Hydrogen Power

[BrilliantBeast]

I am a newbie so go easy on me.

Looking at Bob Park's What's New (http://www.aps.org/WN/) for last Friday, he discusses the efficiency fallacy of hydrogen fuel, i.e. the energy required to make hydrogen fuel is greater than energy provided.

He uses an analogy of "You can buy an apple for one euro. If you really want an apple, you might pay five euros. You could even pay a thousand euros, but you would never pay two apples."

I think this ignores the value of having a clean, consistant source of energy for vehicles. You may trade 2 apples for 1 apple if that 1 apple has a much longer shelf life, for instance.

If I put on my tie-dyed T shirt and sandals, I could say that using deriving hydrogen from an abundant non mobile resource, say wind powered electricity, definately adds value to the fuel. OK, it is not realistic in the short term that all hydrogen would be generated by this process or even nuclear power.

The most likely source is derived from petroleum, a polluting process. But, what this does do is centralize the problem of controlling emissions. If vehicles burn a clean fuel, it does not need equiptment for emission control. This allows vehicles to be less complex and removes requirements of mobile emission control, weight, size, aesthetics. Several large refineries are easier to inspect, regulate and upgrade than 100 million vehicles. Fuel could be generated at times of lower ozone risk.

I don't have the data to say whether deriving hydrogen is from petroleum is economical, but I don't by the efficiency loss argument.

[clusterm2]

So who would want to live near one of these petroleum driven hydrogen creators?... Not bleeding me

[hgc]

Originally posted by clusterm2
So who would want to live near one of these petroleum driven hydrogen creators?... Not bleeding me
What's needed is a really, really tall smoke stack -- say 200 miles?

[BrilliantBeast]

Originally posted by clusterm2
So who would want to live near one of these petroleum driven hydrogen creators?... Not bleeding me

That's not my point at all or Bob's point. Bob's point is that it is a scam because it takes more energy to make hydrogen fuel than you can get out of the fuel.

Let's assume that you can make this process as clean as your regular oil burning power plant. It has no relevance to the original point.

[garys_2k]

Here, please let me try...

Originally posted by BrilliantBeast
I am a newbie so go easy on me.

Looking at Bob Park's What's New (http://www.aps.org/WN/) for last Friday, he discusses the efficiency fallacy of hydrogen fuel, i.e. the energy required to make hydrogen fuel is greater than energy provided.

He uses an analogy of "You can buy an apple for one euro. If you really want an apple, you might pay five euros. You could even pay a thousand euros, but you would never pay two apples."

I think this ignores the value of having a clean, consistant source of energy for vehicles. You may trade 2 apples for 1 apple if that 1 apple has a much longer shelf life, for instance.

But you traded two "dirty" apples for that clean one. IOW, you had to burn more dirty fuel just to obtain a given amount of hydrogen. Hydrogen is a so-so energy TRANSFER device, that's all. It is not an energy source. Think of it as a chemical battery that can only be charged with another primary fuel.

If I put on my tie-dyed T shirt and sandals, I could say that using deriving hydrogen from an abundant non mobile resource, say wind powered electricity, definately adds value to the fuel. OK, it is not realistic in the short term that all hydrogen would be generated by this process or even nuclear power.

Even your windmill is an energy loser. How much energy went into making that windmill to begin with? Photovoltaic is even worse. But all of that completely ignores the most important consideration, economics.

The cheapest (best, most efficient, least likely to cause poverty, least likely to cause a recession, etc) way to "make" hydrogen is reforming fossil fuel. That leaves carbon. Perhaps making all that carbon at one place is better than doing it in lots of little mobile places (as vehicle fuel), but you still have to add in the primary energy costs of building that infrastructure. How much CO2 is created digging those pipeline ditches, making that pipeline steel, building those distribution terminals, etc? Those all count.

The most likely source is derived from petroleum, a polluting process. But, what this does do is centralize the problem of controlling emissions. If vehicles burn a clean fuel, it does not need equiptment for emission control. This allows vehicles to be less complex and removes requirements of mobile emission control, weight, size, aesthetics. Several large refineries are easier to inspect, regulate and upgrade than 100 million vehicles. Fuel could be generated at times of lower ozone risk.

New automobiles are actually pretty efficient right now. In fact, you can no longer commit suicide by locking yourself in the garage with the engine running anymore, not enough CO is produced to do more than give you a good headache. But again, the real costs, the actual fuel CONVERSION efficiency, will be lower if you move the combustion farther from the point of use (the vehicle's engine). Reforming the hydrocarbon has inefficiencies, shipping and storage add inefficiencies, and the final combustion in the vehcile is still just as inefficient. The net-net of all this is that MORE petroleum will be "burned" to get the same amount of BTUs on the road.

I don't have the data to say whether deriving hydrogen is from petroleum is economical, but I don't by the efficiency loss argument.
You don't have to buy it, just acknowledge that no pumping, storage, pipeline friction or leakage rates are realistically ignored. These all add to the losses of energy ultimately paid by the use of more petroleum fuel.

[arcticpenguin]

Hydrogen should not be considered as a source of energy, since it must be generated in one way or another. Instead it is a form of energy, and should probably be compared to electrical batteries in that sense.

Yes, there might be some benefit to not having every car burning fossil fuel.

On the other hand, there are recent claims that hydrogen which escapes from the process may be bad for the ozone layer. The time scale of ozone layer damage is decades or centuries, not the time of day.

Finally, if Americans had any interest in driving smaller, mor eefficient cars, they could do it today.

[jj]

Guys, the point about there being substantial losses in making H2 from water or hydrocarbons is quite true. No doubt about it, so let's use nuclear power and direct heat catalysis. It's been done small-scale, I believe, already...

That way, no carbon remains, only waste heat. With sensible (i.e. reprocess it, don't bury it) use of the nuclear "waste", ((*&&(* all folks, it's not WASTE, its FUEL!!!) we gain quite a bit of efficiency over present plants and cut way down on the total generated waste as well.

BUT...

Burning H2 in a fuel cell is not, I think, a bad thing, and unless they've gotten worse, fuel cells are more efficient than most anything else.

In fact, last time I did the math, IF (big if) we had home fuel cells, we could get both power and heat (for water, home) quite a bit more efficiently by using them on natural gas, and taking the 50% hit from the CO2 heat loss by using that in cogeneration.

And we'd lessen the need for infrastructure by one set of wires.

[TillEulenspiegel]

First of all the type of fuel cell we're talking about does not run on hydrogen, it runs on water. The seperation of the constituant molocules is processed INTERNALLY by the cell.The fuel cell generates electricity and water vapor and heat.The newest flavor is the regenerative cell...no moving parts efficiencies soaring from 50 to 80% i( I.C. engins never break %30 )f you can capture the heat component .The efficiency of fuel cells is staggering if you compare them to I.C. or waste powered turbines. Done the research . The cost now is past the break even point. I remember when digital watches first came out...$1,000 a pop, they are now a give away in cereal boxes. I usta bitch about having to take economics because I was getting my E.E. , well guess the reason was to demonstrate economies of scale. The price, once there is enough demand will not only equal the B-E point but will make the process profitable. Add the almost unlimited source of hydrogen ( most available element in the universe.) and You have a good marriage of technology, conservation and energy policy. I would also mention that I'm not sure the powers that be will allow a renewable, clean, almost free, ( except for the initial investment and membrane replacement ) energy source. Do the reaserch see for yourselves.

[arcticpenguin]

Originally posted by TillEulenspiegel
First of all the type of fuel cell we're talking about does not run on hydrogen, it runs on water. The seperation of the constituant molocules is processed INTERNALLY by the cell.The fuel cell generates electricity and water vapor and heat.The newest flavor is the regenerative cell...no moving parts efficiencies soaring from 50 to 80% i( I.C. engins never break %30 )f you can capture the heat component .The efficiency of fuel cells is staggering if you compare them to I.C. or waste powered turbines. Done the research . The cost now is past the break even point. I remember when digital watches first came out...$1,000 a pop, they are now a give away in cereal boxes. I usta bitch about having to take economics because I was getting my E.E. , well guess the reason was to demonstrate economies of scale. The price, once there is enough demand will not only equal the B-E point but will make the process profitable. Add the almost unlimited source of hydrogen ( most available element in the universe.) and You have a good marriage of technology, conservation and energy policy. I would also mention that I'm not sure the powers that be will allow a renewable, clean, almost free, ( except for the initial investment and membrane replacement ) energy source. Do the reaserch see for yourselves.
A fuel cell that runs on water? Woo-woo-woo.

[TillEulenspiegel]

I'm not sure if that was derision or what , it is not a perpetual motion machine as there are waste factors ..heat generation, consumption of both water and media... There's thousands of sites starting with : http://www.firstgov.gov/fgsearch/index.jsp?nr=20&mt0=all&ms0=should&mw0=fuel+cells&in0=domain&dom0=energy.gov+doe.gov+external.ameslab.gov+anl.g ov+bnl.gov+bpa.gov+fnal.gov+eren.doe.gov+hanford.g ov+inel.gov+lbl.gov+llnl.gov+lanl.gov+nrel.gov+orn l.gov+osti.gov+pnl.gov+pppl.gov+rfets.gov+sandia.g ov+srs.gov&db=www-fed-all&st=AS&rn=6&parsed=true. Kinda wierd that the quirey line has so many filters. doncha think?

[toddjh]

Originally posted by TillEulenspiegel
I'm not sure if that was derision or what , it is not a perpetual motion machine as there are waste factors ..heat generation, consumption of both water and media...

If you're trying to tell us that a fuel cell can run on only water (and air, I suppose), you're either trying to pull a fast one, or you've been taken in yourself. Can you detail the supposed chemical reaction that powers the cell?

Jeremy

[Agammamon]

Originally posted by BrilliantBeast
I am a newbie so go easy on me.

Looking at Bob Park's What's New (http://www.aps.org/WN/) for last Friday, he discusses the efficiency fallacy of hydrogen fuel, i.e. the energy required to make hydrogen fuel is greater than energy provided.


It takes more energy to create gas than you get out of it also. You have to take into consideration where that energy is coming from, and the storage/energy density needs of your supply.

Hydrogen may require more energy to make than you get out of it but;

1) that energy is not provided by you any more than the energy to make gas was
2) you can make hydrogen using energy supplies that would otherwise be inconvenient for your purposes (not having to have an acre of soloar cells strapped to the roof of your car or carrying a nuke reactor in the trunk).
3) you get efficiencies of scale in power generation. If everyone had tocreate their own hydrogen from scratch then they all have to purchase, maintain, and run production facilities. Same with petroleum. Can you imagine 10's of millions of little refineries all over the country? While this is certainly workable, the entry costs become higer than if you centralize production in a "factory" setting. You gain from efficiencies of scale, pollution control is more effective, etc.

[Agammamon]

Also, fuel cells don't run on water. They take a pure (as pure as possible since impurities poison the membranes pretty quickly) hydrogen and oxygen input (sometimes from cracking petrochems with a converter and running through a filter to gert the H2) and output electricity and water . It takes more electricity to crack water into H2 and O2 than you can get back, that's why you can scavenge e- in the reverse.

[LaserCool]

Riddle me this Batman:

Let's suppose all the infrastructural problems and storage problems of hydrogen power have been solved (I know, all you Engineers are groaning, so am I).

Let's even suppose that fuel cells are highly efficient and cheap.

Exactly where are we going to get the electricity to catalyze water into hyrdogen and oxygen, or catalyze petrochems into hydrogen?

We can't get more energy out of hydrogen production that it requires (the second law of thermodynamics holds here), so that means we have to come up with more energy to make this sparkling new fuel.

From oil buring generators perhaps?


Just thinking. Don't mind me.

[toddjh]

Originally posted by LaserCool
We can't get more energy out of hydrogen production that it requires (the second law of thermodynamics holds here), so that means we have to come up with more energy to make this sparkling new fuel.

From oil buring generators perhaps?

Yep. The difference, as others have pointed out, is that you can do it on a large scale and keep the pollution-creating steps in the process in a central location, where you can minimize emissions. You're sacrificing some energy to gain clean-burning fuel for vehicles.

Jeremy

[Ziggurat]

There's actually another way to generate hydrogen that most people overlook, but may play a rather large role in the future: nuclear reactors. Now it's obvious that you can do electrolysis using electricity from nuclear reactors, but that's actually only part of it. Nuclear fission also produces hydrogen by itself - neutrons from fission reactions decay into protons, which of course form hydrogen. In current nuclear reactors this hydrogen is essentially a waste product, but if you had a hydrogen fuel infrastructure, it might start making sense to harvest this hydrogen, in addition to the thermal output of the nuclear reactors.

Not to say there aren't problems with the hydrogen fuel idea - the primary one being that it's mostly an excuse to let car manufacturers off the hook from having to take steps now that we DO have the technology to implement. Is anyone else embarassed that there isn't a single hybrid vehicle available from US manufacturers? Or that the tax code gives small business owners huge tax breaks for buying luxery SUV's instead of smaller cars?

[jj]

Originally posted by TillEulenspiegel
First of all the type of fuel cell we're talking about does not run on hydrogen, it runs on water.

Err, what is the energy input then?


Fuel cells burn O2 and H2 and make water vapor, yes, but if you're saying that they turn water into water vapor with no other energy input, you're saying something very odd.

[jj]

Originally posted by Ziggurat
There's actually another way to generate hydrogen that most people overlook, but may play a rather large role in the future: nuclear reactors.

Now, I'm hardly arguing with you on this point, but I'd swear I already said that a few articles above yours. :cool:

[Jon_in_london]

Best thing to do would be to fit each car with a windmill generator to spilt the hydrogen first. But since its not practical to have one big windmill, we should have lots of little windmills all over the car- each attached to its own little electrolysis aquifer for H2 generation. Purified H2 should then be piped to a centralised storage facility in the back seat of the car before being fed into the fuel cell. Of course the only problem is that the faster the car goes, the more wind and thus more fuel being produced. It would therefore be difficult to slow the car down once it starts to accelerate and this would result in a fatal crash, however, if the ecxess hydrogen produced could be fed into a secondary storage unit, this could be discharged at collection points across the road network (a bit like a gas- station but the other way round) and fed to power plants which would replace damaging nuclear and fossil fuel burning power plants to cool/heat our homes and provide us with all our power requirements and also Im completely mad.

[Leif Roar]

Originally posted by LaserCool
Riddle me this Batman:

Let's suppose all the infrastructural problems and storage problems of hydrogen power have been solved (I know, all you Engineers are groaning, so am I).


We've already solved this for gasoline, so why not? (In fact, despite the problems of producing, transporting, storing and selling gasoline; we've actually created a system for the distribution of many different forms of gasoline and diesel.)


<SNIP>
Exactly where are we going to get the electricity to catalyze water into hyrdogen and oxygen, or catalyze petrochems into hydrogen?
<SNIP>
From oil buring generators perhaps?


Certainly - but mark that that's oil, and not gasoline - that is a pretty big advantage in itself. Hydrogen can also be produced by other energy sources, which means we can diversify our energy production - which is another big advantage. We also gain a lot of flexibility since we can use (practically) any energy source to drive our cars: if we had an energy crisis today, we would not be able to redirect the energy that's used for space heating or heavy industry to road transportation, or vice versa.

Secondly, while burning oil to produce hydrogen won't reduce the emissions of CO2, it might reduce the emmisions of other pollutants that's caused by burning gasoline - such as CO, sulphur dioxide, nitrogen oxides and other.

Neither fuel cells or electrically driven cars really give us "clean energy" - there's always a matter of pollution. Some forms of energy storage might be cleaner, though - and even if it can't be said to be cleaner in all regards, it might still be advantageous to use a mix of energy storage forms, to "spread the problem evenly around", so to speak.

That hydrogen fuel cells are not a silver bullet that solves all our energy and pollution problems, doesn't mean that it's no better than the status quo.

(Edited to fix the Quote tags)

[LaserCool]

Originally posted by Leif Roar
We've already solved this for gasoline, so why not? (In fact, despite the problems of producing, transporting, storing and selling gasoline; we've actually created a system for the distribution of many different forms of gasoline and diesel.)

Storing a pressurized gas is difficult enough, but long-term strorage of hydrogen is nearly impossible; there's too much diffusion through the containers. Remember, we're dealing with the smallest of atoms, the diffusion rate is high because it literally slips through the structure of the container.

Originally posted by Leif Roar
Hydrogen can also be produced by other energy sources, which means we can diversify our energy production - which is another big advantage. We also gain a lot of flexibility since we can use (practically) any energy source to drive our cars: if we had an energy crisis today, we would not be able to redirect the energy that's used for space heating or heavy industry to road transportation, or vice versa..)

Not exactly. As stated before, we still need a centralized energy source to make hydrogen, which will require petroleum, coal or nuclear for the forseeable future. We're still dependent upon the same energy sources as before, just one step removed.

In the case of cracking petrochems, we're still talking oil.

Maybe there's a value in flexibility, but it's far more logical then to push for electric cars. The electric distribution system already exists, and there's no need for vastly new technology.

To me, this hydrogen thing is no different than the hula-hoop, a passing fad.

Originally posted by Leif Roar
Secondly, while burning oil to produce hydrogen won't reduce the emissions of CO2, it might reduce the emmisions of other pollutants that's caused by burning gasoline - such as CO, sulphur dioxide, nitrogen oxides and other..)

Centralizing pollution doesn't mean reduced pollution. A large amount of radiological pollution is centralized in Chernobyl, does that make it "better"?

Also, gas-buring cars still have to meet emissions standards that make them vastly cleaner than 30 years ago. Granted, incomplete combustion of most fuels (wood, petroleum, coal) is going to produce NOx, SOx, CO and CO2; but the technology of gas-burning has made air quality vastly better.

Here's a problem though-oil and gas are the most compact, stable and easily portable energy sources technology to date has made availible to us. I'm OK with that. I accept, for the time being, that oil is the best thing going.


Originally posted by Leif Roar
Some forms of energy storage might be cleaner, though - and even if it can't be said to be cleaner in all regards, it might still be advantageous to use a mix of energy storage forms, to "spread the problem evenly around", so to speak..)

The only "clean" energy I can think of is electricity, but you just can't store it effectively. Every form of storeable energy involves some kind of pollution (including hydrogen; if you haven't heard, it has ozone-depleting properties).

Last I checked, we did use a form of mixed energy storage - coal, oil, nuclear, hyrdoelectric. I just don't see how hydrogen is supposed to replace any of this in an efficient cost-effective way.

Originally posted by Leif Roar
That hydrogen fuel cells are not a silver bullet that solves all our energy and pollution problems, doesn't mean that it's no better than the status quo..)

The fact is it's no better than that status quo. It'll require huge investments of infrastructure that don't offer any clear payoff. At best, it's another step in the petroleum chain we already have, lowering the efficency of fuel in the name of centralizing one kind of pollution.

BTW, I wonder how people will respond to the idea of driving around with a pressurized tank of explosive gases. Granted, gasoline is highly explosive under the right conditions, but tell me how we can crash-proof a hydrogen tank without undoing all the benefits of hydrogen power with armor plating.

I believe this image might do a lot to deter hydrogen powered cars:

http://www.nlhs.com/images/hindenburg/big_hindenburg_explodes_over_lakehurst.jpg

[Jon_in_london]

Originally posted by LaserCool


Storing a pressurized gas is difficult enough, but long-term strorage of hydrogen is nearly impossible; there's too much diffusion through the containers. Remember, we're dealing with the smallest of atoms, the diffusion rate is high because it literally slips through the structure of the container.


BTW, I wonder how people will respond to the idea of driving around with a pressurized tank of explosive gases. Granted, gasoline is highly explosive under the right conditions, but tell me how we can crash-proof a hydrogen tank without undoing all the benefits of hydrogen power with armor plating.


You can store hydrogen in metal oxides cant you? which solves the problem (almost)

/searches for a link.

[Ziggurat]

Originally posted by LaserCool

I believe this image might do a lot to deter hydrogen powered cars:


True, which is really unfortunate, since hydrogen wasn't the real culprit in the hindenburg disaster. Even the photo shows this pretty clearly - hydrogen has an almost invisible flame. What you see burning there is essentially thermite, a combination of aluminum powder and rust, that can burn hot enough to melt through steel. This unfortunate combination of materials was used to waterproof the fabric and reflect sunlight, but once it ignited from a spark, there was no stopping it.

http://www.unmuseum.org/hindenburg.htm

[Jon_in_london]

Originally posted by Ziggurat


True, which is really unfortunate, since hydrogen wasn't the real culprit in the hindenburg disaster. Even the photo shows this pretty clearly - hydrogen has an almost invisible flame. What you see burning there is essentially thermite, a combination of aluminum powder and rust, that can burn hot enough to melt through steel. This unfortunate combination of materials was used to waterproof the fabric and reflect sunlight, but once it ignited from a spark, there was no stopping it.

http://www.unmuseum.org/hindenburg.htm

German engineering.........?

Anyone know anything about metal hydrides as hydrogen storage material? Seems to do away with the problem of carrying around pressurised H2.

[Leif Roar]

Originally posted by LaserCool

Storing a pressurized gas is difficult enough, but long-term strorage of hydrogen is nearly impossible; there's too much diffusion through the containers. Remember, we're dealing with the smallest of atoms, the diffusion rate is high because it literally slips through the structure of the container.


I have seen no numbers that has convinced me that storing, transporting and distributing hydrogen for use in personal vehicles is an unsurmountable problem. The fact that a lot of money and effort is invested in the research and development of hydrogen fuel cells, suggests to me that neither do many others.



Not exactly. As stated before, we still need a centralized energy source to make hydrogen, which will require petroleum, coal or nuclear for the forseeable future. We're still dependent upon the same energy sources as before, just one step removed.


My point was that in case of an energy crisis we could shift our use of energy with more flexibility. When there's a draught, we prohibit the use of water for watering lawns. Today we can't switch the energy we use for personal (or goods) transportation to space heating, or vice versa.


In the case of cracking petrochems, we're still talking oil.


We're not, however, talking about gasoline. That is a significant difference.


Maybe there's a value in flexibility, but it's far more logical then to push for electric cars. The electric distribution system already exists, and there's no need for vastly new technology.


Perhaps - but there are large obstacles for replacing current cars with electric ones, and electric cars bring with them their own problems. Those obstacles and problems might be even worse than those involved with using cars based on hydrogen fuel cells.


To me, this hydrogen thing is no different than the hula-hoop, a passing fad.


Perhaps. Then again, perhaps not. It's certainly a valid possibility, and it's certainly a valied field of research and development.


Centralizing pollution doesn't mean reduced pollution. A large amount of radiological pollution is centralized in Chernobyl, does that make it "better"?


When it comes to combustion, centralized do mean less pollution - there is a huge difference in the amount of pollution-prevention and general regulation of the combustion process you can do at a plant and what you can do in a car.

Centralizing pollution is also an advantage in some cases, since it is easier to contain and process - in the same way that centralizing dust in your vacuum cleaner is better than having it spread out across the room. That said, in some cases it is an advantage to distribute the pollution to dillute it so much it's no longer a problem. The exhaust from combustion is one example where there's no major disadvantage in centralizing the pollution.


Also, gas-buring cars still have to meet emissions standards that make them vastly cleaner than 30 years ago. Granted, incomplete combustion of most fuels (wood, petroleum, coal) is going to produce NOx, SOx, CO and CO2; but the technology of gas-burning has made air quality vastly better.


Certainly - but that doesn't mean that the emmisions have become low enough, or that hydrogen fuel cell powered cars wouldn't be even better.


Here's a problem though-oil and gas are the most compact, stable and easily portable energy sources technology to date has made availible to us. I'm OK with that. I accept, for the time being, that oil is the best thing going.


I don't agree with your assessment. Oil and gasoline are certainly the most economic way of transporting energy for certain uses, but they are not the most compact energy storage, nor are they the most stable or the most easily transportable. Coal, for instance, is both more stable and easier to transport.

Gasoline is the overall best solution for vehicle transportation with today's technology and today's oil-prices. That doesn't mean we shouldn't be looking for a better solution or try to develope new technology which will change that situation.



The only "clean" energy I can think of is electricity, but you just can't store it effectively. Every form of storeable energy involves some kind of pollution (including hydrogen; if you haven't heard, it has ozone-depleting properties).


I very specifically stated that we couldn't get "clean energy", so I don't see what you are arguing against here.


Last I checked, we did use a form of mixed energy storage - coal, oil, nuclear, hyrdoelectric. I just don't see how hydrogen is supposed to replace any of this in an efficient cost-effective way.


I think you're slightly mixing up energy production with energy storage. (One generally don't think of hydroelectric power as "energy storage" - even though you can store energy as water in the reservoirs.)

Why do you believe that hydrogen can't be used cost-effectively as a way of storing energy?


The fact is it's no better than that status quo. It'll require huge investments of infrastructure that don't offer any clear payoff. At best, it's another step in the petroleum chain we already have, lowering the efficency of fuel in the name of centralizing one kind of pollution.


How do you know it's not better than the status quo? To my eyes there are clear advantages to it, which I've stated in my original post.


BTW, I wonder how people will respond to the idea of driving around with a pressurized tank of explosive gases. Granted, gasoline is highly explosive under the right conditions, but tell me how we can crash-proof a hydrogen tank without undoing all the benefits of hydrogen power with armor plating.


If cars using hydrogen fuel cells can be made safe enough, it will not be an issue. You're assuming that it's going to be impossible to make them that safe, but I don't see why that should be.


I believe this image might do a lot to deter hydrogen powered cars:


Please. You might as well argue that since the Titanic sank, we shouldn't be building ferries.

(Edited to fix mangled Quote tags)

[Leif Roar]

Originally posted by Jon_in_london


German engineering.........?

Anyone know anything about metal hydrides as hydrogen storage material? Seems to do away with the problem of carrying around pressurised H2.

I don't know about that, but I came across this link http://www.smlassociates.com/glassspheres.htm which presents a rather ingenious suggestions for storing H2 for use.

[Chad Noles]

FWIW,these guys seem to have a novel way of approaching the hydrogen generation problem….http://solar-h.com/introduction1.html
There can be many ways of generating hydrogen that don’t envolve “cracking” petroleum.You can find some informative articles about hydrogen and power usage in general at http://www.homepower.com/ They have many free downloadable articles covering all types of energy questions,Check them out.Click on “Magazine”and look under “Files and Downloads”.Some of these files include,” Solar Hydrogen Production by Electrolysis”,” Hydrogen Storage (Make a Hydride Storage System)”,and “Fuel Cells and Hydrogen Electrolyzer”.

[RedCoat]

Originally posted by Ziggurat
...it's mostly an excuse to let car manufacturers off the hook from having to take steps now that we DO have the technology to implement. Is anyone else embarassed that there isn't a single hybrid vehicle available from US manufacturers?

Being able to do something does not always imply that it can be done profitably. Right now (for at least one manufacturer) it has been determined that it costs significantly more to produce a hybrid car than it's worth in the market.

There is no conspiracy, as far as I am aware of, on the part of auto manufacturers to purposely NOT make hybrid vehicles. The car market is extremely competitive, margins are very low, and business decisions have to be made. Cut the car companies some slack - we've made a lot of progress and we're getting better all the time. Cars are cleaner now than they've ever been, and the standards get tougher every year.

Sorry if this sounded like a rant, but it's a subject I feel strongly about. Peace.

[Ziggurat]

Originally posted by RedCoat

Being able to do something does not always imply that it can be done profitably. Right now (for at least one manufacturer) it has been determined that it costs significantly more to produce a hybrid car than it's worth in the market.


Maybe, but the Japanese manage to do it fine, and seem to be able to sell hybrid vehicles in the US, why can't we? There's other things that kind of make you wonder, like GM recalling its leased electric cars and refusing to let the leasors buy them. I'm not claiming conspiracy, but I do think that Detroit does not take fuel efficiency very seriously.

[i]
There is no conspiracy, as far as I am aware of, on the part of auto manufacturers to purposely NOT make hybrid vehicles. The car market is extremely competitive, margins are very low, and business decisions have to be made. Cut the car companies some slack - we've made a lot of progress and we're getting better all the time. Cars are cleaner now than they've ever been, and the standards get tougher every year.
[/B]

Cleaner isn't enough, they've got to be more fuel efficient as well. And in that regard we're not making any significant progress (SUV's have offset the gains that were made), and the standards are hardly moving at all. I understand that car companies have to behave selfishly, that's how the market works. But the problem has been exacerbated by things like tax cuts for SUV purchases that encourage businesses to buy inefficient cars rather than efficient ones. If government incentives went the other way (or at least didn't provide any incentive) then car companies would have an easier time (though perhaps less profitable but that's OK) making and selling fuel-efficient cars.

[i]
Sorry if this sounded like a rant, but it's a subject I feel strongly about. Peace. [/B]

No, it didn't sound like a rant, this is a pretty civil discussion. :cool:

[jj]

Originally posted by Jon_in_london
Best thing to do would be to fit each car with a windmill generator to spilt the hydrogen first. But since its not practical to have one big windmill, we should have lots of little windmills all over the car- each attached to its own little electrolysis aquifer for H2 generation. Purified H2 should then be piped to a centralised storage facility in the back seat of the car before being fed into the fuel cell. Of course the only problem is that the faster the car goes, the more wind and thus more fuel being produced. It would therefore be difficult to slow the car down once it starts to accelerate and this would result in a fatal crash, however, if the ecxess hydrogen produced could be fed into a secondary storage unit, this could be discharged at collection points across the road network (a bit like a gas- station but the other way round) and fed to power plants which would replace damaging nuclear and fossil fuel burning power plants to cool/heat our homes and provide us with all our power requirements and also Im completely mad.

Is there a reason for your ridicule? Water splitting via nuclear energy is an entirely valid option.

By the way, Jon, how much radiation does a coal-fired power plant release into the atmosphere. Don't bother saying "zero", please.

[jj]

Originally posted by Jon_in_london


You can store hydrogen in metal oxides cant you? which solves the problem (almost)

/searches for a link.

I believe that would be hydrides, for which the answer is yes. The technology is still way new, but the reactions are well known.

[jj]

Originally posted by Ziggurat


True, which is really unfortunate, since hydrogen wasn't the real culprit in the hindenburg disaster.

Well, I did notice that the same author also had to bring up Chernobyl, and ignore the points about using a clean source of energy, like nuclear, to make H2.

[TillEulenspiegel]

Originally posted by toddjh


If you're trying to tell us that a fuel cell can run on only water (and air, I suppose), you're either trying to pull a fast one, or you've been taken in yourself. Can you detail the supposed chemical reaction that powers the cell?

Jeremy

http://www.eere.energy.gov/hydrogenandfuelcells/fuelcells/types.html#rfc

Regenerative fuel cells produce electricity from hydrogen and oxygen and generate heat and water as byproducts, just like other fuel cells. However, regenerative fuel cell systems can also use electricity from solar power or some other source to divide the excess water into oxygen and hydrogen fuel—this process is called "electrolysis." This is a comparatively young fuel cell technology being developed by NASA and others.

A basic overview from the DOE. (see link above)

Unfortunatly many documents are in pdf format but this is one paper describing the catalytic process.This paper was published in the Journal of the Electrochemical Society

http://216.239.33.100/search?q=cache:MD8MUbtdL6kJ:research.chem.psu.edu/mallouk/articles/chen_support_paper.pdf+chemistry+regenerative+fuel +cells&hl=en&ie=UTF-8

[toddjh]

Originally posted by TillEulenspiegel
Regenerative fuel cells produce electricity from hydrogen and oxygen and generate heat and water as byproducts, just like other fuel cells. However, regenerative fuel cell systems can also use electricity from solar power or some other source to divide the excess water into oxygen and hydrogen fuel—this process is called "electrolysis."

Then the fuel cell doesn't "run on water," like you stated. It runs on hydrogen, created by sunlight. I also have severe doubts that solar-powered electrolysis could create enough fuel to power the average car. It seems to me you'd be better off using the solar energy to charge a battery instead and go with an all-electric vehicle, since no doubt a lot of the power is lost to heat in the electrolysis process.

Jeremy

[TillEulenspiegel]

Now your just engaging in polemics. The base components needed for the system to function is water ( not O2 and H ) and electricity. The water ( pure water yes ) supplies the constituent elements that are separated to O and H, solar cells supply partial E ( to both the cell and the charging system )and the storage batteries provided storage and current on demand.. Occasional charging by house current ( courtesy of the local power barons) is a given but is nominal ..now..with the technology at its infant stage. The main thrust here being one of efficiencies not of brute force
"Then the fuel cell doesn't "run on water," like you stated. It runs on hydrogen, created by sunlight"

No it runs on water which broken down by electrolysis. Also the sun does not create hydrogen it generates electricity which allows the electrolytic process to function . An internal function of the cell as I described. I did not try to assemble a car in my post , rather point out that in the quest for renewable, efficient, portable energy source there exists a technology , the in its embryonic stage offers all these and seems to offer greater promise.

[Agammamon]

So internal combustion engines run on water, with a little carbon added then? After all it is sunlight that combined the existing raw materials and then geophysical processes that turned 'em into oil.

And its not "engaging in polemics", rather its "bandying semantics".

[toddjh]

Originally posted by TillEulenspiegel
Now your just engaging in polemics. The base components needed for the system to function is water ( not O2 and H ) and electricity.

It's the "and electricity" part, which you brush aside, that is my main concern. If the the fuel cell is running completely off O2 and H2 formed by electrolysis of water, then the cell can produce no more energy than that which was used to electrolyze the water. Since you name solar energy as the means for doing that, that means that the fuel cell can produce no more energy than the photovoltaic cells can.

Since solar cars have not, as yet, been made anywhere near practical for the average driver, and your solar-powered fuel cell will incur additional efficiency losses from the added step, I don't see how this kind of system could be workable -- especially since the car would have to carry the PV system, the electrolysis system, and the fuel cell.

I also fail to see the advantage of this kind of system. Hydrogen still needs to be produced for the fuel cell to run; you're just moving the production step from a central location to each individual car. This seems like a terribly inefficient way of producing hydrogen. Even if you want to limit yourself to solar energy, it makes more sense to have a permanent hydrogen production facility someplace that has a lot of sun, where you can take advantage of the greater input as well as the economy of scale. How does your self-electrolyzing fuel cell work during the winter, or in cloudy regions?

The water ( pure water yes ) supplies the constituent elements that are separated to O and H, solar cells supply partial E

Partial E? They'd have to provide the entire E to run the whole system! True, you can stretch it out over a period of time, but there's only so many hours of sunlight in a day.

No it runs on water which broken down by electrolysis. Also the sun does not create hydrogen it generates electricity which allows the electrolytic process to function.

Okay, then a fission reactor runs on hydrogen along with energy from a supernova to convert it into U-235. :rolleyes:

Jeremy

[daver]

Originally posted by Ziggurat


Maybe, but the Japanese manage to do it fine, and seem to be able to sell hybrid vehicles in the US, why can't we?

The last i heard, Japan was selling hybrid cars at a loss. That may have changed.

[daver]

Originally posted by jj


I believe that would be hydrides, for which the answer is yes. The technology is still way new, but the reactions are well known.

Hydride storage is also heavy--commercial hydrides can store about 1% hydrogen by weight. 20 pounds of hydrogen (roughly the equivalent of 10 gallons of gas) would take a 2000 pound tank. They're working on getting the weight down, but it's still going to be a major performance hit.

[arcticpenguin]

Originally posted by TillEulenspiegel
Now your just engaging in polemics. The base components needed for the system to function is water ( not O2 and H ) and electricity. The water ( pure water yes ) supplies the constituent elements that are separated to O and H, solar cells supply partial E ( to both the cell and the charging system )and the storage batteries provided storage and current on demand.. Occasional charging by house current ( courtesy of the local power barons) is a given but is nominal ..now..with the technology at its infant stage. The main thrust here being one of efficiencies not of brute force
"Then the fuel cell doesn't "run on water," like you stated. It runs on hydrogen, created by sunlight"

No it runs on water which broken down by electrolysis. Also the sun does not create hydrogen it generates electricity which allows the electrolytic process to function . An internal function of the cell as I described. I did not try to assemble a car in my post , rather point out that in the quest for renewable, efficient, portable energy source there exists a technology , the in its embryonic stage offers all these and seems to offer greater promise.

Way, way impractical. Have you seen solar cars? I've seen them; they are built of high-tech lightweight components and stripped of all components except the essentials. Almost all their upper surface is dedicated to solar panels. They have enough room for one driver. They don't go very fast, and they don't go at all if the sun doesn't shine. Usually they have a battery for backup, and race teams can take a penalty for externally charging their battery.

Now take that, add more room and weight for passengers and cargo and for safety and comfort systems. Suddenly it doesn't work so well.

Add even more weight for a fuel cell and an electrolysis system: H2O has a mass 9 times that of the H2 you can generate from it. In a realistic hydrogen fuel cell, you get the oxygen for 'burning' the hydrogen from the atmosphere. In your scheme, you carry it around with you at all times. That's an enormous weight penalty.

[TillEulenspiegel]

"So internal combustion engines run on water, with a little carbon added then? After all it is sunlight that combined the existing raw materials and then geophysical processes that turned 'em into oil."
Well that's a stupid thing to say, not ignorant as You seem capable of forming an argument and have a relative command of the subject matter. so You should know better. The petrochemicals that run I.C engines are hardly " water, with a little carbon added". The scales were discussing are in my example on the order of micro seconds , where the processes' You try to hammer Me with are in Eons, so either you do not understand the case in point or You are rather more interested in gainsaying then establishing Your own counter argument. The fact is You have not even addressed the main thrust of my point, which incidently is independently researchable without the " National Inquirer Effect" . The technology exists wether I can speel or not ( satire for all you sourpuss's) and BTW if your looking for an argument about paragraph construction goto WWW.Analenglishmajors.com


"And its not "engaging in polemics", rather its "bandying semantics".
No I meant exactly what I said. Shall I include a definition.. well guess I must. Polemics" an aggressive attack on or refutation of the opinions or principles of another "

Semantics: the study of meanings: a : the historical and psychological study and the classification of changes in the signification of words or forms viewed as factors in linguistic development .

Merriam - Webster...Argue with them.

You, Sir are not a good skeptic. The driving tennent of a skeptic is to find the truth not to superimpose an exclusionary philosophy, rather to hold a distance between themselves and the information being presented and apply controls. If Einstein made errors of language would that make the theory (s) He put forth any less valid?

[arcticpenguin]

Substantive issues aside for jsut a second, your posts would be eaiser to read if you could demarcate your responses from quotes of other's posts somehow. You could try the "quote" button at the bottom right of each post. If you prefer to quote single lines at a time, you can insert the quote functionality by typing left-square-bracket quote right-square-bracket, and ending with lsb /quote rsb.

Thanks.

[arcticpenguin]

Originally posted by TillEulenspiegel
You, Sir are not a good skeptic. The driving tennent of a skeptic is to find the truth not to superimpose an exclusionary philosophy, rather to hold a distance between themselves and the information being presented and apply controls. If Einstein made errors of language would that make the theory (s) He put forth any less valid?
I don't see the relevance if this paragraph. You have not established that you yourself have come within spitting distance of the truth. The technology you tout, vehicles that run on fuel cells that are fueled by solar power, is ludicrous for reasons detailed in several of the preceding posts. If you wouldn't mind, maybe you could either a) try a futile defense of your ridiculous position or b) abandon your ground and apologize.

[RichardR]

Originally posted by TillEulenspiegel
Now your just engaging in polemics. The base components needed for the system to function is water ( not O2 and H ) and electricity. The water ( pure water yes ) supplies the constituent elements that are separated to O and H, solar cells supply partial E ( to both the cell and the charging system )and the storage batteries provided storage and current on demand.. Occasional charging by house current ( courtesy of the local power barons) is a given but is nominal ..now..with the technology at its infant stage. The main thrust here being one of efficiencies not of brute force
"Then the fuel cell doesn't "run on water," like you stated. It runs on hydrogen, created by sunlight"

No it runs on water which broken down by electrolysis. Also the sun does not create hydrogen it generates electricity which allows the electrolytic process to function . An internal function of the cell as I described. I did not try to assemble a car in my post , rather point out that in the quest for renewable, efficient, portable energy source there exists a technology , the in its embryonic stage offers all these and seems to offer greater promise. So a solar cell produces electricity which splits water into hydrogen and oxygen, the hydrogen powers the fuel cell which combines the hydrogen back with the oxygen to make water and powers the car.

Did I get that right?

Why not have the solar cell powering the car directly? (Cut out the electrolysis / fuel cell middle men.)

[arcticpenguin]

TE,

Here's some con artists who would love to meet you: http://www.genesisworldenergy.org/genesis_world_energy.htm

"harnessing an unlimited source of energy from the molecular structure of water"

[rwguinn]

Originally posted by RichardR
So a solar cell produces electricity which splits water into hydrogen and oxygen, the hydrogen powers the fuel cell which combines the hydrogen back with the oxygen to make water and powers the car.

Did I get that right?

Why not have the solar cell powering the car directly? (Cut out the electrolysis / fuel cell middle men.)

Sounds like the guy on one of the engineering USNET groups. his point was that Hydrogen is nasty stuff, but if we combine it with a little carbon, it is easier to handle-just add a little heat and poof! you got hydrogen again....
Seems like we call that stuff "methane", and it burns quite nicely, too...:D

RW

[Agammamon]

Originally posted by TillEulenspiegel



"And its not "engaging in polemics", rather its "bandying semantics".
No I meant exactly what I said. Shall I include a definition.. well guess I must. Polemics" an aggressive attack on or refutation of the opinions or principles of another "

Semantics: the study of meanings: a : the historical and psychological study and the classification of changes in the signification of words or forms viewed as factors in linguistic development . . .

You did not aggressively attack and refute the point I made. You are disputing a definition - do fuel cells run on water or not. Your claim that the ultimate fuel for F/C is water because the process of cracking and recombining H2 and O2 can be done quickly but that ICE run on petrochems because the processes that create it are measured in millenia is a matter of semantics. You and I are merely disagreeing on how, exactly, to define fuel.

[Leif Roar]

Originally posted by arcticpenguin

The technology you tout, vehicles that run on fuel cells that are fueled by solar power, is ludicrous for reasons detailed in several of the preceding posts.

Actually, the technology isn't ludicrous. It has it uses in the same way that using a diesel engine to drive a generator which recharges a battery which in turn runs an electric engine has its uses.

The trouble here is his use of the term "runs on." We generally use that term to denote the main fuel or power source used for a machine. We say that a car with a ordinary combustion engine "runs on" gasoline - not that it "runs on" air - despite air being just as necessary for the combustion as the gasoline is. In the same manner, a steam engine "runs on" coal, not steam; and a CD player "runs on" batteries or electricity, not nickel/metal-hybrides.

[toddjh]

Originally posted by Leif Roar
Actually, the technology isn't ludicrous. It has it uses in the same way that using a diesel engine to drive a generator which recharges a battery which in turn runs an electric engine has its uses.

The concept isn't ludicrous, but it is completely impractical in the foreseeable future. Photovoltaic cells would have to be an order of magnitude more efficient (at least) in order to provide hydrogen for a fuel cell, and even then, I still can't see why that setup would be superior to a simple solar-fed electric engine, which would save tons of weight.

Jeremy

[jj]

Originally posted by TillEulenspiegel
No it runs on water which broken down by electrolysis. Also the sun does not create hydrogen it generates electricity which allows the electrolytic process to function . An internal function of the cell as I described. I did not try to assemble a car in my post , rather point out that in the quest for renewable, efficient, portable energy source there exists a technology , the in its embryonic stage offers all these and seems to offer greater promise.

The cell runs on H2 and O2, which are cracked from water via electrolysis. The electricity was provided by solar means.

All this is, then, is using a fuel cell as a battery. Seems somewhat inefficient, and your argument that it runs on water is misleading, if not seriously confused as well. Please note I'm responding to the claim, not suggesting intent.

[TillEulenspiegel]

arcticpenguin:
"Substantive issues aside for jsut a second, your posts would be eaiser to read if you could demarcate your responses from quotes of other's posts somehow."
Sorry . I did use quotation marks with relevant statements, The boards I belong to are substantially less populated and the authors are easily recognized, so I will strive in the future to make the arguments more attributable to thier author.
I am not sure how to engage in simultaneous debate using quotes from various parties so please excuse my ignorance of the BBS functions.

arcticpenguin: "I don't see the relevance if this paragraph. You have not established that you yourself have come within spitting distance of the truth."
The position that I have put forth and the sources that are the publicly available resources are both easily reserchable and verifiable. I said explicitly that I was not proposing the building a car. However You say:
arcticpenguin: " The technology you tout, vehicles that run on fuel cells that are fueled by solar power, is ludicrous for reasons detailed in several of the preceding posts. If you wouldn't mind, maybe you could either a) try a futile defense of your ridiculous position or b) abandon your ground and apologize."
So it seems that not only do You not possess a passing knowledge of what I have posted , but You have also accepted the arguments of other posters, with no proof but speech ( and as a skeptic, You must know how to disprove an argument and offer counter-proof...you do neither.)

RichardR: "Why not have the solar cell powering the car directly? (Cut out the electrolysis / fuel cell middle men.)"

Richard , because the amount of output of a photo cell is low-medium voltage and low current. Thier ideal function is for recharging ( next time you drive down a highway look at the traffic signs see those blue panels? Photovoltaics =)

Agammamon:
"You did not aggressively attack and refute the point I made. You are disputing a definition - do fuel cells run on water or not. Your claim that the ultimate fuel for F/C is water because the process of cracking and recombining H2 and O2 can be done quickly but that ICE run on petrochems .."

You are correct sir as I did not engage in argument for arguments sake, but others did.

NO , sir I am not disputing a definition, the objects in question operate in the manner I have described, the two definitions are a compleat clusterfudge and the only reason I brought them in to the discussion is to demonstrate the relative efficiencies of the two systems. As far as this technology being " the ultimate" you have filled in spaces I did not provide.

And now the challenge from Till:

All of the detractors of my posts in Re The URFC.. Which has after all the blessings of not only the DOE luddites but countless university and private corporations. Prove me wrong, post a study, paper , experiment that is opposed to the myriad of publications available everywhere, make a case, prove me a fool .......or shut up.

I am disappointed I thought that This forum offered an exchange of ideas founded in reality... what I find is a group that owes no allegiance to any god except the one of disbelief. I am sadly disappointed

P.S. To JJ
Eficenties are all this discussion is about. Look at ( if you don't already know) the loss of power in relation to say.. pullies, or I.C.'s how much loss? 50-70 % ? that's at the first stage of a mechanical device , and it goes down from there, power transmission? application? translation? I am reminded of the general discussion of the "experts" who stated that amorphous solar cells were fiction, some poor schmo proved them all wrong, The newest concept is a " PAINTABLE" photo voltaic surface. Imagine that your 2006 buick has a paint job that is a power generator..Ya That'l work =)

[Leif Roar]

Originally posted by toddjh


The concept isn't ludicrous, but it is completely impractical in the foreseeable future. Photovoltaic cells would have to be an order of magnitude more efficient (at least) in order to provide hydrogen for a fuel cell, and even then, I still can't see why that setup would be superior to a simple solar-fed electric engine, which would save tons of weight.

Jeremy

As far as I understand it, solar panels are very rarely used to provide direct power to engines or appliances. Normally they're used as a way to recharge batteries, which are then tapped for power. I wouldn't be surprised if, for some sizes and power demands, regenerative hydrogen fuel cells might actually turn out to be lighter than a corresponding solution using regular batteries.

[Leif Roar]

Originally posted by TillEulenspiegel
The newest concept is a " PAINTABLE" photo voltaic surface. Imagine that your 2006 buick has a paint job that is a power generator..Ya That'l work =) [/B]

Or not. The maximum power you can generate by sun-light is 1.8 horsepower per square meter (and in real use you'd average a lot less because of cloud-cover, time of day and year and lattitude) - if you want to generate more power by sunlight, you'll have to somehow increase the energy output of the sun.

A car would need many square meters of surface of photo-electric surface to generate enough power to be equal to even a small gasoline powered engine.

[RichardR]

Originally posted by TillEulenspiegel
RichardR: "Why not have the solar cell powering the car directly? (Cut out the electrolysis / fuel cell middle men.)"

Richard , because the amount of output of a photo cell is low-medium voltage and low current. Thier ideal function is for recharging ( next time you drive down a highway look at the traffic signs see those blue panels? Photovoltaics =)Why not have the solar cell charge a battery?

[toddjh]

Originally posted by Leif Roar
As far as I understand it, solar panels are very rarely used to provide direct power to engines or appliances. Normally they're used as a way to recharge batteries, which are then tapped for power. I wouldn't be surprised if, for some sizes and power demands, regenerative hydrogen fuel cells might actually turn out to be lighter than a corresponding solution using regular batteries.

I don't know. Like you said, solar panels are very rarely used to provide direct power. I bet a regenerative fuel cell would still need at least a modest battery.

And like you pointed out in another post, there's only so much energy you can get from solar. The only case where I could imagine a regenerative fuel cell ever being practical is for the niche market currently filled by electric cars: tiny commuter vehicles where you drive them for 10 miles and then let them sit in the sun all day, and hope that cloud cover doesn't make you get stuck at the office. Even then, a simple electric car you just plug into an outlet in your garage at night seems like a more reliable system with fewer moving parts and fewer things that could break down.

Jeremy

[Leif Roar]

Originally posted by toddjh

I don't know. Like you said, solar panels are very rarely used to provide direct power. I bet a regenerative fuel cell would still need at least a modest battery.


The fuel cell would be the battery - i.e. one would use the electricity generated by the solar panel to split water into hydrogen and oxygen, and whenever you needed power, you would "tap" the fuel cell, generating water again.

For this use, we're really just talking about an alternative battery technology - which for some weight/power/price combinations might be a better option than regular batteries.


And like you pointed out in another post, there's only so much energy you can get from solar. The only case where I could imagine a regenerative fuel cell ever being practical is for the niche market currently filled by electric cars: tiny commuter vehicles where you drive them for 10 miles and then let them sit in the sun all day, and hope that cloud cover doesn't make you get stuck at the office. Even then, a simple electric car you just plug into an outlet in your garage at night seems like a more reliable system with fewer moving parts and fewer things that could break down.


Yes, and I don't think that solar panels combined with rechargeable fuel cells are a solution for this use. The technology has its uses, but this is not one of them.

[toddjh]

Originally posted by Leif Roar
The fuel cell would be the battery - i.e. one would use the electricity generated by the solar panel to split water into hydrogen and oxygen, and whenever you needed power, you would "tap" the fuel cell, generating water again.

Yes, of course, but electrolysis has voltage/current requirements, doesn't it? Or at least I bet it's more efficient at higher current. The output from PV cells is extremely variable. Better to charge a battery and get a more controlled output for the electrolysis.

For this use, we're really just talking about an alternative battery technology - which for some weight/power/price combinations might be a better option than regular batteries.

Yes, and I don't think that solar panels combined with rechargeable fuel cells are a solution for this use. The technology has its uses, but this is not one of them.

I'm curious what you have in mind. Can you give me an example of a setup where you think a regenerative fuel cell would be preferable to either a regular fuel cell, an internal combustion engine, or a solar-fed battery system?

Jeremy

[arcticpenguin]

Originally posted by TillEulenspiegel

And now the challenge from Till:

All of the detractors of my posts in Re The URFC.. Which has after all the blessings of not only the DOE luddites but countless university and private corporations. Prove me wrong, post a study, paper , experiment that is opposed to the myriad of publications available everywhere, make a case, prove me a fool .......or shut up.

I am disappointed I thought that This forum offered an exchange of ideas founded in reality... what I find is a group that owes no allegiance to any god except the one of disbelief. I am sadly disappointed

Meet your own challenge. All you have done so far is offer incorrect or misleading descriptions of the technology, leading us to believe that you do not grasp the important concepts. You did post a link to a generic search for "fuel cells" at firtgov.gov, but you did not pick out any specific links that support the particular technology you are promoting. Are we supposed to do your work for you?

In other words, you have provided no evidence yourself and are demanding much more from us than from yourself. You begin to remind me of someone. Someone I don't like.

[jj]

Originally posted by TillEulenspiegel
P.S. To JJ
Eficenties are all this discussion is about. Look at ( if you don't already know) the loss of power in relation to say.. pullies, or I.C.'s how much loss? 50-70 % ? that's at the first stage of a mechanical device , and it goes down from there, power transmission? application? translation? I am reminded of the general discussion of the "experts" who stated that amorphous solar cells were fiction, some poor schmo proved them all wrong, The newest concept is a " PAINTABLE" photo voltaic surface. Imagine that your 2006 buick has a paint job that is a power generator..Ya That'l work =)

Not my buick. I won't own one.

But let's ask you a question. What's the power/sq. meter/day that lands on your car in, say, summer in the Arizona desert?

How far can you go on that amount of power.

What kind of "pully" are you using? Last I saw such things were much more efficient.

You're just using a fuel cell and cracked H2 and O2 from water as a fancy battery. Why not just store the power in a battery right from your solar cells? How much battery would it take to store the entire output from, say 10 sq. meters of solar cell for a day? How far could you go on that amount of power. How fast? How many people?

Any use to crack H2O is only going to CUT DOWN the distance by lowering the efficiency. Just use batteries. I tried to lead you there.

Sheesh!

[jj]

Look, folks, what about the original thread, and don't forget that one way to put down a good idea is to have some fanatical-appearing type come in and promote the good idea in a really dumb way.

So, back to the original, what's wrong with using Nuclear power to crack H2O? Well?

It seems to me that a variety of people are now trying to rain on the idea of H2 without really thinking about it.

[arcticpenguin]

OK, assuming you solve whatever issues you have with nuclear waste, etc.

I then see H2 as being competitive with electrical power. You could use the nuke plant to crack H2, or you could use it to generate electricity.

In either case you have to distribute it somehow. For electric, you pump it onto the existing grid. For hydrogen, you have the choice of whether to crack the H2 right at the nuke plant, then pipe it and ship it around, or distribute electricity to remote H2 plants. In either case you have to build infrastructure to get the H2 to end-use points, but we could assume that by the debate technique of 'fiat'.

It then comes down to which system works best for consumer vehicles.

H2: need to overcome engineering problems with storing large amounts of H2. Need to improve fuel cell performance. Advantage: can refill quickly.

Electric: Disadvantage: Takes a while to recharge. Advantage: this could be done at home or at a 'filling station' (if it becomes fast enough) Would need to improve capacity => driving distance.

Other important issues:
which technology lets you drive furthest on one fill, and
which is more affordable.

There are so many contingencies in there that I'm not sure which would win at any given future date.

This question of H2 damaging the ozone should be looked into; right now there's just one or two preliminary reports.

[Chad Noles]

Here are a few sources relating to fuel cells and/or hydrogen....http://www.mrsolar.com/
http://www.homepower.com/
http://www.ballard.com/
http://www.fuelcells.org/
http://www.metallicpower.com/
http://www.protonenergy.com/
http://www.stuartenergy.com/
http://www.electrolyser.com/
http://hydrogenappliances.com

So many answers,so few questions.

[toddjh]

Originally posted by jj
So, back to the original, what's wrong with using Nuclear power to crack H2O? Well?

It seems to me that a variety of people are now trying to rain on the idea of H2 without really thinking about it.

Who said there was anything wrong with it? My main concern would be whether it's practical to run a reactor hot enough to crack a sufficient amount of water to cover the public demand -- if everybody's car has a fuel cell, you're talking a lot of H2. If not, you're just using electricity to do it, and it's no different from using a conventional power plant to do it.

Ideally, I'd like to think that we'll have fusion plants in the moderately distant future. If they work well, power might be cheap enough that large-scale hydrogen production is perfectly affordable, in which case we could have an all-hydrogen economy with no emissions across the board.

Jeremy

[Chad Noles]

Just a quick thought on the recharging thing.....Do any of you guys barbeque?You know those 20 gal tanks that they just switch out?Why wouldn't "stations" just use a swap out policy to
exchange canisters of H2 for vehicles?Seems more reasonable to me instead of the "filling" concept we are used to for vehicles.

[toddjh]

Originally posted by arcticpenguin
This question of H2 damaging the ozone should be looked into; right now there's just one or two preliminary reports.

I wouldn't have thought that H2 would last long enough in the atmosphere to do any harm. If I recall my chemistry classes, the H2/O2 reaction occurs at well below room temperature, only very slowly compared to the explosive reaction we're used to. Are we talking about dumping millions of tons of H2 into the air or something?

I also thought there was quite a bit of photodissociation of water going on at high altitudes, creating H2 temporarily. I wonder if the amount of leakage we'd produce would even come close to that.

Jeremy

[arcticpenguin]

Originally posted by toddjh


I wouldn't have thought that H2 would last long enough in the atmosphere to do any harm. If I recall my chemistry classes, the H2/O2 reaction occurs at well below room temperature, only very slowly compared to the explosive reaction we're used to. Are we talking about dumping millions of tons of H2 into the air or something?

I also thought there was quite a bit of photodissociation of water going on at high altitudes, creating H2 temporarily. I wonder if the amount of leakage we'd produce would even come close to that.

Jeremy
This was in the news a couple weeks ago. Here's a thread: http://www.randi.org/vbulletin/showthread.php?threadid=21406

[jj]

Originally posted by toddjh


Who said there was anything wrong with it? My main concern would be whether it's practical to run a reactor hot enough to crack a sufficient amount of water to cover the public demand -- if everybody's car has a fuel cell, you're talking a lot of H2. If not, you're just using electricity to do it, and it's no different from using a conventional power plant to do it.

Ideally, I'd like to think that we'll have fusion plants in the moderately distant future. If they work well, power might be cheap enough that large-scale hydrogen production is perfectly affordable, in which case we could have an all-hydrogen economy with no emissions across the board.

Jeremy

Well, I'm still not convinced that we can't ship H2 via the present natural gas system. Yes, it would require a few refits, but would it require new piping? Yes, I know about hydrogen embrittlement. I also know what 1920 gas pipe is like nowdays.

[Leif Roar]

Originally posted by toddjh


Yes, of course, but electrolysis has voltage/current requirements, doesn't it? Or at least I bet it's more efficient at higher current. The output from PV cells is extremely variable. Better to charge a battery and get a more controlled output for the electrolysis.


Actually, I would suspect that it would be more sensible to use capacitators for a "first level" energy storage. But even if you use a small regular battery for this, you will not have to use regular batteries (which have serious weight problems) for the main energy storage.


I'm curious what you have in mind. Can you give me an example of a setup where you think a regenerative fuel cell would be preferable to either a regular fuel cell, an internal combustion engine, or a solar-fed battery system?

Jeremy

Perhaps not the best advertisement, but the recent Helios crash (http://news.bbc.co.uk/2/hi/science/nature/3025242.stm) occured while testing an experimental rechargeable fuel-cell. (At the moment there doesn't seem to be any reason to suspect the fuel-cells caused the crash in any way.)

[arcticpenguin]

Well if we're going to postulate improvements in hydrogen storage and fuel cell performance, I think it's reasonable to postulate that competing technologies will also improve over time. In particular, electrical batteries. Current rechargeables are indeed heavy because they are filled with heavy metals. Perhaps improvements in the rechargability of lithium or other lightweight batteries will occur.

I don't think capacitors can compete with batteries for capacity, and certainly not for long-term storage. They store the energy as static electricity, not chemical potential, and there tends to be leakage over time.

I think the current 'hybrid' vehicles use capacitors to store electricity, I'm not sure what the capacitance or voltage ratings are.

[RedCoat]

Originally posted by Ziggurat


Maybe, but the Japanese manage to do it fine, and seem to be able to sell hybrid vehicles in the US, why can't we? There's other things that kind of make you wonder, like GM recalling its leased electric cars and refusing to let the leasors buy them. I'm not claiming conspiracy, but I do think that Detroit does not take fuel efficiency very seriously.

Cleaner isn't enough, they've got to be more fuel efficient as well. And in that regard we're not making any significant progress (SUV's have offset the gains that were made), and the standards are hardly moving at all...

There are actually a lot of differences between building cars in japan and building them in the US. Without going in to details, suffice it to say that there are vehicles built in Japan that COULD NOT be built in the US, and vice versa. Likewise, for a number of reasons, some vehicles can be profitable for one manufacturer and a complete loss for another. There are a lot of variables (plant location, supplier contracts, union labor, capacity, dealer network, tax codes, etc.) that can influence the business case for certain vehicle. Right now, some of the Japanese companies have *decided* to accept taking a loss on hybrid vehicles. This is (presumably) done as an R&D effort, just like the way GM did the electric car, which was known to be a negative-profit vehicle but was done as a learning venture.

If I had to guess why GM bought back the (lease-only) electric vehicles it is because (by law) manufacturers are required to provide service parts for N number of years after production of a vehicle has stopped. The parts for the electric vehicle were bloody expensive to begin with, and producing parts for a very-low-volume non-profitable vehicle would have been a huge waste of money. Scrapping the vehicles was probably cheaper and easier, and prevents potential future lawsuits, since the high-milage failure modes of an electric vehicle are not known the same way they are for regular vehicle. Imagine if a battery pack leaked on a electric car twenty years and 600,000 miles later - believe it or not, this could be the basis of a lawsuit.

Regarding SUVs - the car companies would LOVE to get milage to be better. Since all the manufacturers are constrained by CAFE requirements, they generally "give away" (sell at a loss) cheap high-mpg vehicles to enable the sale of profitable low-mpg vehicles. Improving fuel economy allows you to sell more high-profit vehicles. The market, however, has an apparantly endless fascination with heavy vehicle with powerful engines. No matter how big and how powerful, there is always a market segment that will pay a premium to get a bigger vehicle with a more powerful engine, and to ignore this market is to essentially give this profitable segment to your competitors.

Finally - may people do not realize that safety standards become more stringent all the time. The gov't keeps upping the speed of crash tests, requiring more content (more air bags, anti-lock brakes, stability control, and now - pending - anti roll over devices) that continuously add more weight and equipment to the vehicles. The market keeps demanding more and more while paying less and less. Since you can't have everything, car companies design around whatever the market is willing to sacrifice. In the US, this happens to be fuel economy. People would rather have a fuel-inefficient vehicle than lose their 14 air bags and quadruple-five-star crash ratings.

If you really want to get companies to build more effiecient cars, the best thing you can do is BUY ONE.

(For the record, I drive a relatively small, efficient 2-door VW golf, and not an SUV.)

Once again, I hope this doesn't sound like a rant, but (from my point of view) people LOVE to beat up the car companies, when all they're doing is building what the market asks for.

[jj]

Originally posted by Leif Roar

Actually, I would suspect that it would be more sensible to use capacitators for a "first level" energy storage. But even if you use a small regular battery for this, you will not have to use regular batteries (which have serious weight problems) for the main energy storage.


And just how much does the H2 storage weigh per unit of energy?

[Leif Roar]

Originally posted by jj


And just how much does the H2 storage weigh per unit of energy?

It's been a long while since last I've opened my chemistry books, and I suspect there's an easier way of calculating this - but here goes, using bond energies (which I don't think is 100% correct, but should be a good approximation).

The reaction we're looking at is 2 * H2 + O2 --> 2 * H2O. We have three different covalent bonds involved: H-H, O-O and O-H - they have the following bond energies:

H-H : 432 kJ / mol
O-O: 146 kJ / mol
O-H: 467 kJ / mol

This bond energy needs to be supplied to break a bond, and is released when a bond is formed. For this reaction we need to break 2 H-H bonds and one O-O bond, and 4 O-H bonds will be formed.

So; dH = 2 * 432 + 146 - 4 * 467 kj/mol = - 758 kJ/mol O2

In other words, this reaction produces 758 kJ per mol O2. (dH is negative since it's a measure of the energy that needs to be added to a reaction.)

Two mol of hydrogen plus one mol of oxygen weights 36g (since we're talking about a rechargeable fuel cell, we have to inclued the weight of the oxygen since we don't get that from the air), so the energy output is 758 kJ / 36 g = 21 kJ / g

21 kJ / g = 21 000 kJ / kg = 21 000 / 3600 kWh/kg = 5.5 kWh / kg

This is of course the absolute maximum energy density you can achieve - as it doesn't take into account energy loss, or the weight of anything else but the reactants. For comparison, the practical (not the theoretical maximum) energy density of a lithium battery would be on the order of 200 - 250 Wh/kg

Edited to fix a error in my calculations, and to add: On second thoughts, I think I might have done something wrong. I'll need to read up on my chemistry a bit. Anyone who knows anything about this, please correct me in the meantime.


Edited yet again to add:

Okay, I've obviously made a serious blunder somehow (perhaps that I've used the bonding energy even though the final product is not a gas). Using the standard enthalpy of formation, I end up with 4.40 kWh / kg - which I believe to be correct.

[jj]

Originally posted by Leif Roar
Edited to fix a error in my calculations, and to add: On second thoughts, I think I might have done something wrong. I'll need to read up on my chemistry a bit. Anyone who knows anything about this, please correct me in the meantime.

In any case, what is the energy density of the STORAGE, including the hydride, etc...

Not just the H2.

[Leif Roar]

Originally posted by jj


In any case, what is the energy density of the STORAGE, including the hydride, etc...

Not just the H2.

From http://www.llnl.gov/str/Mitlit.html:

The team looked at flywheels, supercapacitors, various chemical batteries, and hydrogen- oxygen regenerative fuel cells. The regenerative fuel cell, coupled with lightweight hydrogen storage, had by far the highest energy density--about 450 watt-hours per kilogram--ten times that of lead-acid batteries and more than twice that forecast for any chemical batteries.

[daver]

Originally posted by Leif Roar


From http://www.llnl.gov/str/Mitlit.html:

The team looked at flywheels, supercapacitors, various chemical batteries, and hydrogen- oxygen regenerative fuel cells. The regenerative fuel cell, coupled with lightweight hydrogen storage, had by far the highest energy density--about 450 watt-hours per kilogram--ten times that of lead-acid batteries and more than twice that forecast for any chemical batteries.

That's a 5,000 psi tank. About 300 atmospheres. You'd want the tank to hold on the order of 10 kg of hydrogen in order to have a cruise range comparable to a gasoline car. If my back-of-the-envelope figures are correct, that's about a 0.25 cu meter tank. The article suggested that it would take 5 min to refuel one of these at the pump, but it's going to require a trained refueller (no self-serve). Someone in a different thread suggested swapping out the tanks (like the LP tanks for barbecues). In which case you'd probably want two or three smaller tanks, so you could empty the tanks before exchanging.

The article didn't mention the weight of the tank (or i missed it if it did). I'd guess relatively light--on the order of 100 lbs, but that's a completely uneducated guess.

[TillEulenspiegel]

Originally posted by Leif Roar


Or not. The maximum power you can generate by sun-light is 1.8 horsepower per square meter (and in real use you'd average a lot less because of cloud-cover, time of day and year and lattitude) - if you want to generate more power by sunlight, you'll have to somehow increase the energy output of the sun.

A car would need many square meters of surface of photo-electric surface to generate enough power to be equal to even a small gasoline powered engine.

Your correct Leif, but for some reason the methodology has gotten screwed up as people are inferring statements that I never uttered, they seem rather more interested in argument then discussion or enlightenment. The ONLY thing I posted was about the effacacy of the closed loop RFC as VS. the efficiency of I.C motors and in order to make the process of application more accessible, used the car model as an illustration ( with the disclaimer that i was not attempting to BUILD such a car). There was no implication on my part as to use solar cells to do anything other then to recharge the storage batteries( and supply incidental current to the FC.) . I say so in a previous post. I provided direct links to both the DOE and (because someone asked, tho it doesn't appear this person is a chemist) , one to the Journal of the Electrochemical Society and a page of government listed links to the relevant sites.

As far as the phrase "runs on"the attempt was to be general in speech . not deceptive. Kinda like asking what does a waste incinerator/power turbine run on? Waste?, ya but the waste is just burned..it doesn't run any thing. Heat? No that just heats water in pipes. Water?, no because the water is basically static until the heat hits it then it just turns to steam .. Steam? well it does run past a turbofan imparting a force moment in the turbine..so are you wrong to say that the system runs on garbage because it's actually after many steps that steam turns a turbine? Over simplistic , but I'm sure you see my point.

Till:"The base components needed for the system to function is water ( not O2 and H ) and electricity. The water ( pure water yes ) supplies the constituent elements that are separated to O and H, solar cells supply partial E ( to both the cell and the charging system )and the storage batteries provided storage and current on demand.. Occasional charging by house current ( courtesy of the local power barons) is a given but is nominal ..now..with the technology at its infant stage. The main thrust here being one of efficiencies not of brute force"

Now is there anything in that statement that is Wrong?, Misleading?, Outragious? Exclusive of fact and based on opinion? No.

Now compare this idea of a self contained system that requires a minimum of maintenance, that excludes both the specter of huge government infrastructure and interference. whereas all the hydrogen as fuel prospect,entails all the boogiemen of nuclear science, hazardous storage and transport of the product. And the inevitable stranglehold of big business. Which one seems to make more sense as an investment in future power schemes? (both in automobiles and for the home)

So, now I just must remember to avoid small birds that have frozen asses and screech without making sense.


P.S.
Just saw your post Leif, good explaination for understanding , but the info is actually 6 years old now. Significant improvements have been made in the past 2 yrs. Maybe Ill surf and look to some of my old sources and post um'

[arcticpenguin]

Originally posted by TillEulenspiegel
blah blah blah

Translation: "I made misleading statements and failed to back up my position, but now that someone else has done so, I don't understand why it wasn't clear to everyone else all along, so I will blame them for my failings"

[NoZed Avenger]

Originally posted by daver


That's a 5,000 psi tank. About 300 atmospheres.

Is there an impact on safety issues here? I know a problem with some natural gas vehicles is that ithe fuel is held under pressure, and an undetected leak could effectively spread a rapidly burning and highly inflammable mist into the nearby, oxygenated air.

In layman's terms, all the ingredients for a really good incendiary. And the pressure means that it could spray out in a 4-5 block radius before igniting.

Now, cities still use these vehicles (but do not allow untrained drivers to handle any of the refueling), so it may be safer than it sounds. Is this comparable? Is it nothing to worry about?

[jj]

Originally posted by NoZed Avenger

Is there an impact on safety issues here? I know a problem with some natural gas vehicles is that ithe fuel is held under pressure, and an undetected leak could effectively spread a rapidly burning and highly inflammable mist into the nearby, oxygenated air.


Well, 5000 PSI in a tank strikes me as explosive if it's 5000 PSI worth of Helium, or Neon, let alone if it burns...

What I noticed in the 'regenerative fuel cell' article was that it requires FUEL, by the way.... It doesn' t just cycle water/H2/water all by its lonesome, it wants fuel, in the form of H2. In that 5000 PSI container.

[NoZed Avenger]

Originally posted by jj


Well, 5000 PSI in a tank strikes me as explosive if it's 5000 PSI worth of Helium, or Neon, let alone if it burns...

What I noticed in the 'regenerative fuel cell' article was that it requires FUEL, by the way.... It doesn' t just cycle water/H2/water all by its lonesome, it wants fuel, in the form of H2. In that 5000 PSI container.


It certainly SOUNDS like a safety issue, and the spreading of the hydrogen afterwards is icing on the cake.

/orders asbestos underwear

[arcticpenguin]

Originally posted by NoZed Avenger

It certainly SOUNDS like a safety issue, and the spreading of the hydrogen afterwards is icing on the cake.

/orders asbestos underwear
At least hydrogen dissipates more quickly than any other gas. and does not hang out in low-lying areas like gasoline vapor.

[fishbob]

5000 psi is less than twice the pressure contained in an aluminum scuba tank. So a series of small 5000 psi tanks would do it, and could look a lot like basic scuba tanks.

.25 cubic meters of H2 would require somewhere around 20 scuba sized tanks, at about 50 lbs each = about 1000 lbs. This vs 20 gallons of gasoline or diesel @ about 6.5 to 7 lbs/gallon plus the fuel tank weight, about 200 lbs.

I doubt that H2 gas is any more dangerous than gasoline, for carrying around in a vehicle. Gasoline vapor accumulates in low places, H2 gas dissipates upwards quickly.

[Badger]

Correct me if I'm wrong, but it seems that TillEulenspiegel's proposal would be ideally suited to home or industrial use, rather than a vehicle.

I mean, if I could paint my house with stuff, and have a couple of wires leading to a tank of water in the basement which I plug my appliances in to, that sounds like quite the deal to me!

I think the main problem with applying alternative energy sources to transportation begins with the internal combustion engine. There is a huge amount of wasted energy that is disappated as heat (friction and from combustion) and noise. Another factor is the operational range as opposed to the point where the motor runs at maximum efficiency. IIRC, internal combustion engines are about 20% efficient in that 20% of the energy in the fuel makes it to the output shaft of the engine. Less makes it to the rear wheels. I have heard that turbines are more efficient, in the 40% range, but haven't done enough research to be confident of that. And I don't know where rotary engines (wankles) fall in there, either.

So the main concern is getting the energy from the sun (because no matter what you're talking about, excluding nuclear power) you're converting solar energy into motion, when you get right down to it.

My preference would be for a diesel engine (turbine? IC? Rotary) driving a generator at the most efficient speed/load for that engine/generator set, and taking the electricity to motors at the wheels, and offloading extra energy to a form of battery storage in the vehicle itself. The batteries will provide power for acceleration/load, while the generator will provide power for constant speed. Of course there would be electric braking as well which would provide some battery recharge, and I guess you could paint it photovoltaic as well, and plug it in to the ol' basement watertank at night. But that's just my preference.

With regard to the fuel for the engine in the setup above, I guess it doesn't really matter if it's deisel, gasoline, hydrogen, chickenfat, home brew, ethanol, or what. My point is that there are many energy sources now, but they need to be examined in a different way in order to turn sunlight into motion.

[BrilliantBeast]

Interesting things happen when you start a thread, get busy, then go back to it.

Revising my initial question, it looks like I had the wrong issue, the issue is not pollution, but energy independence. In light of that, the analogy of two apples for one apple holds.

[Agammamon]

A better analogy may that you want an apple but you have two oranges to trade.

It boils down to a matter of efficiencies and energy densities.
Solar power is cheap but it takes a lot of surface area to generate power.
Fuel cells may not be as overall efficient as solar power but they store what energy they have in a more compact form. More compact than batteries. Also, fuel cells can be fueled faster than high capacity batteries can be charged.

So you spread your solar cells out in static locations, where size doesn't matter. Use that to crack water and store the H2/O2 in the car, where it is recombined in the fuel cell. Eventually the mass/capacity ratio and charge times of batteries may exceed fuel cells, in which case you just stop using fuel cells.

[arcticpenguin]

Originally posted by Agammamon

Solar power is cheap but it takes a lot of surface area to generate power.
Current solar cells are not that cheap. Break even times are a couple of decades.

[chipotle]

Good info at:
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/electrol.html

The H2 storage problem does have a simple solution. Add carbon to the H2 so you get a denser, less volitile fuel that does not have the embrittlement problems of H2. Something like C8H15 fould work fine. An added benefit would be that this fuel would work in existing cars.

[aerocontrols]

Originally posted by chipotle
Good info at:
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/electrol.html

The H2 storage problem does have a simple solution. Add carbon to the H2 so you get a denser, less volitile fuel that does not have the embrittlement problems of H2. Something like C8H15 fould work fine. An added benefit would be that this fuel would work in existing cars.

oh, LOL! :D :D :D

I just had to read that out loud to my office buddies.

[Mr. Skinny]

Originally posted by NoZed Avenger



It certainly SOUNDS like a safety issue, and the spreading of the hydrogen afterwards is icing on the cake.

/orders asbestos underwear
Hydrogen ignites so readily, it's unlikely to spread out and then explode. I've read that the energy generated by the hydrogen molecules escaping through a pinhole leak in a tank is sometimes enought to ignite it. Add that to the invisible flame, and it can be scary stuff.

Years ago I did the safety work on a hydrogen burning prototype aircraft engine supplied by two tube trailers (semi sized) of gaseous hydrogen. It took nearly eight years to work all the issues, many of which were safety related.

That said, it will be interesting to see what creative ways can be developed to handle/distribute hydrogen safely.

[jj]

Sorry, but you need to go a bit farther. All of that carbon will require more oxygen to burn, so you need to add a bunch of NO3's to it.

Perhaps 1,3,5,7 Tetra dinitro octane, perhaps?

[arcticpenguin]

Someone want to take a look at this?

http://www.sciencedaily.com/releases/2003/06/030626235144.htm

ARLINGTON, Va. — Scientists have developed a hydrogen-making catalyst that uses cheaper materials and yields fewer contaminants than do current processes, while extracting the element from common renewable plant sources. Further, the new catalyst lies at the heart of a chemical process the authors say is a significant advance in producing alternate fuels from domestic sources.

In the June 27 issue of the journal Science, James Dumesic, John Shabaker and George Huber, of the University of Wisconsin at Madison, report developing the catalyst from nickel, tin and aluminum and using it in a process called aqueous-phase reforming (APR), which converts plant byproducts to hydrogen. The process performs as well as current methods that use precious metals such as platinum, yet runs at lower temperatures and is much cleaner.

[chipotle]

Normal decomposition produces methane, which is denser and safer than H2. Why would anyone want to produce H2 instead of CH4? You can always trade the safer CH4 for CO2 and H2 later on.

[arcticpenguin]

Here (http://story.news.yahoo.com/news?tmpl=story&cid=96&ncid=753&e=10&u=/space/20030709/sc_space/fuelcellspowerplantsforaircraft) is an article on fuel cells for aviation. There's something about designing a fuel cell to use jet fuel isntead of H2 for use as an auxiliary power unit, to run the electrical equipment aboard the aircraft.

There's also mention of a solar/fuel cell combo, but I don't think this would be currently anywhere near practical for the lifting capacity and speeds of passenger aircraft.

[arcticpenguin]

http://story.news.yahoo.com/news?tmpl=story&cid=570&ncid=753&e=5&u=/nm/20030718/sc_nm/environment_hydrogen_dc

WASHINGTON (Reuters) - Two U.S. energy experts cast more doubt on Friday on a push to develop hydrogen-powered cars as a means to cut air pollution and reduce oil imports.



Cheaper and faster ways already exist to achieve the same effect, including raising fuel efficiency and toughening environmental standards, David Keith and Alexander Farrell, wrote in Friday's issue of the journal Science.

"Hydrogen cars are a poor short-term strategy, and it's not even clear that they are a good idea in the long term," Farrell, assistant professor of energy and resources at the University of California, Berkeley, said in a statement.

"Because the prospects for hydrogen cars are so uncertain, we need to think carefully before we invest all this money and all this public effort in one area."