High Hub-Height Wind Resource Assessment for Coastal Bangladesh: Energy-Based Validation and Turbine Height Optimization Under Cost Scaling

Abstract

This study evaluates high hub-height wind resource potential (80-200 m) in two coastal regions of Bangladesh (Kuakata and Sandwip) to identify energy-efficient and cost-informed turbine height ranges under modern wind configurations. WRF-based wind data from the NLR Wind Resource Data Base (WRDB) for the years 2011-2021 were analysed using five Weibull parameter estimation methods. Model performance was assessed using both statistical (RMSE) and energy-based (RPDE) validation metrics. Results show that wind power density increases consistently with hub height, reaching 161.85 W/m² at Kuakata and 164.82 W/m² at Sandwip at 200 m. The Energy Pattern Factor Method produced the lowest RPDE values (<0.6%) across all heights, indicating superior accuracy in energy estimation. However, the rate of energy gain decreases with height when compared to the corresponding increase in structural cost. A normalized tower cost-scaling framework was integrated with wind resource results to evaluate marginal energy-cost efficiency. Sensitivity analysis (=1.5-2.0) identified optimal hub-height ranges of 100-140 m for Kuakata and 120-180 m for Sandwip. These ranges provide the most efficient balance between energy gain and cost escalation. Within these optimal ranges, estimated annual energy production is approximately 6.1-6.6 GWh per turbine for Kuakata and 6.1-7.0 GWh per turbine for Sandwip, corresponding to capacity factors of approximately 14.6%-16.7%. The analysis is based on mesoscale data and simplified cost modelling and does not account for site-specific measurements or full project economics. The proposed framework provides screening-level decision support for wind energy planning in coastal Bangladesh and offers a transferable methodology for hub-height optimization in emerging wind markets.