By 2022, three purpose-built offshore installation vessels will join the global fleet to support the development of offshore windfarms with larger, more powerful 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
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.
|Offshore installation vessels at a glance|
|Vessel||Length (m)||Beam (m)||Main crane capacity (t)||Builder||Owner|
|GustoMSC SC-14000XL||142||50||2500||Japan Marine United||Shimizu|
|Les Alizés||237||52||5000||CMIH||Jan De Nul|
|Voltaire||169||60||3000||Cosco Shipping Heavy Industry||Jan De Nul|
Jan De Nul designed Voltaire to operate on gasoil, but it is fitted with a highly advanced exhaust gas filtering system by means of a selective catalytic reduction (SCR) system and a diesel particulate filter (DPF).
Jan De Nul’s second new generation offshore installation vessel, Les Alizés, is being built by China Merchants Industry Holdings Co Ltd (CMIH) shipyard, located in Haimen, Nantong City, China.
Les Alizés is specifically designed for loading, transporting, lifting and installing offshore wind turbine foundations. Key features include a main crane of 5,000 tonnes, a deck loading capacity of 61,000 tonnes and a deck space of 9,300 m². With these characteristics, Les Alizés can transport the heavier future foundations, several in one trip, to the offshore installation site, with direct benefits in planning, fuel consumption and emissions reduction.
Unlike Voltaire, Les Alizés is a dynamic positioning class 2-capable crane vessel for floating installation, making it independent of water depth and seabed condition.
“The end goal of the offshore wind industry is to have a competitive electricity cost,” said Mr Heiremans. “We expect the next generation of turbines to grow rapidly, from 12 MW to 14, 16 or even 18 MW. At the same time, winning projects are also getting larger in size. The Doggerbank project is a good example, where 3,600 MW are planned to be built by one client in a three-year period. In such a project, Voltaire is a necessary tool and helps to bring the cost of electricity down.”
Both vessels, Voltaire and Les Alizés, are due to be delivered in 2022.
New offshore installation vessel for Japan
The third offshore installation vessel is under construction for Japanese construction, engineering and real estate company Shimizu Corporation.
In August, Shimizu awarded a contract to US-based National Oilwell Varco, Inc (NOV) to supply equipment and design one of the world’s largest offshore installation vessels. NOV marine engineering subsidiary GustoMSC teamed with Shimizu to develop the customised jack-up vessel, which will have a telescopic leg crane with a capacity of 2,500 tonnes designed specifically for the offshore wind market, providing a unique combination of high elevation hoisting capability for turbine installation and heavy load capability for foundation installation. The jack-up vessel will have a length of 142 m, beam of 50 m, and will accommodate 130. The vessel’s crane will be able to lift foundations up to 2,500 tonnes at a height of 121 m and install wind turbine components at a height of 161 m, with a maximum load of 1,250 tonnes.
Based on a GustoMSC SC-14000XL design, the jack-up vessel is under construction at Japan Marine United (JUM) shipyard, with an expected delivery in H2 2022.
Planning is underway in Japan for a total of 9 GW of offshore windfarm generation capacity using a new generation of larger, more economically efficient, ultra-large-scale wind turbines of 9 to 12 MW in size.
Shimizu will co-operate with Fukada Salvage Construction on the operational management of the vessel.