Model Tests on Waterlily Shaped Offshore PV System

The European Union funded NATURSEA-PV project aims to develop a lily-inspired PV substructure solution to meet the specific needs for Offshore Floating PV. The substructure will be manufactured of a flexible, light and ecofriendly type of concrete which will give the substructure the advantages of flexibility and lightness to withstand offshore conditions. As part of the project, model scale tests on the flexible substructure are performed to capture the behavior of the substructure to waves. These basin tests are conducted in the MARIN shallow water basin at scale 1:30. To allow for numerical model validation, the tests are conducted using two sets of soft-mooring system to ensure that there is no interaction between the natural periods of the mooring system and wave frequencies. During irregular wave tests, different vertical behavior is observed at the outer ring of the substructure compared to the inner ring. Wave response is more extreme in high frequency ranges (smaller wave length) for the outer ring, which is related to the number of beams connected to the floater constraining the vertical motion. Strain measurements perpendicular to the longitudinal axis show the largest deformations, but this is not observed along the longitudinal axis. There is no exceedance of the air gap for the tested wave conditions. These basin tests demonstrate the validity of the original design, and serve as input for future numerical model validation.