Vertical Characterization of the Wind Energy Resource in Kassa, Guinea, Using NASA POWER and ERA5 Data

This study focuses on the vertical characterization of the wind energy resource in Kassa, Guinea, using NASA POWER and ERA5 data covering the period 2020-2025. Wind characteristics established at the reference height of 10 m were extrapolated to heights of 30, 50, and 100 m using the Justus and Mikhail model. The analysis examines the evolution of mean wind speed, the Weibull parameters k and c, mean wind power density, and the maximum theoretically extractable wind energy according to the Betz limit. The results show a systematic increase in wind energy potential with height. Between 10 and 100 m, the mean wind speed increases from 3.77 to 6.72 m/s for NASA POWER and from 4.10 to 7.21 m/s for ERA5, corresponding to increases of 78.1% and 75.7%, respectively. This evolution leads to a substantial increase in energy potential: the maximum theoretically extractable annual wind energy increases from 208.76 to 1105.69 kWh/m² for NASA POWER and from 233.05 to 1246.98 kWh/m² for ERA5, corresponding to increase factors of approximately 5.30 and 5.35, respectively. Despite some monthly and seasonal differences, the two data sources show a broadly similar vertical trend. However, the values obtained at 30, 50, and 100 m result from extrapolation using the Justus and Mikhail model based on the reference data at 10 m and do not constitute independent observations at these heights. Therefore, the common vertical trend obtained for NASA POWER and ERA5 results from applying the same model to both datasets and does not constitute independent validation of either data source. These results provide a basis for further studies focusing on the selection and sizing of wind turbines adapted to the site characteristics.