Manufacturers are designing a new generation of more powerful and efficient marine heavy-lift cranes to handle mammoth offshore wind turbines
Heavier and larger components such as rotor blades, turbines and foundations for offshore windfarms are challenging the capabilities of existing offshore vessels, driving the need for a new generation of ships with more powerful, efficient and reliable lifting solutions.
Components for one such lifting solution arrived at China Merchants Heavy Industry (CMHI) in Jiangsu, China, in April for installation on OHT’s new offshore windfarm foundation installation vessel Alfa Lift. Shipped from Rostock, Germany onboard BigLift Barentsz, the slewing platform and A-frame are key elements of a new 3,000-tonne-capacity offshore crane being supplied by Liebherr.
Once the installation of the two components is complete, the boom will be shipped from Rostock to the shipyard for Liebherr’s heavy-lift crane HLC 150000.
With a maximum lifting capacity of 3,000 tonnes at 30 m and 1,000 tonnes at 76-m outreach, the HLC 150000 has a slew bearing diameter of 14 m – minimising its footprint on the deck, leaving more room for project cargo. A special slip ring configuration allows the HLC to have a 360-degree unlimited slewing range.
Additionally, a foldable A-frame will reduce the height of the crane when needed, permitting Alfa Lift to sail routes with limited air draft restrictions, such as those crossed by bridges. This, says Liebherr Rostock sales director of ship and offshore cranes Gregor Levold, “provides more flexibility, which in turn leads to both operational and cost-efficiency, increasing the number of charter days and vessel availability.”
To support the main crane during monopile installation, Norway’s Red Rock Marine AS will supply a 30-tonne capacity telescopic boom crane.
But Alfa Lift’s heavy-lift crane is just one weapon in the ship’s impressive arsenal. Another is a specialised monopile installation system being jointly developed by partners MacGregor and Kongsberg Maritime. MacGregor’s work scope covers a motion-compensated pile gripper frame that will integrate with Kongsberg’s Pile Gripper Guidance System (PGGS). Combined with full dynamic positioning and several other KM systems, this newly developed monopile installation solution will eliminate temporary mooring, increasing efficiency and reducing the cost of installing foundations.
“We’re significantly raising the bar for safety, sustainability, precision and efficiency by dispensing with so many of the challenges traditionally posed by complex offshore operations of this nature,” says MacGregor director sales and marketing Kristina Arutjunova. Using this technology, adds Kongsberg Maritime sales director offshore Birger Evensen, will “make harnessing wind power safer and more efficient by streamlining installation processes.”
“We’re significantly raising the bar for safety, sustainability, precision and efficiency”
The ship’s 10,000+ m² ‘smart’ deck will have the capacity to carry 14 XL monopiles per voyage, with the ability to submerge to a depth of 14.66 m and still perform heavy-lift crane operations.
Calling it ‘truly exceptional’, ship designer Ulstein Designs & Solutions says Alfa Lift is capable of transporting and installing 10, 1,500-tonne, ultra-large jacket foundations or 11, 2,000-tonne XXL monopiles, plus transition pieces for the largest anticipated wind turbine generators.
When delivered, Alfa Lift will be out to work transporting and installing monopiles and transition pieces for the Dogger Bank A and B offshore wind projects, offshore UK, from Q3 2022 to early 2024.
It’s clear why Alfa Lift, OHT CEO Torgeir Ramstad called the vessel “a true game changer” that will allow the company to “take the wind industry to the next level” at its steel cutting ceremony two years ago.
Getting ready for larger wind turbines
An even larger-capacity main crane is being supplied by Huisman for the DP2 heavy-lift crane vessel Les Alizés, under construction at CMHI for Jan De Nul. A keel laying ceremony was held at the shipyard in March for the vessel, which is specifically designed for loading, transporting, lifting and installing offshore wind turbine foundations. Key features include a Huisman 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 heavier foundations, several in one trip, to the offshore installation site, with direct benefits in planning, fuel consumption and emissions reductions.
Huisman has secured several notable offshore crane orders for the windfarm market, most recently for a 2,600-tonne, leg-encircling crane for a jack-up wind turbine installation vessel (WTIV) ordered by Eneti in May. The US$330M vessel will be built by South Korea’s Daewoo Shipbuilding & Marine Engineering (DSME), based on an NG-16000X design by GustoMSC, part of National Oilwell Varco.
When delivered in early Q3 2024, the vessel will be capable of installing mammoth, new generation 20-MW turbines in water depths of up to 65 m and can be adapted to operate on fuels such as LNG or ammonia.
Emanuele Lauro-led Eneti, formerly Scorpio Bulkers before its transformation, is in discussions to build a Jones Act-compliant WTIV at a US shipyard.
Commenting on Eneti’s newbuild WTIV, Mr Lauro says: “This vessel will have the advanced lifting capabilities and energy efficiency that offshore wind developers require, not just today but well into the next decade.”
Those next generation wind turbines will most likely exceed the size of one of the world’s largest, Siemens Gamesa SG-14-222 DD 14-MW wind turbine, which will have a rotor diameter of 222 m and blade length of 108 m when it becomes available in 2024.
Taiwan’s first ‘homegrown’ WTIV, Green Jade, is under construction at CSBC’s shipyard in Kaohsiung, Taiwan for the Taiwanese wind market.
Owned by CDWE, a joint venture between CSBC and DEME Offshore, DP3-capable Green Jade will have the capability to transport next-generation, multi-megawatt turbines, jackets and components in a single shipment.
Huisman is building the heavy-lift main crane for the vessel at its production facility in China for delivery in 2022.
With a lifting capacity of 4,000 tonnes 125-m above deck and outfitted with auxiliary systems for handling tall structures, the crane is prepared for a super fly jib with significant lifting capacity and a whip hoist, which allows smaller components to be lifted to a height of 185 m above deck.
In addition to the main crane, Huisman will deliver a 65-tonne knuckleboom crane for general lifting purposes.
A crane with this kind of lifting height has an influence on a vessel’s stability because of the weight of the crane and its high centre of gravity. This impact is minimised in the mast crane, in which the winches are installed at deck level, instead of at the level of the slewing platform.