Geothermal resource exploration and development in Ethiopia

Category Petrology
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Teklemariam, Meseret
Holding Date 04 October 2008

Ethiopia launched a long term geothermal exploration undertaking in 1969. The study has revealed the existence of both low and high enthalpy geothermal resources in the Ethiopian Rift Valley and in the Afar depression, which are both part of the Great East African Rift System.
Over the years, a good inventory of the possible resource areas has been built up and a number of the more important sites have been explored. Of these areas, about sixteen geothermal prospect areas are judged to have potential for electricity generation. A much larger number are capable of being developed for applications in agriculture, agro-industry etc.
Exploration work peaked during the early to mid-1980s when exploration drilling was carried out at the Aluto-Langano geothermal field. Eight deep exploratory wells were drilled to a maximum depth of 2.5 km and temperature up to 350° C, of which four are potentially productive. During the early 1990s, exploration drilling was also carried out at Tendaho. Three deep (about 2100m) and three shallow (about 500m) wells were drilled at the Tendaho geothermal field, and proved the existence of high temperature and pressure fluid.
A new era of resource utilization started in 1998 by installing the 7.2 MWe net capacity pilot plant at Aluto-Langano geothermal field. Initially, there was a disruption in power generation due to technical problems. These were studied and are currently being rectified. The plant is now achieving partial generation (3MWe).
In the Tendaho geothermal field, a production test and geochemical monitoring is currently in progress. The techno-economic study indicates that four productive wells (out of six) of this geothermal field could supply a pilot power plant of about 5 MWe, and the potential of the deep reservoir is estimated about 20 MWe. Other geothermal prospect areas in the Ethiopian Rift Valley are at various stages of exploration that vary from reconnaissance to detailed geoscientific studies including drilling of temperature gradient (TG) wells. These include: (i) Corbetti and Tulu-Moye: Detailed geoscientific studies including drilling of TG wells; (ii) Abaya, Fantale and Dofan: Detailed geoscientific studies; and (iii) Teo, Danab, Meteka, Kone and others: Reconnaissance investigations.