ASSESSMENT OF SOLAR AND WIND ENERGY-RESOURCES IN ETHIOPIA .1. SOLAR-ENERGY

This paper describes how data from a variety of sources are merged to present new countrywide maps of the solar energy distribution over Eth iopia. The spatial coverage of stations with radiation data was found to be unsatisfactory for the purpose of a countrywide solar energy ass essment exercise. Therefore, radiation had to be predicted from sunshi ne hours by employing empirical models. Using data from seven stations in Ethiopia, linear and quadratic correlation relationships between m onthly mean daily solar radiation and sunshine hours per day have been developed. These regional models show a distinct improvement over pre viously employed countrywide models. To produce a national solar-energ y distribution profile, a spatial extension of the radiation/sunshine relationships had to be carried out. To do this, the intercepts (a) an d slopes (b) of each of the seven linear regression equations and anot her six from previous studies, completed in neighbouring Sudan, Kenya and Yemen, were used to interpolate the corresponding values to areas between them. Subsequent to these procedures, 142 stations providing o nly sunshine data were assigned their ''appropriate'' a and b values t o estimate the amount of solar radiation received, which was then used to produce annual and monthly solar radiation distribution maps for E thiopia. The results show that in all regions solar energy is an abund ant resource. Copyright (C) 1996 Elsevier Science Ltd.