The first of 78 Siemens 3.6MW turbines was installed by A2Sea's Sea Installer vessel at the site 37 kilometres off Germany's north coast.
This project landmark is a few weeks later than scheduled following a delay in the turbines being delivered. In August, Siemens admitted to manufacturing problems as a cause for the delay.
Siemens and developer Dong said the project's commissioning date – planned for the first half of 2015 – should not be affected.
The SWT-3.2-120 turbines have been optimised by Siemens to increase the output up to 4MW.
Monopile foundations at Borkum Riffgrund were installed in July. One of the foundations is a full-scale prototype of a suction-bucket jacket foundation, which was installed in August.
In January, the Carbon Trust awarded £6 million (EUR 7.3 million) to Dong to build the foundation as part of the Offshore Wind Accelerator programme.
