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Wind turbine installation vessel
From Wikipedia, the free encyclopedia
A wind turbine installation vessel (WTIV) is a vessel specifically designed for the installation of offshore wind turbines. There were 16 such vessels in 2020.[1]
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Most are self-elevating jackup rigs. To enable quick relocation in the wind farm it is self-propelled. It also has a slender ship shaped hull[2] to achieve a quick turnaround time with the vessel carrying several foundations or wind turbines each time.[3] Azimuth thrusters are used to position the vessel during jack-up operations.[3] Some vessels use the thrusters in dynamic positioning (without jacking up) to keep the vibrating pile driver steady when installing foundations.[4] Some may carry five modern wind turbines and lift 700 tonnes 125 metres (410 ft) above deck.[5][6]
A vessel can cost[7] $335 million, or $220,000 per day.[8] A 3-year leasing may cost €90 million.[9]
The fleet of 16 vessels are scheduled to expand to 23 vessels by 2023, of which seven can handle the largest turbines.[8][1] The fast growth of turbine size challenges even the largest vessels.[10] In China, lack of suitable vessels are slowing the construction of offshore wind farms.[11]
A supplement to crane-equipped WTIVs can be crane-less feeder vessels with motion compensation.[12][13] Some WTIVs have a crane but no legs.[14][15]
Projects include a 155 m (509 ft) crane height, and lift capacity of 1,600[16]–3,000 tonnes.[17]
Some WTIV use biodegradable hydraulic fluids to minimize ecosystem impact during leaks.[18] In Korea, some vessels are approved for liquefied natural gas.[19]
Construction of the four-legged US Jones Act-compliant Charybdis started at Keppel in Texas in late 2020, at a cost of a half billion dollars,[20][21] scheduled for the 700 MW Revolution Wind in 2023 and the 924 MW Sunrise Wind in 2024.[22] Such vessels require 500–800 MW of installation per year for five years to be economical.[23] The Jones Act makes it much more difficult to install offshore wind, introducing complications of transferring parts between ships and raising costs.[24][25]