The monopile is dead – Long live the monopile!

Latest developments for large diameter turbines in the North Sea

Company / Unternehmen: REpower Systems SE
Speaker / Referent: Marc Seidel
Position: Leading Expert Offshore Engineering

The trend for offshore wind turbines is towards a rated of power of 6MW with rotor diameters of around 150m. The goal when increasing rotor size is of course to optimize cost of energy, to which cost-effective substructures contribute significantly. For this presentation, recent developments regarding application of very large monopiles will be presented. While monopiles where seen as an alternative for water depths up to 25m only until recently, this barrier is currently being challenged. Even for turbines of the 150m class, water depths up to 40m in the German North Sea are discussed with monopiles. The most recent findings at the time of the conference will be presented, based on several projects where REpower is investigating monopile feasibility. Some of the items that will be discussed are: – Impact of tower head mass on monopile feasibility – how much are heavy turbines punished?

– Importance of adequate assessment of soil stiffness
– Benefits of integrated support structure designs – how much can we gain by looking at the whole structure during optimization?
– Grouping of monopiles – is eigenfrequency the correct parameter?