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Is this hydrogen fuel technology possible?

  1. Jan 16, 2008 #1
    When hydrogen combusts it is turned into h20. H20 can be broken down into hydrogen and oxygen. NASA has been using solar panels power hydrogen generators in space for this purpose.

    Say you had a vehicle that carried a water tank, a hydrogen generator a solar panel a battery and a hydrogen powered engine. You could use the solar panel to run the H. Gen. Then you could have the o2 flow into the car to breath easier.

    Here is the question though. Could you run the exhaust through an air cooler and back into the water tank and reuse the hydrogen over and over again. It seems that this would work.
     
  2. jcsd
  3. Jan 16, 2008 #2
    Actually a power plant may be a more useful purpose if possible because they aren't burdened by power to weight ratios.
     
  4. Jan 16, 2008 #3

    russ_watters

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    Well, in that power plant, all the power would come from the solar panels, so if the sun's out it is more efficient just to use the solar panels to directly power the car. And, of course, solar panels do not generate enough power to directly power a regular car.
     
  5. Jan 16, 2008 #4
    Your chemistry is a little off. You would want to recombine all the hydrogen with all the oxygen. There would then be only water vapor in the exhaust.
     
  6. Jan 16, 2008 #5
    Is it not possible to use some of the energy from burning the hydrogen to run the hydrogen gen while the sun is out?

    Still I get your point.
     
  7. Jan 16, 2008 #6

    mgb_phys

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    Actually you might decide to vent the oxygen to save the weight of the oxygen collecting equipement and storage tank - assuming you had a fuel cell whohc could use atmospheric air as the oxygen source.
    You could use burning hydrogen to run the hydrogen gen. but then you couldn't use it to power the car.

    It's best to think of the hydrogren fuel cell as simply a rechargeable battery.
     
  8. Jan 16, 2008 #7

    Mech_Engineer

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    Now you're trying to invent an impossible machine. You can't get more energy out of burning oxygen and hydrogen than you put in separating them in the first place.

    A classic perpetual machine that many people have tried to invent is one that burns hydrogen and oxygen in an internal combustion engine, and uses the power from the machine to separate water into oxygen and hydrogen. Such a device obviously defies the laws of thermodynamics...
     
  9. Jan 16, 2008 #8

    russ_watters

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    Put another way, if you use some of the energy from the engine to run the hydrogen generator, some of the energy from the solar panel to move the car, and some of the energy from the solar panel to run the hydrogen generator, the net result is the same as if you left the water in the tank and used the solar panel to move the car.....assuming everything was perfectly efficient.
     
  10. Jan 16, 2008 #9

    Mech_Engineer

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    Last edited: Jan 16, 2008
  11. Jan 16, 2008 #10
    Ok. Well then how about this idea. You use hydrogen to heat your house. You keep the o2 for the hell of it and drop the extra cash. You use the solar panels to convert water to hydrogen and o2. When it is dark they shut off. Your furnace exhaust recycles the water.
     
  12. Jan 16, 2008 #11
    I guess the solar panels are providing most the power, but at least you don't need batteries which are the most costly because they need to be replaced over time.
     
  13. Jan 16, 2008 #12
    I guess in space it would work better because there is a constant source of high energy radiation.
     
  14. Jan 17, 2008 #13
    Hydrogen as an energy carrier would never be a replacement for gasoline in a car for several reasons.

    1) There is no abundant source of pure hydrogen on earth.
    2) Making hydrogen from non-renewable sources (such as natural gas) only adds to the pollution compared to using those sources directly. As well as greater inefficiencies.
    3) Our world power production from renewable sources like air and solar is miniscule compared to our reliance on coal and oil such that if we use all renewable energy to generate hydrogen through electrolosis, you will not even have anywhere close to the amount of hydrogen you need to sustain energy demand. Or not even enough hydrogen just to power all the hydrogen cars people will drive around the world.
    4) If you can overcome the above problem, you still have the problem of creating pipelines to transport your hydrogen. Oil and gas pipelines are mostly made of steel and hydrogen just diffuses right through steel. There will be an enormous cost to create a new network to transport hydrogen.
     
  15. Jan 17, 2008 #14

    mgb_phys

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    True hydrogen is a storage medium rather than a primary fuel. There is also no abundant source of pure gasoline, methane is about the only fuel you can use with little processing.

    The same as electricity, it's just easier to store a kg of hydrogen than a kg of electricity.

    The internet is impossible, the availability of fibre optic links is miniscule compared to telegraph wires. If you replace all the telex transmissions with email there is not enough capacity.
    If there is a market demand, and someone can money out of it, it will get built.

    Oil and gas pipelines are mainly used to transport raw oil/gas from the production field to the nearest distribution terminal. Most transport is by sea tanker. Transporting hydrogen is about as simple as transporting LPG and rather safer.
    Remember hydrogen is just a way of transporting electricity. a lot of the palces you can make renewable power (geothermal in iceland, solar in africa, hydro in n. canada) have no local customers, make hydrogen and ship it to LA is a solution.
    Even for some distant oil fields, like Alberta's oil sands, it might be cheaper to use the oil in-situ to generate hydrogen than to extract, transport and refine the oil into gasoline.
     
  16. Jan 17, 2008 #15
    Let me give you an example as to why you cannot just change society to be dependent on hydrogen alone. There are simply limitations to what we can do.

    Example taken from European Fuel Cell Forum
    Frankfurt Airport (2004)
    520 jet departures per day, 50 Jumbo Jets (Boeing 747)
    130,000 kg of kerosene per Jumbo = 50 t of liquid hydrogen
    For 50 Jumbo Jets per day:
    (2,500 t LH2/day, 36,000 m3 LH2/day, need 22,500 m3 water/day)
    Continuous output of eight 1-GW power plants needed
    for electrolysis, liquefaction, transport, transfer of LH2!
    At least 25 nuclear power plants plus the entire water consumption of
    Frankfurt needed to serve all 520 jet aircrafts per day at Frankfurt Airport

    Now if you don't want to go the renewable route, then by all means use reforming to get your H2. But in the end H2 will have to compete with its own energy source so it will always be expensive.

    I live in Canada. And I know that the hydropower is mostly concentrated in Quebec and they do sell it but also sell locally. Solar only has 6GW of capacity but I recognize that is growing but Geothermal only constitutes 8GW of global power with little growth. And since we're talking about fuel here for vehicles, well if you want to drive 300million vehicles considering only the US alone well you would need 400GW of capacity. And that's why I am saying global power production of energy through renewables is miniscule. You would need to spend upwards up to a trillion dollars in investing into renewables like wind to get that kind of output. Sure, it is possible - but with current cost of technology, people are not interested. They would rather spend a trillion on a war instead.

    You would have to show me how you could use existing infrastructure to transport hydrogen because I don't think it is simple. You have to redesign your storage tanks and even inner-city piping. Natural gas fuels my burner in my house to heat my home. So if I get a new burner to burn hydrogen, I don't think the gas company will be able to shove H2 through the pipes to reach my home. It won't work. How do you transport fuel from coast to coast, from north to south.. again pipelines won't work.
     
  17. Jan 17, 2008 #16

    mgb_phys

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    Methane is pretty unbeatable for heating/cooking in homes - which is why it is stupid to waste it burning it to generate electricity. The dash-for-gas was mainly because the way markets were deregulated it made commercial sense to build stations as quickly as possible.
    Hydrogen isn't easy to transport, although in technology where there's a profit theres a way, it is easier to transport than batteries.
    Quebec is lucky in that there is hydro relatively close to Montreal, the problem with most hydro is that people don't live in areas with high mountains, deep valleys, fast rivers and high rainfall. One of the most common uses of hydro is to run high energy processes like aluminium smelters so you are shipping 'power' in the form of aluminium.

    Hydrogen will only compete in areas where the weight and power density of batteries is unacceptable, that is probably cars and planes. LPG is obviously much better than H2 as a primary fuel for these, but when these run out / get too expensive then H2 is currently beating batteries. Of course someone might make better cells / super capacitors.

    The only real source of H2 as a primary fuel is things like abandoned coal mines, oil sands where you can reform in situ to save the cost of extraction.

    I think we are both argueing the same thing - that the "replace oil with hydrogen industry" is complete snakeoil. ;-)
     
  18. Jan 17, 2008 #17
    What you could do is you could make pipelines that ran seawater into areas where there are lots of wind or lots of sun and use it in conjunction with those systems to make local powerplants.

    Another option would be to have each community have a station which extracted the hydrogen locally from seawater using solar panels. That way the storage and transportation issue would be solved.

    The benefit is in the long term. How much water is there in the ocean. Plus burning hydrogen leaves us with no change in the atmosphere.

    I know that h2 isn't ready to fill all our demands, however as oil supply's are used up we need to make some kind of huge change anyways. We are kind of planning ahead now by making fuel from plant sources. Why not start the use of h2 also and slowly work it into the system.
     
    Last edited: Jan 17, 2008
  19. Jan 17, 2008 #18

    chroot

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    Why would you pipe water to the energy source, rather than wiring electricity to the water source? You're not making any sense. Piping water is enormously expensive.

    The main problem -- that solar energy is not an adequate solution for anything but a coffee grinder -- would not be solved.

    The amount of water in the ocean is irrelevant. A hydrogen infrastructure would not affect the net amount of water on the planet; at worst it would move a pretty insignificant amount of it around.

    - Warren
     
  20. Jan 17, 2008 #19
    My point was that moving electricity to the water source wouldn't solve the transportation issue. You still would need to transport the hydrogen all over the country.

    Is it harder to pipe water than oil?

    Solar panels could generate enough power to run the entire world if we built enough of them plus breakthroughs in using a wider range of the EM spectrum keep making them more powerful. My friend just hooked solar to his home and he has two panels about 2' by 4' he runs them into an inverter and the extra power charges batteries. Those two panels run his entire house including a coffee grinder.

    My thoughts were that fresh water is important to cities for other reasons so we can't use that. We would need to use sea water to not interupt the current water systems.
     
    Last edited: Jan 17, 2008
  21. Jan 17, 2008 #20

    russ_watters

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    So could nuclear power - and at a fraction of the cost. That's the reason we're not using solar power. It's too expensive (not to mention unreliable).
     
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