Boa awarded caisson contract for Belgian offshore energy island

The Princess Elisabeth Island, which will be built in the Belgian sector of the North Sea, will bring electricity from Belgian windfarms to shore, and form the first building block in an integrated European offshore electricity grid that will connect other hubs and countries together, including, potentially, interconnections with the UK and Denmark.

As previously highlighted by OWJ, Princess Elisabeth Island will combine the use of high-voltage direct current and high-voltage alternating current. The island’s high-voltage infrastructure will bundle windfarm export cables from the Princess Elisabeth zone together, also serving as a hub for future interconnectors such as Nautilus, to the UK, and TritonLink, to Denmark.

The island will be built approximately 45 km off the Belgian coast within the Princess Elisabeth wind zone and will be constructed from concrete caissons filled with sand. A small harbour and helicopter platform will also be installed to allow maintenance crews to visit the island. 

Boa will use the semi-submersible barge Boa Barge 33 to launch the caissons, which will weigh up to 22,400 tonnes. The barge will be modified to manage load-outs over its stern.

Boa Barge 33 can submerge to a depth of 21.5 m of water over its deck, has a uniform deck strength of 31.5 tonnes/m² and a free deck are 5,800 m².

The contract awarded to Boa includes project engineering and operational management. Operations will commence Q2 2024.