Flying Electric Generators

Discussion in 'Science' started by HereWeGoAgain, Apr 1, 2019.

  1. HereWeGoAgain

    HereWeGoAgain Banned

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    So here is how wind will be made practical: They are called FEGs - Flying Electric Generators.

    The power in wind goes as the cube of the wind speed.
    [​IMG]

    Generators can now be flown in the jet stream on tethers, where the average wind speed is 110 MPH, with top speeds of 250 MPH [111 meters/sec]. Because the power goes as the cube of the speed, winds blowing at 110 MPH have 1300 times as much power as winds blowing at 10 MPH. Generators designed for these conditions can not only be kept aloft on tethers, but the power can now be reasonably transmitted down a fairly small wire on the tether. By using very high-voltage generators, the weight is minimized. Modern materials and generators make this all practical.

    The wind in the jet streams generally blow 24/7. The FEGs can even track and be flown to the strongest regions of the jet stream.

    Winds blowing at 250 MPH have over 15,000 times as much power as winds at 10 MPH.

    They fly far above the birds. Jets are the real concern. But that is just a matter of controlled flight paths, as with other restricted areas.

    The wind turbines double as powered propellers by simply reversing the flow of power. So they can be maneuvered, landed, and relaunched as any drone would be launched and landed. Once up in the jet stream, they switch over to power generation mode.

    Upon failure, they auto-rotate down. They are essentially gliders. And ideally they would be located over mountain ranges, where you are up 10,000 feet before you ever launch. They might even be flown over the oceans.

    This idea has been around for a long time. But what changes the game are new materials, like carbon fiber, and very high-voltage generators, which can be made extremely light but still produce large amounts of power.

    Here is a paper on the subject:
    https://minerva-access.unimelb.edu.au/handle/11343/91085
     
    Last edited: Apr 1, 2019
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  2. Gelecski7238

    Gelecski7238 Well-Known Member Past Donor

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    A cross between a far strung-out kite and a drone. One helluva lightning rod.
     
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  3. HereWeGoAgain

    HereWeGoAgain Banned

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    At the voltage generators can run now, over a million volts, you could almost use any lightning to charge capacitors for stored energy. :D The circuitry would require design against lightning strikes. However the FEG itself would be above the clouds, and well above most.

    If a fleet of FEGs was launched from the top of the Rockies, they would already be above most lightning events at the launch altitude.

    Keep in mind that each one of these might replace 2000 land-based turbines.
     
    Last edited: Apr 1, 2019
  4. tecoyah

    tecoyah Well-Known Member Past Donor

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  5. Thought Criminal

    Thought Criminal Well-Known Member Donor

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    It seems like there are a lot of factors working against each other, here.

    Could the FEG generate enough lift to raise a cable strong enough to hold it in place? If it's desired to fly it four miles above mountain peaks, it would probably require ten miles of cable.
     
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  6. HereWeGoAgain

    HereWeGoAgain Banned

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    Yes. A group of engineers, scientists, and I actually did the calculations based on materials available. We used the wings from a 747 as a model.

    Keep in mind for example that a 747 has a max takeoff weight of almost a million pounds at about 170 mph.

    20,000 feet is only about 4 miles of cable. If you launch from 10,000 feet, you may only need another 10,000 feet to get in the jet stream.
     
    Last edited: Apr 2, 2019
  7. Hoosier8

    Hoosier8 Well-Known Member Past Donor

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    There is a nightmare waiting to happen.
     
  8. HereWeGoAgain

    HereWeGoAgain Banned

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  9. tecoyah

    tecoyah Well-Known Member Past Donor

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  10. HereWeGoAgain

    HereWeGoAgain Banned

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    Be afraid! Be very afraid!!!

    Typical trumper.
     
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  11. drluggit

    drluggit Well-Known Member

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    just curious, but how does one get the generator up there in the first place, and once there, how does it stay there? winds move. Tethers don't.
     
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  12. HereWeGoAgain

    HereWeGoAgain Banned

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    You fly it up like a drone. Then it flies like a kite. You switch from powering the turbines to lift off, to generator mode, once at altitude. It is more complicated because you can use the auto-gyro effect to help generate lift. This takes power from the generating capacity and wings add weight. So it is a balance between using a wing for lift, and auto-gyro lift.
     
    Last edited: Apr 2, 2019
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  13. HereWeGoAgain

    HereWeGoAgain Banned

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    Years ago when I was first interested in this idea and had been pursuing the practical questions, I happened to watch an old HG Wells movie - the shape of things to come; 1936. In one the opening scenes, you see flying electric generators!
     
  14. Thought Criminal

    Thought Criminal Well-Known Member Donor

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    Have you ever seen a kite fly in 100+mph winds?

    It's not going to be directly overhead.
     
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  15. HereWeGoAgain

    HereWeGoAgain Banned

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    Have you ever seen a kite designed to fly in 100 mph winds?

    True. I was only talking about the actual altitude. Without even going to carbon fiber we found there is more than enough lift. There are some amazing materials out there.

    At 45 degrees, it is only root 2 multiplier.

    The hard part is getting the power back to the ground. But with 1 million volt generators, a relatively small conductor can be used.

    1 amp at a million volts can be transformed to 4400 amps at 220 volts. So a 20 gauge wire [very tiny] could carry enough power for 20 homes. You can use a much larger wire but it provides perspective.

    Even 4/0 wire only has a weight of 700 pounds per 1000 feet. 4/0 is good for about 200 amps. So in principle this one wire [two for a circuit] could power 4000 homes.
     
    Last edited: Apr 2, 2019
  16. Thought Criminal

    Thought Criminal Well-Known Member Donor

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    https://researchdirect.westernsydney.edu.au/islandora/object/uws:674

    This guy guesstimates a 40° angle for a 1000m straight line; neglecting cable sag. That would raise the generator 640m. A longer cable must reduce that angle.

    He likes kevlar for the cable material. He would sheath the kevlar with aluminum; for the conductor.

    A PDF of the 159 page report is here (I skipped over the math):

    https://researchdirect.westernsydney.edu.au/islandora/object/uws:674/datastream/PDF/download/citation.pdf
     
    Last edited: Apr 2, 2019
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  17. HereWeGoAgain

    HereWeGoAgain Banned

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    Yes, the design for the tether and conductor is key. Braided or sheathed kevlar are probably two of the best options. We too landed on kevlar rope. But there were other materials with great strength-to-weight ratios for tension.

    I think Boeing has developed a process for impregnating carbon fiber with metal to manage lightning strikes. But then you might start compromising the conductivity, which would generate heat. So a dedicated conductor mated with the tether material is probably best. If you run high-frequency AC generators, the skin effect even allows for hollow conductors, to reduce weight. [Higher frequencies tend to move through the skin of a conductor and not the core, so all you really need is the skin.). This may not be practical but it's another thing to consider.

    If the author is intending to use low frequency AC with a sheath, there might be too many losses. He might need to go to something like 1000 Hz generators. [Just a wild ass guess]

    I was using the weight for copper. Clearly you would want to use aluminum or other light-alloy conductor.
     
    Last edited: Apr 2, 2019
  18. HereWeGoAgain

    HereWeGoAgain Banned

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    How this calculates out:
    From the graph in the op, it is seen that at the rated wind speed of about 17 mph,, and after accounting for the efficiency of the system, we expect 1000 Watts per Meter Squared, of turbine area [the swept area].

    The largest wind turbines have a diameter of 90 meters, which results in an effective area of 6400 meters squared.
    6400 meters squared x 1000 Watts per meter squared is 6,400,000 Watts, or 6.4 MW
    If we assume the same effective area for a FEG at 170 mph, we get 1000 times the power, or 6.4 MW x 1000 = 6.4 GW

    The largest nuclear power plant in the US produces just under 4000 MW = 4.0 GW

    https://www.eia.gov/tools/faqs/faq.php?id=104&t=3

    So just one FEG having the same effective area as one of the largest land-based wind turbines in use, can produce 160% as much power as the largest nuclear power plant in the US.

    I know from previous calculations that 1000 of these nuclear power plants could replace all other energy sources, at least in principle. It works out that using the average jet stream speed of 110 mph, about 2000 FEGs having a total swept area of 6400 meters squared, could in principle replace all energy sources. One can imagine that each wing might have 4 or more turbines. So perhaps 1000 FEGs could in practice replace all oil and diesel, natural gas, coal, nuclear, hydro, and all other sources of energy.
     
    Last edited: Apr 2, 2019
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  19. Gelecski7238

    Gelecski7238 Well-Known Member Past Donor

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    "almost" is news to me. The last I heard, there was no good way to harness static electricity.
     
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  20. HereWeGoAgain

    HereWeGoAgain Banned

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    Sure you can. That's what batteries and capacitors do. But lightning doesn't actually deliver that much energy. It isn't worth doing.


    https://www.realclearscience.com/blog/2012/05/could-we-harness-lightning-as-an-energy-source.html
     
  21. HereWeGoAgain

    HereWeGoAgain Banned

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    As for cost:
    https://www.ucsusa.org/nuclear-power/cost-nuclear-power

    The Palo Verde plant considered earlier cost $5.9 billion.

    Does anyone think we can make a FEGs for less than $6 billion each? I would bet they could be built for about 1% of that cost.
     
    Last edited: Apr 4, 2019
  22. HereWeGoAgain

    HereWeGoAgain Banned

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    1% of $6 billion is $60 million.

    A new 787 only costs $150 million. I doubt an FEG would cost more than a new 787. It is basically just a flying wing with two or more big props and generators.

    A delta shaped wing having the same span as a 787 [200 feet], with a turbine located on each end, is large enough to accept turbines [props] having about a 100 foot radius. This is just large enough to get the required swept area of 6400 meters squared, so that it can produce as much or more power than the largest nuclear plant.

    It could lift about half a million pounds in 155 mph winds. But this assumes the same wing design. A wing designed for the jet stream wind speeds would be far more efficient.
     
    Last edited: Apr 4, 2019
  23. FivepointFive

    FivepointFive Banned

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    I'm interested more in about how this tethering from above is done and how much the FEG weighs

    I assume buoyancy will be used which is not easily accomplished with electricity

    And if buoyancy is used it'll get blown by the wind to

    Tethering from a geostationary satellite seems difficult

    Nevermind I see they're tethered from the ground now

    Definitely the wright brothers glider at Kitty hawk on steroids
     
    Last edited: Apr 4, 2019
  24. HereWeGoAgain

    HereWeGoAgain Banned

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    Haha, yes, these tethers will be 22,232 miles shorter than you were thinking. :DBut there are plans to make a space elevator with tethers that long. So this is a piece of cake, relatively speaking.

    And the sound of these doesn't cause cancer. :D :D :D
     
    Last edited: Apr 4, 2019
  25. HereWeGoAgain

    HereWeGoAgain Banned

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    Here are some technical specs for off-the-shelf generators; really big generators!

    Technical specifications for the SGen-3000W generator series
    Frequency Apparent power
    Efficiency Design power factor
    Terminal voltage
    Design insulation class
    Approx. weight
    SGen5-3000W 50Hz up to 1,300 MVA Up to 99% 0.80 Up to 27 kV Class F Up to 425t
    SGen6-3000W 60Hz up to 1,300 MVA Up to 99% 0.85 Up to 26 kV Class F Up to 390t
    https://assets.new.siemens.com/siem...ens-generator-sgen-3000w-factsheet-web-en.pdf

    Translation, a generator that can produce 1300 MW at 26,000 Volts, weighs 390 tons. We need 3 to get to 4000 MW.

    But note that the generator rated for 60 Hz weighs 15 tons less than the generator rated for a frequency of 50 HZ. So it would take some design and upping of the frequency and the voltage, to reach the goal of 4000 MW at 250 tons total;. But again, this is 1/10 the design voltage I was considering. And a wing designed for 200 mph wind instead of 600 mph wind, will generate much more lift for the same span.
     
    Last edited: Apr 4, 2019

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