TenneT has issued a call for tenders for Structural Health Monitoring systems (SHM systems) and their installation on twelve offshore HVDC platforms, including both existing and platforms yet to be installed offshore.
Under a five-year, EUR 3.25 million contract, the tender winner will develop and install a monitoring concept for the support structures of the twelve platforms.
On nine platforms, which are in operation, the installation of the SHM systems will be carried out offshore during operation, while for the three platforms which are under construction or in the planning phase the installation will take place in the respective shipyard during the construction phase.
The transmission system operator’s tender notice lists the places where work will be carried out as German Bight in the North Sea for offshore installation and a shipyard in Cadiz in Spain for onshore installation of SHM systems, with another shipyard yet to be determined.
In Germany, TenneT’s platforms that are in operation are the main part of the following grid connections: BorWin1, BorWin2, BorWin3, DolWin1, DolWin2, DolWin3, HelWin1, HelWin2, and SylWin1. Currently under construction are platforms for BorWin5, DolWin5, and DolWin6 that will go online by 2025, and for BorWin6 which is planned to be up and running in 2027.
In connection with the installation of the SHM system, a platform-specific monitoring concept has to be developed that is based on periodic data determination, therefore periodic reporting should be implemented, the tender notice reads. In addition to the immediate detection of beyond-design-basis events and changes in the foundation structure, this should also enable the total service life of the structures to be recorded mathematically.
The tender also lays out options including monitoring of the operating structure and substructure during temporary conditions, and local scour monitoring.
Bids can be submitted until 15 October, with TenneT reserving the right to negotiate with a maximum of four candidates after the submission of tenders.