COBRA interconnector cable ready to transport green energy

IGBT converter tower inside the COBRA cable converter station in Eemshaven (photo: Siemens)

As of delivery day 7 September, the 700 MW COBRA interconnector cable between the Netherlands and Denmark will be available for the electricity market.

The subsea high-voltage direct current cable of approximately 325 kilometres is an initiative of the Dutch high-voltage grid operator TenneT and the Danish electricity and gas grid operator Energinet. The cable makes Dutch capacity available on a structural basis for the Danish electricity grid and vice versa.

The interconnector cable runs between Eemshaven (the Netherlands) via Germany and Endrup (Denmark). Two onshore converter stations, one in the Netherlands and one in Denmark, convert alternating current into direct current. The converters also convert direct current back into alternating current; electricity grids operate on the basis of alternating current.

Siemens is the main contractor for design and technical equipment of the converter stations in Denmark and in the Netherlands and for the construction of the converter station in Eemshaven. The cables were manufactured and installed by Prysmian. Construction started in 2016 and was completed earlier this year.

The Netherlands can import more sustainable electricity via this interconnector cable, mainly wind energy from Denmark. Ensuring security of supply is of great importance to Denmark. Furthermore, the cable connection has been designed in such a way that it will be possible to connect an offshore wind farm at a later stage. Source: TenneT