The installation of all 23 caissons for the 3.5 GW Princess Elisabeth Energy Island has been completed 45km off the Belgian coast in the North Sea, marking the conclusion of the project’s foundation works.
The artificial island is being developed on behalf of Elia Transmission Belgium by the TM EDISON consortium, which comprises Jan De Nul and DEME.
It is considered to be a significant step in expanding Belgium’s offshore wind capacity and aims to facilitate future energy links with the UK.
Princess Elisabeth Island will connect the second Belgian offshore wind zone and is described as a major component of the country’s energy transition efforts.
Elia Transmission Belgium CEO Frédéric Dunon said: “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.”
The completed caisson foundations form the protective outer shell of the island. This phase began in 2024 with the installation of the first caisson and has now concluded, allowing the project to advance to the next stage.
In the coming months, work will continue to reclaim land inside the caisson structure with sand.
Installation of cable connections to the mainland is scheduled for 2027 and 2028, while electrical infrastructure works on the island are set to begin in 2029.
The project is scheduled for completion in 2031, in line with recently confirmed legislation.
The project’s timeline enabled Elia to qualify for a €99m ($115m) subsidy provided by the EU for this phase, highlighting the priority placed on European energy independence and cross-border exchange.
Throughout construction, the consortium implemented a nature-inclusive design.
Each caisson measures approximately 58m in length, 28m in width, and between 23m and 32m in height, weighing around 22,000t.
The caissons were constructed in Vlissingen, and then transported and installed at sea.
Elia’s artificial island will serve as a hub for transmitting renewable energy from offshore wind farms to Belgium’s high-voltage onshore grid and as a junction for planned connections with the British and Danish networks.
The six-hectare island will ultimately be linked to the mainland by undersea high-voltage cables with a combined length of 165km and a capacity of 220 kV each.
The final use and environmental role of the structure after its expected service life is under consideration.
