Subsea inspection and data analysis will support verification of the technologies used in the world’s first fully industrialised floating offshore substructure.

TetraSpar Demonstrator ApS, a project company owned by Stiesdal Offshore, RWE and TEPCO Renewable Power, today announced the planned decommissioning of the floating TetraSpar Demonstrator. The operation, scheduled for the summer of 2026, marks the final phase of a five-year demonstration project and reflects the successful delivery of its objectives.

The TetraSpar Demonstrator was originally developed in partnership between Stiesdal Offshore, RWE, Shell, and TEPCO Renewable Power. Shell is no longer part of the project.

Since its installation, the TetraSpar Demonstrator has validated key design and industrialisation principles for floating offshore wind. Over nearly five years of operation, the system has delivered strong and reliable performance and valuable operational data to its partners.

Since commissioning, the 3.6 MW 130-meter Siemens turbine has produced almost 70 million kWh, reaching an aggregate capacity factor of 51.4% at an availability of 98%.

Long-term performance & behaviour is crucial data

As the floating wind sector moves towards large-scale deployment, access to long-term operational data and physical verification of structures is increasingly important. The decommissioning of the demonstrator will enable full inspection and analysis of the submerged structure after nearly five years of uninterrupted normal operation.

The results will provide unique insights into structural integrity, material performance and long-term behaviour under real offshore conditions. This knowledge will support ongoing efforts across the industry to reduce risk, optimise designs and accelerate the commercial scaling of floating wind.

Performing reliably under real offshore conditions

Following a competitive tender process, TetraSpar Demonstrator ApS has recently awarded the decommissioning contract to Global Maritime. The decommissioning work will be carried out in close coordination with Global Maritime and the METCentre test facility.

Henrik Stiesdal, Chairman of the Board of TetraSpar Demonstrator ApS, says:

“The TetraSpar Demonstrator has shown that industrialised floating wind concepts can perform reliably under real offshore conditions over extended periods of time. The project has provided valuable experience and data for all partners involved, and I would like to thank everyone who has contributed to its development and operation. By completing the project with a full inspection of the structure, we are able to extract additional knowledge that will contribute to the continued development and scaling of floating offshore wind. This is an important step in making the technology ready for broader commercial deployment.”

Floating offshore wind is expected to play an important role in strengthening energy security, supporting electrification and contributing to a more resilient and independent global energy system.

Demonstration projects such as TetraSpar are essential in bridging the gap between innovation and large-scale deployment.