Equinor and SSE, developers of the UK's 3.6GW Dogger Bank complex, have chosen Norwegian vessel owner OHT as preferred contractor to install foundations on the 2.4GW Creyke Beck A&B sub-projects of what is slated to be the world's biggest offshore wind array.

The contractor will use its new Alfa Lift - set to be the world’s largest custom-built offshore wind foundation crane vessel when launched in 2021 – to transport and install the monopile foundations and transition pieces for the two wind farms in the North Sea.

“The monopiles that will be installed at Dogger Bank will be among the largest ever used on an offshore wind farm and we needed a vessel that allow us to deliver our project in the safest and most efficient way,” said Steve Wilson, project director, Dogger Bank Wind Farms.

The Creyke Beck A and B projects are moving towards a final investment decision, expected in 2020.

The three Dogger Bank developments – comprising Creyke Beck A, Creyke Beck B and Teesside A – won 15-year contract-for-difference awards from the British government in mid-September.

OHT said the foundations will be transported to the offshore site, around 130km off the north-east coast of England, and installed in water depths of up to 35 metres. The Alfa Lift vessel will carry ten monopiles and transition pieces on her deck per voyage.

The monopile foundations will form the base for GE Renewable Energy’s Haliade-X,the world’s first 12MW turbine, which recently recorded first power from its prototype in Rotterdam.

Halfdan Brustad, vice president for Dogger Bank at Equinor, said that “by bringing new, innovative and efficient vessels into the market, like this Alfa Lift vessel, we are helping to revolutionise the offshore wind industry. We need new entrants that can think differently and make the industry even more competitive”.

The transport and installation of the monopiles and transition pieces for the wind farms is expected to be carried out between 2022 and 2024.

SSE Renewables will lead the development and construction phases of the Dogger Bank wind farms while Equinor will lead on operations once the projects are completed.