TetraSpar

In many locations around the world, it is not possible to install offshore wind turbines due to the depth of the sea, but with the newly developed floating foundations, wind turbines will in the future be able to stand at great depths far out at sea. Normally, an offshore wind turbine is installed on a strong structure on the seabed, now a large floating pyramid shaped structure will keep the turbine above water, while a heavy keel provides stability.

 

The development of the new TetraSpar floating foundations is a result of a cooperation between among others; Stiesdal Offshore Technologies, Siemens Gamesa, Aalborg University and DIS.

 

For the project, DIS has provided product development and calculations on the structure. Based on the preliminary test results from a wave pool at Aalborg University, DIS has converted the results into loads applied to the concept for the structure in the calculation program ANSYS.
The calculation results have formed the basis for optimizing the structure and maturing the concept. The structure with sub-components more than 60 meters long and four meters in diameter also has to be handled during shipping and installation. DIS has supported this part of the project with development and knowledge sharing on installation equipment, transport options and lifting equipment designed and calculated according to current standards.

 

“We hope that the TetraSpar project can help making electricity more efficient, cheaper and climate friendly. With the concept’s strong focus on modularity, for example, the costs will be lower as the complicated installation and assembly is moved from the sea to the harbor, and only the transport of the entire construction and turbine will happen at sea with the assistance of conventional tugs. The floating foundations will make it possible to place turbines at great depths and make offshore wind turbines an option in locations where so far it has been technologically and economically impossible”, says Morten Thøtt Andersen, Postdoc and Project Manager from Aalborg University.

 

In January 2020, the components for the foundation prototype will be transported to the harbor in Grenaa, Denmark, for assembly. The wind turbine will be installed on the platform at quayside using a land-based crane. From here, the entire structure will be towed to Norway, where the wind turbine will be placed at a depth of 200 meters, 10 kilometers off of the coast of Stavanger.