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Floating Out to Sea

DW staff with wire services (emw)
July 7, 2007

They are loathed as blights on the landscape and menaces to migrating birds. But a new partnership between two European innovators could create wind turbines that can float on the ocean's surface.

Currently wind turbines have to be fixed on land or the sea bed. Floatation could extend their reach.Image: picture-alliance/dpa

Norwegian energy group Norsk Hydro and German engineering firm Siemens recently announced that they have joined forces to research and build a floating wind turbine.

Currently, windmills have to be built on land or in shallow off-shore seabed sites, where they often generate complaints that they spoil the landscape, and concerns that the turbines batter birdlife. A floating windmill could be placed far out at sea.

Affordable and effective design

BdT Offshore Windkraftanlage Ostsee
A fixed turbine off the Baltic Sea.Image: AP

“Windmills standing in waters deeper than about 30 meters (98 feet) become prohibitively expensive," said Henrik Stiesdal, chief technology officer of Siemens' wind power unit told Reuters. Hydro's "is the most elegant and simple solution we have seen."

Hydro's design consists of an upright steel tube with a concrete base about 200 meters long with 80 meters extending above the water and three blades that are 60 meters long. The wind turbine is fixed to the seabed by three cables to hold it steady in seas where waves can be 30 meters high. Hydro believes it can work in waters up to 700 meters deep.

The research partnership hopes to have the first turbine generating clean energy in the North Sea by 2009.

Bring together specialists

Hydro will bring its expertise in floatation technology, which it currently develops for North Sea oil rigs and tankers. Siemens has a strong history in designing and building turbines for electricity generation.

It is expected that the floating turbines will be more expensive than land based turbines, but could supply energy to offshore oil and gas platforms and coastal communities. The attraction of wind turbines is that they produce electricity without releasing greenhouse gases.

Powering the North Sea

Norwegische Bohrinsel Gulfaks in der Nordsee
The new technology could power oil and gas platforms.Image: Statoil

Hydro hopes to have a prototype operating in the North Sea by 2009. It is projected to cost 200 million Norwegian kroner (25.2 million euros or $34.3 million), although the project's finances have yet to be agreed on.

Hydro has already spent 30 million kroner on developing its floatation technology. Siemens says it will spend several million euros on the project over the next two years.

If all goes well, the partnership is hoping to have an off-shore wind energy field set up by 2013, using 5 megawatt wind turbines.