The floating TetraSpar demonstrator, owned by Shell, Tepco, RWE and Stiesdal Offshore Technologies, and featuring a 3.6MW Siemens Gamesa turbine, has been fully connected to Norway's grid.
The concept, designed by industry veteran Henrik Stiesdal, is hailed by the partners as having the potential for “important advantages” over existing floating wind concepts, with the potential for leaner manufacturing, assembly and installation processes, as well as lower material costs.
"All indications are that our key target — to accelerate the industrialisation of floating offshore wind — can actually be met, not only at prototype level but at large scale,” said Stiesdal, chairman of the board of directors of TetraSpar Demonstrator.
Towed from the port of assembly in Grenaa, Denmark to the Metcentre test site in Norway in July, commissioning of the turbine is “a huge milestone” for the project, Stiesdal said. It is now producing power in automatic, unattended operation, anchored in place at 200 metres water depth.
The project will now enter its test phase, in which data on the performance and characteristics of the TetraSpar floating foundation will be captured and analysed, so the four partners can further refine the technology and pave the way for commercial-scale floating wind projects.
Sven Utermöhlen, CEO for Offshore Wind at RWE Renewables, said: “This project has been both challenging and inspiring. The spark of genius with the TetraSpar concept is its industrialised manufacturing and assembly methodology, which we think is crucial for long-term cost reduction. Our deep involvement in this project means we have now gathered first- hand evidence about how this approach can be scaled up to commercial projects."
Factory manufacturing of the components and fast assembly of the modules at the quayside, requiring no welding and no special port facilities, were critical, as was being able to launch using a semi-submersible barge, followed by rapid turbine installation using an ordinary onshore crane. Being able to deploy the TetraSpar Demonstrator from an ordinary, shallow-water port, also makes it the world’s first spar foundation capable of doing so.
Tepco president Seiichi Fubasami said the concept will prove especially useful in the Japanese market, which expects to ramp up floating wind development from 2030. "The TetraSpar concept can be utilised in Japan’s natural conditions and enables the easy construction of regional supply chains thereby playing an important role as we aim to transition to renewable energies as baseload power sources. This is a promising new technology for the future, and we expect the TetraSpar floater to perform well during operation off the coast of Norway over the next couple of years.”