The grid connection is capable of transmitting 864MW of clean electricity from offshore wind units.

Power generated from the three offshore wind farms, including 288MW Butendiek, 288MW DanTysk and 288MW Sandbank, will be transmitted to the land-based station Büttel in northern Germany, through the SylWin1 grid connection.

The electricity supplied is enough to meet the needs of more than one million German households.

The offshore platform of the SylWin1 grid connection is located around 70km west of the island of Sylt.

TenneT TSO managing board member Lex Hartman said: "This year we have completed the world’s first three offshore grid connections with efficient direct-current technology – SylWin1, BorWin2 and HelWin1.

"We also intend to put the fourth project HelWin2 into commercial operation as planned in the coming weeks.

"As we will be completing further offshore grid connections by the end of the year, meaning that all in all we will have implemented a capacity of more than 5,000 MW, or more than two-thirds of the offshore expansion goal set by the Federal German government by then."

The government’s offshore expansion goal aims at implementing 6,500MW by 2020.

Siemens has already completed three of five North Sea grid connection projects for TenneT, including 800MW BorWin2, 690MW HelWin1 and 864MW SylWin1, while 690MW HelWin2 and 900MW BorWin3 projects are under construction.

Image: Siemens delivered SylWin1North Sea grid connection to TenneT. Photo: courtesy of Siemens AG.