Environmental Contour Assessment for Floating Offshore Wind Turbines Installation in the Mediterranean Sea

Characterizing site-specific environmental loading critically affects the structural analysis of FOWTs. Current guidelines specifically addressing FOWT design suggest the Environmental Contour via the inverse first-order reliability method as a practical approach to estimating long-term extreme environmental conditions. However, while the interest in the Mediterranean Sea has grown within the offshore renewable energy sector, most existing research and technical guidelines are tailored to basins in Northern Europe. In this respect, this study compares metocean parameters statistically extrapolated for ultimate strength analysis using the approach outlined in IEC 61400-3, with a refined approach based on the joint Environmental Contour estimation of all relevant parameters. Four sites suitable for semi-submersible FOWT installation in the Mediterranean Sea are analyzed using a 42-year hindcast dataset spanning the period from 1979 to 2020, serving as the basis for environmental characterization. The findings provide insights into the applicability of existing standards to Mediterranean-specific conditions, highlighting a tendency towards overly conservative structural loading predictions for semi-submersible FOWTs.