Heerema Marine Contractors has installed what has been described as the world’s first unmanned High Voltage Direct Current (HVDC) offshore substation at the Dogger Bank Wind Farm project site in the UK North Sea.
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, and which will, once operational, be the world's largest offshore wind farm.
The Dogger Bank A platform measures 65 x 36 meters across and 39 meters high and sits on a four-legged steel jacket foundation structure which is fixed to the seabed, at a water depth of around 28m. Heerema Marine Contractors installed the Dogger Bank A substation using its Thialf heavy lift vessel, as a subcontractor for the Italian offshore services firm Saipem.
The platform is located some 146km from the nearest point of land at Flamborough Head, near Bridlington in East Riding of Yorkshire.
"The innovative offshore platform has 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 1.2GW 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 converter station near Beverley in East Riding of Yorkshire," SSE Renewables, a partner in the Dogger Bank project, explained.
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 minimizing losses, the company said.
SSE Renewables is leading the development and construction of Dogger Bank Wind Farm while Equinor will operate the wind farm on completion for its expected operational life of around 35 years.
Olly Cass, Project Director for Dogger Bank Wind Farm, said: "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 wind farm it is also a major milestone for the UK industry more widely.
“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.
“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.”
Dogger Bank Wind Farm, a joint venture between SSE Renewables, Equinor, and Vårgrønn, will comprise 277 wind turbines. The wind farm will be capable of of generating 3.6GW of renewable energy which is enough electricity to power more than 6 million homes.