Impact of Hub Height, Rotor Diameter, and Terrain Roughness on Wind Energy Yield in Central Iraq: A Controlled Three-Factor Analysis

This study investigates the combined effects of hub height, rotor diameter, and surface roughness on wind energy yield in Najaf, Iraq, a typical desert area with weak winds. Capacity factors (CFs) were simulated across ۴۸ distinct configurations using validated power curves for Vestas V۴۷, V۵۲, and V۶۶ turbines and five years of hourly wind data from the NASA Power database (۲۰۲۰–۲۰۲۴). Surface roughness was the primary factor influencing the capacity factor, accounting for about ۹۱% of the total variance, according to a three-way ANOVA. Rotor diameter (η² = ۰.۰۳۶) and hub height (η² = ۰.۰۳۴) followed, with highly statistically significant main effects and smaller but non-negligible interaction effects (p < ۰.۰۰۱). Notably, the largest turbine (V۶۶) demonstrated a lower capacity factor due to its higher rated power, even though it achieved the highest annual energy production (AEP = ۱۸۷۶.۵ MWh/year), while the smallest turbine (V۴۷, ۴۷ m diameter) achieved the highest capacity factor (۰.۱۶۵۶) at a ۶۰ m hub height on a smooth surface (z₀ = ۰.۰۱ m). This highlights an important trade-off: annual energy production must be taken into account, as relying solely on capacity factor can lead to incorrect turbine selection in desert regions with low wind speeds. Additionally, as surface roughness increased from ۰.۰۱ to ۰.۳۰ m, the capacity factor, normalized to rated power, dropped by more than ۸۰%, underscoring the crucial importance of careful site selection. These results provide practical, physics-based guidance for improving wind energy deployment in desert regions with limited data.

کلیدواژه ها:

Wind Energy ، Hub Height ، ANOVA ، Surface roughness ، Capacity factor ، Iraq