World’s biggest wind turbine to take a spin in Norway
The Sway wind turbines bob in the water like partially filled bottles
The world’s biggest wind turbine will be constructed in Norway. The prototype turbine will stand 162 meters (533 feet) tall and feature a rotor diameter of 145 meters (475 feet). It is expected to be capable of generating 10-megawatts – enough to power 2,000 homes. The turbine will be tested on land in Øygarden in Hordaland County, Norway, for two years but is intended for offshore placement, where the winds are stronger and more consistent, and the concerns of ruined views and vibrations are removed.
Like the HyWind turbines, the turbines to be built by Sway AS are floating turbines. The Sway system is based on a floating tower which extends far below the water surface. The tower consists of a floating pole with ballast in the lower end, similar to a floating bottle. The tower, which is filled with ballast, has its center of gravity located far below the center of buoyancy of the tower. This gives the tower sufficient stability to resist the large loads produced by the wind turbine mounted on top of it.
The floating structure is anchored to the seabed with a single pipe and a suction anchor. When the wind hits the rotor the tower is capable of tilting 5-8 degrees and when the wind changes direction, the entire tower turns around a subsea swivel. This, in turn, makes it possible to reinforce the tower with a tension rod system similar to wire stays on a sailboat mast. Due to the resulting reduction of stresses in the tower, the tower is capable of carrying a much larger turbine.
Sway AS developed the concept in cooperation with Norwegian technology firm Smartmotor AS with a view towards reducing turbine weight ad the number of moving parts, as well as the use of a gearless generator system. Now Enova SF, a public enterprise owned by the Royal Norwegian Ministry of Petroleum and Energy, has provided NOK 137 million (US$24 million at time of publication) of funding towards the NOK 395 million (US$67.5 million) it will cost to construct and demonstrate the wind turbine prototype.
It is hoped the new turbine prototype will be installed in 2011.
About the Author
Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag.
All articles by Darren Quick
These are downwind turbines. The blades are behind the mast. Look at the direction the turbines are tilting in the first rendering. There will be pretty nasty wind shadow problems behind the masts, though, increasing stress on the blades as they pass through the masts\' wake.
How to use such a concept on land, for example in countries that are landlocked?
I\'m looking at this design and thinking the following:
Aren\'t the stays around the wrong way to be in tension?
Force at the top would reduce the force in the stays?
However, I took a look at the SWAY website:
They loose some wind capacity but also loose weight requirements by mounting the blades in the wake of the tower.
About 3 decades back somebody in Europe developed a Wind Turbine on Moored Ships. Commonsense tells that any moving object has a lot of vibrational forces which should be taken care. 162 meters (533 feet) tall and a rotor diameter of 145 meters (475 feet) that too floating is mind boggling.
I think there must be a limit to the size of the Wind Turbine. In the past NASA has designed and developed MOD -A and MOD - B large Wind turbines and Growian in Germany. They were not successful as the technology was much ahead of the times. However the oldest large wind turbine has been Tvind Windmill in Denmark which has been successfully running. I saw it in 1999. It was a wonderful feat by students and teachers of Tvind Schools as an answer to do away with Nuclear power. There is a lift inside which takes tourists to the top. Incidentally it is a Downwind machine (where the wind strikes the tower first and then the blades (now a days we have only upwind machines which operate in reverse).
The bigger the machine it should be fool proof. Any small down time costs heavily.
Though Big is Bountiful, SMALL IS BEAUTIFUL TOO!!
Dr.A.Jagadeesh Nellore (AP), India
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