Dogger Bank C Offshore Wind Farm, North Sea, UK

Dogger Bank C is a 1.2GW offshore wind farm being developed in the UK North Sea by a joint venture between SSE Renewables, Equinor, and Eni.

Dogger Bank C is the third and final phase of the 3.6GW, £9bn ($11.9bn) Dogger Bank wind project, which is expected to become the world’s biggest offshore wind farm upon completion. The first two phases, Dogger Bank A and B, have a power generation capacity of 1.2GW each. Eni also owns a 20% stake in the first two phases.

The investment in the Dogger Bank C wind farm is estimated to be £3bn ($3.99bn). The project is expected to generate approximately 6TWh of clean and renewable electricity to be fed into the UK’s national power grid.

First power is expected in the third quarter (Q3) of 2025, while the wind farm will become fully operational in Q1 2026. Dogger Bank C will have an estimated operational life of approximately 35 years.

Dogger Bank C wind farm location and development details

To be located off the east coast of Yorkshire, England, Dogger Bank C will occupy an area of approximately 560km². It is expected to be 196km away from the closest land point. The landfall will be situated between the towns of Redcar and Marske-by-the-Sea.

Eni signed agreements with SSE and Equinor to purchase 10% interest from each company in the project, in November 2021. The ownership in the wind farm will change to SSE (40%), Equinor (40%), and Eni (20%), upon completion of the transactions by the end of the first quarter (Q1) of 2022.

Site preparation work for the onshore works of the project began in July 2021. It involved enabling works for the onshore converter station platform. Civil work associated with onshore cable installation is expected to start in the first quarter (Q1) of 2022, while the construction of onshore converter station is planned to begin in the second quarter (Q2) of 2022.

Offshore construction works include installation of offshore export cable, platform and foundation, which is expected to commence in 2024, followed by turbine installation in 2025.

Turbine details

GE was preferred for the supply of the turbines. The supply contract along with a service and warranty contract was finalised in May 2021. The five-year service and warranty will begin upon commissioning the wind farm in 2026.

The Dogger Bank C offshore wind farm will be powered by 87 GE Haliade-X 14 MW wind turbines. It will be the first wind farm to feature the 14MW variant.

Haliade-X is GE’s latest offshore turbine model, which is available in 14MW, 13MW and 12MW capacities. The 260m-high turbine has a 220m rotor, a 107m-long blade, and a capacity factor ranging between 60% and 64%. It has a swept area of about 38,000m² (409,028ft²).

The Haliade-X turbine is designed to generate more power even at low wind speeds. Each 14MW turbine can generate up to 74GWh of gross energy output a year while saving up to 52,000t of carbon dioxide (CO₂) emissions.

Grid connection

The electricity generated from Dogger Bank C will be fed into a converter station platform near Redcar and will be connected to the national grid at Lackenby, Teesside. The onshore converter station will be located on a land parcel owned by Sembcorp Energy UK.

The project will use a high voltage direct current (HVDC) connection to reduce transmission losses.

Hitachi ABB Power Grids and Aibel were selected to supply the offshore converter platform and associated transmission link for the wind farm.

Hitachi ABB Power Grids will install HVDC Light technology for efficient transmission of electricity from the project to the onshore grid, while Aibel will supply the offshore converter platforms to be installed at the sea for the three phases.

Offtake agreements supporting Dogger Bank C

SSE Renewables and Equinor signed 15-year power purchase agreements (PPAs) with for the wind farm in November 2021.

Danske Commodities agreed to purchase 40% (480MW) of the wind farm’s output. SSE Energy Supply, Centrica Energy Marketing and Trading, and Shell Energy Europe agreed to purchase the remaining 60% of the output. Each of the three companies will receive 240MW of power under the agreements.

Financing

The financial closure for the third phase of the Dogger Bank project was achieved in December 2021. The funding was secured through a group of lenders including 28 banks and three export credit agencies.

Contractors involved

A consortium of Sif Netherlands (Sif) and Smulders Projects Belgium (Smulders) was selected to supply monopile foundations and transition pieces for the project in November 2021. Sif is responsible for the fabrication and supply of monopiles and primary steel for the transition pieces. Smulders is responsible for the manufacturing of secondary steel for the project. The company will also assemble, coat and test the transition pieces.

The consortium was previously contracted to supply monopiles and transition pieces for the first two phases of the Dogger Bank wind farm.

Jan De Nul received a contract to transport and install 87 turbines at the wind farm. It will use the Voltaire jack-up installation vessel with a lifting capacity of more than 3,000t, to deliver the contract.

Seaway 7, an offshore wind farm solutions provider, was selected to transport and install the foundations and transition pieces for the wind farm. It will use the Alfa Lift specialist heavy vessel for the project. The installation work is expected to begin in 2024, upon completion of the installation of the foundations at Dogger Bank A and B.

Danish cable solutions provider NKT was contracted to deliver and install HVDC onshore and offshore export cable systems for the Dogger Bank C project. It will supply more than 500km of 320kV offshore export cables and accessories. The cables will be installed using the NKT Victoria cable-laying vessel.

Jones Bros Civil Engineering UK was appointed to execute enabling works for the grid connection of the project.

DEME Offshore, the renewables business unit of DEME Group, was awarded a contract to provide engineering, procurement, construction and installation (EPCI) services for the inter-array cables for the project, in December 2021. It subcontracted Hellenic Cables to supply the inter-array cables in January 2022.

North Star Group, a shipbuilder based in the UK, was engaged to provide a service operations vessel (SOV) to support offshore wind technicians working on the Dogger Bank C project.