Allseas to Install Norfolk Boreas Substation

Switzerland-headquartered Allseas has been awarded a contract for the transportation and installation (T&I) of Norfolk Boreas high voltage direct current (HVDC) converter station in the UK.


The contract was awarded by Aker Solutions and Siemens Energy which are responsible for Boreas’ engineering, procurement, construction, and installation (EPCI) of HVDC onshore and offshore substations and connection to the national grid.

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The platform installation vessel Pioneering Spirit will install the substation in 2026.

Allseas also has T&I options for two similar HVDC platforms for the neighbouring Norfolk Vanguard offshore wind farm, pending an investment decision by Vattenfall.

The three platforms – Boreas, Vanguard East, and Vanguard West – will house HVDC conversion technology. Topsides’ weights are between 10,000 and 11,300 tonnes, with the jackets weighing about 3,000 tonnes.

Located 47 kilometres off the Norfolk coast in southeast Britain, the 1.4 GW Norfolk Boreas wind farm is the first phase of Vattenfall’s Norfolk Offshore Wind Zone which also includes the Norfolk Vanguard offshore wind project.

Subject to a final investment decision, construction on the project will begin this year and the wind farm is expected to produce its first power in 2027.

Last month, Vattenfall announced that it will increase the capacity for the Norfolk Offshore Wind Zone off the UK from 3.6 GW to over 4.2 GW.

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