Bold Tern installs Alstom’s pioneering Haliade 150-6MW offshore wind turbine

Fred. Olsen Windcarrier and its specialist jack-up vessel Bold Tern has installed the largest offshore wind turbine ever to be positioned in sea waters.

Installation of Alstom’s 6MW Haliade 150 was successfully completed on November 16th despite serious interruptions from severe weather at the Belwind site 45km off the Ostend coast.

The exceptional dimensions of the new turbine meant Alstom called for the Bold Tern, one of the latest generation of jack-up vessels, which entered service with Fred. Olsen Windcarrier in February 2013.

As well as its large deck area of 3,200m2, the Bold Tern is equipped with a robust and versatile crane capable of handling 800tonne components at sea.

The Bold Tern also has a DP2 dynamic positioning system for increased safety and can cope with challenging weather conditions. It was ideal to manage Alstom’s massive turbine with its 73.5m long blades and rotor diameter of 150m. The overall weight of the turbine and its structure totals 1,500tonnes.

The installation set up consists of the three tower sections, the nacelle with hub and two blades attached in the bunny ear configuration and a single third blade. Fred. Olsen Windcarrier’s scope of work was to deliver the fully mobilised Bold Tern along with engineering services, lift supervision and WTG technicians, supplied by Fred. Olsen related company Global Wind Service, to ensure successful installation for a pioneering project.

Bold Tern was loaded at the Port of Ostend during the week beginning September 30th and left for Belwind on October 7th, ready to start installation the following day.

“The tower sections were smoothly installed before there was a period of severe winds when work was halted,” said Fred. Olsen Windcarrier lead engineer Sten Rundström. “When the required weather window finally happened, the remaining installation of the nacelle and final blade went very well and in the early hours of November 16th the first Alstom Haliade 150 6MW offshore turbine was successfully installed.”

The installation will demonstrate how the machine behaves in the offshore environment for which it was specifically designed and developed. It follows successful tests performed in March 2012 at Le Carnet site in France.

Its scale makes the turbine more efficient, with a yield 15% better than existing offshore turbines, supplying power to the equivalent of about 5,000 households.

Operating without a gearbox (using direct drive), its permanent-magnet enerator means there are fewer mechanical parts inside, making it more reliable and helping reduce operating and maintenance costs.

This installation is seen as a key milestone in the industrialisation process of Alstom’s 6MW turbine. The current construction of two factories in Saint-Nazaire (nacelles and generator) should be complete by summer 2014. Work on two Cherbourg factories (blades and towers) will follow.

“This project with Belwind asserts our technological leadership and our innovative abilities. The installation of our turbine which is simple, robust and efficient thus contributing in boosting the competitiveness of offshore wind energy,” said Alstom Wind senior vice-president Alfonso Faubel.

Project Manager Per Dyberg said ‘the strong relationship between Fred. Olsen Windcarrier and Alstom, based on mutual trust and respect, was fundamental to the entire project.

‘The successful installation was thanks to the skilled and flexible engineering team, the proactive and dedicated project management team and the vast experience of the offshore construction team. And having a highly competent client that was able to take decisions on site ensured that the installation of the prototype went smoothly in spite of many challenges.’

This installation concludes the sixth successful project for Fred. Olsen Windcarrier jack-up vessels Bold Tern and her sister ship, Brave Tern, in their inaugural year of operation.