Work has started on the installation of 277 of some of the world’s largest offshore wind turbine foundations in the North Sea, in what is another major milestone for the 3.6 GW Dogger Bank Wind Farm, being developed 80 miles off the Yorkshire coast.
The project, which will be capable of powering 6 million U.K. homes annually on completion, is a joint venture between SSE Renewables (40%), Equinor (40%) and Eni Plenitude (20%). SSE Renewables is lead operator for the development and construction of Dogger Bank Wind Farm, while Equinor will be lead operator of the wind farm on completion for its expected operational life of around 35 years.
The campaign to install turbine foundations at what will be the world’s largest offshore wind farm has commenced in recent days, with the installation of the first monopile and transition piece on Dogger Bank A. The installation campaign is being led by Seaway 7 supported by DEME.
The turbine foundations for Dogger Bank Wind Farm feature a unique split-level transition piece, as well as an eight-meter flange – or projecting flat rim – to support the turbine towers.
Installation of GE Renewable Energy’s Haliade-X turbines onto each of the installed turbine foundations will commence from Spring 2023.
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 to support this project.
“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,” says Steve Wilson, SSE Renewables’ project director for Dogger Bank Wind Farm. “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.
“Successful installation of our first monopiles and transitions pieces is a giant leap for offshore wind globally and will lay the foundations for Dogger Bank Wind Farm to contribute to meeting the UK’s net zero target, enabling the development of a future energy system that is cleaner, cheaper and more secure,” Wilson continues. “It also demonstrates the continued innovation in our sector as we begin to install the increasingly larger and more powerful turbines that are needed to fuel our homes and businesses safely and securely in a net zero world.”
Designed in the U.K. by experts from Wood Thilsted, the foundations have been optimized to tackle challenging wave loads in the Dogger Bank area of the North Sea, with installation in water depths of up to 32 meters and at a distance of 130 kilometers from shore, and provide a solid and stable base for the scale of the GE Renewable Energy’s groundbreaking Haliade-X turbines.
“Wood Thilsted is proud to be a part of making Dogger Bank Wind Farm a success,” mentions Alastair Muir Wood, CEO of Wood Thilsted. “Our team faced challenges including working with the largest turbine at the time, an innovative dynamic positioning installation vessel, and some very significant wave loads. What made success possible was the collaborative working relationship shared with the Dogger Bank team and the other key stakeholders. This project is a model of success for current and future projects.”
Over the three-year installation program for the three phases of Dogger Bank Wind Farm, a total of 277 monopiles and transition pieces will be loaded onto installation vessels in Rotterdam ahead of transfer out to the offshore wind farm site deep into the North Sea. Using dynamic positioning technology, the vessels will pinpoint the installation site in the seabed at which point a monopile measuring up to 72 meters 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 record-breaking eight-meter 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.
Seaway 7 was awarded the tier one contract for foundation installation on all three phases of Dogger Bank Wind Farm, with sub-contractor DEME deploying its Innovation vessel for installation of the first foundations on Dogger Bank A. Following the DEME Innovation, the Seaway Strashnov will deploy on Dogger Bank A to continue the foundation installation.
“The successful installation of the first Dogger Bank foundation marks the start of a multi-year installation campaign for Seaway 7,” adds Wouter van Dalen, project director 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. Seaway 7 is proud to be part of the team that is constructing the Dogger Bank project and is looking forward to safely installing the remaining 276 foundations.”
“We are extremely proud to be supporting the construction of the world’s largest offshore wind farm with foundation installation and later in the program as inter-array cable installer,” comments Lucien Romagnoli, business unit director of renewables at DEME Offshore. “These unique foundations are huge but also, they are technically complex. This is an important moment for the offshore wind industry and the energy transition. It is wonderful to be working alongside like-minded partners with the joint goal of achieving a net-zero energy system.”
In November 2020, the consortium 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.
