Seagreen offshore wind farm

With a capacity of 1,075 MW, the Seagreen Offshore Wind Farm provides renewable energy to almost two-thirds of all Scottish homes. Appointed by Total Energies and SSE Renewables Ramboll provided the detailed design services for the foundation sub-structures.
Seagreen offshore wind farm, Scotland

The Seagreen Offshore Wind Farm is a joint venture between TotalEnergies, a global integrated energy supplier, SSE Renewables, a leading developer and operator of renewable energy and PTTEP, which joined the consortium in 2024.

Seagreen currently holds the record for being Scotland’s largest and the world’s deepest offshore wind farm. The wind farm is located 27 kilometres off the coast of Angus, Scotland in the North Sea, and will consist of a total of 150 turbines with 114 turbines of phase 1 already fully operational and 36 more planned for phase 1A. The 114 10MW wind turbines in Phase 1 provides enough green energy to power more than 1.6 million homes, which is equivalent to almost two-thirds of all Scottish homes.

Ramboll was appointed by TotalEnergies and SSE Renewables to provide the detailed design services for the foundation sub-structures,Subsequently novated to the EPCI contract, Seaway 7, Ramboll undertook the following services including:

  • Supporting the ground investigation and production of the geotechnical interpretive report
  • Jacket transition piece and suction caissons design (including soil-caissons interaction)
  • Upending, lifting and installation assessment
  • Jack-up interaction study between spudcan and caissons
  • Transportation assessment covering sea fastening and grillage study to ferry the foundations from Asia to Europe
  • Low-voltage system and electrical design
  • Providing support during fabrication and installation phases
  • Installation risk mitigation support, including assessment of installation using pressure cycling and micrositing of foundations

Greener foundation design

For Seagreen offshore wind farm, Ramboll designed all 114 suction bucket foundations, which offers a greener alternative to conventional offshore wind foundations by producing minimal noise and disturbance to marine life during installation. Despite their sustainability benefits, they are perceived as riskier and are less commonly used in the industry. However, Seagreen offshore wind farm has successfully deployed suction bucket foundations, achieving full installation and electrification by October 2023. For this extraordinary effort the project team received the prestigious Fleming Award in 2023 awarded by the British Geotechnical Association.

Towards Scotland’s net-zero ambitions

The Seagreen wind farm was in 2014 granted consent for Phase 1 to construct 114 wind turbines with an installed capacity of 1,075 MW. The turbines connect to the UK national electricity transmission system via consented export cables and inshore transmission works at a new substation at Tealing in Angus, Scotland. The remaining 36 offshore wind turbines under Phase 1A are consented, and the power from these will be exported to the grid via the substation Cockenzie in East Lothian, Scotland.

The renewable energy from Phase 1 has replaced the electricity that would have been generated by fossil fuels, which will lead to a reduction in CO2 emissions of over 2 million tonnes every year. It is equivalent to removing more than a third of all Scotland’s annual car emissions and represents an important contribution to Scotland’s ambitions to reach Net Zero by 2045.

In December 2020, Ramboll was also appointed as the Environment and Consents Manager for Seagreen 1A Onshore Transmission Works, which will secure grid connection for the remaining 36 wind turbines.

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