GERMANY – TenneT has contracted the McDermott and GEIRI/C-EPRI consortium to construct the converter stations at sea and on land for the offshore grid connection system BorWin6.

Within the consortium, McDermott will focus on the converter stations, drawing on a wide range of offshore experience and their own worldwide fabrication yards. Global Energy Interconnection Research Institute Co. Ltd. (GEIRI) & C-EPRI Electric Power Engineering Co. Ltd. (C-EPRI) will focus on electrical engineering, TenneT said in a press release.

BorWin6 is the last offshore grid connection system to be implemented by TenneT in the German North Sea with 320 kV technology. The technological leap to 525 kV and a transmission capacity of 2 GW will be implemented in future projects, TenneT said in a press release.

The 235 km (146 miles) long HVDC connection includes 45 km (27 miles) of land cable, 190 km (118 miles) of subsea cable and a maximum transmission capacity of 980 MW.

TenneT connects the wind turbines directly to the offshore platform BorWin kappa via 66 kV three-phase cables, thus eliminating the need for transformer stations in every wind farm. 155 kV three-phase cables are not required to connect the offshore platform with that of the wind farm, which enables significant cost savings.

The construction of the land station in Büttel is scheduled for 2024. The construction of the converter station at sea in Qing-dao, China is expected to start in mid-2023, and the construction of the jacket in Batam, Indonesia should start at the end of 2023.

In 2023, horizontal drillings are also planned to underpass the land protection dike near Büsum, Germany and the Kiel Canal; the land cable should be laid in 2024 and 2025, and the subsea cable in 2025 and 2026.

BorWin6 is scheduled to go into operation in 2027.

Source: TenneT