Topside Installed: Another Milestone Passed at Scotland's Largest Fixed-bottom Offshore Wind Farm

Credit: SSE
Credit: SSE

Construction of Seagreen, Scotland's largest fixed bottom offshore wind farm and the world's deepest of its kind, has reached another critical milestone with the installation of the 4,800-tonne offshore platform topside off the Angus coast.

"The topside forms the backbone of the offshore wind farm," SSE said Monday.

According to the photo shared by SSE, the topside was lifted by Heerema Marine Contractor's Thialf heavy transport vessel and onto the previously installed 6-legged jacket foundation. The completed structure sits in water depths of around 55m and will be one of the largest AC platforms in UK waters.

At 40 meters long, 45 meters wide and 15 meters high, the heavyweight superstructure’s role is to collect and manage 1,075MW of power generated by the 114 Vestas wind turbines before transferring it ashore via around 60km of offshore subsea cabling.



Image Credit: Seagreen Wind Energy LtdOnce onshore, the electricity will continue to the new Tealing substation near Dundee via a further 19km of cabling for onward distribution to homes and businesses via the national electricity network.

Specialist cable installation and support vessels will continue to install the onsite inter-array network of cables to the turbines and to the offshore platform. Another vessel is currently installing the export cable from the landfall point at Carnoustie.

"Once again, the many years of careful design and planning have come to fruition with the arrival and successful installation of one of the UK’s largest offshore AC platforms, serving what will become Scotland’s largest offshore wind farm," said John Hill, Director of the Seagreen wind farm project.



Petrofac is responsible for the engineering, procurement, fabrication, transportation, offshore installation, and commissioning of the High Voltage Alternating Current (HVAC) offshore substation platform. In addition to the topside, this includes the jacket that supports the offshore platform substation, which was successfully installed and secured on the seabed earlier this year. An onshore substation scope with all civil work and major equipment is also included.

Vipul Sawe, Petrofac’s Senior Project Director said:"The safe and successful installation of the substation topside is a significant milestone in the delivery of this important energy transition project for the UK. Everyone involved should be proud of this achievement and the great teamwork and collaboration shown between all partners and parties working together.”

Situated around 27 kilometers off the Angus coast, the Seagreen wind farm is a joint venture between SSE Renewables (49%) and TotalEnergies (51%). SSE Renewables is leading the development and construction of the Seagreen project and will operate Seagreen on completion for its expected 25-year lifetime.

The Seagreen Wind Farm is scheduled to enter operation in early 2023. 

At 1.1GW, the wind farm will be capable of generating around 5,000 GWh of renewable energy annually which is enough electricity to power more than 1.6 million UK homes.  

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