Laying the foundations for net zero on Dogger Bank

The installation of the first foundations for 277 wind turbines at Dogger Bank Wind Farm in the North Sea has commenced this week. The wind farm, which will be located more than 130km off the North East coast of England, will be the largest offshore wind farm and when operational will generate 3.6GW of energy – enough to power 6 million UK homes annually on completion.

The world-class renewable energy project is making a major contribution to SSE’s plans to invest in excess of £24bn this decade in Great Britain’s electricity infrastructure system. SSE Plc’s Net Zero Acceleration Programme (‘NZAP’) major infrastructure projects including Dogger Bank are expected to provide a huge boost to the UK’s ambition to provide everyone with cheaper, cleaner, more secure energy.

Dogger Bank Wind Farm, a joint venture between SSE Renewables (40%), Equinor (40%) and Eni Plenitude (20%), is made up of three offshore wind farm sites in the North Sea. 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 installation of the first monopile and transition piece at Dogger Bank A, marks a significant milestone in the project.

The foundations, designed by UK-based designers from Wood Thilsted, are up to 72m in length, weigh on average 1057 tonnes and include the world’s largest 8m offshore wind flange. The design includes the world’s first split-level transition piece for safe installation and operation, with installation works being led by Seaway supported by DEME.

Installation of GE Renewable Energy’s ground-breaking 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 innovative and world-leading project.

"Today we are delighted to announce that we’ve installed the first turbine foundation monopile and transition piece at our flagship Dogger Bank offshore wind project in the North Sea. This is a really important milestone for the project as it marks the commencement of our campaign to install 277 turbine foundations across the three phases of what will be the world’s largest offshore wind farm", said Paul Cooley Director of Offshore Wind, SSE Renewables. "At SSE Renewables, we’re already building more offshore wind energy than any other company in the world. As lead operator during the construction phase of Dogger Bank Wind Farm, we’re working with our development and supply chain partners to install some of the world’s largest turbine foundations on this world-class project. We’re also particularly proud of how this project is helping develop more secure and affordable homegrown UK energy. SSE is the UK’s clean energy champion, and no project epitomizes this status more than Dogger Bank. During this campaign we’re using foundations that are UK-designed and with components made from UK-manufactured steel, all of which are helping to support UK jobs and a fair and just transition to net zero."

The foundations have been optimised to tackle challenging wave loads in the Dogger Bank area of the North Sea, with installation in water depths of up to 32m and at a distance of 130km from shore and provide a solid and stable base for the scale of the GE Renewable Energy’s groundbreaking Haliade-X turbines.

Alastair Muir Wood, CEO of designers, Wood Thilsted, said: “Wood Thilsted is proud to be a part of making Dogger Bank Wind Farm a success. 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 programme 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 72m (equivalent to more than 6 double-decker buses end-to-end), 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 8-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.

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.

Lucien Romagnoli, Business Unit Director Renewables at DEME Offshore, said: “We are extremely proud to be supporting the construction of the world’s largest offshore wind farm with foundation installation and later in the programme as inter-array cable installer. 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.”

• To find out more about SSE’s Net Zero Acceleration Programme click here