Owned by TEPCO Renewable Power, RWE, and Stiesdal Offshore, the TetraSpar foundation has been operating at the Marine Energy Test Centre offshore Karmøy, Norway, since 2021. The floating foundation features a 3.6 MW Siemens Gamesa Renewable Energy wind turbine and a tetrahedral steel structure. The decommissioning of the TetraSpar Demonstrator marks the final phase of the project, following the successful completion of its demonstration objectives.

The decommissioning will enable detailed inspection of the submerged structure after nearly five years of operation, providing valuable input to the verification of Stiesdal Offshore’s commercial TetraSub foundation.

Under the agreement, Global Maritime will deliver the complete execution of both offshore and onshore decommissioning activities. The scope of work encompasses end‑to‑end project management, engineering, procurement, and operational execution, ensuring a safe, efficient, and environmentally responsible decommissioning process, comprising:

Project Management & Engineering

• Full project management services supporting planning and execution of offshore decommissioning.
• All engineering activities required for safe and effective dismantling operations.

Procurement & Logistics

• Supply and coordination of all vessels, equipment, tools, consumables, and specialist personnel.
• Oversight of custody transfers linked to offshore and onshore works, including issuance of all required handover certificates.

Offshore Decommissioning Operations

• Inter Array Cable (IAC) disconnection, retrieval, storage, transport, and recycling.
• Station Keeping System (SKS) disconnection, retrieval, storage, transport, and recycling.
• Towing of the full TetraSpar structure to a deepwater sheltered area for temporary mooring.
• Keel handling and deballasting operations.
• Harbor towing and docking of the keel and floater.

Onshore Decommissioning Operations

• Careful dismantling of the wind turbine generator (with nacelle and rotor shipped to OEM‑designated facilities; tower sections recycled).
• Keel dismantling, marine growth removal, hazardous material segregation, and recycling.
• Floater dismantling, marine growth removal, hazardous material segregation, and recycling.

The onshore scope will be executed inpartnership with Semco Maritime,as subcontractor at their Hanøytangen yard, providing specialist capabilities in material handling, waste management, and recycling.

Global Maritime brings deep technical and operational expertise to the project, underpinned by extensive experience supporting complex offshore assets across their full lifecycle. This capability is closely aligned with Stiesdal Offshore’s ambition to deliver innovative, industrialised solutions that set new benchmarks for the offshore energy sector.

“This appointment reflects our strong Marine Operations capabilities and our growing involvement across offshore renewable energy projects. We look forward to working closely with Stiesdal to deliver the safe and efficient decommissioning of the floating wind demonstration unit. The project represents an important opportunity to contribute to the full lifecycle of innovative offshore energy solutions,” said Rolf Åge Vågen, Business Stream Director – Marine Operations, of Global Maritime.