Working out the behavior of the sea bed using the full data from a complete wind turbine is usually awkward, but that wasn’t necessary in this experiment with the foundations. The experiment gave us a very interesting set of data," says Bongers.
In Bongers opinion, although they were still busy with the analyses, they could conclude that their hypothesis was correct. The soil behaved more stiffly than expected, and with a proper soil survey one could get closer to the needed stiffness a factor of 4 or 5. This meant that in some cases, considerably lighter foundations are sufficient and the costs are reduced accordingly.
"We are very pleased that we’ve had the opportunity to perform this experiment,” concludes Bongers. "All the parties involved have set aside their own interests despite the time pressure, the cost, and the risks, which is really commendable. The results of the investigation, which scientists will use as their theses this year, can be of great benefit to the development of wind farms in the future.
We want to use all these data to develop a design model that can be certified by DNV-GL and, thereby, become a sort of standard or reference for designing offshore wind turbines.
The consequence will be that more extensive soil surveys will be carried out in the future at the wind turbine locations than is the case at the moment. That is only a small additional investment, but it can be recovered quickly because the foundations and the mast will be lighter, and therefore, cheaper.”