Sandbank Partners Streamlining Turbine Installation Process

Vattenfall and Stadtwerke München (SWM), together with project partner Siemens, have developed an optimised concept for constructing and commissioning the 72 wind turbines for the 288MW Sandbank offshore wind farm which is expected to cut the time between erecting the first wind turbine and commissioning the last one to around 89 days, a 23% reduction compared to the original plans.

This time saving will be possible thanks to the use of a modified Service Operations Vessel (SOV), Eidesvik Offshore’s Acergy Viking, which will both house the construction team and transfer them to and from the wind turbine site once the turbine installation works start in August 2016.

This combined hotel/transfer vessel features a special gangway system which enables the commissioning team to climb onto the wind turbines directly. The system also equalizes the effect of any waves caused by the motion of the ship, making the step over safe in waves of up to 2.5 metres.

Gunnar Groebler, Head of Business Area Wind at Vattenfall, said: “Since the start of this emerging industry, the construction of this offshore wind farm has undergone a series of rapid, technical developments in just a few years. This trend is continuing steadily, including in the field of offshore wind turbine operation and maintenance. I am convinced this will have a positive effect on costs, and therefore on competitiveness, especially for future offshore projects. After all, we need true competition in order to further reduce costs and ultimately to increase the acceptance of this technology in the long term.”

The new concept is expected to enable work on offshore wind turbines in weather conditions which would previously have caused teams to stop working due to so called “weather downtimes,” especially in autumn and winter.  The concept also plans for work to be carried out 24 hours per day.

Dr Florian Bieberbach, CEO of SWM: ”For a long period of time we have already seen efforts to shift wind farms faster and more favourable into the operational phase. Many smaller improvements have been realized by the industry so far. Now we see a big step in the field of logistics. Longer working hours, not interrupted by weather downtimes or transfer times are of great advantage. We are happy that we achieved this substantial progress together with our partners – and thus to push on offshore wind as an industry as well as a strong pillar for the security of energy supply.”

The Sandbank offshore substation has been installed in April. Meanwhile, work on the cabling for the wind farm itself is underway, as well as the production of the nacelles, hubs and rotor blades for the wind turbines. The 72 foundations for the wind turbines were fully erected in mid-February 2016.

Siemens won the contract to provide 72 Model SWT-4.0-130 wind turbines for Sandbank, and to perform maintenance services on the wind farm’s installations for an initial period of five years. The wind turbines will be installed by MPI Offshore’s MPI Adventure.

Michael Hannibal, CEO Offshore at Siemens Wind Power and Renewables Division: “On our path to lower costs of offshore wind energy we continuously optimize our solutions as well as logistics. This includes transport solutions as well as technicians’ accommodation and access to wind turbines regardless of weather conditions. Sandbank is one of the first projects to sustainably benefit of these improvements.”

The investment costs for the Sandbank offshore wind farm are around EUR 1.2 billion. Vattenfall holds a 51% stake in Sandbank Offshore GmbH, which was set up to implement the project, while SWM holds a 49% stake.

Sandbank is scheduled to go into operation in 2017, providing Vattenfall and SWM with a combined portfolio of 576 MW of installed generation capacity.