Van Oord Sofia first monopile

Van Oord Installs First Monopile at RWE’s Sofia Offshore Wind Farm

Van Oord’s offshore installation vessel, Aeolus, has installed the first of 100 monopile foundations at the 1.4 GW Sofia project in the UK, RWE’s largest offshore wind farm to date.

Van Oord Sofia first monopile
Source: Van Oord

The Sofia offshore wind farm is located on Dogger Bank in the central North Sea, 195 kilometres from the North East coast of the UK.

Van Oord is responsible for the design, engineering, procurement, construction, and installation (EPCI) of the monopile foundations and array cables for this project under a contract signed with RWE in 2021. Project execution is being managed by Van Oord Offshore Wind UK from their MPI Offshore office in Stokesley, Teesside.

The Dutch company deployed its fallpipe vessels Bravenes and Nordnes to install scour protection at the locations where the monopiles are now being installed.

Manufactured by EEW in Rostock, Germany, the monopiles have a diameter of up to 8.8 metres, a length of up to 92 metres, and a weight of up to 1,530 tonnes.

The units are being transported by barges to the Port of Tyne which serves as the storage and marshalling base for the wind turbine foundations and is located near Newcastle on the River Tyne in North East England.

For the Sofia offshore wind project, so-called extended monopiles are used, eliminating the need for a transition piece. To complete the wind turbine foundations, the monopiles will be equipped with secondary steel components consisting of main access platforms, internal platforms, boat landings, and upper ladders.

Van Oord will deliver the installation of three foundations per cycle, with a transit time of up to 16 hours, said RWE. The total duration of this campaign phase will depend on sea conditions, but all 100 monopiles are expected to be installed by spring 2025.

The placement of the first monopile follows the installation of the high voltage direct current (HVDC) export cable which started in 2023.


Later this year, Van Oord’s cable-laying vessel Calypso and trencher Dig-it will be deployed to install the 360 kilometres of array cables which are manufactured in Greece and stored in the Port of Blyth.

“Sofia is RWE’s largest offshore wind construction project to date, and its furthest from shore. Installing the first monopile is a highly symbolic moment in the construction of every offshore wind farm. After 14 years of planning and preparation, this is a great achievement for the entire RWE team,” said Sven Utermöhlen, CEO RWE Offshore Wind.

The Sofia offshore wind farm will use 100 SG 14-222 DD wind turbines. A total of 44 of the project’s 100 units will be equipped with recyclable blades.

Once completed, each 14 MW unit will be 252 metres tall, with a 108-metre carbon and fiberglass blade, and a 222-metre diameter motor sweeping an area of 39,000 square metres, according to RWE.

The 1.4 GW offshore wind project is expected to be commissioned in 2026 when it will be capable of generating enough electricity to power the equivalent of 1.2 million UK homes.


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