| Abstract |
The Aluto Langano Geothermal field is located in the Lakes District, Ethiopian Rift Valley, about 220 Km South of the capital, Addis Ababa. Aluto Langano geothermal field has been prioritized with commercial interest since 1969 by conducting several surface geoscientific investigations resulting in drilling of eight (8) deep wells in early eighties and commissioning of a pilot binary power plant (7.3 MWe) in 1998. to 2010. Two (2) directional wells were also drilled in 2015. Six (6) wells (LA-3, LA-4, LA-6, LA-8, LA-9D and LA-10D) are found to be productive and one well (LA-7) is used as a reinjection well for the pilot power plant. The objective of this report is to study the current status of the productive wells (LA-3, LA-4, LA-6, LA-8, LA-9D and LA-10D) and the progress of the overall activities being conducting in the Aluto Langano geothermal field. Monitoring the wells through conducting a down hole measurement was the main task to evaluate the status of the reservoir in addition to taking a wellhead pressure reading during static and flowing conditions. As the pilot power plant has been none-operational since 2010 because of some defects in electro mechanical parts, the old wells (LA-3, LA-4, LA-6 and LA-8) has been under shut in condition. The down hole survey results at different time interval shows that the depth of the wells is getting reducing with depth and calliper size because of the scaling deposition. But one good promising of the wells shows that no temperature decline and pressure drop is being observed as the down hole surveys conducted in 2017 and 2018 revealed since the wells has been drilled in 1980s. No maintenance works to the power plant has been taken place since 2010, the plant stop working completely, though in 2006 a rehabilitation work to the wells and maintenance work to the power plant has been taken place. The recently drilled two directional wells (LA-9D and LA-10D) in 2015 do not start supplying a steam to a planned future power plant yet, however, a construction of wellhead power system is under tendering process using a grant finance from the Government of Japan. Furthermore, a contract agreement has been signed between Ethiopian Electric Power (EEP) and a drilling company to drill 22 wells in Aluto geothermal field to construct a 70 MWe power plant with the loan from World Bank. Out of them, approximately 4 wells are intended to be used as reinjection wells. A drilling consultancy service contract agreement has been signed in 2017 between EEP and Elctro Consultant (ELC S.p.A) of Italy. In order to develop the geothermal sector of the country, an establishment of an independent institution structure is being considered by the Ministry of Water, Irrigation and Electricity (MoWIE) as it is very necessary to follow, manage, explore, exploit and utilize the resource and achieving the energy mixing policy of the country in medium and long term development plan. |