The offshore substation and jacket foundation for the 1.1-gigawatt Inch Cape offshore wind farm have been successfully installed in the North Sea, approximately 21 kilometres off the coast of Angus, Scotland.
The installation was carried out by Heerema Marine Contractors using the semi-submersible crane vessel Sleipnir. The substation, a Siemens Energy Offshore Transformer Module (OTM), is the company’s first double OTM unit. It weighs 2,700 tonnes and is supported by a 68-metre steel jacket foundation.
The platform houses two electrical circuits, including transformers and reactors, in a compact modular configuration. Fabrication and assembly of the OTM and jacket were completed over an 18-month period at the Smulders yard in Wallsend, Newcastle. The process involved a core team of 250 workers and about 80 subcontractors from across the UK.
“This has been an impressive team effort by Siemens Energy, Smulders, Heerema and the myriad smaller contractors who contributed to ensuring the safe and efficient fabrication and installation of these major Inch Cape components,” said Inch Cape project director John Hill.
The Inch Cape wind farm is jointly owned by ESB and Red Rock Power and is currently the largest offshore wind project under construction in Scotland. Once operational, it is expected to produce up to 5 terawatt-hours (TWh) of electricity annually—enough to supply power to roughly half of Scotland’s households.
Onshore construction at the project’s substation site in Cockenzie, East Lothian, is progressing, with the installation of the first of two export cables scheduled for late summer. First power is anticipated in late 2026, with full commercial operation planned for 2027.
