The COBRA fibre optic cable between the Netherlands and Denmark


TenneT and have recently started work on realizing a 326 kilometer long undersea HVDC (high voltage, direct current) cable between the Netherlands and Denmark. Following advice of Dialogic, this cable will have a fibre optic cable attached. The cable is expected to enter service beginning 2019.

On the Danish side, the cable will terminate in Endrup; on the Dutch side, this cable will land in Eemshaven. Eemshaven is also a location often eyed for data centers, and has perfect connectivity to the Dutch infrastructure and beyond (through AMS-IX and others). As such the option of attaching a fibre optic cable (FOC) to the HVDC cable was immediately considered. Although the costs of adding the FOC are substantial, they are also relatively low compared to a ‘greenfield’ (or should you say, ‘blue sea’?) deployment. As the cable crosses preserved areas, it is also a rare opportunity for such a cable to be  deployed at all.

Operating an undersea FOC is also quite risky – the cable may break due to various issues, primarily fishing activities and anchors. In this case, the FOC is safely buried below two cables carrying high voltage (which should be quite a good protection in itself already!). Near the shores, the cable is also buried quite deep.

While both TenneT and will be primary users of the cable, there is a large amount of overcapacity. This is being put to market by Relined, a Dutch subsidiary of (among others) TenneT who commercializes excess connectivity from utility companies.

Near the beginning of 2016 I was part of the team that performed market analysis, followed by business case calculations and simulations concerning the FOC, on behalf of TenneT and Energinet. Very good to see that the cable is now being built.

More info: Relined – COBRA cable