The Nissum Bredning Offshore Windfarm is a Test and Development Windfarm consisting of four turbines connected via three inter array cables and connected to shore by one export cable.
The project included two different cable installation concepts, being respectively:
1) HDD (Horizontal Directional Drilling) for the export cable from shore to first turbine.
2) Subsea laying and burial of HDPE pipes and cables in between the four turbines.
Both installation concepts were based on pre-installation of HDPE pipes in the seabed via horizontal drilling and jetting. Then followed the installation of the cables into the pre-installed pipes. The cables were installed by the use of the WaTuCab cable installation method.
JDC and Siemens Gamesa dealt with many changes and scenarios of installation sequences for the cable installation campaign. This was to match the progress and planning of parallel foundation and WTG installations at the work site. The Cable installation campaign was therefore carried out in parallel to the actual foundation work. With good cooperation between Siemens Gamesa and other contractors at the work site the most optimal planning was achieved with high flexibility from all parties.
One of the challenges on this project was the very shallow water and extreme current and tide conditions coupled with a very dynamic seabed with vast amounts of natural sand movement.
The cable installation was completed successfully in accordance with the method statements and risk assessments developed for the work.
During the Nissum Bredning Offshore Project a track record of ZERO incidents involving personal injuries was maintained as a result of strong focus on safety from all parties.
The cooperation between Siemens Gamesa, MWS and JDC were generally good throughout the project where all parties contributing to positive progress and results. The extended project period resulted in replacement of more key personnel than originally planned for, among others a large part of the Siemens Gamesa project Team, but this was handled very smoothly and without consequences to the project.
Hence, good straightforward cooperation between Siemens Gamesa and JD-Contractor with a strong focus on problem-solving proved to be the key to the successful completion of the cable installation at the Nissum Bredning Offshore Project.
See video from Siemens Gamesa here: