New class of installation vessels to handle ‘super-sized’ wind turbines

With sky-scraping heights of more than 270 m and blades 120 m in length, a new generation of powerful wind turbines will be the backbone of future offshore windfarm development. Offering improved efficiencies and lowering costs, these 12-MW behemoths are challenging the operational limits of the current fleet of offshore installation vessels.

“Offshore installation vessels currently available on the market are facing increasing difficulties installing these types of turbines, due to their size and installation heights and the ever-increasing foundation dimensions and water depths,” said Carl Heiremans, business development manager at Jan De Nul Group, Offshore Division. “At this moment several of these next-generation offshore wind turbines are being tested and the first sales have been made.”

Recognising the need for a more efficient offshore installation vessel to handle these ‘super-sized’ wind turbines, Jan De Nul ordered two new vessels designed with superior lifting and loading capabilities and exceptional lifting heights in 2019.

The first of these, Voltaire, has been contracted to install a total of 2,400 MW of GE`s 12-MW Haliade-X wind turbines on the Doggerbank Wind farm in the UK, with installation scheduled in 2023 and 2024.

Voltaire: key features

Huisman main crane: lifting capacity 3,000+ tonnes

7,000 m² cargo deck

Operating water depth: approximately 80 m

Payload: about 14,000 tonnes

Accommodation: 100

Voltaire is specifically designed to transport, lift and install offshore wind turbines, transition pieces and foundations. The vessel will have better operational limits compared to the existing jack-up installation vessels, said Mr Heiremans.

Voltaire’s key features are a Huisman main crane with a lifting capacity of over 3,000 tonnes, a cargo deck with 7,000 m² of area, an operating water depth of approximately 80 m, a payload of about 14,000 tonnes and accommodation for 100. Equipped with a dynamic positioning class 2 system, the vessel has four legs to lift itself above the sea level for stable working conditions.

Compared to Jan De Nul’s two other jack-up vessels, Vole au vent and the Taillevent, Voltaire has almost double the deck space. “Not only is this vessel capable of loading the next generation of wind turbines and foundations, the larger deck space will also enable Jan De Nul to optimise installations at sea and to lower the fuel consumption and emissions,” said Mr Heiremans.

Under construction at China’s COSCO Shipping Heavy Industry, Voltaire will also be deployable for offshore renewable projects and the oil and gas industry, and for decommissioning of offshore structures.

Thanks to its advanced technology and size, said Mr Heiremans, Voltaire “will be able to install the turbines and foundations cheaper per MW of capacity.”

When Voltaire was ordered, Jan De Nul Group offshore director Philippe Hutse, said the vessel was a logical step forward in the development of the company’s offshore wind capacities. He said: “We recognise the global trend towards larger wind turbines for increased green energy demands. Voltaire will have all the required specifications to meet the upcoming challenges.”

One of those challenges will be tightening emissions regulations, as the sector moves towards decarbonising its supply chain. “Voltaire will be environmentally compliant by taking the same highly advanced emission control technology on board as all other ultra-low emission vessels (ULEVs) in the Jan De Nul fleet,” said Mr Heiremans.

The latest generation of Jan De Nul vessels are equipped with a filtering technique for exhaust gases which complies with the stricter European land and inland waterways emission regulations, Euro Stage V.