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View Diary: Wind is king, biofuels are bunk (118 comments)

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  •  What do mean RE an ammonia fuel cycle? (1+ / 0-)
    Recommended by:
    Stranded Wind

    That one I haven't heard of before.

    What's the concept here, and what's been tried?

    "If another country builds a better car, we buy it. If they make a better wine, we drink it. If they have better healthcare . . . what's our problem? "

    by mbayrob on Sat Dec 13, 2008 at 07:03:28 PM PST

    [ Parent ]

    •  Ammonia (1+ / 0-)
      Recommended by:
      UneasyOne

      Stranded Wind is a big backer of ammonia in vehicles, but I have to staunchly disagree with him.  It's toxic, only half as energy dense as diesel (barely better than a li-ion EV in terms of total system weight), very flammable, highly corrosive, and so on down the line.  It's production using electric power is highly inefficient (and that comes after the losses in generating that electricity), and on top of that, if you burn it, you then have the major losses already inherent in internal combustion engines on top of that (your average ICE vehicle is only about 20% efficient).  You can get better efficiency using a fuel cell, but fuel cells cost an utter fortune and use far more resources to make than batteries.  And the fuel efficiency still wouldn't approach a BEV.

      •  minor quibbles (1+ / 0-)
        Recommended by:
        Stranded Wind

        Ammonia's flammability range is fairly narrow - 16% to 25% by volume, and requires a pretty strong ignition source - I think of 850 C or so.  Gasoline is 1.4%-7.6%, methane (natural gas) 5%-15%, methanol 6.7%-36%, ethanol 3.3%-19%, and propane 2.1%-10.1%.

        The energy in ammonia is around 58 to 70 percent of the power needed to produce that ammonia via SSS.  While ICEs are not very efficient, ammonia fueled ones can use higher compression ratios; efficiencies run around 30% for automotive size engines on up to 40% or so for those in large equipment.  Fuel cell systems would give 50% for lower temperature cells, intermediate temperature cells need no PGM and run 5% or so higher in efficiency.

        Note that Stranded Wind is talking about using renewable power sources for production of electricity, and the efficiency of generation is the same be the power targeted at charging batteries or making fuel.

        BEVs make more sense for most urban driving, but past 100 miles or so some sort of fuel burner - be that a PEHV - starts to look better with existing technologies.  Those current battery technologies have some resource issues, too. Lithium isn't real common, there is argument about the implications of converting to lithium-chemistry BEVs and PEHV.  Dewvelopment of sodium-ion batteries, or further refining of the Zebra battery (although it has some toxicity issues) would alleviate issues of resource scarcity.

        •  Quibble quibbles :) (0+ / 0-)

          58-70%?  That's not the sort of numbers I'm seeing.  Example:   around 30% average for Canadian plants.  And that's with hydrogen fixation from natural gas, which is very efficient in bulk scale with cogen, not electrolysis.

          Engine efficiency is not the number you're looking for.  Good gasoline engines can hit 40% efficiency and a good diesel 50%.  The number you're looking for is vehicle efficiency.  Engine efficiencies are for peak operating conditions only, and fall off precipitously from there; there are also parasitic losses in a car that you have to account for.

          Fuel cells are worth their weight in gold and require platinum, which is mined in low PPM quantities in very environmentally destructive methods.  That's a complete non-starter.

          BEVs make more sense for most urban driving, but past 100 miles or so some sort of fuel burner - be that a PEHV - starts to look better with existing technologies.

          Not in the least.  The overwhelming majority of the energy that goes into a vehicle is consumed by operation, not production.  So operational efficiency is key, and ammonia-fuelled vehicles have atrocious system efficiency.  

          And, FYI, even a mere 100 miles is an hour and a half of freeway driving.  Is it really that much of a burden, an hour and a half of driving and then ten minutes of rapid charging?  Really?

          Those current battery technologies have some resource issues, too. Lithium isn't real common

          Myth,     You could produce thousands of BEVs for every man, woman, and child on the planet with lithium recovered from the oceans at a couple dozen dollars per kilogram, and it's doubtful we'll ever have to tap that (see the Kings Valley as an example of on-land resource scaleup).  And lithium is only a tiny fraction of the cell cost anyways.  Traditional li-ion are actually cobalt-limited.
          while the newer variants are capital cost limited.

          or further refining of the Zebra battery (although it has some toxicity issues)

          What toxicity issues?  Zebras are essentially nontoxic.

      •  absolutely wrong (0+ / 0-)

        Ammonia is not very flammable - it requires a starter fluid to get it moving. The MSDS lists it as "mildly flammable".

         Carrying on about battery vehicles is pretty silly in the context of a corn field - we're never going to have battery powered tractors and combines. Batteries don't have the energy density of liquid fuel. Urban Kossacks come up with the silliest ideas in this area - battery power or in one case tethering combines to the many (NOT!) overhead electrical lines in the area, just like city buses.

    •  Here (2+ / 0-)
      Recommended by:
      Stranded Wind, ImpactAv

      FDR 9-23-33, "If we cannot do this one way, we will do it another way. But do it we will.

      by Roger Fox on Sat Dec 13, 2008 at 07:16:37 PM PST

      [ Parent ]

    •  To clarify in terms of efficiency: (5+ / 0-)

      The average coal plant in the US is somewhere around 32% efficient.  Natural gas is something like 42% efficiency on average.  Nuclear, around 30%.  Solar thermal, somewhere in the 30% range.  Let's go with 35% for our power plant efficiency.  Commercial electrolysis is about 50-70% efficient on average.  You can get more efficiency, but it gets less economical as the rate of reaction decreases rapidly.  Let's be optimistic and say 70%.  The Haber process to create ammonia is 30% efficient.  Tack in 95% efficiency for compression and delivery.  The average internal combustion engine-powered vehicle is only about 20% efficient (the peak efficiency of the engines is higher, but that isn't experienced in practice).  Let's multiply: 0.35 * 0.7 * 0.3 * 0.95 * 0.2 = 1.4% efficiency.

      Now, let's look at a BEV (Battery Electric Vehicle).  Same power generation efficiency, 35%.  Average transmission losses in the US (which we didn't even count last time) is 92.8%.  A reasonable charger efficiency is 93% or so.  Li-ion batteries  usually range from 96 to over 99% efficient; let's say 98%.  Let's say that your EV drivetrain only gets 85% efficiency on average (in peak efficiency, EVs motors can get over 95%, although that's only for very limited circumstances).  Multiplying it out, that's: 0.35 * 0.928 * 0.93 * 0.98 * 0.85 = 21.6%.  Not counting regen.

      So, 1.4% system efficiency versus 21.6% system efficiency.  Take your pick!   ;)  And if you want a power generation method that's very efficient -- say, wind or hydro -- or just want to negate the amount of solar energy the power plant can harness (since wasting it isn't like wasting coal or oil) -- then we can remove the generation efficiency aspect from our two numbers, getting 4% and 62%,  respectively.

      I'm sure you can see why I oppose ammonia as a fuel.

      And to anyone asks about the energy to produce the batteries: the energy consumed by a vehicle in its manufacture is almost always way dwarfed by the energy it consumes in its lifetime.  EVs are no different.  I can get you studies if you'd like.  And no, automotive-grade li-ion batteries are not toxic, no, there's absolutely no lithium shortage, and no, they do not have short lifespans (conventional li-ion does, but that's not what we're talking about; titanates, phosphates, and stabilized spinels last decades).  Just ask for refs to anything if you need it!

      •  What's the definition of efficiency here? (1+ / 0-)
        Recommended by:
        Stranded Wind

        In an electric appliance, you'd assume that an appliance that was 100% efficient took all of the power applied to it and put it to use.  So a light bulb that was 100% efficient would convert all of the electrical energy put into it as light, for example.

        What does it mean to say that a coal plant is 32% efficient?  What's 100% mean in that context -- all of the chemical energy in the coal, or all of the heat energy extracted from the coal vs. the amount of electricity we pull out of that heat?

        "If another country builds a better car, we buy it. If they make a better wine, we drink it. If they have better healthcare . . . what's our problem? "

        by mbayrob on Sat Dec 13, 2008 at 08:41:56 PM PST

        [ Parent ]

        •  Power plant efficiency: (1+ / 0-)
          Recommended by:
          mbayrob

          Chemical energy in over AC energy out.

          As stated earlier, Carnot gets his cut.   ;)  Now, as I pointed out above, when comparing two drivetrains whose source of power is both electricity, you can generally leave that step out.

          •  Nuclear power: over 90% capacity average (0+ / 0-)

            Wind: about 32% capacity (intermittent)
            Solar: about 24% capacity (intermittent)

            Also, a general observation:  Jacobson, referred to in the diary as a source, is wrong about nuclear power's life cycle emitting "25 times more carbon" than wind power.  This is just not so.

            See comparisons of carbon foot print of various energy sources; nine studies.

            Per Peterson of UC Berkeley calculates that wind requires 10X the amount of steel & concrete as nuclear per watt.  These materials are made by burning coal.

            The IPCC predicts average global temperatures to rise enough by 2050 to put 20-30% of all species at risk for extinction.

            by Plan9 on Sun Dec 14, 2008 at 09:59:45 AM PST

            [ Parent ]

            •  Capacity factor is only part of the picture (0+ / 0-)

              If I could build a 1GW plant for $1 that had a 1% capacity factor, that'd obviously be a much better decision than a 1gW plant for $100 million that has a 100% capacity factor.  In all cases, you need a full lifecycle cost analysis.  Nuclear has so far performed very poorly in terms of pricing, even with subsidy.  I won't rule out next-gen nuclear performing better, however; I think it deserves a shot.  Just note that if next-gen nuclear fails to perform better financially, I'd expect another, bigger nuclear dark age.

              •  It comes down to a series of (1+ / 0-)
                Recommended by:
                Plan9

                Factors which at the end of the day is usually price per KW over the lifetime of the project;

                Reliability.

                The interesting thing about your comparison of "a 1GW plant for $1 that had a 1% capacity factor, that'd obviously be a much better decision than a 1gW plant for $100 million" is that given just these two plants, I know I'm getting power when I turn on the lights with the 1gW plant.

                Nuclear pricing is actually rather good specially since these plants are being paid off and their are no more payments on the notes.

                David

                •  Baseload is an entirely different issue (0+ / 0-)

                  You were discussing capacity factor before, but we can discuss baseload vs. intermittent if you'd rather.  :)

                  Indeed, nuclear is baseload, and this is one of its biggest selling points -- not its capacity factor, which is offset by its extremely high capital costs.  But a couple points:

                  1. Not all non-nuclear renewables are non-baseload.  High-altitude wind is baseload.  EGS is baseload.  Space solar is baseload.  OTEC is baseload.  Ocean current is baseload.  Tidal is baseload.  Hydro is baseload plus storage.  And so on down the line.  
                  1. Intermittent is fine if you have an appropriate combination of long-distance transmission (eg., a HVDC network like the Obama administration wants to build) and/or storage.  Storage isn't only dedicated facilities -- pumped hydro, compressed air, etc.  It's also things like battery-electric vehicles on a smart grid (another thing Obama wants to build).  Or conventional hydro, which inherently has energy storage (ramp up when you want more, down when you want less).

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