The installation of the 77 monopile foundations and transition pieces
were successfully finished Tuesday, 29, July 2014. Well-defined working
processes in addition to skilled operations ensured a very fast installation
process for the foundations.
Take a look at the photos below to
get an impression of the installation. Click on the photos to see them
A view of Borkum Riffgrund 1 with its substation and foundations in place.
Pacific Orca: The installation vessel for the foundations at the construction
site in the North Sea.
The offshore wind farm Borkum Riffgrund 1 is
located around 37km north of the isle of Borkum.
Lys Rhilinger, Offshore Installation Manager of the foundations, at DONG
Energy, said: ”I’m very happy that we have successfully completed the
installation work. The cooperation within the team was very good and has become
more and more routine in the course of time. Together with the nice weather
which we’ve had during the last weeks, we now had a turnaround* of the Pacific
Orca loaded with four foundations in less than four days. This is almost half of
what we had hoped for during the planning.”
(*A turnaround is the cycle from loading in
Eemshaven, sailing to the construction site, installation of the four foundation
and going back to Eemshaven.)
Storage of the more than 600 tones heavy steel foundations for the offshore wind
All in all 77 of these monopile constructions were anchored to the
seabed. At the same time, the connecting pieces, the so-called transition
pieces, were also installed. The 78th foundation will be a suction bucket
jacket. It is a prototype with a three-legged steel construction with bucket
foundations which will use a vacuum-assisted installation method and will be
installed for the first time in an offshore wind farm.
Preparing for the installation: A noise mitigation tool is being used. This
silencer guarantees that all noise levels stipulated by the authorities are met.
Søren Sørensen, the Foundation Project Manager responsible for the installation
of monopiles and transition pieces, said: "We’ve made the right decision to use
this optimised installation method in relation to mitigation of underwater noise
during piling. It has never been used in this way before and we’ve received
As soon as the foundation was installed into the seabed, a crane lifted the
approximately 330 tonnes heavy and approximately 25 meter high transition pieces
on top of the monopile foundation. It contains a landing stage, ladders and
internal and external working areas. Later on, the transition piece will
support the tower of the wind turbine.
When fully operational in 2015, Borkum Riffgrund 1 will be able to supply
green power corresponding to the annual consumption of approximately 320,000