World’s First Unmanned Offshore Substation Stands at Dogger Bank

Grid Connection

April 20, 2023, by Adnan Durakovic

The world’s first unmanned High Voltage Direct Current (HVDC) offshore substation has been installed at what will be the world’s largest offshore wind farm, the 3.6 GW Dogger Bank, off the UK.

The substation is the first of three platforms, supplied by Aibel, to be installed at Dogger Bank, which is being constructed in three 1.2GW phases known as A, B, and C.

The Dogger Bank A platform measures 65 x 36 metres across and 39 metres high and sits on a four-legged steel jacket foundation structure which is fixed to the seabed, at a water depth of around 28 metres.

Approximately 146 kilometres from the nearest point of land at Flamborough Head, near Bridlington in East Riding of Yorkshire, the platform installation was delivered by principal contractor Sapiem using the vessel Thialf.

The offshore platform is said to have a lean design and is the first unmanned HVDC platform which will be operated from shore and accessed only by a Service Operations Vessel.

The platform will receive 1.2 GW of AC power from Dogger Bank A’s 95 offshore wind turbines and convert it to DC, which will then be sent ashore to an onshore convertor station near Beverley in East Riding of Yorkshire.

Fitted with Hitachi Energy’s latest generation HVDC converter technology, Dogger Bank will be the first offshore wind project in the UK to use this technology to transmit the electricity produced back to shore, ensuring that the electricity is transmitted efficiently over long distances while minimising losses.

”The safe and successful installation of the offshore platform marks a major milestone in the Dogger Bank project. As the UK’s first HVDC platform for an offshore windfarm it is also a major milestone for the UK industry more widely,” Olly Cass, Project Director for Dogger Bank Wind Farm, said.

”The platform will be controlled from shore and by removing the need for personnel to stay on the platform meant it has been possible to eliminate elements such as the living quarters, helideck and sewage systems, resulting in a 70% reduction in weight (per megawatt) of the topside compared to previous platforms installed, and cost savings of hundreds of millions of pounds.”

Dogger Bank Wind Farm, a joint venture between SSE Renewables, Equinor, and Vårgrønn, is set to be the world’s largest offshore wind farm consisting of 277 wind turbines. The wind farm will be capable of generating enough electricity to power more than 6 million UK homes.

”Teams continue to make good progress with the installation of turbine foundations and later in Q2 specialist cable installation and support vessels will start to install the inter-array network of cables that will connect the turbines to the offshore platform to enable transmission of first power in the summer,” Cass said.

Aibel plans to deliver the Dogger Bank B substation in Q2 of 2024, and the Dogger Bank C offshore platform is expected to be delivered in Q2 2025.