Business World of Renewable Energy

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Shell, Innogy and Stiesdal are Testing New Foundations for Offshore Wind Turbines

Essen, Germany – Offshore Wind Energy offers huge potential for power generation along the coasts. Because of the prevailing water depths, the conventional foundation technology is reaching its limits. Floating foundations are an alternative approach.

Innogy SE, Shell and Stiesdal Offshore Technologies A/S (SOT) have taken the final investment decision on the ‘TetraSpar’ floating foundation demonstration project which will be tested off the Norwegian coast in 2020. Its modular layout consists of a tubular steel main structure with a suspended keel. It is expected to offer important competitive advantages over existing floating wind concepts, with the potential for leaner manufacturing, assembly and installation processes with lower material costs. The project has a budget of €18 million.

Shell has increased their share in the project from 33 percent to 66 percent. Innogy retains 33 percent in the newly founded project company and SOT is contributing to the project with its modular TetraSpar concept and holds the remaining shares (1 percent). As technology partner, Siemens Gamesa Renewable Energy (SGRE) will provide the wind turbine and required services. The partners will be part of a project team that will gain detailed, practical insights into the construction, installation and operation of the TetraSpar concept as well as detailed performance data.

Dynamic stability tests on a true-to-scale model have been running since last December, using the wavewind channel at the University of Maine, USA, and the wave tank at FORCE in Lyngby, Denmark. This year, the components for the large floating prototype will be manufactured by Welcon A/S in Give, Denmark. The components will be transported to the Port of Grenaa to be assembled. Following launch of the foundation, the wind turbine will be mounted on the foundation at the quayside using a land-based crane.

From there, the foundation structure including the turbine will be towed to the test site in the northern part of the North Sea, moored to the seabed with three anchor lines and connected to the electrical grid. It will be located approximately 10km from shore in water depths of 200m at the test site of the Marine Energy Test Centre (Metcentre) near Stavanger in Norway. The demonstration project will use a 3.6MW SGRE direct drive offshore wind turbine.

Source: IWR Online, 15 Feb 2019