Deepest Ever Fixed-Bottom Wind Turbine Foundation Stands Offshore Scotland

April 12, 2023, by Adnan Durakovic

The world’s deepest fixed-bottom wind turbine foundation has been installed at what will be Scotland’s largest offshore wind farm – Seagreen – off the coast of Angus.

On Friday, 7 April, the jacket foundation was transported to the project site on a barge operated by the main contractor, Seaway 7, where it was met by the Saipem 7000 – the semisubmersible crane vessel which is used to lift each of the 2,000-tonne turbine foundations into place.

The installation of the jacket means Seagreen has now topped its own record from October 2022, when a previous foundation was installed at a depth of 57.4 metres. The deepest foundation has been installed at a depth of 58.6 metres.

“This is another terrific milestone for both Scotland and the UK’s world-leading offshore wind industry,” the UK Minister of State for Energy Security and Net Zero, Graham Stuart, said.

”As I saw first-hand last week, Seagreen is making history with the world’s deepest wind turbine foundation which, once operational, will play an invaluable role in powering more of Britain from Britain.”

The milestone also marks the installation of the 112th jacket at the 114-wind turbine wind farm which is a GBP 3 billion joint venture between SSE Renewables and TotalEnergies. The final wind turbine foundation is expected to be installed later this week.

”We already know that Scotland has the skills, innovation and natural resources to be a true world-leader in offshore wind technology – from ScotWind, to INTOG, to the spectacular Seagreen installation,” Scottish Cabinet Secretary for Wellbeing Economy, Fair Work and Energy, Neil Gray MSP, said.

”As set out in our draft Energy Strategy and Just Transition Plan, offshore wind power will play a key role in our energy transition, and the Scottish Government will continue to support the sector to continue to deliver innovative, landmark projects like this – not only generating clean, green energy, but delivering increasing economic benefits across our wider supply chains and communities.”

Each foundation will support a Vestas V164-10 MW turbine. First power was achieved in August 2022 with the offshore wind farm expected to enter commercial operation later this year.  

”Seagreen is an important part of SSE’s £12.5bn Net Zero Acceleration Plan, through which we’re investing £7m a day in critical low-carbon infrastructure that will help the UK achieve energy independence. By the end of the decade, we have plans to invest over £24bn in Britain alone,” Alistair Phillips-Davies, Chief Executive of SSE, said.  

”This is not only a significant step on the road to project completion but also shows how we continue to innovate and push the boundaries of technology to power change. Everyone involved in the project can be very proud of their contribution. Thanks to a strong and stable policy framework, the UK has established itself as the world leader on offshore wind and SSE Renewables is building more offshore wind than anyone on the planet. But we want to do more and now is the time to accelerate if we are to achieve the UK’s target of 50GW of offshore wind by 2030.”

When complete, the 1,075 MW wind farm will be capable of generating around 5,000 GWh of renewable energy annually which is enough clean, secure, sustainable electricity to power more than 1.6m UK homes.

”Reaching this major milestone is testament to the skill of our project team and all our contractors including those who are part of our Scottish and UK supply chain,” John Hill, Seagreen’s Project Director, said.

”More than 50 people are involved each time a foundation installation takes place including the onshore team, ballast engineer, tug captain, crew, riggers, welders, tow master and pilot. Our ability to install jackets at this depth, in what is a challenging geographical area, boosts the UK’s energy security and means that consumers can benefit from the strong winds available far out in the North Sea.”

In October 2022, SSE Renewables and TotalEnergies received a go-ahead from the Scottish Ministers to increase the combined capacity of the remaining 36 wind turbines of the Seagreen offshore wind farm, at Seagreen 1A, from 360 MW to 500 MW, which will bring the project’s total installed capacity to 1,575 MW.