Dudgeon Offshore Wind Farm

The 402MW Dudgeon offshore wind farm is located in the North Sea approximately 32km off the coast of North Norfolk, the UK.

The project is owned by Equinor (35%, operator), Masdar (35%) and China Resources (Holdings) Company Limited (30%).

The construction of the wind farm began in the third quarter of 2014 following the Final Investment Decision (FID), and it was fully commissioned in late 2017.

The wind farm is capable of producing approximately 1.73 Terawatt hours (TWh) of clean energy annually, enough to power more than 400,000 UK homes. It displaces around 893,000 tonnes of carbon dioxide per year.

Location details

The Dudgeon offshore wind farm is located in a 35km² area, around 32km off the coast of the seaside town of Cromer in North Norfolk. It is one of the furthest away wind farms from the UK’s shoreline.

Water depth at the site ranges from 18m to 25m with wind speed averaging 9.8m/s.

The Sheringham Shoal Offshore Wind Farm is situated around 20km from the site.

Project background and approvals

The Government of the UK awarded the licence for the Dudgeon offshore wind farm site during the Round 2 allocation in 2003.

The project secured all consents by 2012. It also received approvals for subsequent multiple variations.

Dudgeon wind farm required approvals from the Department of Energy and Climate Change; the North Norfolk District Council; Breckland Council; as well as a marine licence from the Marine Management Organisation (MMO).

The development of the wind farm involved an investment of around £1.25bn.

Dudgeon wind farm infrastructure 

The Dudgeon offshore wind farm comprises a total of 67 Siemens 6MW wind turbines placed on monopile foundations fixed to the seabed.

Each turbine consists of three tower sections, a nacelle and three separate rotor blades. The 75m-long rotor blades were manufactured using single-cast Siemens Integral Blade production technology.

The power generated by the wind turbines is collected by the offshore substation and exported to the shore using a subsea cable.

The 24-mile (38km) long 132kV cable was laid on the seabed and it stretches from the wind farm to landfall at Weybourne Hope on the coast of North Norfolk.

A 30-mile (48km) underground cable was laid in ducting at a depth of 1.4m to transmit the electricity from landfall to the substation at Necton in the Breckland district of Norfolk. Thereafter, the renewable electricity is fed into the National Grid from the onshore substation using a 400kV overhead line.

The wind farm’s operations and maintenance base (O&M) building is situated at Great Yarmouth.

Construction of Dudgeon wind farm

The construction of the Dudgeon wind farm began with onshore substation site preparation in the third quarter of 2014. The onshore cable construction works started in 2015.

The installation of monopile foundations began in 2016 using Seaway Heavy Lifting’s crane vessel Oleg Strashnov.

The first turbine was installed at the site in January 2017 by the vessel Sea Challenger.

The wind farm delivered the first electricity to the UK National Grid in February 2017 by putting the first turbine into production.

The wind farm was officially opened in November 2017.

Contractors involved

In January 2014, Siemens was selected to engineer, procure, assemble and commission 67 Wind turbine generators (WTG) for the Dudgeon Offshore Wind Farm. The company supplied Siemens SWT 6.0 MW turbines for the project.

In addition, Siemens secured a contract in September 2014 to deliver the grid connection for the project.

Steel construction company Smulders produced the 67 transition pieces required for the wind farm. Dubai-headquartered engineering firm Kent was engaged to undertake the concept, FEED and detailed design of the 67 individual monopiles and 67 individual transition pieces.

Environmental consultant Land Research Associates (LRA) conducted a detailed soil survey along the cable connection route. It also prepared a soil management plan to guide the programming of cable installation as well as reduce agricultural soil erosion.

Sif Group, which specialises in offshore foundations, received the contract for the fabrication of the monopile foundations required for the project, while Atkins was responsible for monopile foundation design and engineering work.

Dudgeon Offshore Wind contracted construction company R G Carter to build the wind farm’s new O&M base at Berth 9 located next to the River Yare within the Great Yarmouth port.

In October 2014, Carillion Utility Service won the EPCI contract for the onshore cables of Dudgeon Offshore Wind Farm. This included the design, construction, supply and installation of two circuit onshore 132kV onshore export cable circuits for the 402MW wind farm.

Cable and pipeline installation specialist VolkerInfra was in charge of designing, installing and making the final connections to both the offshore and onshore substations.

In February 2014, ABB won an order worth around $55m to supply a submarine AC (alternating current) power cable system for the Dudgeon offshore wind farm.

Visser & Smit Marine Contracting [VSMC] secured the Export Cable Installation contract for inter-array cables and the installation of the submarine export cables, while JDR was responsible for the design and supply of inter-array cables and accessories for the project.

Development consultant Pegasus Group provided Seascape and Visual Impact Assessment services for the wind farm.