The scope of the contract also includes providing 20-year maintenance services for the extension, which is expected to become operational in September 2014.

The existing Norderhof I project features seven Siemens Model SWT-2.3-93 wind turbine units with a total capacity of around 16MW.

Burgerwindfarm Galmsbull has selected service-proven offshore turbine unit for the Norderhof II extension owing to success at the neighboring Marienkoog wind farm.

The company claims the coastal location and erection of turbines, each with a hub height of 89.5m, will enable optimum energy yield.

The company’s project team and Denker & Wulf’s consultant engineers had looked into potential shadowing effects and increased turbulence for the legacy installations in advance, and considered these factors when planning.

Burgerwindpark Galmsbull managing director Torsten Levsen said owing to the shorter distances between the turbines, taking optimum advantage of the additional useful wind area increases the burden on the existing turbines.

"However, the sturdy, robust design of Siemens’ wind turbines units makes them so stable that hardly any compromises were needed when planning Norderhof II," added Levsen.