Swiss power and automation technology group ABB has commissioned the subsea transmission link that connects Thornton Bank offshore wind farm and the Belgian grid.

The transmission link, as part of an expansion of the Thornton Bank wind farm, was constructed in phases. First phase involved installation of six wind turbines with a total capacity of 30MW and were temporarily connected to the mainland by ABB.

The second and third phases of the project involved addition of 48 wind turbines to the wind farm and connecting the complete wind farm, taking its overall capacity to 325MW. The transformer station platform collecting and transmitting the power to the coast of Belgium is located 30km offshore in the North Sea.

Under the terms of the turnkey project, ABB was responsible for the system engineering, design, supply and commissioning of the alternating current (AC) subsea cables, the land-based cable systems as well as the offshore substation and platform that houses it.

The wind turbines are connected via underwater medium-voltage cables to the offshore transformer station where the voltage is boosted to 150kV and connected to the mainland grid.

The electricity is then fed into the grid at the Slijkens high-voltage substation, which is located at Bredene, about 3km inland.

The Thornton Bank project, which was developed for the Belgian company C-Power, was completed on schedule. The wind farm has a generating capacity of more than 1,000GWh of electricity per year, which is equivalent to the annual consumption of about 300,000 Belgian households.

According to ABB, the Thornton Bank project will contribute approximately 7% of Belgium’s targeted renewable energy commitment by 2020. The wind farm will reduce CO2 emissions of approximately 415,000 tons per year compared to a traditional gas-fuelled power plant.

ABB’s head of power systems division Brice Koch said, "Integrating renewable energy sources to the grid is a key focus area as Europe strives to balance the need for electricity with minimizing environmental impact.

"The close collaboration with C-Power combined with ABB’s technologies, domain competence and experience were key success factors in the smooth execution of this project," Koch added.