Using a specialised service operation vessel to transfer personnel and equipment to floating wind turbines will be more cost-effective than crew transfer vessels, it is claimed.
The claim was made by Siem Offshore Contractors, whose accommodation and personnel transfer vessel Siem Moxie has begun work on the world’s first floating windfarm, Statoil’s Hywind Scotland. Siem Moxie went on charter to Statoil working on the floating windfarm on 24 August 2017.
Siem Offshore Contractors managing director Regis Rougier highlighted that this is the first time a motion-compensated gangway on a service operation vessel has been used to connect to a floating wind turbine.
Mr Rougier said that using a vessel such as Siem Moxie to provide a connection to the floating structure would have advantages compared to using a much smaller, less stable crew transfer vessel of the type used to date to access bottom-fixed offshore wind turbines.
Using a larger vessel such as Siem Moxie will enhance the ‘weather window’ during which transfers can take place, he said.
“We firmly believe that the use of more capable and weather-resilient walk-to-work vessels such as Siem Moxie will help to reduce the levelised cost of energy from offshore wind,” Mr Rougier said.
Crew transfer vessels have long been used to provide access to bottom-fixed turbines in shallow water, but as windfarms are built further offshore larger, more stable platforms are needed. Future floating offshore windfarms are likely to be built further from land than bottom-fixed windfarms, where conditions for vessels and access equipment are more challenging.
Hywind Scotland is the world’s first floating windfarm and will consist of five 6 megawatt Siemens Gamesa wind turbines installed at Buchan Deep off the coast of Scotland, mounted on spar-buoy floating foundations. The project is expected to be fully commissioned by October 2017.