NORDERNEY/BALTRUM (dpa-AFX) - In order to lay additional power cables to wind farms in the German North Sea, the East Frisian islands of Norderney and Baltrum will be drilled under this summer. On Baltrum, transmission system operator Tennet is starting drilling for the BalWin3 and LanWin 1 and 4 grid connection systems. Initial drilling is scheduled to begin in the next few days, according to the company. Construction is also underway on the neighboring island of Norderney. "Horizontal drilling for BalWin1 and BalWin2 will take place this summer," said a spokesperson for Amprion, the transmission system operator responsible for the project, in response to an inquiry.
These power lines are needed because offshore wind energy is set to play a greater role in the energy transition in the future. The cable systems will transport the wind power from converter stations at sea to the mainland. However, before the cables arrive there, they must pass under the East Frisian islands. A large part of the grid connection systems will run through the North Sea via Lower Saxony and thus also through the Wadden Sea National Park.
On Baltrum, drilling will take place in the east of the island. There is a construction site on the north beach and a hydraulic engineering site south of the eastern end in the mudflats. According to Tennet, the island will be crossed by several horizontal boreholes up to 1,800 meters long. The power cables will then be pulled into the boreholes. Drilling on Baltrum for these grid connection systems is scheduled to be completed next year.
What is planned on Norderney
On Norderney, work on the horizontal drilling for the BalWin1 and BalWin2 grid connection systems will be carried out around the clock in shifts due to a tight time window in the summer. According to Amprion, there are three basic steps involved in this type of drilling: In a pilot drilling, the ground is mechanically and hydraulically flushed out using an environmentally friendly drilling fluid. A second drilling is then carried out to widen the borehole to the target diameter. Finally, cable ducts are pulled in, through which the power cables will later run.
According to Amprion, the grid connection systems on Norderney are in a new performance class, which means that three cables per system must be laid instead of two as in previous systems. The island will be crossed in two steps. Between mid-July and the end of September, six boreholes will be drilled – one per cable
from the center of the island to the Norderney mudflats south of the island,
The Amprion spokesperson announced that the drilling from the center of the island to the northern beach is then planned for 2026.
How noise pollution will be avoided
Tourists and islanders can find out about the construction work. Amprion plans to set up an information container at the construction site for this purpose. Noise pollution from the drilling will be minimized as much as possible. To this end, sound barriers around ten meters high will be erected.
The BalWin1 and BalWin2 cable systems are scheduled to go into operation in 2030 and 2031. The lines will then be able to transport up to 2,000 megawatts of wind power, which, according to Amprion, is enough to cover the electricity needs of four million people.
