TM Edison, a consortium of Belgian marine construction companies DEME and Jan De Nul, has installed the first two of a total 23 caissons in the Belgian North Sea, marking the start of construction for the Princess Elisabeth Island, the ‘world’s first’ artificial energy island.Caissons are concrete building blocks that form the outline of the future island. In a later phase, the interior will be filled with sand to build high-voltage infrastructure that will connect new offshore wind farms.TM Edison is carrying out the work on behalf of grid operator Elia Transmission Belgium (Elia).