DONG Energy says that all of the foundation work is now completed on the 400 MW Anholt Offshore Wind Farm in Denmark. The next step will be to install the 111 wind turbines.
The installation vessel Svanen, which was originally built to construct large parts of the Great Belt bridge, installed the foundations into the seabed. Svanen installed the first foundation, while the installation vessel Jumbo Javelin installed the transition pieces. The 111 foundations were manufactured by Bladt Industries and installed by MT Hojgaard.
The installation encountered some challenges along the way, says Flemming Thomsen, project director.
"The wind and weather conditions in the Kattegat, where the turbines are to be erected, can be rough," Thomsen explains. "This is, of course, a good thing when the turbines are spinning, as it will result in large power production. However, during construction of the wind farm, we are not too fond of strong winds, and we've had to suspend installation of the foundations many times."
It has not always been easy to prepare the seabed for the driving of the monopiles, as the seabed holds a lot of challenges, DONG Energy adds. Particularly in the northern part of the wind farm site, there are areas with very soft seabed, while there are many large boulders in the seabed in the southern part of the wind farm. DONG Energy has moved a total of 5,000 boulders that have now been placed in 30 artificial reefs.
"Before we started the work, we scanned all the turbine positions," Thomsen says. "We have considered all possibilities, and we have the tools in place that are necessary to handle the challenges that the different seabed characteristics pose.
"Now that we have completed the foundations, we can focus on the next important tasks to come," he adds. "We're well under way with installation of cables between the foundations, and then we will start installing turbines on the foundations."
DONG Energy expects to start installing the turbines in early September.