Comparative study of thirteen numerical methods for evaluating Weibull parameters for solar energy generation at ten selected locations in Cameroon

Abstract

This study aims to compare thirteen computational methods with the goal of pointing out the more relevant method for the determination of Weibull parameters using forty-year daily average solar irradiance data collected at the NASA website from the first of January 1980 to the thirty first of December 2020. The studied sites are the headquarters of the ten regions of Cameroon which include Maroua, Garoua, Ngaoundéré, Bamenda, Yaoundé, Douala, Buea, Bertoua, Bafoussam and Ebolowa. The methods accuracies were checked using five statistical indicators. The results revealed that the appropriate method varies from one site to another. The maximum likelihood method and the modified maximum likelihood method were found to be the suitable methods to estimate the solar irradiance distribution for the sites of Maroua, Garoua and Ngaoundéré. The empirical method of Justus was the most efficient method for the sites of Bamenda, Yaoundé, Bertoua, Bafoussam and Ebolowa while the energy pattern factor method was the method that best fits the observed solar irradiance data for the sites of Douala and Buea. The graphical method is recommended for the evaluation of the cumulative distribution of solar irradiance because it was found to be the best method of estimating the cumulative distribution of solar irradiance in all the considered sites. The highest annual energy output from a photovoltaic panel was recorded to be 604.51 kWh/year for the site of Maroua.