Global warming

Discussion in 'General Discussion' started by Frank, Oct 22, 2010.

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  1. eastmen

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    Solar is a smart way foward. In the winter when the sun is the weakest towards the poles people use heat which is rarely generated from electricty. Its mostly gas heat.

    In the summer when the sun is the strongest people turn on air conditioning and they greatly tax the grid using all that extra power.

    And solar is getting better every day . Today two start ups announced the most efficent panels yet.
     
  2. epicstruggle

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    I've been hearing about how solar is just around the corner for almost a decade. When it's ready for prime time it will succeed without any subsidies. We are not there yet. My point is that until that time comes move away from coal/oil power plants to nuclear. That is if AGW is a serious problem. ;)
     
  3. eastmen

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    Is Nuclear possible without huge subsidies ?

    Who pays for the waste disposal and where is it disposed of ? Who pays for the upkeep over hundreds if not thousands of years for the waste ?

    At least solar is largely a one time fee and if the goverment devoted the money to it that going full nuclear would cost i'm sure prices of the tech would drop like a stone

    http://www.engadget.com/2012/02/08/two-us-startups-break-solar-efficiency-records-aim-to-light-up/.
     
  4. epicstruggle

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    Subsidies for Nuclear are required and it sucks. However, it can easily replace coal/oil. With solar your still stuck with having a back up power plant. which generates the dreaded co2. The goal is to move quickly to a green energy source.

    We have the means of storing/disposing of nuclear waste, if we could get the uneducated mass from the decision. You can glassify the waste and drop it in one of the subduction zones in the ocean. Sounds scary, but its actually quite safe way of permanently disposing of nuclear waste.
     
  5. eastmen

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    I'd rather have as much energy generated at the point of usage . Do we really need power lines all over the place ?

    I'd rather see them invest heavly in solar. I'd love to have every house covered with panels , cars , mobile phones , clothes , parking lots , and hell even roads if we are able to figure out a way to do that.
     
  6. hoho

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    In Estonia we have websites reporting wind power generation in pretty much real time, e.g this: http://www.4energia.ee/online/veeb/chart2/7p.php?park=pakri
    That small park has total peak output of 18,4 MW and average yearly production of 53 GWh giving it roughly 30% efficiency.

    Is there similar data availiable for larger installations, preferrably spread over huge areas?
    How efficient were they? How much better can they theoretically get?
    Aren't usual panels close to around 20% efficiency in real-world use at the moment? I'd be surprised to see that double before we get fusion reactors :)
     
  7. KimB

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    Huh, what? Solar, right now, is about as expensive as coal power. I may be mistaken, but I don't think wind power is one tenth that cost.
     
  8. KimB

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    It's the other way around, epic. Nuclear may be required to fill in the gaps of baseline power generation that solar and wind leave behind, but just as a practical matter we can build far, far more solar and wind power generation right now than we can build in nuclear power generation.
     
  9. KimB

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    Yes, we are. Solar panels have reached cost parity with coal power at retail. That is to say, the cost of buying electricity from a coal-fired plant and buying some solar cells to supply your home with power is about equal. And the cost of solar panels just continue to drop, meaning that solar cells will easily be cheaper than the wholesale cost of coal power generation within 5-10 years.

    Um, we can build solar and wind plants today without much cost premium. Nuclear plants take years to be built.
     
  10. KimB

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    http://en.wikipedia.org/wiki/File:PVeff(rev111205).jpg

    But really, this isn't what is important right now. Instead, it is power generation vs. cost efficiency that is the important metric for getting solar cells adopted. Sure, maybe after a decade or so of building solar plants, when space starts to become a premium, then efficiency will start to matter more. But it doesn't matter much at the moment.
     
    #1370 KimB, Feb 9, 2012
    Last edited by a moderator: Feb 9, 2012
  11. Gubbi

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    Energi Net has a flash app that displays danish power production and import/export real time:
    http://energinet.dk/Flash/Forside/UK/index.html

    You can get production numbers by diving into the market reports here:
    http://www.energinet.dk/EN/El/Engrosmarked/Markedsrapporter/Sider/default.aspx

    Production numbers are usually on the bottom of page three. E.g. here's december 2011:
    http://www.energinet.dk/SiteCollect...kumenter/El/Market report - December 2011.pdf

    As is evident from december market data, wind power production exceeds consumption in short intervals, which is sold off. We have quite a liquid power market in Scandinavia / Northern Germany, a requirement for large scale wind power IMO.

    Currently between 21 and 23% of electricity in Denmark is produced by wind power, the plan is to expand this to 50%. This requires the capability to store at least a days worth of consumption to be feasible IMHO.

    Cheers
     
  12. Sxotty

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    ACtually yes Nuclear is possible without subsidies, but generally companies like quicker payback times

    The nuclear industry pays for disposal. They have been paying a tax for decades to pay for it. That is where all the money for Yucca mountain came from.

    Solar isn't a one time fee since like anything it wears out.

    Efficiency of solar doesn't matter. Cost does.

    Show me your numbers. I see you are comparing home installation which is fair enough, but still foolish unless you are also planning to install battery backup at the home then the home owner will still have to pay T&D costs. I don't think you have any idea how cheap coal actually is.
     
  13. Gubbi

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    I know it depends on perspective, but the conclusion I draw from the above presentation is that the sooner coal is phased out the better. Wind is in-flexible in production, but so is coal. Coal is only really useful for base load. In Colorado daily demand variability has been met by gas fired turbines. They state wind causes problem because the variability of wind power production adds to the daily demand variability and thus coal power plants needs to throttle back.

    Well gee, lower base power production by coal.

    Agree. Large scale wind power ( (>25% power production from wind) will need some sort of temporary storage to reach 50%. If we want to go higher we need to store the energy chemically. Efficient storage capability would also change the economics of wind power radically.

    There is still a long way to go.

    There's an annual flux of kinetic energy of 3.8x 10^22 J in the atmosphere below 1km ¹, or 1.2 x 10^15 W. Aggregate installed wind power in the world as of 2010 was 194 GW. With a generous capacity factor of 35% that means we extract 0.005% of this.

    *1: Smil, Vaclav. Inherent Limits of Renewable Energies. 2004

    Cheers
     
    #1373 Gubbi, Feb 9, 2012
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  14. epicstruggle

    epicstruggle Passenger on Serenity
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    Coming from a respect site, so no shooting messenger:
    http://www.spiegel.de/international/world/0,1518,813814,00.html
     
  15. hoho

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    Can we realistically use the energy from higher than, say, 100m? I would guess it's less than 10% of that due to objects nearer the ground "eating up" some of the kinetic energy.
    Entire world today uses around 13TW of energy. About 3 decades ago it was half that. I have a hunch that power usage will keep rising in the future.
    How big areas of Earth do we need to cover to get meaningful amount of energy from it through wind turbines? By meaningful I mean enough to actually make up at least half of all energy production.

    Also, considering the enormous storage needs you need to take into account the efficiency of that storage system as well and on the average day be able to produce more energy than is actually used so that you can fill that storage as needed.

    Here is an interesting picture:
    [​IMG]
    First a little explanation for the graph from here: http://physics.ucsd.edu/do-the-math/2011/12/wind-fights-solar/

    US uses around 4TW/h electricity (~25TWh together with liquid fuels and heat) per year or on average ~470MW but I'll round to 500MW for simplicity. average solar turbines get installed in the 500W/m^2 area US would need to cover around 1000000m^2 or roughly 1km^2 with wind turbines assuming 100% efficiency[/y]. Now correcting that with the real-world 1.6% we get around 62.5km^2. Now add in storage system and extra production power to fill the storage in reasonable speed and you'll need something like 150-200km^2 of turbines. Simple, right? Now add storage system via artificial dams and pumping water and you'll need to multiply that area usage by several orders of magnitude.


    And another quote from same site:
    So yeah, why on Earth would anyone want to use wind when direct solar is that much better and lacking moving parts should be siginificantly cheaper to maintain? Though yes, it still has the storage problem just like anything else that relies on solar in some form or another.

    Obviously this was just my quick back-of-the-envelope math. The article linked that used far more accurate methods came up with theoretical potential for whole world at around 1TW.
     
    #1375 hoho, Feb 9, 2012
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  16. Gubbi

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    I'm just saying we're a long way away from affecting global wind patterns, not that we need to meet world demand for electricity by wind power alone.


    The U.S. consumes 4000 TWh electricity per year, that's 456 GW ( jigga-watts )

    Cheers
     
    #1376 Gubbi, Feb 9, 2012
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  17. hoho

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    True but my point was wind is rather pointless to pursue anyway.
    Yeah, thanks for the correction. I somehow missed billion between million and trillion. So basically instead of that 150-200km^2 you'd need 1000 times that (+ storage needs) :)
     
  18. Gubbi

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    Your point is pointless. You want a single solution to meet *all* of U.S.'s demand for electricity. Nobody ever claimed that.

    Wind power makes sense in lots of places in the world where you have stable wind patterns. That implies coastal regions and thus is a poor single solution for the U.S. which stretches across a effing continent.

    Danish electricity demand could be met by 10 London Array sized facilities, perfectly doable (10 15x15 km installations). Multiply by 10 for the U.K.

    Cheers
     
  19. hoho

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    In what way do they have the storage problems solved? By offloading it to other countries to provide them with fossil-fuel based electricity?
     
  20. Gubbi

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    That's a differnet matter than the area argument, no ?

    But you know they haven't solved the storage problem yet. I already stated that myself earlier: To expand wind power production from 25% of average consumption to 50% you need to be able to store a days worth of consumption. Beyond 50% you need to store the energy chemically (synthetic methane, ammonia, hydrogen, whatever).

    Cheers
     
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