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Floating wind turbines at sea Henrik Stiesdal’s TetraSpar project

Floating wind turbines at sea
Wind energy pioneer Henrik Stiesdal (right) receives the German Renewables Award 2014 for his lifework (Image: EEHH GmbH)

Quite a sensation: Offshore farms built on foundations at depths of up to 1,000 m – Henrik Stiesdal’s Tetra Spar project makes it possible. Since retiring as Chief Technological Officer at Siemens Wind Power in 2014, the wind pioneer has been researching the development of floating wind turbines. His partners in this ground-breaking project: RWE, Shell and Siemens Gamesa Renewable Energy.

The TetraSpar floating platform

Until now, offshore wind turbines have only been built on the seabed at depths of up to 50 m. Anchored to the bottom of the sea, the TetraSpar platform enables depths of up to 1,000 m, opening the door to new locations for offshore wind farms with significantly lower installation costs. Stiesdal and his team have already conducted tests off the US coast. Starting 2020, they will build a prototype off Stavanger, Norway, at a depth of 200 m. The plan is to use gearless 3.6 MW offshore wind turbines by Siemens Gamesa Renewable Energy. The rotor blades have a diameter of 154 m. Investment volume for TetraSpar: €18 million.

TetraSpar's ultralight floating constructions enable cost-efficient mass production in many regions of the world, so also in the vicinity of planned offshore wind farms. A floating construction needs at least seven steel pipes with very narrow diameters. The floating foundation only requires a weight of around 1,000 tons to stabilise a six-megawatt turbine.

First generation wind pioneer: Henrik Stiesdal

Henrik Stiesdal, CEO of Stiesdal Offshore Technologies A/S: “Green-lighting investments to deploy and test our first full-scale demonstration project is a very important milestone for us. Even when planning the project, we benefited greatly from our discussions with Shell, innogy and Siemens Gamesa Renewable Energy, and we now look forward to strengthening our talks during the implementation phase.”

A Danish citizen, Henrik Stiesdal holds several patents and has won numerous awards. Many of the technologies that are currently used for the construction of wind turbines were originally his brainchild – also the method of producing rotor blades from a single casting. In 1991, he helped to build the world’s first offshore wind farm in Vindebey. Stiesdal has held senior positions with Vestas, Bonus Energy and Siemens. The industrious pensioner has been researching floating wind turbines, storage solutions, alternative fuels and lidars since 2014. He also teaches wind energy at the Danish Technological University and the University of Maine.

About Tom Mikus

Profilbild zu: Tom Mikus

I’ve been working as an International Project Manager for the Renewable Energy Hamburg Cluster since 2019. At the cluster, I focus on sharing information about renewable energies beyond Germany's borders. I report on the current developments and activities of the Hamburg cluster and renewable energy hub at an international level.