Growth in size of offshore wind turbines drives need for larger lifting capacities
Offshore wind turbines continue to grow in size and capacity, with next-generation units expected to reach 25 MW. Mass-produced lifting equipment and existing logistics are not capable of handling the components for these turbines, according to a heavy-logistics executive.
“Contractors and developers will need much more lifting and marshalling capacity, as well as cargo vessels and other support equipment, to meet projected windfarm demand,” says Heavy Lift Projects (HLP) managing director Alex Fyfe. “They will also need to consider new approaches to the supply chain and how to plan for handling of higher volumes of larger components.”
Until now, the windfarm industry has managed by transferring legacy knowledge, technology and processes from construction and oil and gas into this new sector, explains Mr Fyfe. “Going forward, windfarm construction will demand specialised logistics and handling for component shipping, assembly and load out,” he says.
Using data produced by Maritime Strategies International, forecasting the total number of offshore wind projects to be installed per year, for both fixed and floating foundation windfarms, UK-based HLP believes project developers will struggle to meet demand, based on current logistics practices and equipment provision.
In 2030 alone, when 54.9 GW of windfarm capacity is expected to be installed, HLP estimates that the market will require 28 ring cranes with capacity great enough to handle these larger units. In 2050, when 87.1 GW of windfarm capacity is expected to be installed, HLP estimates that the market will require 43 ring cranes.
“Contractors and developers will need much more lifting and marshalling capacity”
Jacket and monopile windfarm projects, with either floating or fixed foundations, usually require two ring cranes, one at each fabrication and at the marshalling/loading-unloading installation location, or one at either location, according to Mr Fyfe. “All floating foundations require a ring crane during the turbine installation stage at quayside,” he says.
Only nine such ring cranes are in operation, all originally built for the nuclear power and oil and gas industries. Three of these are currently employed on offshore wind projects.
“Today, full towers are assembled on shore, but the size of the next-generation turbines puts this work out of reach of the largest crawler cranes,” says Mr Fyfe. “Discussions about how to manage the growing capacity of crane components suggest they may need to be loaded in sections, with final assembly on the deck of the wind turbine installation vessel.”
This could prove to be a costly solution. “With transfer vessels commanding US$350,000 per day at current rates, developers would take a painful hit. It would make better economic sense to fully assemble the towers on the quay. To do so will require a re-think of methodology for tower pre-assembly,” he concludes.
Mammoet, which provides jacket handling, monopile marshalling and turbine pre-assembly, reported its new 6,000-t ring crane should be ready by 2024. Called the SK6000, it will be the highest capacity land-based crane, capable of operating on electric power. “This 6,000-t ring crane will set a new standard in worldwide heavy lifting capacity, [allowing] customers to construct heavier and larger components,” said the company.
New Ram Luffing crane
Dutch marine lifting equipment specialist, KenzFigee, has signed a contract with Aker Solutions to design, fabricate and deliver an offshore pedestal crane for installation on ScottishPower Renewables HVDC converter station for the East Anglia Three offshore windfarm in the UK.
The Ram Luffing 2400-type electric hydraulic box boom offshore crane will be designed and verified in accordance with EN13852-1 and certified against DNVGL-ST-0378 lifting requirements. KenzFigee will deliver the Ram Luffing offshore crane in Q2 2024.
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