Dynamic response of a semi-submersible floating wind turbine-point absorption wave energy hybrid energy system under rated and extreme conditions.

This article investigates the dynamic response of a hybrid offshore energy system combining a semi-submersible 10 MW offshore wind turbine (OWT) and Wave Star wave energy converters (WECs) after the failure of a single mooring line (ML) under rated and extreme wind-wave conditions. Using a coupled FAST to AQWA (F2A) simulation framework, the study analyzes platform motions, turbine power output, and tensions in the remaining mooring lines, highlighting that mooring line failure reduces turbine power and increases platform motions, with the WECs contributing to enhanced stability by increasing heave and reducing roll. Shutdown measures of the turbine after ML failure reduce mooring tensions but lead to larger platform motions, and the most severe displacement occurs with failure of the upwind mooring line due to combined wind and wave forces. Under extreme conditions, turbine shutdown leads to responses dominated by platform drift and mooring line tensions differ from rated conditions, suggesting higher fatigue risk in remaining moorings; the study notes that further research is needed for misaligned flows and multiple mooring failures.