Wind turbine installation vessel

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]

TIV MPI Resolution, the first WTIV

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] Some WTIV use biodegradable hydraulic fluids to minimize ecosystem impact during leaks.[7] A vessel can cost[8] $335 million, or $220,000 per day.[9] A 3-year leasing may cost €90 million.[10] The fleet of 16 vessels are scheduled to expand to 23 vessels by 2023, of which seven can handle the largest turbines.[9][1]

Projects include a 155 m (509 ft) crane height, and lift capacity of 1,600[11]–3,000 tonnes.[12] In Korea, some vessels are approved for liquefied natural gas.[13] In China, lack of suitable vessels are slowing the construction of offshore wind farms.[14] 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,[15][16] scheduled for the 700 MW Revolution Wind in 2023 and the 924 MW Sunrise Wind in 2024.[17] Such vessels require 500–800 MW of installation per year for five years to be economical.[18]

A supplement to crane-equipped WTIVs can be crane-less feeder vessels with motion compensation.[19][20] Some WTIVs have a crane but no legs.[21][22]