Defining and optimizing strategy for floating wind installation in challenging environmental conditions

Raf Somers, IMDC
Efficient offshore installation is key to developers to realize their projects and successfully deliver returns for investors. On the other hand, there is a lot of uncertainty due to limited experience and dynamic offshore conditions.

The advantage of floating foundations has always been to be able to perform big assembly and operation and maintenance (O&M) works in a port (i.e. large component installation and replacements).

There are many factors affecting assembly but also accessibility of floating wind turbines, namely environmental conditions, the method of access, floating platform type and the geometry of the substructure below and above the water line.

IMDC has provided advisory services to WindFloat Atlantic floating OWF and Kincardine floating OWF which allowed to successfully assemble wind turbine generators (WTGs) on floating structures during both single summer and autumn season.

IMDC will share unique experience on how to prepare assembly of WTGs that require grounding of the floating platforms onto a foundation before the turbine can be installed from the quay. IMDC will share pictures from assembly activities with some practical examples and analysis of all forces acting on the foundations due to wind, wave and current loads or loads due to filling of ballast tanks. The stability verification includes calculations related to bearing capacity, horizontal sliding, sliding surfaces and settlements. Foundation design (both geotechnical as well as hydraulic) will also be explained. Aspects related to health and safety will be also highlighted.

The fundamental difference for technicians working on a floating wind turbine platform as opposed to a fixed platform is that they are exposed to the motions of the platform in performing assembly and maintenance. IMDC will discuss how modelling of sea conditions and estimating weather downtime could help project developers to prepare and plan offshore installations in the most effective and economic way.