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View Diary: The Nuclear Shill Apologizes. (157 comments)

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  •  I will touch on this subject in my next diary. (1+ / 0-)
    Recommended by:
    LIsoundview

    Hold on for a bit.

    •  consider a couple of things please: (1+ / 0-)
      Recommended by:
      NNadir

      What if coal was only the source of carbon in FT?  H2 and energy provided by nuclear.

      Is there a way to get CO2 out of the air that's possible on an industrial scale?  This would enable either synthesis of hydrocarbon fuels or DME carbon neutral.

      Hold yourself to the same standard that you have when you are critical of the wind and solar.  Not wishful thinking, but actually consider the equipment and energy required.

      •  I will do my best on this score. (0+ / 0-)

        It may be possible that I don't know everything, but I hope you will be able to discern what I do understand on this score.

        •  I'll count on it! (0+ / 0-)

          Your diaries are always informative and I look forward to reading them.

          You have previously posted on running direct methanol fuel cells backwards.  (Would that make them direct methanol electrolysis cells?)  This is a new method of producing a hydrocarbon fuel without going through synthgas first.

          All others I'm aware of go through synthgas.  So whether its methanol, DME, or FT production of gasoline, what matters is the source of synthgas, not the product produced.

      •  I can think of at least three ways (0+ / 0-)
        1. freeze CO2 out of the air,
        2. separate it using a molecular sieve,
        3. chemically absorb it, then desorb it using heat

        I think I read somewhere that absorbing atmospheric CO2 on lime and then driving it off using heat to use it in FT would require only 6% more energy input that if pure CO2 was readily available.  Doesn't sound like a good reason to continue the use of coal to me.

      •  CO2 from the air (0+ / 0-)

        David Keith at the University of Calgary has done some work on removing CO2 from the air.

        http://www.ucalgary.ca/...

        It is POSSIBLE, but costs several times as much as removing CO2 from a more concentrated gas stream.  There is also a land issue due to the diffuse nature of atmospheric CO2.  You need a lot of area to capture any amount.  So for those believers in carbon capture and storage, doing it at the source is the best bet (more economical).  For the rest of us, we know that nuclear energy avoids the problem.

        •  not to save coal plants (0+ / 0-)

          but to provide the carbon for liquid fuels.

          Even under the most aggressive replacement of transportation with non-liquid fuels, there are applications where liquid fuels are the only viable solution.  The best example is agriculture.

          I don't buy hydrogen as a feasible fuel.  The only proposed synthetic fuels I am aware of require carbon.  If we wish to provide the carbon without using fossil fuels, that means it needs to come from the air.

        •  and should have mentioned this in my first post (0+ / 0-)

          Thanks for the links on chemical separation of CO2.

          I think that's the most feasable method.  I'm arware of the costs of cryogenic removal and don't think it will pan out.

        •  How about plants?? (1+ / 0-)
          Recommended by:
          Stewart Peterson

          Isn't there an easier (and much older) way to remove CO2 from the air, using these things we call "plants"?  Chlorophyll, that is.  Nature's been doing it for eons.

          I know that biomass schemes have some potential technical and environmental problems.  In fact, for those reasons, I generally don't support using biomass source as a straight fuel for transportation (where all the energy comes from the crop).  However, I would support biomass as the carbon feedstock for a synthetic fuel program, where most of the energy is in hydrogen supplied from a non-fossil energy source (e.g., nuclear).

          Even more importantly, this fuel should be used to fuel PHEVs, as opposed to standard cars.  Studies show that the average PHEV driver can travel ~85% of his miles on pure electric power.  Thus, not only is most of the energy in the fuel from the non-biomass hydrogen, but the fuel is only being used for ~15% of the miles/energy.  Thus, the amount of carbon/biomass feedstock needed would be very small indeed.

          Depending on the chosen crop, and how the biomass production operation is run, such a scheme could approach total carbon neutrality.  That said, we mustn't let the perfect be the enemy of the good enough.  The above approach would clearly reduce net CO2 emissions to a tiny fraction of today's, which is good enough!  We don't need to engage in very costly, technologically challenging schemes just to remove every ounce of net CO2 emission.  Just something to keep in mind.

          Heck, the adoption of PHEVs all by itself is probably enough to reduce transport sector emissions to acceptable levels (even assuming they ran on gasoline, that is).  Any further reduction in emissions from reducing the net CO2 of the fuel itself is just gravy.

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