Princess Elisabeth Island, Belgium
A World first for the future
Belgium is investing in renewable forms of energy to get ready for the 2030 European energy targets. One of them is increasing offshore wind power, accounting for some 100 GW. With a capacity of 3.5 GW, the island will make a significant contribution to that.
The energy island combines two functions. On the one hand, renewable electricity from the Princess Elisabeth area is transformed for transmission to the mainland. On the other hand, the island also serves as a junction with other energy grids, such as the Nautilus link with the UK and the Triton link with Denmark. This allows energy to flow smoothly between the grids to avoid overloading.
We also take into account the island's impact on nature during construction. At the outer edge of the island, we provide ledges to give seagulls nesting places. There will be relief panels underwater for small marine life, and various forms of scour protection and gravel beds around the island provide a safe haven for fish. This is how we create a hotspot for biodiversity.
Alexander De Croo, Prime Minister of Belgium:
The North Sea is set to become the powerhouse of our energy independence, and Princess Elisabeth Island will be a crucial part of this process. Belgium has long been a pioneer in offshore wind, and by continuing to innovate, we are further consolidating our position for the future. This gives our Belgian companies more opportunity to do groundbreaking work, both here and abroad, as well as guaranteeing sustainable, competitively priced energy for our citizens and businesses. Once again, we are putting Belgium on the map.
Princess Elisabeth Island in numbers
Did you know?
- We are not only building the energy island. We are also connecting it to the mainland via undersea high-voltage cables. These have a combined length of 165 km, with a capacity of 220 kV each.
- We use different types of vessels to get this feat completed: dredgers level seabed, rock installation vessels protect the caissons with rocks, cable layers place the cables on the seabed and assistance vessels place protection.
- The island can be fully dismantled after its end-of-life. But it doesn’t have to be. Research will show what the best plan of action will be after 100 years of service. Keep it as a hotspot for biodiversity, give it another function, or remove it? It’s all possible.
Princess Elisabeth Island in detail
On the site location, we first conduct a thorough survey, to make sure all works can proceed safely and uninterrupted, without any unforeseen obstacles on the seabed. Afterwards, our trailing suction hopper dredgers level the sand and prepare the seabed for the next steps.
In the meantime, we construct the caissons that will form the outer ring of the island. The 23 armoured concrete blocks all have a size of 58 m long, 28 m high and 28 m width, with a weight of 20,000 tonnes apiece. The building process of the caissons takes place in Flushing and contains five major production steps. We start of with the bottom plate, on which we construct the walls. Next, we prepare the cable entries, the top plate is formed, and we add the storm walls. The whole process for a caisson takes up about 85 days, but thanks to the slide-through system with five workstations, five caissons can be in production at the same time.
While we’re working on the caissons, our rock installation vessel Simon Stevin places rocks on the seabed to serve as a firm foundation for the caissons. The caissons, which will form the contours of the island, are placed in a timespan of two years. During the stormy winter months, the works are temporarily suspended.
Once finished, we bring the 23 partially submerged caissons with tugboats to their final location at sea. Our dredging vessels fill the inside with sand, which makes the caissons sink further and take up their final position on the rock foundations. Around the caissons, we place scour- and toe protection to avoid damage during heavy storms.
Afterwards, we fill up the core of the island with sand and compact it. On the island, Elia will build the necessary electrical infrastructure.
We also provide the island with a small harbour with mooring berths for safe and smooth personnel transfers. The works are planned to finish in 2026.
