TenneT’s 2GW Offshore Grid Platforms Take Shape in Singapore, Batam

Construction of TenneT’s next-generation offshore grid platforms is progressing at Seatrium’s yards in Singapore and on the Indonesian island of Batam. Working with Seatrium and GE Vernova, the transmission system operator is developing four 2 GW high-voltage direct current platforms to connect future North Sea wind farms to the onshore grid. Platforms for IJmuiden Ver Beta, IJmuiden Ver Gamma and Nederwiek 2 are under construction, while preparations for BalWin 5 are under way.

 

The Four Platforms

 

Each platform will form the heart of a grid connection capable of bringing 2 GW of offshore wind power ashore. IJmuiden Ver Beta, IJmuiden Ver Gamma and Nederwiek 2 will serve wind farms in the Dutch North Sea, while BalWin 5 will connect wind power to the German grid. IJmuiden Ver Beta is the furthest advanced, with steel first cut in September 2024 and commissioning planned for 2029. IJmuiden Ver Gamma followed in May 2025 and Nederwiek 2 in February 2026.

The step up from TenneT’s existing 700 MW connections to 2 GW represents a major advance in offshore grid capacity. A single 2 GW connection can carry the output of a very large wind farm, reducing the number of separate cables and platforms needed. On the Dutch projects, power will be converted to direct current offshore and carried by 525 kV cables to shore. It will then be converted back to alternating current for the national grid.

 

Standardized Design and Shared Learning

 

The program is about more than building larger platforms. TenneT is standardizing the design across the series so that lessons from one platform can be applied directly to the next. Experience gained on IJmuiden Ver Beta is being used on Gamma, Nederwiek 2 and BalWin 5. This approach is intended to cut risk, cost and construction time as the series progresses.

Standardization also extends to the substructures. The jackets supporting the Dutch platforms are being built to the same 2 GW design at Heerema Fabrication Group’s yard in Vlissingen, the Netherlands. Repeating proven designs allows suppliers to plan capacity and improve productivity over several units. For grid operators facing tight offshore wind deadlines, predictable delivery is as valuable as technical performance.

 

Roles of the Partners

 

Seatrium is responsible for constructing and integrating the platforms at its yards in Singapore and Batam. GE Vernova provides the HVDC technology that converts and transmits large volumes of electricity efficiently over long distances. TenneT’s project teams work closely with both companies to ensure the platform structure, electrical systems, and engineering come together as one integrated unit. Seatrium has also contracted heavy-lift specialist Mammoet to carry out load-out operations for platforms in the program.

Astrid Hoetmer, Executive Director Offshore at TenneT, said the project teams take ownership, solve problems and use what they learn on one project to improve the next. She said close cooperation between TenneT, Seatrium and GE Vernova across countries, cultures and organizations is essential. Hoetmer added that this cooperation, combined with the teams’ expertise and commitment, turns the company’s ambitions into reality. The partnership spans engineering teams in Europe and construction teams in Southeast Asia.

 

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From Fabrication to Integration

 

Work is progressing at both locations. In Batam, components are being fabricated, assembled, and integrated into larger modules. In Singapore, work is moving toward installing and testing the HVDC equipment, a critical phase before the platforms can be shipped. Each completed stage brings the platforms closer to transport to the North Sea.

Once finished, the topsides will be loaded out and transported to their offshore locations, where they will be installed on the jackets. The platforms must then be connected to the wind farm array cables and the export cables to shore. Commissioning will involve extensive testing of the converter systems before power flows to the grid. Any delays in this chain can affect when power delivery from the wind farms begins.

 

Significance for European Offshore Wind

 

The 2 GW program is central to Dutch and German plans to expand offshore wind substantially over the coming decade. Grid connections are now widely seen as a key bottleneck for new projects, alongside supply chain capacity. Large, standardized platforms help grid operators connect more capacity with fewer assets. The program also secures long-term manufacturing slots in a market where HVDC equipment is in high demand.

Building the platforms in Asia reflects the limited capacity of European yards for structures of this size and complexity. Seatrium’s yards have become an important part of the global supply chain for offshore converter platforms. As more European grid operators move to 2 GW designs, demand for this kind of fabrication capacity will rise. TenneT’s experience with the series will be closely watched by other operators planning similar programs.

 

Source: TenneT