BalWin3 & LanWin4

The significantly increased expansion targets for offshore wind energy across Europe and in Germany are leading to a simultaneous increase of demand for capacities of construction companies in the field of HVDC technology, offshore platforms and cable systems. This is causing shortages among manufacturers and resulting in necessary planning changes for the realisation of offshore grid connections. The BalWin3 offshore grid connection system is also affected by this: the planned commissioning will therefore be postponed to 2031 (instead of 2029). With the successful award of six 2GW offshore grid connection systems in April 2023, TenneT will provide a total transmission capacity of approximately 22.8 GW in Germany by 2031.

After the commissioning of the two offshore grid connections BalWin3 & LanWin4 are going to supply green wind power from the North Sea. The offshore grid connections will significantly strengthen the energy security in Germany.

Each project includes an offshore converter station on the North Sea and on onshore converter station in Wilhelmshaven. 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 45 km until it finally reaches the land converter, which once again transforms the current into alternate current. Alternate current is then fed into the transformer station Wilhelmshaven2, from where it is distributed into the high-voltage grid.

The BalWin3 & LanWin4 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.

BalWin3 &LanWin4 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.

Due to the innovative design and higher capacities, BalWin3 & LanWin4 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.