COBRAcable

Two cables, each 13 cm across, lie side by side for 325 km under the German Bight. Together they make COBRAcable, the first direct power link between the Netherlands and Denmark, running from Eemshaven in Groningen to Endrup near Esbjerg on the west coast of Jutland.

The aim, in the words of the COBRAcable article, was to strengthen the European grid so that more variable wind power could enter the system while keeping supply reliable. One design choice looks ahead: the link was built so that an offshore wind farm could be connected to it at a later stage. That makes it an early step towards the hybrid links now planned in the North Sea, such as LionLink.

The European Commission named COBRA a Project of Common Interest in November 2015, which brought subsidy support. TenneT and Energinet signed contracts with Siemens and Prysmian in 2016. Onshore work began in Denmark in October 2016 and in the Netherlands in January 2017, and after testing over the summer the link was commissioned in September 2019. It cost DKK 4.7 billion, about €580 million. T&D World’s report on the Siemens order describes a 700 MW voltage-source scheme at ±320 kV, with fibre-optic communication built into the cable.

The first months were busy. In its first half-year the link ran at a 79% capacity factor, moving 1,400 GWh to the Netherlands and 700 GWh to Denmark. Then, in September 2020, a fault put it out of action until January 2021.

The Dutch end is shared ground: NorNed from Norway also lands at Eemshaven. The seabed share of the 325 km route has not been published separately, though almost all of it crosses the German Bight.