BritNed

BritNed was finished on time and on budget, which in subsea power is rare enough to mention first. The €600 million project was announced in May 2007, the cable installation began on 11 September 2009, the laying was complete by October 2010, and the link went into operation on 1 April 2011.

The route runs about 260 km under the North Sea from the Isle of Grain in Kent, at the mouth of the Thames and Medway, to Maasvlakte, the reclaimed port land west of Rotterdam. ABB made the bipole 450 kV cable, Global Marine Systems laid it and a BAM Nuttall and Siemens consortium built the converter stations. The BritNed article records that the project was framed as a first step towards a European super grid in the North Sea. That phrase has since gone out of fashion, but the Isle of Grain end has become a hub anyway: the NeuConnect cable to Germany starts at the same site.

National Grid and TenneT built BritNed as a joint venture that funds and operates the link on its own account. As of January 2012 most of the electricity had flowed from the Netherlands to Britain.

The link’s worst period came in 2021. An undersea cable fault took it out of service on 9 March; restoration was first planned for 8 May and then slipped until 7 June. Three months without the link shows how long a seabed repair takes once a repair vessel, a spare section and a weather window all have to line up (the guide to subsea power cables explains why).

Sources disagree slightly about the length: the BritNed article gives 260 km and the List of HVDC projects gives 245 km. The figure above uses 260 km. The next cable planned between the two countries, LionLink, will connect a Dutch offshore wind farm on the way.