DEME and Jan De Nul Complete Final Caisson for Princess Elisabeth Energy Island
All 23 caissons, each around 22,000 tonnes, now form the ring of the world's first energy island.
The TM Edison consortium, combining DEME and Jan De Nul, has installed the 23rd and final caisson for the Princess Elisabeth Island, completing the foundation works for what is being built as the world's first artificial energy island.
DEME is executing the project for Belgian grid operator Elia as part of the TM Edison consortium. The 23 concrete caissons, each weighing around 22,000 tonnes, form the protective outer ring of the island. They were built in Vlissingen and transported offshore for installation, a phase the consortium describes as one of the most complex of the entire project.
The island is designed to connect Belgium's second offshore wind zone to the mainland grid and to enable potential interconnections with the UK, functioning as a hub that gathers power from surrounding wind farms before sending it ashore rather than requiring each farm to cable directly to the coast. The project also incorporates nature-inclusive elements: specially designed rock structures seeded with young oysters have been placed around the island to support new reef development and marine biodiversity, alongside the primary engineering work.
With caisson installation finished, the project now enters its next phase. The island will be gradually filled with sand and prepared to receive the electrical infrastructure that will eventually route offshore wind power to homes and businesses onshore. That infrastructure build-out — rather than the caisson ring itself — is now the pacing item for when the island becomes operational.
The scale of the individual components gives some sense of why this counted as a milestone rather than routine progress: 23 caissons at 22,000 tonnes each is roughly half a million tonnes of concrete structure, built onshore and floated into position one piece at a time. For a first-of-its-kind structure, getting the ring closed without incident is the kind of achievement that matters more for what it de-risks going forward than for what it delivers today.
