Riffgat OSS J-Tube Installation

Clients Omexom and TenneT are very satisfied with the successful J-Tube installation.

Conbit, alongside the main contractor, was contracted to install a J-Tube at the Riffgat Offshore Substation, owned by Tennet and serviced by Omexom. This installation was critical to the efficient operation of the offshore wind farm, as the J-Tube serves as a vital component in protecting and guiding subsea cables. To complete this complex operation, the scope was divided between N-Sea, handling the subsea operations, and Conbit, responsible for the topside works. Both teams had to execute their roles with precision to ensure a smooth, safe, and efficient installation process.

Watch how we prepare and execute

The new J-Tube was installed at the Riffgat Offshore Substation to facilitate the safe and efficient routing of new subsea cables. This installation protects the cables as they enter the substation, ensuring reliable transmission for offshore wind energy generation.

Partnership with N-Sea

‍The partnership between Conbit and N-Sea proved to be highly successful, showcasing effective collaboration and seamless execution. N-Sea, known for its expertise in subsea Inspection, Repair, and Maintenance (IRM) and Construction, played a pivotal role in managing the subsea scope, which included providing all necessary marine assets and support. Their professional dive team worked in close coordination with Conbit's rigging team, ensuring flawless handovers of the J-Tube components from the Diving Support Vessel to the above-water crew. This strong partnership allowed both companies to maximize operational efficiency and adhere to tight project timelines, leading to a successful installation that met the highest safety and quality standards.

Innovative Solution

‍The solution required to install the J-Tube was both technically challenging and meticulously planned. Prior to the J-Tube’s installation, a lower support structure and clamp had to be precisely positioned. The J-Tube, composed of three sections, was transferred from the crane of the Diving Support Vessel into a pre-installed platform-based lifting configuration. The largest section, along with the support structure and clamp, was lifted in a single operation. The two smaller components were lowered using the OSS deck crane and then seamlessly transferred to Conbit’s below-deck rigging team. Conbit’s bespoke lifting systems, designed specifically for this project, were essential in executing this delicate operation, requiring expertise in rope access and temporary rigging systems.

Riffgat OSS

Riffgat Offshore Substation is the second offshore grid connection using three-phase AC technology, connected by TenneT to the German transmission grid. Located 15 kilometers northwest of Borkum, it efficiently serves the Riffgat Wind Farm, with a total capacity of 113 MW, making it a key asset in Germany’s renewable energy infrastructure.

Conbit's Role in the Offshore Wind Industry

‍Conbit’s engineering expertise, combined with its innovative lifting solutions and rope access capabilities, makes it an ideal partner for the offshore wind industry. By offering a fully integrated service that reduces interfaces and project risks, Conbit is well-positioned to support offshore wind developments. Its ability to deliver safe, efficient, and cost-effective solutions for complex lifting and rigging operations enables wind operators to streamline projects and reduce overall costs. Conbit’s dedication to safety, innovation, and technical precision makes it a valuable asset to the growing renewable energy sector.

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