The one clean-tech breakthrough that could lead to a core climate solution: Thermoelectricity 10

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1. 

   bigTom Posted 11:30 am
   19 Sep 2008

   you are overly optimistic about this.  The only number I've seen that hints at energy conversion efficiency is something like 10%. Assuming the technology is reasonably cheap, that would be enough to capture some value from some waste heat streams, such as car exhausts. Also where fuel or wood is burned for low grade heating (space or water), it would be useful to interpose these babies betwen the high temperature combustion chamber, and the low temperature object being heated, to get some electricity out of them. But, I'm afraid TE is not going to be an energy silver bullet. At best another silver BB. Every BB we can get adds up, but no single one will make much of a difference.

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2. 

   GRLCowan Posted 11:37 am
   19 Sep 2008

   Listen to physicist A.P. Smithwho commented in the version of this thread at ClimateProgress, where it was billed as a core climate solution breakthrough. Perhaps that idea survived until the name MIT appeared. (The T once stood for Technology. Interesting point of trivia.)
   Sunlight absorption by the Earth amounts to something like 110 petawatts. It's true that heat engines inevitably fail to convert a lot of heat, but if you use that 110 PW as a basis, maybe make a unit of measure of it ... or let's say the unit is a  round 10^17 watts, 100 PW, and call this a theat ... it doesn't look so bad. A typical large power station yields 0.000000035 theats of electricity and discards 0.00000007 theats as waste heat. So the Earth's heat budget has room for plenty of non-carbon-emitting heat engines, especially if the waste from earlier carbon-emitting ones is removed.
   If thermoelectrics grow up to be really big, they may be able to convert 12 percent of a flow of heat at 120°C to electricity, the way a Kalina-cycle power station apparently was able to do in this earlier discussion. So the 0.00000007 theats of waste thermal power might be reduced to 0.0000000616. But the apparatus to do this, the "bottoming-cycle" apparatus, is larger than power plant whose not-entirely-waste heat it takes; thermoelectrics don't change this.
   A real-world application of thermoelectrics, out where reliability for many unattended years matters more than efficiency.
   --- G.R.L. Cowan, H2 energy fan 'til ~1996

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3. 

   amazingdrx Posted 3:32 pm
   19 Sep 2008

   GeothermalThere are infrared PV cells.  These would be excellent operating in conjunction with concentrating solar and regular PV.
   Or maybe with concentrating collectors that focus on an open lava source from a safe distance?  Power all day and all night.
   TE drilled deep into the hot earth might work.  I read of a very efficient form of TE that uses radio frequency electricity.
   
   http://amazngdrx.blogharbor.com/blog John Schneider, Northern Wisconsin

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4. 

   Pangolin Posted 7:25 pm
   19 Sep 2008

   Hmm,I still don't get why CSP isn't storable as steam in geo-exchange/geothermal wells. I keep thinking inject steam and recover heat in Kalina cycle on cold nights but I don't see anything like this anywhere but in that Alaskan geothermal project.
   Since large chunks of our power supply goes to heating or cooling buildings anyway the steam doesn't have to be particularly high grade. A house should be able to pull 2.5 Kw of power and heat from a 4 square meter dish.
   My next life, I get that engineering degree.
   
   Put the Carbon Back

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5. 

   Jonas Posted 11:32 pm
   19 Sep 2008

   TE is years awayRomm is wishful thinking again. Cost-effective and efficient thermoelectric devices are years away. There haven't been that many breakthroughs in the sector.
   But if a cost-effective one hits the market, the potential is huge.
   Just think of all the power plants which lose so much heat. If all that heat could be tapped, we wouldn't have to build a single new plant.
   So yes, if commercially viable and available, then it's a great technology.

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6. 

   Billhook Posted 2:17 am
   20 Sep 2008

   The Means [applied] are the End [received]Joseph -
   
   I'm puzzled by the schedule and orientation of your recommendations.
   Thermo-electric would predictably be applied, if researchers are succesful after maybe 20 years of RD&D, primarily to raising the efficiency of FF combustion plants. That efficiency gain (counted in $ & C) would, predictably, raise the saleability of such plants, as is amply evidenced under Jevons Paradox.
   TE could of course be applied to H Fuel Cells, or Geothermal, or even Woodgas power, but none of these will gain as much cred from the prospect of TE as will the well-heeled fossil fuel industry.
   Declaring that TE is the one tech with potential for a significant scale of breakthrough hints at a dubious orientation. A technology that results in making FF more attractive is surely the antithesis of advancing sustainable energy supply ?
   The schedule you propose, of cutting global GHG output by 50% by 2050 [that is, halving it in two generations time] is so late that it's supported by Tony Blair.
   You must know better than most that such a delay in energy reform will, very probably, massively accelerate the major feedbacks, (albido loss, forest & soil loss, permafrost, clathrates etc) putting the possibility of reliable harvests, let alone stable seashores, simply beyond our reach. Permanently.
   I doubt that you seek merely to appease the status quo, since again you have to know how totally counter-productive appeasement is.
   Care to explain ?
   Regards,
   Billhook

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7. 

   racc Posted 10:23 am
   20 Sep 2008

   Possible Does not MatterJust because something is possible does not mean it will be ever practical or cost effective on a mass scale
   We can send one or two people to the moon but we can't send everyone.
   Even photo electric still needs breakthroughs before it can make really any difference on a mass scale.
   What we know will work is people using less energy. Lets focus on that rather than miracle cures.

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8. 

   Gary Gifford Posted 1:29 pm
   20 Sep 2008

   Practical ApplicationThis may not be the solution to our energy needs,  but its part of the solution and certainly more than just wishful thinking.  Here's an article about research into trying create an automobile alternator using heat from the exhaust.  Getting rid of the drag of a mechanical alternator would certainly save fuel.  Put it in a hybrid and this could be a source of free electricity.  Every little bit is a wedge...
   http://www.physorg.com/news131711988.html
   
   
   
   Cheers,
   
   Gary Gifford

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9. 

   Duggles Posted 2:34 am
   22 Sep 2008

   TE isn't really a cure-all.Like most things in life, thermoelectrics are not going to solve all of your problems.  Clearly it's an avenue worthy of research, but I'm certainly not going to put all of my eggs in its basket, especially when you look at the delta-T necessary for efficient operation of TE for power generation.
   I'd say give it a few years, and maybe you'll see it show up in the hybrid vehicles, where you have exhaust gas that is of sufficient temperature to get your high delta-T.
   As a random aside, I actually had Kanatzidis for freshman chemistry.

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10. 

    sunflower Posted 2:47 am
    22 Sep 2008

    Hot on the pressTE at 20% requires 1000C cooled to 200C, Thermionic Diamond Converter, a candidate for high-intensity  solar thermal concentrators.  Low grade heat has thermal dynamic limits affecting efficiency.
    
    

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