GE Consortium to Build State-of-the-Art HVDC System for RWE Sofia Offshore Wind Farm

RWE has moved a step closer to the realisation of its 1.4 gigawatt (GW) Sofia Offshore Wind Farm with the selection of the preferred suppliers for the project’s high voltage direct current (HVDC) electrical transmission system.

A specially formed consortium of GE Renewable Energy’s Grid Solutions and Sembcorp Marine is set to supply the state-of-the-art system for Sofia, one of the world’s largest offshore wind farm projects, located on Dogger Bank, the shallow area of the central North Sea, 195 kilometres from the UK coast’s nearest point.

RWE is the UK's second largest generator of electricity. Via its subsidiary, RWE Renewables, the company has significant experience in the British offshore market with nine wind farms in operation off the UK coast and Triton Knoll (857 MW) under construction. Further offshore development projects, like Sofia – 100% owned by RWE – underline the growth ambitions of the company.

Sven Utermöhlen, Chief Operating Officer Wind Offshore Global of RWE Renewables, said:
“We are keen to support the growth of both onshore and offshore wind energy in UK, one of our core markets in Europe. The choice of GE’s Grid Solutions and Sembcorp Marine for the supply of the electrical system is an important statement of our commitment to grow our renewables portfolio in the UK and reflects our ambition to strive for continuous innovation in the development, construction and operation of our offshore wind farms.”

As the consortium leader, GE’s Grid Solutions will be responsible for the engineering, procurement, construction and installation of two HVDC converter stations capable of transmitting 1,400 megawatts (MW) of power at 320 kilovolts (kV). Innovative converter modules and a new high-tech control system have been deployed for Sofia. It will be the most powerful offshore converter station ever fabricated and will be installed at a point 220 kilometres from shore, so will also be the most remote.

The selection of the consortium is positive news for the UK as a significant element of all the primary HVDC equipment will be manufactured and fabricated at GE’s Grid Solutions’ Stafford facilities, which employ more than 1,000 workers.

Richard Sandford, RWE’s Director Offshore Development Europe, said: “It is a particular pleasure to announce the HVDC agreement for Sofia because it is such good news for the UK economy, particularly at this unprecedented time. More than 50% of the components will be manufactured in local facilities, securing jobs and boosting the economy.”

The project will be based on GE Grid‘s latest technology, utilising its second-generation voltage source convertor valve and featuring the first application of its state-of-the-art eLumina™ HVDC Control System. eLumina is the industry’s first HVDC solution to use a digital measurement system fully based on International Electrotechnical Commission (IEC) 61850, an important international standard defining communication protocols for intelligent electronic devices at electrical substations.

“We are delighted to be chosen as the consortium leader for Sofia Offshore Wind Farm,” said Raj Iyer, Grid Integration Leader at GE’s Grid Solutions. "This is recognition of our advanced technology, specifically our world-class eLumina HVDC Control System and second-generation converter modules, as well as our expertise in delivering this type of complex HVDC solution."

The offshore converter platform will be built and installed by Sembcorp Marine. At the heart of the wind farm, it will comprise a 10,000 tonne topside attached to a jacket foundation piled into the seabed. The onshore converter station will convert the electricity generated by the wind farm to 400 kV, before it enters the national grid.

“Sembcorp Marine is excited to team up with GE to support the Sofia Offshore Wind Farm project,” said Samuel Wong, Sembcorp Marine Head of Offshore Platforms. “We thank RWE for this opportunity and for their confidence in our track record of delivering offshore platforms to major field developments in Europe and Asia.”

GE’s Grid Solutions and Sembcorp Marine are starting early design works in July, with the full contract subject to the project’s final investment decision, due in the first quarter of 2021. The HVDC transmission system represents Sofia’s second largest contract and will include the design, manufacture, installation, commissioning and maintenance of the offshore converter platform and the onshore converter station, including all ancillary equipment.

Construction of the wind farm is due to begin onshore at its Teesside converter station site early next year, with offshore construction expected to get underway in 2023.

The HVDC transmission system news follows the announcement that Sofia has signed a preferred supplier agreement with Siemens Gamesa Renewable Energy for 100 of its SG 14-222 DD offshore wind turbines, a 14MW design that is 25 percent more powerful than its next largest model. For more information about Sofia visit: www.sofiawindfarm.com