Hydrodynamic analysis of a 2MW offshore floating solar farm with breakwater protection

Within the EU project SUREWAVE a new concept for the upscaling of Floating PhotoVoltaics (FPV) to offshore environments is developed. The new concept integrates an existing FPV design with a floating breakwater ring that provides shelter against waves. The system is designed for harsh offshore conditions at sites in the Baltic, Mediterranean and North Seas. A series of model tests was performed with a simplified setup of a 3x5 array of FPV panels behind a floating breakwater. These model tests showed deficiencies in the design of the hinge connections between panels (sensitive to buckling) and lead to an improved hinge design.

The model tests have been used to validate the numerical model of the system based on linear diffraction analysis. The validated numerical model has been used to scale up to a 2MW system (3660 solar panel panels and 32 floating breakwaters) and investigate the effectiveness of the breakwater ring in reducing motions of the panels, loads in the panel connectors (hinges) and wave drift loads on the system. Due to the size of the structure and the large number of floating objects and degrees of freedom the computations have been carried out on a high-performance computer in parallel.

The simulations show that the floating breakwater is capable of reducing the short-wave energy inside the breakwater ring and the related hinge loads, but it may also lead to the development of standing waves inside the breakwater ring. Longer waves are not affected but due to the flexibility of the FPV system the modules follow the wave motions which does not result in high loads. The presence of the floating breakwater leads to a significant increase in wave drift loads. As a consequence, a stronger mooring system needs to be used which is capable of handling these loads.