Wind energy resource assessment for Kiribati with a comparison of different methods of determining Weibull parameters

Abstract

Wind energy resource assessments at two locations in Kiribati are carried out. The wind resource on the main atoll of Tarawa is analysed along with a nearby atoll Abaiang. Measurements of wind speed, direction, ambient temperature and pressure were performed and analysed. The Tarawa site has an average wind speed of 5.355m/s at 34m above ground level (AGL) and the Abaiang site has an average wind speed of 5.4575m/s at 34m AGL. The wind direction for both the sites is predominantly East-North-East. Average diurnal wind shear coefficient correlated well with the variation in temperature. The overall average turbulence intensity was about 10% at 34m and about 13% at 20m AGL for both the sites. The Weibull parameters were obtained for both the sites using seven methods and the most accurate method, which was found to be the Moments method, was used to find the Weibull parameters and the wind power density. The Weibull parameters were also obtained for the two seasons of Kiribati – the dry and the wet seasons. A high resolution wind resource map of both the sites is obtained using Wind Atlas Analysis and Application Program (WAsP). The WAsP analysis indicates reasonably good wind power development potential for the Tarawa and Abaiang atolls. Annual energy production with five Vergnet 275kW turbines for both the locations is estimated and an economic analysis is performed, which showed a payback period of 5.42years to 8.74years.