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In know this is a bit off topic but someone else raised the issue...
For those interested in the details of hydrogen power in cars.
According to Science and Technology Review, 11 M3 of hydrogen is sufficient to take the place of a gallon of gasoline as a motor fuel.
That assumes you can work out the mechanical and engineering issues with burning hydrogen in a conventional piston engine. Wankel engines are better suited to burn hydrogen but they are less efficient.
Anyway, generation of the hydrogen is also an issue. Assuming electrolysis is the most efficient means of creating hydrogen let's use that method.
According to Stuart Energy, who claim to be very clever when it comes to extracting hydrogen from water, they can get one cubic meter of hydrogen out of water using only 3.5 kilowatt-hours of electricity to do it.
A healthy nuclear plant (e.g. San Onofre, Unit#2 abd Unit #3 for the year 2001) can, over the course of a year, generate 15 terawatt-hours of electricity.
Assuming a 100% efficient and lossless system for the sake of easy math, we see that a single nuclear reactor can generate enough electrity to electrolyze roughly 4.2 billion cubic meters of hydrogen.
To do so, it would require just over 910,000 gallons of purified water. Or, if you prefer, about 2,500 gallons/day. Again, this assumes 100% conversion efficiency. In the real world, we'd achieve a fraction of that.
On the other side...
Assuming a wildly optimistic average fuel efficiency of 30mpg and an average of 12,000 miles/year, this would fuel the cars of just under 1,000,000 people for one year.
The actual wholesale cost of gasoline as a fuel runs about USD$0.55/gallon if memory serves.
That means that in a perfect world where people will run out and buy hydrogen cars as long as the fuel costs are the same as gasoline, our hypothetical facility has the ability to earn $211 million/year in revenue.
This may sound like a lot but when you consider the billions that it costs to build, operate and de-commission a nuclear reactor over its limited life-cycle and the many millions more it would cost to operate this theoretical electrolysis plant, it is tough to make it economical.
Also, keep in mind that the figures I gave didn't make any allowances for waste, loss, accidents, etc... and I also didn't allow for the costs of packaging and transporting the hydrogen or the costs to retailers to sell the hydrogen to the public.
So the actual revenue figures would be much lower in the real world.
Also, there no way to even remotely predict the results of removing such a large amount of water from the ecosystem and/or moving it to areas where it wasn't previously so plentiful. Take the US southwest as an example. It is an arid, desert region but one which has many cars. If lots of people started burning hydrogen instead of gasoline, the net effect would be to suddenly bring a lot of water into an area that previously had little. The climate-change crowd should be worried about this.
There are many such issues and all of them very serious. For all of its warts, petroleum isn't that bad a deal as a motor fuel compared to the alternatives. Alcohol would probably be an easier transition to make but isn't going to happen any time soon if the oil companies have anything to say about it. Hydrogen has too many problems to be overcome at least in any of our lifetimes.
For those interested in the details of hydrogen power in cars.
According to Science and Technology Review, 11 M3 of hydrogen is sufficient to take the place of a gallon of gasoline as a motor fuel.
That assumes you can work out the mechanical and engineering issues with burning hydrogen in a conventional piston engine. Wankel engines are better suited to burn hydrogen but they are less efficient.
Anyway, generation of the hydrogen is also an issue. Assuming electrolysis is the most efficient means of creating hydrogen let's use that method.
According to Stuart Energy, who claim to be very clever when it comes to extracting hydrogen from water, they can get one cubic meter of hydrogen out of water using only 3.5 kilowatt-hours of electricity to do it.
A healthy nuclear plant (e.g. San Onofre, Unit#2 abd Unit #3 for the year 2001) can, over the course of a year, generate 15 terawatt-hours of electricity.
Assuming a 100% efficient and lossless system for the sake of easy math, we see that a single nuclear reactor can generate enough electrity to electrolyze roughly 4.2 billion cubic meters of hydrogen.
To do so, it would require just over 910,000 gallons of purified water. Or, if you prefer, about 2,500 gallons/day. Again, this assumes 100% conversion efficiency. In the real world, we'd achieve a fraction of that.
On the other side...
Assuming a wildly optimistic average fuel efficiency of 30mpg and an average of 12,000 miles/year, this would fuel the cars of just under 1,000,000 people for one year.
The actual wholesale cost of gasoline as a fuel runs about USD$0.55/gallon if memory serves.
That means that in a perfect world where people will run out and buy hydrogen cars as long as the fuel costs are the same as gasoline, our hypothetical facility has the ability to earn $211 million/year in revenue.
This may sound like a lot but when you consider the billions that it costs to build, operate and de-commission a nuclear reactor over its limited life-cycle and the many millions more it would cost to operate this theoretical electrolysis plant, it is tough to make it economical.
Also, keep in mind that the figures I gave didn't make any allowances for waste, loss, accidents, etc... and I also didn't allow for the costs of packaging and transporting the hydrogen or the costs to retailers to sell the hydrogen to the public.
So the actual revenue figures would be much lower in the real world.
Also, there no way to even remotely predict the results of removing such a large amount of water from the ecosystem and/or moving it to areas where it wasn't previously so plentiful. Take the US southwest as an example. It is an arid, desert region but one which has many cars. If lots of people started burning hydrogen instead of gasoline, the net effect would be to suddenly bring a lot of water into an area that previously had little. The climate-change crowd should be worried about this.
There are many such issues and all of them very serious. For all of its warts, petroleum isn't that bad a deal as a motor fuel compared to the alternatives. Alcohol would probably be an easier transition to make but isn't going to happen any time soon if the oil companies have anything to say about it. Hydrogen has too many problems to be overcome at least in any of our lifetimes.
JonGwynne said: In know this is a bit off topic but someone else raised the issue...
For those interested in the details of hydrogen power in cars.
According to Science and Technology Review, 11 M3 of hydrogen is sufficient to take the place of a gallon of gasoline as a motor fuel.
That assumes you can work out the mechanical and engineering issues with burning hydrogen in a conventional piston engine. Wankel engines are better suited to burn hydrogen but they are less efficient.
Anyway, generation of the hydrogen is also an issue. Assuming electrolysis is the most efficient means of creating hydrogen let's use that method.
According to Stuart Energy, who claim to be very clever when it comes to extracting hydrogen from water, they can get one cubic meter of hydrogen out of water using only 3.5 kilowatt-hours of electricity to do it.
A healthy nuclear plant (e.g. San Onofre, Unit#2 abd Unit #3 for the year 2001) can, over the course of a year, generate 15 terawatt-hours of electricity.
Assuming a 100% efficient and lossless system for the sake of easy math, we see that a single nuclear reactor can generate enough electrity to electrolyze roughly 4.2 billion cubic meters of hydrogen.
To do so, it would require just over 910,000 gallons of purified water. Or, if you prefer, about 2,500 gallons/day. Again, this assumes 100% conversion efficiency. In the real world, we'd achieve a fraction of that.
On the other side...
Assuming a wildly optimistic average fuel efficiency of 30mpg and an average of 12,000 miles/year, this would fuel the cars of just under 1,000,000 people for one year.
The actual wholesale cost of gasoline as a fuel runs about USD$0.55/gallon if memory serves.
That means that in a perfect world where people will run out and buy hydrogen cars as long as the fuel costs are the same as gasoline, our hypothetical facility has the ability to earn $211 million/year in revenue.
This may sound like a lot but when you consider the billions that it costs to build, operate and de-commission a nuclear reactor over its limited life-cycle and the many millions more it would cost to operate this theoretical electrolysis plant, it is tough to make it economical.
Also, keep in mind that the figures I gave didn't make any allowances for waste, loss, accidents, etc... and I also didn't allow for the costs of packaging and transporting the hydrogen or the costs to retailers to sell the hydrogen to the public.
So the actual revenue figures would be much lower in the real world.
Also, there no way to even remotely predict the results of removing such a large amount of water from the ecosystem and/or moving it to areas where it wasn't previously so plentiful. Take the US southwest as an example. It is an arid, desert region but one which has many cars. If lots of people started burning hydrogen instead of gasoline, the net effect would be to suddenly bring a lot of water into an area that previously had little. The climate-change crowd should be worried about this.
There are many such issues and all of them very serious. For all of its warts, petroleum isn't that bad a deal as a motor fuel compared to the alternatives. Alcohol would probably be an easier transition to make but isn't going to happen any time soon if the oil companies have anything to say about it. Hydrogen has too many problems to be overcome at least in any of our lifetimes.
Jon,
You just refuse to see the light don't you?? Your recent post boasts the increased cost of producing Hydrogen vs the wholesale cost of a gallon of gasoline.
But you don't take into account all the subsidised costs that help the cost of gasoline at the wholesale level stay so low.
The cost of equipping cars with emissions devices, costs to the environment not to mention the added healthcosts because people suffer greater/higher amounts of pulmonary diseases due to smog and other auto related ailments. I have a study, published in Scientific American several years ago that equates the real cost of a gallon of gasoline closer to $4.50 and that was 5 or more years ago. It will take me a day to dig the article out, but I will qupte directly from it tomorrow.
Also, you voice a concern about the use of water from which to extract hydrogen. Well, the byproduct of hydrogen consumption is water. There would be no net gain or loss to the system at large. Happy Motoring...Jim '85TE
JonGwynne said: If lots of people started burning hydrogen instead of gasoline, the net effect would be to suddenly bring a lot of water into an area that previously had little. The climate-change crowd should be worried about this.
Hi Jon,
You're forgetting to take into account that petrol/gasoline engines already produce water as a by-product of combustion. Seem to remember a figure of 1 gallon of water produced per 1 gallon of fuel burnt but not sure if that's right.
No doubt that water is produced though, and you can see it both as vapour and even as drops coming out of the end of the exhaust pipe.
I know from your postings that you're obviously not a fan of hydrogen power - or any 'alternative' fuel - but don't think you need to worry about them replacing petrol/gasoline just yet.
You never know though, in a few years we might all be getting round in flying De Loreans fuelled by rubbish from the trash can...
OK, I see where you're coming from with this now, but I'm afraid I think it's a non-issue.
If the sun shines on a patch of ordinary ground, much of the heat is reflected away and only a portion of it is absorbed by the various things you mentioned (dust, carbon componds, etc).
If you then build something on that patch of ground which absorbs the radiant energy and convert it to thermal energy, some of that thermal energy will be conducted directly to the air in contact with the device. This air will, being warmer than the surrounding air, rise and be replaced with air that is not as warm. Thus, the process is repeated and will continue even after sun sets until the temperature of the object in question falls to that of the surrounding air.
Still, you propose building vast numbers of solar collectors to generate power for the production of hydrogen in order to combat global warming.
The question of whether the cure is worse than the illness is worth asking.
The idea of a solar power plant is not to convert solar energy into heat. Its function is to turn it into electricity. If solar panel collectors were perfect black-body absorbers, and the plant was 50% efficient, then you'd still only end up with half the incoming solar flux converted to heat.
If you are worried about the effects of changing the albedo of the planet's surface, then perhaps you might consider the effect of roads and urbanisation first?
v8guinness said:
lotusguy said: Jon,
With only 65% of the work potential of petroleum being captured by today's most efficient engines,
Sorry, to the best of my knowledge a figure of 35-40% useful output is more realistic.
Hi,
No argument here, but I stated the Most efficient engines. I agree with you that the norm is closer to 35-40%, then add to thet the inefficiencies of the drivetrain and aerodynamics of the overall design, and total work potential drops horribly low. Happy Motoring...Jim '85TE
MEMSDesign said:OK, I see where you're coming from with this now, but I'm afraid I think it's a non-issue.
If the sun shines on a patch of ordinary ground, much of the heat is reflected away and only a portion of it is absorbed by the various things you mentioned (dust, carbon componds, etc).
If you then build something on that patch of ground which absorbs the radiant energy and convert it to thermal energy, some of that thermal energy will be conducted directly to the air in contact with the device. This air will, being warmer than the surrounding air, rise and be replaced with air that is not as warm. Thus, the process is repeated and will continue even after sun sets until the temperature of the object in question falls to that of the surrounding air.
Still, you propose building vast numbers of solar collectors to generate power for the production of hydrogen in order to combat global warming.
The question of whether the cure is worse than the illness is worth asking.
The idea of a solar power plant is not to convert solar energy into heat. Its function is to turn it into electricity. If solar panel collectors were perfect black-body absorbers, and the plant was 50% efficient, then you'd still only end up with half the incoming solar flux converted to heat.
If you are worried about the effects of changing the albedo of the planet's surface, then perhaps you might consider the effect of roads and urbanisation first?
Exactly, but that ship has already sailed. The only remaining question is whether we want to make a bad situation worse by increasing the amount of solar heat absorbed by the earth.
Do the math. Work out the area of a solar power station. Compare it to some other areas, like the latest housing estate near you, or the M1. Then compare it to the total planetary area. I think you'll find it's a non-issue.
Exactly, but that ship has already sailed. The only remaining question is whether we want to make a bad situation worse by increasing the amount of solar heat absorbed by the earth.
lotusguy said:
Jon,
You just refuse to see the light don't you?? Your recent post boasts the increased cost of producing Hydrogen vs the wholesale cost of a gallon of gasoline.
But you don't take into account all the subsidised costs that help the cost of gasoline at the wholesale level stay so low.
The cost of equipping cars with emissions devices, costs to the environment not to mention the added healthcosts because people suffer greater/higher amounts of pulmonary diseases due to smog and other auto related ailments. I have a study, published in Scientific American several years ago that equates the real cost of a gallon of gasoline closer to $4.50 and that was 5 or more years ago. It will take me a day to dig the article out, but I will qupte directly from it tomorrow.
Also, you voice a concern about the use of water from which to extract hydrogen. Well, the byproduct of hydrogen consumption is water. There would be no net gain or loss to the system at large. Happy Motoring...Jim '85TE
Yes, please quote from the article you mentioned.
And I don't think it is fair to characterize what I said as a boast of "the increased cost of producing Hydrogen vs the wholesale cost of a gallon of gasoline". All I'm saying is that hydrogen isn't as cheap as some people would like us to think. Gasoline isn't either? You're probably right. But I think you go a little too far in your post.
The cost of equipping cars with emissions devices is nothing to do with the cost of gasoline, it is part of the cost of buying a car. If you're going to be that oblique, you might as well add the cost of my time to travel to the station and pump the gas.
While we're at it, does gasoline save consumers money because it generates tax revenue for govenments who would have to raise other taxes if they lost that revenue?
And as far as burning hydrogen and the water as a byproduct goes, You're right, there's no net change to the eco-system in terms of the amount of water if you keep a very narrow view. But even with those blinders on, there are still potential problems.
Let me explain: You build a hydrogen generation plant in Area A and convert 1,000 gallons of water into hydrogen. Then, you ship the hydrogen to Area B and burn it. The hydrogen oxidized and is converted back into water releasing thermal and kinetic energy in the process.
What you've done is move 1,000 gallons of water from Area A to Area B.
When you're talking potentially about hundreds of millions of gallons of water being shifted it is important to consider the consequences of this before doing it. Particularly if Areas A and B are a significant distance from one another.
Now, for the wider view. The water converted to hydrogen will remain as hydrogen for extended periods of time. After all, it will take time to package and deliver the hydrogen to retail outlets - remaing in storage until purchased and naturally, the retailers will want to keep a significant stock on hand so they don't run out between deliveries. During this time, the water from which the hydrogen was extracted is removed from the eco-system. How many hundreds of millions of gallons of water would be permanently tied up in this reserve? This may or may not be a problem but it is something that should be considered.
>> Edited by JonGwynne on Wednesday 22 January 09:56
MEMSDesign said:Do the math. Work out the area of a solar power station. Compare it to some other areas, like the latest housing estate near you, or the M1. Then compare it to the total planetary area. I think you'll find it's a non-issue.
Exactly, but that ship has already sailed. The only remaining question is whether we want to make a bad situation worse by increasing the amount of solar heat absorbed by the earth.
The housing estate near me and the M1 are already built. Hence my term "this ship has already sailed".
Also, neither the housing estate in question nor the M1 are specifically designed to concentrate and absorb solar radiation in order to convert it to thermal or electrical energy.
grahambell said:
JonGwynne said: If lots of people started burning hydrogen instead of gasoline, the net effect would be to suddenly bring a lot of water into an area that previously had little. The climate-change crowd should be worried about this.
Hi Jon,
You're forgetting to take into account that petrol/gasoline engines already produce water as a by-product of combustion. Seem to remember a figure of 1 gallon of water produced per 1 gallon of fuel burnt but not sure if that's right.
No doubt that water is produced though, and you can see it both as vapour and even as drops coming out of the end of the exhaust pipe.
I know from your postings that you're obviously not a fan of hydrogen power - or any 'alternative' fuel - but don't think you need to worry about them replacing petrol/gasoline just yet.
You never know though, in a few years we might all be getting round in flying De Loreans fuelled by rubbish from the trash can...
Is the steam that comes out of a tailpipe just reheated condensate? I didn't realize that burning gasoline produced free hydrogen.
Also, I've got nothing against alternative fuels. In fact, I would welcome one. My problem is that most of the alternatives now considered seem to be non-starters because of one or more insurmountable obstacles to them being practical.
As I said in a previous post, I think the most practical route is for research to be done toward creating a cost-effective, plant-based replacement for petroleum. That way, we can leave the remaining petroleum in the ground where it belongs and still use the existing infrastructure and equipment.
So no-one is putting up new housing estates near you then? That's why I said the latest housing estate near you. Well spotted, they aren't designed to convert solar radiation into thermal energy, but I think you'll find anything black does a very good job of it.
The housing estate near me and the M1 are already built. Hence my term "this ship has already sailed".
Also, neither the housing estate in question nor the M1 are specifically designed to concentrate and absorb solar radiation in order to convert it to thermal or electrical energy.
The point is that the change in the global heat balance is negligable. If you really needed to please someone who couldn't understand this basic fact, you could easily offset it by painting an area of desert white.
>> Edited by MEMSDesign on Wednesday 22 January 14:57
JonGwynne said: [quoteIs the steam that comes out of a tailpipe just reheated condensate? I didn't realize that burning gasoline produced free hydrogen
It's fairly simple, petrol is a Hydrocarbon, burning it creates hydrogen/oxygen bonds (H2O) and Carbon/Oxygen (CO2). It does not produce free hydrogen though.
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