C-Power investigates ageing process in offshore turbine foundations

C-Power operates the very first offshore wind farm off the Belgian coast. Since offshore wind farm construction is still in its infancy stage compared to conventional power sources, and as turbine foundations are exposed to extreme conditions at sea, C-Power has teamed up with Sirris/OWI-Lab and VUB to monitor the structures. This will enable it to keep track of the ageing process and plan maintenance work in an informed way.

• Unique European research into ageing process in offshore turbine foundations 
• Optimizing structural maintenance based on field data
• Smarter design and construction of new turbine foundations

C-Power,  a consortium of Belgian and international shareholders, operates the very first offshore wind farm off the Belgian coast. The 54 turbines are among the largest of their kind and are set on solid foundations.

 “Research is needed into the ageing process in offshore turbine foundations, not only for maintenance purposes but also to ensure smarter designs for wind farms in future.” 

Highly aggressive conditions

The offshore wind industry is growing fast as the technology matures. However, even today little is known about the ageing process in these offshore structures. Foundations are exposed to a range of stresses: vibrations from the turbine itself, waves and marine currents, climatic conditions, changes on the seabed, corrosion, and so forth.

During the foundation design phase, C-Power assumed a lifetime of 30 years based on simulation models. However, to closely track the ageing process over this period and to test and validate the simulations, field data was needed on the various external influences affecting the structures.

Collecting data on external influences 

For this, C-Power called on Sirris/OWI-Lab. In collaboration with VUB, experts from the OWI-Lab fitted different sensors and measuring systems on two of the turbines’ foundations in order to record the external influences as part of a new R&D project: weather conditions, sea and seabed conditions, as well as various types of vibrations caused by the turbines themselves. The analysis also examined critical welds and joints in the foundation design. To analyze all this 'big' data quickly and efficiently, OWI-Lab developed a brand new data warehouse which collects all different data sources.

Optimizing maintenance and design

The measurement results in this research project will give the researchers and wind farm operators a better insight into the ageing process in the foundations caused by external influences. This means that maintenance work on existing structures can be planned more efficiently, but also that new offshore wind turbines can be optimized right from the design stage based on actual data from the field.

More information: pieterjan.jordaens@owi-lab.be