Offshore wind service provider Seaway 7, together with subcontractor Deme, has begun the installation of turbine foundations for what will become the world’s largest offshore wind farm.
The campaign to install the 277 turbine foundation monopiles and transition pieces across three phases of the Dogger Bank wind farm has begun.
The wind farm is being built in the North Sea, 130km off the Yorkshire coast. It is being developed in three 1.2GW phases, Dogger Bank A, B and C.
The project, which could power 6M UK homes annually on completion, is a joint venture between SSE Renewables, Equinor and Eni Plenitude.
SSE Renewables is the lead operator for the development and construction of the project, while Equinor will be lead operator of the wind farm on completion for its expected operational life of around 35 years.
Seaway 7 was awarded the tier one contract for foundation installation on all three phases. Deme has deployed its Innovation vessel for installation of the first foundations on Dogger Bank A. Following this, the Seaway Strashnov will deploy on Dogger Bank A to continue the foundation installation.
The offshore turbine foundations were designed by UK-based designers from Wood Thilsted to tackle challenging wave loads in the Dogger Bank area.
The foundations are more than 72m in length, weigh on average 1,057t and include an 8m offshore wind flange – or projecting flat rim – to support the turbine towers. They will be installed in water depths of up to 32m.
They also feature the “world’s first” split level transition piece design for safer installation and operation.
Dogger Bank wind farm project director Steve Wilson said: “These foundations have been designed for what is arguably the most demanding wave environment to be encountered on an offshore wind farm and are a testament to the many companies involved in collaborating to reach this unprecedented milestone.
“As well as the sheer scale of the foundations, we’ve incorporated a unique split-level transition piece which allows safe access for technicians directly into the turbine tower from our service and operations vessels, eliminating thousands of manual handling activities and lifting operations over the lifetime of the assets.”
In November 2020, the consortium between Sif and Smulders was awarded the contract for the manufacture of all 190 monopiles and transition pieces for the Dogger Bank A and B phases of the wind farm, with a contract for Dogger Bank C’s remaining 87 monopiles and transition pieces awarded to the consortium in 2021.
Steel manufactured by Tata Steel in Wales and processed in Corby and Hartlepool is being used in the supporting components of the transition pieces, while South Tyneside based Metec and Rochdale based Granada Material Handling have also won contracts with Smulders.
Seaway 7 project director Wouter van Dalen said: “The successful installation of the first Dogger Bank foundation marks the start of a multi-year installation campaign for Seaway 7. In good cooperation with our client Dogger Bank wind farm and our partners and suppliers, this complex project has been prepared for installation with a number of different heavy lift vessels, starting with Deme’s Innovation.”
Over the three year installation programme for the three phases of Dogger Bank wind farm, the 277 monopiles and transition pieces will be loaded onto installation vessels in Rotterdam ahead of transfer out to the offshore wind farm site. Using dynamic positioning technology, the vessels will pinpoint the installation site in the seabed at which point a monopile will be upended and transferred to a pile gripper, before being lowered into the seabed.
A hammer will be used to drive the monopile to the design depth in the seabed before a guidance system aligns the installation of the 8m metre flanges which act as a connection for the transition piece, which is then installed onto the monopile. The foundations require 152 giant M80 bolts to secure them before a cover is inserted onto the top of the transition piece to leave it watertight.
The installation of GE Renewable Energy’s Haliade-X turbines onto the foundations will start in spring 2023.
Want to read more? Subscribe to GE’s enewsletters and follow us on Twitter and LinkedIn
Tagged with: Deme Dogger Bank Equinor foundations monopile offshore wind Seaway 7 SSE Renewables
Fugro has completed a geotechnical site investigations for a 2GW wind farm…
Fugro is collecting geo-data to support the development of RWE’s Thor offshore…
A Deme Group and Ferrovial consortium has won a contract to build…
National Highways has completed a complex £1.5M repair programme to the concrete…
Sign in or Register a new account to join the discussion.
Business, International, Project, Industry, Weekly