TenneT continued to expand electricity infrastructure in the Netherlands and Germany during 2025, with a focus on strengthening grid capacity and supporting the integration of offshore wind energy. Grid availability remained high despite increased renewable energy generation, with onshore grid availability reaching 99.99977%. TenneT also introduced a new funding structure in 2025 under which TenneT Netherlands and TenneT Germany operate as independent transmission system operators within the group.
The transmission system operator reported underlying revenue of € 9,101 million in 2025, compared with € 8,430 million in 2024, reflecting continued investment in grid infrastructure and a growing regulatory asset base. Underlying earnings before interest and tax increased to € 2,746 million from € 1,745 million in the previous year.
In the Netherlands, the offshore grid connection Hollandse Kust (west Beta) reached grid readiness in 2025. The project is the seventh 700 MW offshore grid connection completed by TenneT in the Dutch North Sea. Onshore, the company completed grid reinforcements including a 150 kV underground link between Goes and Westdorpe and a 380 kV connection between Borssele and Rilland.
TenneT Netherlands added around 300 projects to its grid expansion portfolio, bringing the total number of projects to approximately 1,000. Between 2025 and 2029 the company plans to invest € 43 billion in the Dutch onshore and offshore grid.
In Germany, TenneT completed the offshore converter platforms BorWin Epsilon and DolWin Epsilon, which form part of the BorWin5 and DolWin5 grid connection systems and increased offshore transmission capacity to almost 10 GW. Progress was also made on onshore grid expansion, including Germany’s SuedLink direct current transmission project, where final construction approvals were obtained in all six federal states in 2025.
TenneT Germany plans to invest € 65 billion in grid infrastructure between 2025 and 2029 to support offshore wind connections, large-scale direct current transmission projects and expansion of the alternating current grid.
Across both countries, TenneT plans to more than double its offshore grid capacity in the North Sea by 2032 as part of broader efforts to integrate large volumes of offshore wind power into the electricity system.
