Geothermal Energy Development in Uganda: A Country Update 2012

Abstract

Exploration for geothermal energy in Uganda has been in progress since 1993. The studies have focused on three major geothermal areas namely Katwe, Buranga and Kibiro. The three areas are in advanced stages of surface exploration and will soon be subjected to exploratory drilling that will pave the way for a feasibility study. The overall objective of the study is to develop the country¡¯s geothermal energy resource in order to complement hydro and other sources of power to meet the energy demand especially in the rural areas. Recent works carried out included geological, geochemical, hydrological and geophysical surveys in order to elucidate subsurface temperatures and the spatial extent of the geothermal resource. The results indicate that the geothermal activity in the three areas is related to the volcanic and tectonic activities of the Rift Valley, which has a higher thermal gradient than the surrounding Precambrian crust. Subsurface temperatures of approximately 140-200¢ªC for Katwe, 120-150¢ªC for Buranga, and 200-220¢ªC for Kibiro have been estimated from geothermometry and mixing models. Anomalous areas have been delineated in Katwe and Kibiro prospects using geophysical methods. Drilling of shallow boreholes to a depth of 200-300m for temperature gradient measurement was carried out. The temperatures measured (30-36¢ªC/km) were slightly above the global average of 30¢ªC/km, which suggests that either reservoirs in Katwe and Kibiro are deeper or geothermal reservoirs were offset from the drilled areas. Additional geophysical surveys to locate the deep reservoirs and drill sites in the two areas are recommended. The results will then be used to update the geothermal models that will be a basis of siting and drilling of deep geothermal wells in the two areas. The Buranga area still needs detailed geophysical surveys to delineate anomalous areas that could be targets for drilling. The fourth area, Panyimur in Nebbi district, West Nile region, has indications of a geothermal resource following the results of the petroleum drilling programme that encountered high temperature gradient (maximum 80¢ªC/km) in the vicinity of the thermal area. Preliminary investigations to promote the area for further studies are under way. Three areas Katwe, Buranga and Panyimur have been licensed to the private sector for exploration and development. Preliminary geothermal investigations on other geothermal areas of Uganda have been done. The results indicate subsurface temperatures in the range of 100-160¨¬C which is suitable for electricity generation and direct uses. Further geothermal investigations are recommended for these areas.