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BalWin4 & LanWin1

Grid connection point Unterweser: With a transmission capacity of 2 x 2 Gigawatt (GW) BalWin4 & LanWin1 will provide green wind power from the North Sea for up to 5 million households. The first grid connection will already go into operation in 2029.

Lower Saxony, North Sea
new construction
  • grid connection point Unterweser
  • BalWin4
  • LanWin1
Header BalWin4 LanWin1

About the project

2 x 2.000 Megawatt direct current connection


BalWin4 LanWin1 Map

After the commissioning of the two offshore grid connections BalWin4 & LanWin1 are going to supply green wind power from the North Sea. The offshore grid connections will significantly strengthen the energy security in Germany.

Cable length, power

  • 275 km (BalWin4)
  • 275 km (LanWin1)
  • each 2 GW


  • 2029 (BalWin4)
  • 2030 (LanWin1)

Connection concept

Reliably bring wind power from sea to shore

Each project includes an offshore converter station on the North Sea and on onshore converter station in the region of Wesermarsch. These converters are connected by powerful submarine and land cables. These consist of a plus and a minus pole as well as a metallic return conductor.

The offshore converter transforms the alternating current generated by the wind farms into direct current, which is then transported to the mainland via submarine cables. Once reaching land, the cable continues for 110 km until it finally reaches the land converter, which once again transforms the current into alternating current. Alternating current is then fed into the transformer station Unterweser, from where it is distributed into the high-voltage grid.

  • 2GW grid connection system

    Scope of a 2 GW grid connection system from offshore to onshore converter station

  • 2GW Offshore Converter

    a 2GW Offshore Converter

2GW grid connections

Ensuring green energy supply

The BalWin4 & LanWin1 projects are important milestones in ensuring the energy supply of the future – for Wilhelmshaven and its surrounding region, for Germany, and for Europe! The high-performance grid connections underline the green transformation of the energy state of Lower Saxony and make an important contribution of the security of supply in Germany.

BalWin4 technical benefits

2GW Program

More than just two grid connections

BalWin4 &LanWin1 are part of the 2GW program. With its transnational approach and a new standard for offshore grid connection systems, the 2GW program accelerates European offshore grid expansion and secures energy supply for Europe. Together, the total of 14 offshore grid connections in the 2GW program will supply up to 35 million households with green wind energy.

2GW Program


Technical innovation protects valuable natural areas

Due to the innovative design and higher capacities, BalWin4 & LanWin1 are even more environmentally friendly compared to previous grid connection systems. Environmental protection and sustainability are also top priorities in construction: TenneT uses only the most modern and particularly environmentally friendly technologies to protect the sensitive natural environment in the Lower Saxony Wadden Sea National Park. For example, TenneT uses the Horizontal Directional Drilling (HDD) method when crossing Baltrum Island. The process minimizes the necessary interventions and enables trenchless cable laying. Only substances that are permitted in groundwater-bearing layers and are also used, for example, in well construction are utilized.


Tobias Biener

Tobias Biener

Referent Projektkommunikation Offshore