FEB 25

A lot of EcoGeeks think that there is a beauty to wind turbines, even beyond their ability to provide emissions-free energy. But to others, wind turbines are an eyesore. A Norwegian company called Sway is developing a deepwater system that will allow turbines to be situated farther out to sea where winds can be steadier and stronger, and where the turbines are hidden from all save a few passing ships. "The SWAY® system is a floating foundation capable of supporting a 5MW wind turbine in water depths from 80m to more than 300m in some of the world's roughest offshore locations." This could allow wind farms to be farther off shore where they would be out of sight.

Off-shore wind turbines have needed to be situated in relatively shallow waters to be able to have sufficient footings to anchor and support them. This new deep-water turbine uses a floating tower to support the turbine, and is anchored to the sea bed with a single tension rod. Because the turbine body floats itself, the rod only needs to help the structure resist the forces of wind and waves, but does not need to support the entire structure.

The SWAY concept, which is covered by several patents, is based on a floating elongated pole extending far below the water surface with ballast at the bottom part. Since the center of gravity in this manner is placed far below the center of buoyancy the tower has sufficient stability to resist the large loads and weight from the wind turbine placed on top of the tower.

The more compelling part of the Sway system is that it keeps the tower upright against the wind forces that would otherwise overturn it. (The wind pressure on the rotor for a 5MW turbine is approximately 60 tons.) The Sway tower maintains a nearly vertical configuration, and only tilts less than 1 degree from its equilibrium position in storm conditions so as not to lose power.

There is some added cost in situating these turbines further from shore and from the end energy users. But the tradeoff with political acceptability and availability of wind may make these turbines more than useful for providing wind power. Sway wind-power towers could also be used near off-shore oil and gas rigs, and provide clean power for their operation, instead of the diesel generators these platforms utilize presently.

Comments (12)

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Why not...
written by Jinks, February 25, 2008

May as well design one of those floating buoy mechanisms into the shaft of the wind turbine so it can extract wave power and wind power simultaneously since it will be bobbing up and down from the waves while its out there anyways. That way these things serve double duty and are taking up less ocean space.

-Jinks

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hmm
written by jc, February 26, 2008

with these windmills so far out at sea, how will we collect power from them?

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Good for Norway!
written by N. & J., February 26, 2008

My fiance and I were very impressed to see the Norwegian wind farms on TV, and we'd like to see them in person some day.
We were also very impressed by the progressive attitude of the companies making the investment in these farms, as well as the Norwegian government for at least allowing these organizations to take action, if not being proactive themselves.

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written by RhapsodyInGlue, February 26, 2008

I've been eagerly awaiting further development of this technology. Can't wait to see the first deployments. The Norwegian's do some awesome things with offshore engineering.

The torsion forces on the tension rod would seem to be the really problematic thing. I'm surprised they don't have to use multiple anchor points more similar to the tension oil platforms.

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Engineering work of art.
written by RhapsodyInGlue, February 26, 2008

Just looked at a larger version of the picture. It shows a yaw mechanism at the bottom of the tower. I wonder if the nacelle also has a yaw and they use the two combined with the water viscosity to get the turbine pointing the right way without twisting the tension rod/wire too much? Seems like a pretty tricky controls system problem.

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Could deep water wind turbines be a sour
written by Terence, February 28, 2008

I wonder whether these could have an impact on marine mammals like whales and so forth, because in this deeper water, I would imagine the machine noise and other vibrations from the wind turbine would inject this as sound or ocean noise quite deep into the water where it could been transmitted for many 10s of miles. We already know military sonar is causing major problems. Could these too?

If so, then this needs urgent research, so that noise suppressors if required can be added. Other than that, they are a great idea.

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written by Adam, March 04, 2008

They have to be far quieter than offshore drilling platforms with all the diesel generators and pumps running. We don't have problem running thousands of those.


How do these thing stay pointed into the wind?

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Very Exciting
written by Fayetteville Hotels, March 13, 2008

Seems like it would need some kind of rudder, to keep the turbine pointed up-wind. And the weight would have to be very big to keep it upright.

Maybe a big barge combined with a elongated ballast.

PS to the Norwegians, I'm available!

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written by CHRIS J, March 15, 2008

I like jinks' comment and would like to add that I have given this a great deal of thought for the past ten years. Add to this device an underwater current driven turbine and a network linking many of the towers to each other, offshore drill rigs, and the land on either side and you start to see the 'wave of the future'. The next great land rush will be over seas which constitute 3/4 of earth's surface and more than half it's biodiversity. Check out last year's pop.mech. article about supersonic underwater trains for the next step after this!

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Not for Everyone
written by josh, March 22, 2008

These may be great in Norway, but how would they do off the coast of FL or TX? What do you think a hurricane would do to them?

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written by John anderason, May 01, 2009

I have been wondering if combining wave generation with an uplift wave turbine would draw nutrient rich water from depth and create and area richer in plankton and fish. Maybe set up fish farms down current from the wind/wave farm?

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i wonder.
written by blb, November 05, 2009

okay so if there going to be in the sea won't a ship be able to hit it? and if it does what would happen? i mean you say it will be invisable to ships but that does mean a ship won't hit it. and lets say that they do put them in the ocean and a ship does hit one does the place that its giving energy to does that place loose energy?

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