Sembcorp Marine and GE Renewable Energy’s Grid Solutions have won a deal worth around £600 million ($826 million) to supply the high-voltage direct-current (HVDC) electrical transmission system for RWE Renewables’ Sofia offshore wind farm in the UK.

Located on the Dogger Bank, 195 kilometres offshore, Sofia spans an area of 593 square kilometres. The 1.4 gigawatt capacity project will be one of the largest wind farms in the world when completed.


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Sembmarine and GE last July began early design works for the project after being selected as the preferred supplier of the HVDC electrical transmission system that represents Sofia’s second-largest contract.

The workscope comprises the design, manufacture, installation, commissioning and maintenance of the offshore converter platform (OCP) and the onshore converter station (OCS), including all ancillary equipment.

Singapore-based contractor Sembmarine’s scope of work includes the design, construction, installation and commissioning of the OCP.

1.4 gigawatt scheme: location of the Sofia offshore wind project Photo: Image INNOGY

The OCP, at the heart of the wind farm, comprises a 17,000-tonne topsides and jacket foundation structure piled into the seabed. Located 220 kilometres from the nearest landfall, it will be the most powerful and most remote OCP ever built.

“The 1.4-GW Sofia project is our first to use the HVDC technology, which was selected to maximise the wind farm’s export capacity from a location so far from shore,” said RWE Renewables chief operating officer, Sven Utermohlen.

“We are delighted to be working with such a strong pairing on the delivery of this flagship project located on the remote Dogger Bank, in the middle of the North Sea.”

Sembmarine will this year start construction of the OCP, with delivery and installation at the Sofia wind farm scheduled for 2023.

“The award of Sofia and operational success of DolWin3 offshore wind HVDC last year are evidence that GE’s Voltage Source Converter technology is now well established, and that GE has the ability to commercially deliver on this latest and most advanced HVDC technology," said Raj Iyer, grid integration leader at GE’s Grid Solutions.

Sembmarine said this contract win strengthens its position in the renewable energy segment, “validating its strategy to transform itself into an innovative engineering solutions provider in the offshore, marine and energy industries with a focus on sustainability”.

“In keeping with the global shift towards a cleaner and greener energy mix, Sembcorp Marine has proactively diversified into cleaner, greener and renewable energy solutions since 2015,” said company chief executive Wong Wen Sun.

“We have made strategic investments to augment our world-class assets, engineering talent and technological bench strength to position Sembcorp Marine in the centre of the fundamental shift to a low-carbon economy.”