inflexible (as well as ungodly expensive) employee benefits program in the form of Railroad Retirement.
At the same time, the only way that we really tax truckers for the infrastructure that they use, via the tax on diesel fuel, stifles innovation in the passenger-car market by driving automakers away from what is really a superior internal-combustion technology.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
Even educated, thoughtful Japanese men still do not want a woman who is successful. Rather, they want a pet housewife to take care of the kids and whipe their butt. Sexual harrassment that would get you canned on the spot and sued into oblivion in the US is the norm here. Women are not given important jobs because everyone knows they will quit when they get married. Of course, because they have crappy jobs, they DO quit when they get married. For all their brilliance in Japan, they still have a tought time understanding circular reasoning, apparently.
One nice thing about using breeder reactors is that you also reduce the half-life of the spent fuel by separating the fissable (sp?) material out of it so that you can reuse it, leaving the less potent stuff behind - which has a shorter half-life. Also, again, you reduce the fuel needed by (IIRC) three orders of magnitude, which means that you have three orders of magnitude less waste to deal with, too (for the same energy production). Ultimately, the best plan is to either drop it into a subduction zone, or someday when we have a space elevator, discard it permanently. After all, it's highly unlikely that we'll care about nuclear fuel on the kind of time scale that is necessary for it to be eaten by a subduction zone and spit out again someplace else :P
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Actually, it was stupid emissions controls that killed consumer diesel, but yeah. The east coast could have had better mass transit. You can probably blame airport subsidies on this as well. The europeans still have higher density than even the east coast and they've paid a high price for their transit systems. You could even argue that the destruction of WWII paved the way for some of the improvements.
Personally I have high hopes for PRT, which would solve many of the problems mass transit faces in the USA.
Development and adoption of standardized containers that can be carried by trucks, trains, and cargo ships have really reduced the number of long-haul trucking going on. There's alot fewer trucks on the road compared to when I was a kid. There used to be a big labor penalty in unloading and reloading onto trucks, thus making it cheaper to ship all the way in trucks. This is both labor and fuel inefficient. A train can haul hundreds of containers with only a few workers. The fuel efficiency is greaty increased, rails average much less friction than rubber wheels, you have less wind resistance at a given speed, and the larger size of trains allows the engines to be built with more energy saving features
I don't read AC A human right
Since all this icky hydrogen is, like, real dangerous and a drag to carry around at high pressure /low temperature, why don't we CENTRALIZE these fuels cells in a few convenient places?
They would be BIG fuel cells and produce lots an lots of lectricity! We then string wires from them along the railroad tracks and have the trains pick up this lectricity from the wires! That way there is no pollution and no dangerous hydrogen being carried around!
And we have MANAGED TO USE HYDROGEN ! A CLEAN AND NONPOLLUTING ENERGY SOURCE!
So where do we locate these big fuel cells? That's easy! Near power plants- either coal or hydro.
That way we can make lots an lots of hydrogen from the electricity available from these power plants! And the hydrogen will power the fuelcells and produce only CLEAN NON-POLLUTING WATER along with electricity!
See? Ain't this a great idea? Ain't this new hydrogen economy wonderfull?
If you see fit, please forward this to your local politician or 'Alternative Energy' committee.
.
- aqk
F U
FYI: Hydrogene Fuel Cells are currently in an efficiency range of 75% - 85%.
;D
Google is your friend
angel'o'sphere
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
"how much energy did it consume to produce those huge amounts of Hydrogen & Oxygen? Will it be lesser than the power generated by the reaction between them?"
Get more out than you put in? It's a neat trick if you can do it.
Exxon should be worried.
When you figure the relative efficiency of Fuel Cells to anything else you need to take into account the whole process from original fuel to final power output. So you need three numbers, the efficiency of converting fuel to power at the power plant, the efficiency of converting power to fuel cells, and then the efficiency of converting fuels cells back to power. Overall = Power Plant * Fuel Cell Generation * Fuel Cell Consumption