Lifting system will make offshore access safer and eliminate the need for much secondary steelwork on turbines
Wind energy leader Ørsted is to begin using an innovative ladder-free offshore access system on an offshore windfarm in its portfolio of upcoming projects.
Pict Offshore’s motion-compensated, ladder-free access system is set to enter production within months and will be used on an as yet unnamed near-term project to be built by the wind energy company.
The technology – which removes the need for a turbine boat landing and ladder – will see Ørsted modify the design of the transition pieces on the turbines for the as yet unnamed windfarm to incorporate the new system.
Transfers will be safer without the need for windfarm technicians to step across from the deck of a crew transfer vessel (CTV) to the ladder attached to the turbine. Using the technology will also allow the complete removal of access ladders and boat landing metalwork from the offshore turbines.
Eliminating ladders and boat landings will reduce costs by removing the need for significant quantities of steel and the associated cost of that steelwork. It will also mean technicians no longer need to undertake a sometimes arduous climb of 20 m or more to reach the base of the turbine and will instead clip onto the system and be safely hoisted up to the turbine base directly from the CTV.
Speaking exclusively to OWJ, Pict Offshore managing director Phil Taylor says the company was gearing up to assemble the Get Up Safe (GUS) system at its facility in Inverkeithing, Fife, Scotland.
As previously highlighted by OWJ, in September 2019, Ørsted acquired a 22.5% stake in the Scottish company that was formed to commercialise the technology used in the GUS, which was originally developed by height safety company Limpet Technology.
Limpet Technology began developing the GUS in 2016, helped by a Scottish Government innovation grant. Having originally developed the system with onshore wind applications in mind, the company built a CTV simulator to determine its suitability for offshore wind applications and tested the system to see what modifications might be required if it was to successfully compensate for the motion of a CTV.
In 2017, prototypes of the system were tested at the Offshore Renewable Energy Catapult’s 7-MW Levenmouth demonstration turbine in Scotland. Real-world testing commenced in 2018 on the Walney offshore windfarm near Barrow in the UK. Between April and December 2018, more than 1,600 successful transfers were undertaken.
Originally seen as a ‘lifting and ladder’ system that could augment personnel transfer from the deck of a CTV, feedback from Ørsted saw the GUS evolve into a ladder-free system that can lift a turbine technician directly from the deck of a vessel to a transition piece.
The system operates using lasers mounted on a turbine to measure CTV motions. These measurements enable the hoist to automatically adjust the line to take account of a CTV’s movements so that even in periods of high, varying wave heights there is no danger of collision between the technician and the boat. Mr Taylor says the system is capable of operating in a significant wave height of 2.5 m and has been successfully tested in wind speeds of up to 20 knots.
Having invested in and helped to de-risk development of the GUS, Ørsted will be the first user of the system, but Mr Taylor says that, subject to certain commercial considerations, it is Pict Offshore’s intention to make the novel access system available for use elsewhere in the offshore wind industry.
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