Determination of wind energy potential in the Mwingi-Kitui plateau of Kenya

Abstract

Wind energy can be used to enhance access to affordable energy to the rural poor owing to its cost effectiveness, enormity of availability and non-polluting nature. Kenya is however yet to embrace this technology due to non-availability of the resource data for most parts of the country. This study endeavors to provide the missing data and investigate the feasibility of employing Small Wind Turbine Generators (SWTG) for provision of modular power to the arid rural Mwingi-Kitui plateau where access to electricity is very low yet the land is flat with visible effects of wind on trees such as tree flagging. The region lies between the earlier studied coast and north eastern parts of the country both of which have good wind potential, raising the prospects of finding sustainable quality wind in it. Ten-minute interval wind speed data was collected at 20 m and 40 m elevations above the ground for a period of one year and analyzed to portray the vertical wind shear exponent, mean wind speed (daily, monthly and annual) variations, wind gusts, probability distributions, directional data and wind power density over the study period. The study gave annual mean wind speed at the 20 m and 40 m heights above the ground as 4.24 m/s and 4.88 m/s respectively leading to vertical wind shear exponent (α) of 0.20. Wind speeds at 40 m hub height and above rated above 3.5 m/s cut-in speed with flow prevalently from south east direction for most of the year. The maximum available wind power densities at 60 m, 80 m and 100 m were 84.3 W/m2, 100.5 W/m2 and 115 W/m2 respectively. These findings reflect characteristics suitable for operation of small wind turbine electricity generators.