Transferable Data-Driven Hydrodynamic Variability-Based Stability Assessment for Marine Renewable Energy Site Selection: A Case Study in Spanish Waters

Early-stage planning of floating marine renewable energy infrastructures can benefit from identifying areas with favorable hydrodynamic conditions. Hydrodynamic stability assessment can support the planning of floating photovoltaic systems, offshore wind turbines, and renewable hydrogen production facilities. This study presents a transferable, data-driven multivariate framework that quantifies hydrodynamic variability to identify areas of higher relative hydrodynamic stability for marine renewable energy site selection. It integrates sea surface potential temperature, salinity, water velocity, wave characteristics, and bathymetry; quantifies temporal variability using waveform length; and combines the resulting variable layers through a hybrid stability index and parametric weighting procedure. Applied to Spanish marine subdivisions shallower than 1000 m using Marine Copernicus data, the results show that wave-related variability is the dominant contributor, while the Levantine–Balearic subdivision exhibits the largest relative extent of stable zones and the highest overall relative stability under global normalization. The resulting relative stability index provides a transferable hydrodynamic pre-screening layer that can be integrated into Geographic Information System (GIS)-based marine spatial planning before technology-specific renewable-resource and other planning assessments.