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

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  •  Burning H2 directly works best. (6+ / 0-)

    Less loss of energy.  BMW has some demonstration cars that burn the hydrogen directly same as they would burn gasoline. There's not even a significant amount of change to the engine.

    There is much less loss of energy than the fuel cell to electricity to battery to electric motor route of H2 in fuel cells and the life cycle manufacturing process has a much smaller carbon footprint than fuel cells.

    The BMW Hydrogen 7 is the world's first production-ready hydrogen vehicle. It's already proving itself in the real world too: we're putting 100 of them to the test as loan cars for leading figures from the worlds of culture, politics, business and the media,
    •  so (4+ / 0-)

      what's the catch?

      safety?  infrastructure? wear and tear on the engine?


      I'm assuming H2 ==> has No CO2 outputs.


      Got Time?
      Take ten, to find something else informative and fun to read. Thx.

      by jamess on Sun Apr 24, 2011 at 07:07:42 AM PDT

      [ Parent ]

      •  So direct burn H2 more efficient, better. (4+ / 0-)
        Recommended by:
        jamess, Gustogirl, Matt Z, JohnnySacks
        "what's the catch? safety?  infrastructure? wear and tear on the engine?"

        Physics does not provide a free lunch. What are the "catches" to fuel cells powered by H2?

        One of the many advantages to direct burn of H2 in internal combustion engines is that it requires no change in current automobile manufacturing or engineering. It could be deployed in mass production immediately.

        The infrastructure build out would be adding hydrogen filling stations to current gasoline filling stations, a necessity for any hydrogen powered vehicle whether directly burning hydrogen or indirectly and less efficiently burning hydrogen such as in the fuel cells.

        Fuel cells would be more appropriate in homes generating electricity.

        •  This is an important point: (2+ / 0-)
          Recommended by:
          jamess, Matt Z
          Fuel cells would be more appropriate in homes generating electricity.

          Admittedly, my interest in this stems from owning a remote, off-the-grid cabin; but eliminating the grid altogether strikes me as an extremely desirable goal.

          If each house could produce its own electricity directly, the terrible waste of "line loss" (the loss of electricity in transport on the grid) could be eliminated.  Even better - the enormous vulnerability of the grid to terrorist attack or natural disaster  damage would be eliminated.

          Remember when a problem with the grid blacked out everyone on the eastern seaboard and west into the great lakes states a few years back?

          At least in a natural disaster area, if each home were self-sufficient for power, there would be pockets of working energy sources that could help residents whose energy sources were damaged while repairs were being made.  As it stands now, huge swaths are rendered helpless in freezing cold when the grid goes out.  Sometimes it takes weeks to restore power.

          Government of the people, by the people, for the people, shall not perish from the earth - Abraham Lincoln

          by Gustogirl on Sun Apr 24, 2011 at 08:31:35 AM PDT

          [ Parent ]

        •  Thermal Energy Per Pound (0+ / 0-)

          Gasoline is about 18,500 BTU/lb vs. hydrogen at 51,500 BTU/lb

          (Damn, it's been a long time since I've been in engineering)  The problem is that if a gallon of gas provides 114,000 BTU and 1 cubic foot of hydrogen at atmospheric pressure (14.7psi) produces 319 BTU then 8 gallons of hydrogen at 5,000 psi would be equivalent to a gallon of gas.  I don't know how willing I am to drive around with 8 gallons of hydrogen at 5,000 psi.

      •  Right now I think the catch is *getting* H2 (2+ / 0-)
        Recommended by:
        jamess, OtherDoug

        Unlike O2, which naturally exists in the atmosphere, H2 is not; it's so light that it just escapes into space.

        We don't want our country back, we want our country FORWARD. --Eclectablog

        by Samer on Sun Apr 24, 2011 at 08:34:43 AM PDT

        [ Parent ]

    •  second law, Carnot (2+ / 0-)
      Recommended by:
      OtherDoug, JeffW

      Fuel cells are not heat engines and therefore can in principle achieve very high efficiencies. Electric motors are already very high efficiency. Only some of the free energy goes to and from the battery, which can be done at fairly high efficiency. Direct combustion engines are heat engines and have severe intrinsic Carnot efficiency limits. So there's very good reason to do fuel cell R&D.
      The big hang-up is hydrogen storage. The current energy density limits are terrible. But that hang-up is there for H2-burners also.

      Michael Weissman UID 197542

      by docmidwest on Sun Apr 24, 2011 at 12:18:25 PM PDT

      [ Parent ]

      •  Not really (3+ / 0-)
        Recommended by:
        OtherDoug, Recall, JeffW

        Fuel cells are Carnot-limited.

        Remember that Carnot's theorum is not a fundamental law, but a direct consequence of the fundamental laws; if it's violated, perpetual motion becomes possible.  This applies to fuel cells as well.  Part of some of the claims that fuel cells are not carnot-limited requires not counting some of the losses, which are then instead attributed to the electrolysis side.

        •  nope (0+ / 0-)

          All devices are limited by the first and second laws. However, Carnot only applies (as is obvious from its simple derivation) to engines powered by the transfer of heat from a cold to hot reservoir. Electric motors, etc. have no Carnot limit. Of course, if you redefine the meaning of Carnot efficiency to simply being "obeying thermodynamics" then all devices are Carnot limited.  

          Michael Weissman UID 197542

          by docmidwest on Sun Apr 24, 2011 at 08:25:15 PM PDT

          [ Parent ]

          •  whoops- I meant hot to cold! duh nt (0+ / 0-)

            Michael Weissman UID 197542

            by docmidwest on Sun Apr 24, 2011 at 08:26:06 PM PDT

            [ Parent ]

          •  nope (0+ / 0-)

            When you have a peer-reviewed paper saying you're wrong, unless you can present a counter peer-reviewed paper, you're wrong.  Nothing against you personally.

            •  peer-reviewed paper (0+ / 0-)

              As I read that abstract (the journal was so obscure that we don't seem to have it in our major university library, so I wasn't going to pay for the full article) it was dealing with a purely semantic issue. The available work is given by the excess of G (Gibbs free energy) over the equilibrium value. That already takes into account the entropic second-law limits, via the -TS term in G. (There is no relevant T_H to even use in a Carnot expression, 1-T_C/T_H.) Peer reviewed papers are nice but we don't usually turn to them for the standard material we teach in sophomore courses.

              It ain't peer-reviewed, but (with a few awkward starts) the Wikipedia summary of the efficiency of fuel cells actually ends up giving a good description of the thermodynamics and some of the practical issues. It at least avoids getting hung-up on verbalisms.

              Michael Weissman UID 197542

              by docmidwest on Mon Apr 25, 2011 at 01:12:34 PM PDT

              [ Parent ]

            •  teachable thermodynamic moment (0+ / 0-)

              Maybe this will help. In this context (fixed p, T environment) the available work is given by the excess of G, the Gibbs free energy, above its equilibrium value. By the second law, all spontaneous changes are in the direction of lowering G. Combustion is such a change. Therefore it lowers G. In a burning system that process, in which G is lost, occurs before anything starts to extract work. Therefore it causes a loss of available  work. That's why combustion-based heat engines have intrinsic inefficiencies, in addition to practical problems.

              Michael Weissman UID 197542

              by docmidwest on Mon Apr 25, 2011 at 02:26:12 PM PDT

              [ Parent ]

    •  No, it is not less loss of energy. (4+ / 0-)
      Recommended by:
      OtherDoug, Recall, Odysseus, JohnnySacks

      But even PEMFCs are much more inefficient than EVs.  Here's a nice chart:

      Link.  That's from this research paper.  Acronyms: ICE = Internal Combustion Engine, PEMFC = Proton-Exchange Membrane Fuel Cell, NG = Natural Gas, CNG = Compressed Natural Gas.

      I'm really frustrated by how many people here read some hype piece and just buy into whatever it says without knowing anything about the topic.  This isn't so much a commentary on your post as on all of the "hooray!  the future is here!" posts scattered throughout this thread.

      •  the people (0+ / 0-)

        need hope in the future.

        Peak Oil is coming.

        We HAVE to do Something.

        Want would you have us do Rei?

        Maybe invest in Clean Coal,
        or Safe Nuclear?

        Maybe wait for the Perfect Tech, and the Perfect Implementation.

        the people need hope in the future,
        that it will be better,

        that it can work out.


        Got Time?
        Take ten, to find something else informative and fun to read. Thx.

        by jamess on Sun Apr 24, 2011 at 11:42:29 PM PDT

        [ Parent ]

        •  Electric. (0+ / 0-)

          It's a much more near-term approach than hydrogen, and far more efficient (read: scalable).  Beyond that, for any vehicle (gasoline included):

           * Vehicle mass reduction, esp. a switch to composites (which will also increase vehicle lifespans and safety)
           * Vehicle streamlining (we need to stop letting unaerodynamic style trends dominate vehicle design)
           * Increasing use of hybrid technology
           * More widespread adoption of LRR tires
           * The continued incremental progress in ICE efficiency

          There's no reason why two-seater hybrids shouldn't get 100+ MPG, and four-seaters 70+.  If you let streamlining and composites/weight reduction dominate your design process, you absolutely can make cars with those numbers that are still as safe or safer than ever, and plenty good performing to boot (electric motors have tons of power).

      •  I'm Confused (0+ / 0-)

        I just realized I may be one of the 'hooray' people without knowing one of the details.

        Let's face it, if the best we can do is produce hydrogen from hydrocarbon sources, then this diary's entire premise is 100% bullshit.  I'm making a blanket assumption that the hydrogen is produced from solar.  

        If we ignore the cost to produce the hydrogen and focus on fuel cell vs. internal combustion...  

        Is more or less useable horsepower produced from the same amount of hydrogen from a fuel cell or from internal combustion?  

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