Princess Elisabeth Energy Island: Foundation Works Completed in the Belgian North Sea

The final foundation element of the Princess Elisabeth Energy Island has been successfully installed 45 kilometres off the coast in the North Sea, completing the foundation works for the world-first offshore energy project.

The installation of the 23rd and final caisson was carried out by Jan De Nul, as part of the TM EDISON consortium, together with DEME and on behalf of grid operator Elia Transmission Belgium. The project is a key link in expanding offshore wind capacity and enabling a future electricity connection with the United Kingdom.

Strategic project for energy, the economy and the climate

Belgium needs more low-carbon electricity to drive its energy transition, strengthen its energy independence and keep its economy competitive, and offshore wind is an essential building block. The country's first offshore wind zone already delivers around 2.2 GW of capacity from nearly 400 turbines; the second zone that the island will connect is planned to add approximately 3.5 GW, which would take Belgium's total offshore wind fleet to well over double its current size. To bring this energy efficiently from sea to shore, Elia Transmission Belgium is constructing the Princess Elisabeth Island in the Belgian North Sea. The energy island will connect the second Belgian offshore wind zone and create opportunities for a future energy link with the United Kingdom — the two countries have been directly linked since 2019 by the 1 GW Nemo Link interconnector, and the island is designed to host additional cross-border connections such as the planned Nautilus link to the UK and TritonLink to Denmark.

Frédéric Dunon, CEO of Elia Transmission Belgium: "Completing the foundation works marks a major step in developing Belgium's offshore energy infrastructure, which plays a crucial role in the energy transition and in strengthening our energy independence."

Crucial construction phase successfully completed

The 23 foundation elements together form the protective outer shell of the future energy island. What began in 2024 with a technically challenging construction phase and the installation of the first caisson has now resulted in the completion of the island's full foundation structure.

The project is now entering a new phase. Over the coming months, the island will continue to be reclaimed with sand within the caisson structure. In 2027 and 2028, the cable connections to the mainland will be installed, and in 2029 the installation of the island's electrical infrastructure will begin. Final completion is planned for 2031 — a timeline recently confirmed by law — by which point the energy island will be ready to bring its first electricity ashore.

Every effort was made to complete the foundation works within the planned timeframe, enabling Elia to qualify for the €99 million European subsidy allocated to this phase. This European support for a world-first project highlights the importance of European energy independence and cross-border energy exchange. The island also carries the EU's Project of Common Interest designation, and the project fits the wider North Sea build-out agreed in the 2023 Ostend Declaration, under which nine North Sea countries and the European Commission targeted 120 GW of offshore wind in the region by 2030 and 300 GW by 2050.

Nature-inclusive design

The island's foundation elements were developed with careful attention to the surrounding environment. In collaboration with marine experts, a nature-inclusive design was created with the aim of supporting and enhancing biodiversity on and around the island. Native oyster reefs have largely disappeared from the North Sea, which gives these reef measures wider ecological significance.

Bart Callens, Project Director for the Princess Elisabeth Island at Jan De Nul: "A key part of the nature-inclusive design is the creation of new oyster reefs. Through the Reefcovery project, we worked with our partners to grow young oysters on rocks, which we installed around the island at the end of July. A win-win: the rocks protect the island against erosion and form the basis for a new oyster reef. This installation builds on our expertise in restoring oyster reefs in the North Sea and reinforces our ambition to embed nature-positive design in our core activities."

Belgian offshore expertise

The successful installation of all 23 caissons showcases the expertise available in Belgium for complex offshore infrastructure projects. Each caisson weighs approximately 22,000 tonnes and measures 58 metres long, 28 metres wide and between 23 and 32 metres high.

The caissons were built in Vlissingen in the Netherlands, where around 300 people worked on their construction every day and building a single caisson took approximately three months. Each element was then transported to its final location at sea and installed — a highly weather-dependent operation.

Source: Jan De Nul (X post), republished by Hellenic Shipping News, Port News, 22 August 2026.