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View Diary: Recent DOE Break-Through with Hydrogen Fuel Cells, should make them Affordable (275 comments)

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  •  It depends.. (4+ / 0-)
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    Erasmussimo, OtherDoug, EricS, Odysseus

    Using natural gas directly might be as good, depending on what is done with the carbon during the conversion process in question. If it ends up as CO2, then burning it might be just as well. If not, then not. Then there is the other question, how is the methane stored in the vehicle. If cryogenically, then you also have the continuous emission of methane, which is 25 times as effective a greenhouse gas as CO2 is.

    They had some LNG powered buses at the Idaho National Lab when I worked there some years ago. At a transportation open house at which those buses were one of the "stars", I asked the bus operations manager about the LNG storage system and about how much gaseous methane it emitted, and he said it didn't emit any, except for when the relief valve opened from time to time, lol. As a profligate user of LN2 in my nuclear measurements lab, I just had to chuckle a little at that.

    The buses would run dry in about 2 weeks, actually, if allowed to sit that long with initially full tanks, if I remember correctly.

    Moderation in most things. Except Reactors. IFR forever!

    by billmosby on Sun Apr 24, 2011 at 08:53:28 AM PDT

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    •  Wow! Didn't think about that! (3+ / 0-)
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      billmosby, JeffW, OtherDoug

      The methane emissions from tanks had slipped right by me. Yes, that's a serious problem. With hundreds of cars storing tons of LNG in tiny tanks, sitting in the sun in parking lots all day long, it's conceivable that we could get a natural gas explosion.

      Sounds like an excellent reason NOT to burn LNG in cars.

      •  I think it's mainly applied to (4+ / 0-)
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        JeffW, Erasmussimo, OtherDoug, Odysseus

        larger vehicles, like buses or trucks, but I don't really know. You'd want to vent your garage pretty well, eh?

        Most of the smaller vehicles I am aware of use CNG, compressed natural gas. No leaks necessary there. Although methane leakage does occur to some extent in any handling system I suppose, just a question of how much.

        Moderation in most things. Except Reactors. IFR forever!

        by billmosby on Sun Apr 24, 2011 at 09:09:07 AM PDT

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        •  Another point... (2+ / 0-)
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          billmosby, OtherDoug

          ...there are fuel cells that will run on natural gas, emitting carbon dioxide as well as water vapor. They require catalysts, too, but may be able to take advantage of these discoveries. The big problem is that they have higher operating temperatures than hydrogen fuel cells, so you have to provide for insulation and cooling.

          Float like a manhole cover, sting like a sash weight! Clean Coal Is A Clinker!

          by JeffW on Sun Apr 24, 2011 at 09:21:22 AM PDT

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        •  CNG versus CH (2+ / 0-)
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          billmosby, OtherDoug

          Obviously, the constraint on CNG is the amount of energy you can store per unit volume. I wouldn't expect it to be much, although perhaps high strength materials would permit high enough pressures to store an adequate amount of CNG.

          But the same considerations apply to hydrogen -- and the volumetric energy content of H2 gas is less than that of CH4 gas. On the other hand, we should get higher energy efficiency out of a fuel cell. Hmm....

    •  Boston's buses run on natural gas (6+ / 0-)
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      Sparhawk, Crider, OtherDoug, Recall, JeffW, Odysseus

      The MBTA bus fleet is powered by gas.  It's cleaner than liquid fuels and probably a lot cheaper.  And Honda makes a gas-powered version of the Civic.  It doesn't leak out in normal use.  Metal tanks hold it in tightly.

      Hydrogen is much, much harder to contain in fuel tanks.  It's the smallest atom, and squeeze through materials that are impervious to everything else.  Storage probably requires using hydrated metal, but that's not fully developed either.

      Hydrogen is simply not a fuel, since it has to be manufactured using a of energy or from fuel.  It's not even a good medium for storing energy to be released via fuel cells.  Hydrogen fuel cell vehicle research was a Bush feint. It gave the Village press something to look at and say, lookie, we're working on alternatives to oil.  But they and their oil-company sponsors knew it could never succeed.  We should not waste any more time on it.  The platinum catalyst issue is trivial; it's like saying you've solve the homelessness problem by coming up with a water closet that's $50 cheaper than the current $200 models.

      •  Yes (5+ / 0-)
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        squarewheel, OtherDoug, Recall, JeffW, Odysseus

        And at the end of the day, hydrogen fuel cells are just another kind of battery with different trade-offs. As far as I can tell, it simply isn't far superior to existing electric-car technology and the storage problem is massive.

        People forget that it's one thing to demonstrate something in a lab and quite another to commercialize it to sell millions of it. These processes take years and sometimes don't work at all because the thing you are trying to commercialize ends up being more expensive than it is worth at the end of the day.

        Commercialization is a huge problem.

        (-5.50,-6.67): Left Libertarian
        Leadership doesn't mean taking a straw poll and then just throwing up your hands. -Jyrinx

        by Sparhawk on Sun Apr 24, 2011 at 10:29:10 AM PDT

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        •  Yes, a battery (2+ / 0-)
          Recommended by:
          OtherDoug, Odysseus

          It's not even a metaphor.  Batteries work by changing chemistry which releases energy.  Fuel cells do pretty much the same thing but inject the ions directly, rather than storing them in changing chemistry.  Batteries release hydrogen when overcharged.

          Fuel cells might make some sense when combined with the reformer, which breaks down a fuel into hydrogen and whatever else.  So there are natural gas fuel cells, which are a nice alternative to moving-part generators.  Reformers, though, tend to require catalysts and very high operating temperatures, limiting their applicability.

        •  my money is on battery technology improving (2+ / 0-)
          Recommended by:
          JeffW, chipoliwog

          to the point that fuel cells are unnecessary, since hydrogen production and storage are such big problems.

          big badda boom : GRB 080913

          by squarewheel on Sun Apr 24, 2011 at 05:26:43 PM PDT

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