Stiesdal Starts Producing First TetraSub Floating Wind Foundation

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Norwegian energy technology developer Stiesdal has started production of the first TetraSub floating foundation, the semi-submersible variant of the company’s Tetra concept, which it says is best suited for water depths ranging from 50 to 200 metres.

Stiesdal has marked four years since its first full-scale floating wind turbine, the TetraSpar Demonstrator, was installed at the METCentre test site off the island of Karmøy near Stavanger.

The 4 MW prototype was commissioned at the end of 2021 and has, according to Stiesdal, delivered very solid operational data and proven the potential of the company’s modular approach.

In May last year, Stiesdal said the TetraSpar Demonstrator recorded an availability of 97 per cent and 98.3 per cent in the first two years of operation, respectively. In 2024, the availability increased to 99.5 per cent with a capacity factor of almost 63 per cent, according to the company.

In a social media post on 7 July, Stiesdal said the demo turbine’s availability was at 99.3 per cent in the latest reporting year.

Marking four years since its TetraSpar floating wind foundation was installed, Stiesdal also revealed the company had started work on its first semi-submersible variant of the Tetra foundation.

“Today, we’re happy to share the first glimpses of what comes next: TetraSub, our semi-submersible floating foundation, now in production. Designed for the world’s largest offshore turbines” , the company said via social media.