Substructure optimization of a 10MW floating wind turbine for installations in the Mediterranean Sea

In this contribution, a multi-objective, site-specific optimization procedure aimed at finding the optimal substructure configuration for a 10MW FOWT is presented. An in-house developed Frequency Domain (FD) model is adopted for the simulation of the coupled system. An installation site near to the Italian coastline is selected. The probability distributions of wind speed, significant wave height and peak spectral period are calculated based on a metocean 20-year database of wind and wave records. The multi-objective optimization concerns the joint minimization of the tower structural response under an extreme event and the manufacturing cost of the substructure. Constraints on the admissible platform displacements, cables geometry, and anchor loads are considered. Results show that the optimized solutions significantly reduce the cost of the system with a moderate increase of stresses, opening interesting perspectives for the reduction of the Levelised Cost of Energy (LCOE) in sites characterized by mild sea states and low wind resource.