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wave power

Discussion in 'Alternative Energy' started by philba, Apr 20, 2007.

  1. philba

    philba New Member

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  2. CheapSlider

    CheapSlider Member

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    There does appear to be scope with the idea and several trials have been made over the last 30 yrs or so.

    The main issues have been:
    efficiency - if below a certain threshold then it's not worth the effort
    reliability - has to be low maintenance
    durability - can it withstand a battering from a storm ?
    cost - will there be a return on investment ?

    It does appear more attractive then wind, where backup capacity is needed in case of no wind.

    Tidal power seems attractive due its predictability, but there are massive construction costs and environmental impact. Also the tides can't provide power continuously.
    There has been a tidal barrage power plant at Rance estuary in France since 1966.
     
  3. Hero999

    Hero999 Banned

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    Tidal power seems the best way of harnessing energy from the sea. Wave power seems like a waste of time.
     
  4. dave

    Dave New Member

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  5. Pommie

    Pommie Well-Known Member Most Helpful Member

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    Out of pure curiosity, where does tidal power come from? As the energy has to come from somewhere, what will loose energy. Will the moon slow down? Earth slow down? Moon speed up? Earth speed up.

    My vote goes with, moon speeds up.

    Mike.
     
  6. Hero999

    Hero999 Banned

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    Why would the moon speed up?
     
  7. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Because it will get closer, so automatically speeds up as it's then in a lower orbit - lower the orbit, faster the speed!.

    However, using tidal power won't have any effect on this, just the gravitational attraction between the earth and moon.
     
  8. Hero999

    Hero999 Banned

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    True if you increased the energy in the system that would happen, but if you removed energy from the system the moon would slow down and the orbit would get larger.

    I agree.
     
  9. Oznog

    Oznog Active Member

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    The energy comes from the kinetic energy of the moon's velocity relative to the earth. The moon will slow down and assume a closer orbit.

    This has been happening since the moon was formed. The effect is quite small since the moon is such a huge mass. Furthermore, harnessing tidal power has no additional effect. The water will be lifted and fall back regardless of whether the energy is captured by man or not.
     
  10. Pommie

    Pommie Well-Known Member Most Helpful Member

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    The moon will speed up. This is due to the tide acting as a brake between the earth and the moon. The earth rotates at 1 rev per day, the moon at 1 rev per month. The brake effect will cause the moon to speed up and the earth to slow down. Eventually the moon will be fast enough to leave earth orbit. Thankfully, I won't be around when that happens. The rather surprising fact is that tidal energy does not come from the moon at all but instead comes from the earths spin.

    Mike.
    edit, actually the moon won't leave earth orbit, it will stop accelerating when the earth and moon rotate in unison once every 47 days!! See here for more info
     
    Last edited: Apr 21, 2007
  11. Oznog

    Oznog Active Member

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    Ooops you're right! The moon will speed up, the earth slows down.
     
  12. philba

    philba New Member

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    the problem with tidal power is that it will cause significant [perceived] ecological impact. even a small change in the average water level will have impact on any species in the inter tidal zones. Constructing a man-made lagoon to harness the power will be expensive. I think in many countries, tidal power would be politically untenable.

    Why do you think wave power is a waste of time? Unlike tidal power, it is fairly continuous and can be deployed in smaller, incremental units. Please expound on your point.
     
  13. Tim_B

    Tim_B New Member

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  14. Sceadwian

    Sceadwian Banned

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    Mmmm, sea water and electricity, wonderful combination!
     
  15. philba

    philba New Member

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    well, some smart people seem to think it's possible.

    by the way, I saw a story about tidal generators in the lower Hudson River, it was short on details but seemed to say they are using underwater turbines "just like windmills underwater". I assume it wasn't a literal statement.
     
  16. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    It's certainly possible, there are a number of tide and wave power generators all over the world.
     

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