Maina Anne Wandia, Kamau Joseph Ngugi, Timonah Nelson, Nishizawa Y, Churchill Saoke
The wind speed characteristics of Juja, (altitude of 1416 m above sea level; 10 10’ S, 370 7’ E), Kenya was analysed at heights of 10 m and 30 m. The wind speed averages at 10 m and 30 m were found to be 2.54 m/s and 3.04 m/s, respectively. The wind shear exponents and roughness parameters were analysed and found to be 0.1652 and 0.0374 respectively. Weibull scale and shape parameters were obtained using Weibull-fit, Regression and the Maximum Likelihood. Wind speed modelling was done using the Weibull and Rayleigh probability distribution functions. Power densities for different methods were calculated. Results obtained from Juja site were compared with results acquired from Naivasha, St. Xavier site which is at an altitude of 2,086 m; 0° 43' 0" S, 36° 26' 0" E. The mean wind power densities for Juja (10 m and 30 m) and Naivasha (10 m) were 12.68 W/m², 20.65 W/m² and 39.95 W/m² by Weibull model and 14.51 W/m², 22.43 W/m² and 28.63 W/m² by Rayleigh model respectively. The Weibull-fit and Maximum Likelihood fitted best Juja site and Naivasha site respectively.