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WaveNET – the Floating, Flexible Wave Energy Generator

Posted by Soulskill on from the making-bernoulli-work-for-us dept.

Zothecula writes: Scotland's Albatern is putting a new, modular spin on renewable energy generation. WaveNET is a scalable array of floating "Squid" generator units that harvest wave energy as their buoyant arms rise and fall with the motion of the waves. Each Squid can link up to as many as three others, effectively creating a large, floating grid that's flexible in every direction. The bigger this grid gets, the more efficient it becomes at harvesting energy, and the more different wave movements it can extract energy from. Albatern's 10-year target is to have 1.25 kilometer-long floating energy farms pumping out as much as 100 megawatts by 2024.

11 of 90 comments (clear)

  1. Niche energy by amorsen · · Score: 4, Insightful

    Median energy density in waves is too low in most places. You need way too large machines to extract useful amounts of power. The few times you get sufficiently powerful waves they tend to rip your equipment to bits.

    Wave energy is one of those ideas which seem really obvious from a distance, so the fact that project after project fails does not seem to dissuade anyone. They were obviously just doing it wrong.

    I really hope that I am wrong and this turns out to be a great success, but I am not holding my breath.

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    1. Re:Niche energy by Solandri · · Score: 2

      I am wondering why you think the energy density is low? I think it is huge, a lot more kinetic energy per square meter than faster moving, but lighter, air.(wind)

      That's the problem - you can't really tap into the kinetic energy of the wave from the surface. The up-down motion of the wave is just a boundary layer height change due to a transient lateral pressure differential in the water. i.e. The water pressure is higher at this point than at a point 1 meter away, while the air pressure is the same in both spots. So the water is higher at this point, creating the height differential we call a wave. The vast majority of the energy is transmitted under the surface - even if you covered the ocean surface with a solid 100% energy-absorbing material, the wave would still propagate. The amount that'd be lost to the surface (due to harvesting) is just the difference in cross sectional area of the wave front from one end of the harvesting device to the other if the wavefront were allowed to expand upwards. Unless you're in very shallow water, the vast majority of the energy simply passes underneath your device.

      So a floating structure is a terribly inefficient way to extract energy from the wave. It'd be like trying to extract wind energy using balloons which flop around in the wind. A turbine is a much more efficient way to harvest the kinetic energy, except underwater turbines tend not to last very long due to corrosion, biological fouling, and experience higher wear due to the incompressibility of water.

      If you don't believe me, ask yourself why sailing ships were designed to use wind energy instead of wave energy. Waves are more consistent than wind - even when there is no wind there are frequently ocean swells which could've provided energy to propel ships. It's because average wind energy is denser than the fraction of wave energy you can extract from something bobbing on the surface.

    2. Re:Niche energy by Applehu+Akbar · · Score: 4, Interesting

      There may be amore important reason to develop wave energy. In most parts of the UK, shoreline erosion is a serious problem. Any technology that saps the energy of incoming waves is a good thing for countries with this problem.

  2. Saltwater and MTBF by jgtg32a · · Score: 3, Insightful

    I wish them the best of luck but saltwater is particularly nasty stuff over over an extended period of time. Hopefully they can find a cheap way to insulate against it.

    1. Re:Saltwater and MTBF by Spy+Handler · · Score: 3, Funny

      Stop trying to be so nice and polite. What you really meant to say is that this aint ever gonna work because salt water is a crazy fucked up environment. Harebrained schemes like this always fail because seawater is so corrosive that maintenance costs will eat up any and all profits.

      Haven't seen anyone mention it yet, but only a couple months ago there was a Slashdot story about another wave power generation scheme that failed. Cause? Salt water and high maintenance costs.

    2. Re:Saltwater and MTBF by Hillgiant · · Score: 5, Informative

      Cathodic protection is a well understood science. I have seen sub-sea pipeline equipment that had been immersed for 20 years actuate like they are brand new.

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    3. Re:Saltwater and MTBF by MrL0G1C · · Score: 2

      Rance Tidal Power Station opened in 1966, still going strong, salty water not a problem.

      The UK is planning a large tidal lagoon, backed by Prudential Insurance, they don't seem to be in the slightest bit worried about salty water either. UK Renewables May Be Turning The Tide

      And of course there's a global shipping industry. Coal doesn't go by airplane.

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  3. bad idea by slashmydots · · Score: 2

    The alternative to this is one that resides on the ground and it generates the same power no matter what the height of the waves are. That's a lot more logical.

  4. Kevin Costner would approve by sansprivacy · · Score: 2

    The modular design is cool. It's going to come in handy ...

  5. ah yea... by Charliemopps · · Score: 2

    This wont work...
    Here's the key piece of their mechanism:
    http://images.gizmag.com/galle...

    It's 25 meters beneath the north sea... in the midst of a spiderweb of steel...
    That joint is most likely to fail during a storm.
    When it does fail, you'd now have a floating buoy dangling a giant steel beam beneath it, riding storm waves...
    and crashing into the rest of the network.

    Storm conditions will prevent you from doing anything about it until the damage is done.

    1. Re:ah yea... by Required+Snark · · Score: 2
      Yes, Mr. ShashDot Pundit. You're absolutely right.

      You are so smart and they are so dumb. it's guaranteed that they spent no time doing any calculations about this. Every engineer they have has never even seen the ocean, only designed stuff on paper/computers in nice clean rooms. They've never run any simulations, or done any physical testing at all, because all engineers just know that complex new things always work perfectly the first time.

      So just call them and talk to the receptionist, or send them an email and tell them about your brilliant insight. I'm sure that once they hear your detailed criticism it will bring their foolish scheme to a screeching halt. At the very least they will give up, or see the light and appoint you the head honcho. Only your fantastically sharp mind can save them.

      Good luck with your new position.

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