Van Oord wraps up inter-array cable installation at UK’s Sofia offshore wind farm

September 9, 2025, by Adnan Memija

Van Oord has completed the installation of 109 inter-array cables, which marks the conclusion of its full scope of work on the 1.4 GW Sofia offshore wind farm in the UK.

Approximately 360 kilometers of inter-array cables have been installed and tested, connecting the wind farms’ 100 14 MW turbines to the project’s offshore converter platform.

The substation converts electricity generated from 66 kV alternating current (AC) to 320 kV direct current (DC). The power travels along two export cables, which run about 220 kilometers along the seabed from the offshore substation to the Teeside coastline.

Much of the array cable installation work was delivered by Van Oord’s cable-laying vessel Calypso, marking the first operational deployment of this ship.

The remaining cables were completed with the Boka Ocean cable-lay vessel, contracted and managed by Van Oord.

Following the cable-laying operations, the Dig-It trencher, deployed from Subsea Viking, ensured burial of more than 360 kilometers of cables, according to Van Oord.

“The completion of these works is another hugely significant milestone for the project, coming so soon after the completion of the foundation installation works. With each passing milestone we get closer and closer to completing this enormous project, which promises to be an outstanding addition to RWE’s UK portfolio,” said Matthew Swanwick, project director at RWE.

In addition to installing inter-array cables, Van Oord was responsible for the installation of Sofia’s 100 monopile foundations, which the company completed in July of this year.

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Vessels

The 1.4 GW Sofia offshore wind farm is located approximately 195 kilometers off the northeast coast of England.

The project is being fitted with the very latest Siemens Gamesa SG 14-222 turbines with 108-meter-long blades and a 222-meter rotor diameter. Half of the wind turbines will be fitted with recyclable blades.

Once fully operational, Sofia is expected to generate enough electricity to power approximately 1.2 million typical UK households.