Long-Term Wind–Wave Climate and Integrated Metocean Screening for Offshore Wind Development in the Binh Thuan–Phu Quy Offshore Domain, Vietnam

Offshore wind development in the Binh Thuan–Phu Quy offshore domain requires regional, multi-variable preliminary metocean screening that extends beyond wind-resource mapping alone. This study presents a 32-year integrated wind–wave–bathymetry screening of four representative offshore wind sites in the Binh Thuan–Phu Quy offshore domain, Vietnam, using hourly ERA5 reanalysis data (1993–2024) and GEBCO 2025 bathymetry. The sites span four water-depth classes: shallow nearshore (BT01, 27 m), bottom-fixed (BT02, 49 m), transitional (BT03, 81 m), and floating-suitable (BT04, 161 m). For the IEA Wind 15 MW reference turbine at 150 m hub height, mean wind speed increases from 7.71 m s−1 at BT01 to 9.75 m s−1 at BT04, gross single-turbine capacity factor from 46.7% to 62.2%, and gross annual energy production from 61.4 to 81.7 GWh yr−1. Along the selected BT01–BT04 sequence, mean significant wave height increases from 1.06 m to 1.49 m, with P95 Hs rising from 2.15 to 3.27 m. The northeast monsoon (November–March) dominates both wind and wave energy at all sites, whereas the mildest sea states occur during the April–May transition months. These conditions identify April–May as having the lowest monthly mean sea states; monthly means alone do not define operational weather windows. Interannual variability of annual gross capacity factor is moderate, with coefficients of variation of 9.8–10.2%. The integrated screening matrix shows that wind resource, energy yield, water depth, and wave exposure increase together along the selected four-site sequence, without implying a causal depth relationship or a domain-wide trend: the highest-yield site requires a floating substructure under the most exposed conditions, whereas the most benign site yields the least energy. All reported values are gross, reanalysis-based screening indicators rather than bankable resource estimates. From a sustainability perspective, the framework supports balanced early-stage planning by considering energy yield together with depth and marine exposure, while its open, long-term datasets provide reproducible, comparatively low-cost decision support for data-scarce emerging offshore wind markets. It does not quantify lifecycle, ecological, social, or economic sustainability.