The wind farm, located 12km off the Kent coast, is made up of 100 Vestas 3MW, V90 wind turbines and will have a total capacity of 300 MW when fully operational. It will be located in water depths of 20mt-25mt and cover an area of 35sqkm.
Literally counting the time from start to finish, the number of days to complete the project was 198. However, when deducting days for bad weather and the time for loading and transit, the actual installation process was accomplished in less than 100 days, an industry record.
Continuously looking to improve productivity, Vestas was able to accomplish this record installation by creating new ways of handling the wind turbine blades while loading and shipping. “The installation vessel ‘MPI Resolution’ proved to be an efficient platform, carrying nine complete turbines on each trip with full height towers. This alone saves a huge amount of time spent on commuting to and from port. Sometimes the vessel was moving from location to location every 18 hours, making it possible to install nine wind turbines in six to seven days,” Fyhn Friis said.
David Hodkinson, director and head of development at Vattenfall Wind Power In UK, said: "The experience Vattenfall has gained on Thanet is contributing to our drive to make our future offshore wind projects safer and more cost effective to install and operate, both of which are needed to establish the sector as a major source of low carbon electricity and jobs."
Vattenfall claims that the connection of Thanet’s 300MW of capacity will boost UK offshore wind capacity by more than 30% and will produce on average enough electricity to supply more than 200,000 homes with clean electricity.
To carry individual blades aboard the ship, Vestas engineers devised a stacking system that carries 27 blades, creating a safer and faster process of loading the vessel and reducing the number of trips needed to transport the cargo to the site.
With Vestas’ productivity increases and the innovative way of handling wind turbines, a new standard has been set for the wind energy industry: With less time spent waiting for the weather and more time spent producing a quality product for the customer.
Six months and 100 wind turbines later, Fyhn Friis and his colleagues can look back at a job well done: “The installation of the Thanet Offshore Wind Farm is a remarkable achievement, and it would not have been possible without the huge team effort from everyone involved,” he concluded.
No more “bunny ears”
On previous projects, each nacelle has left the quayside with two blades attached. This “bunny ears” arrangement required a lot of transport space and left the third blade to hang vertically as it was lifted into position, leaving it vulnerable to gusts of wind.
To allow the installation crews to work faster and safer in higher winds, a special new blade gripper was devised to keep the blades balanced in the horizontal position. At Thanet, the bare nacelle was installed first and then added the blades one at a time.