THE FEDERAL DEMOCRATIC REPUBLIC OF ETHIOPIA
MINISTRY OF MINES
Geothermal exploration and resource assessment core process
COUNTRY SUMMARY
I-OVERVIEW OF GEOTHERMAL EXPLORATION AND DEVELOPMENT IN
ETHIOPIA
II- SUMMARY OF GEOTHERMAL PIPELINE PROJECTS
March 2012
ADDIS ABABA, ETHIOPIA
I. OVERVIEW OF GEOTHERMAL EXPLORATION AND
DEVELOPMENT IN ETHIOPIA
Ethiopia is among the few countries in Africa with a significant amount of geothermal resources.
These resources are found scattered in the Main Ethiopian Rift and in the Afar Depression that
covers an area of 150,000 Km2 (Figure 1). Based on the results of the investigations, Ethiopia
could possibly generate more than 5000 MWe of electric power from geothermal resources alone.
Ethiopia launched a long term geothermal exploration undertaking in 1969. About sixteen
geothermal prospect areas are judged as having potential for electricity generation. A much larger
number are capable for direct use applications (e.g. horticulture (for maximizing production in
flower farming), 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. 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.
A new era of resource utilization started in 1998 by installing the 7.2 MWe net capacity pilot
power plant at Aluto-Langano. 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 (5MWe).
During the last three decades that geothermal resources exploration work was carried out in
Ethiopia, a good information base and a good degree of exploration capacity, in human and
infrastructure terms, have accumulated, ensuring that selected resources sites can be advanced to
the resource development phase much more rapidly than before.
In view of the above, the government is planning the following tasks for the coming four years:



Expansion of the Aluto-Langano Geothermal Pilot Power Plant
Work at Tendaho geothermal field for progressing it towards development; and
Completion of the detailed exploration works at two more geothermal prospects.
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Fig.1 Location Map of the Geothermal Prospect Areas within the Ethiopian Rift Valley.
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Status of Geothermal Exploration and Development
No.
1.
Prospect
Aluto-Langano
Recon.
Explor
ation
Surface
Exploration
Yes
Yes
Temperature Gradient
wells
Exploration
Drilling
Drilling
Yes
Estimated Potential
(MWe)
Developed
For 30 Years
Yes
30
Pilot Power Plant
(5 MWe)
2.
Tendaho
Yes
Yes
Yes
Yes
20
No
3.
Corbetti
Yes
Yes
Yes
No
Not Known
No
4.
Tulu Moye
Yes
Yes
Yes
No
Not Known
No
5.
Abaya
Yes
Yes
No
No
Not Known
No
6.
Dofan
Yes
Yes
No
No
Not Known
No
7.
Fantale
Yes
Yes
No
No
Not Known
No
8.
Others (Teo,
Kone, Danab,
Meteka, L .Abe)
Yes
No
No
No
Not Known
No
(Dubti)
II. GEOTHERMAL PIPELINE PROJECTS
The following are three projects that the Ethiopian government wishes to implement. These
Projects include:
PROJECT 1- Tendaho Geothermal Resource Development
PROJECT 2. Aluto - Langano Geothermal Pilot Power Plant Rehabilitation and Development
PROJECT 3: Surface Exploration in Five Geothermal Prospects and Development of Two
selected geothermal Fields
PROJECT 1- TENDAHO GEOTHERMAL RESOURCE AND DEVELOPMENT
The overall objective of project 1 is to increase the level of knowledge that exists for the Tendaho
geothermal field to a level that would encourage a developer to assume responsibility for its
development.
The project is proposed to deal with progressing the geothermal resource identified by earlier
exploration in Dubti area, Tendaho, to the development phase with the purpose of supplying
electricity to the national grid that is planned to be extended to Semera.
Detailed geoscientific studies (geology, geochemistry and geophysics) followed by the drilling of
temperature gradient wells were carried out in two phases during the late 1970s to the early
1980s. Exploration drilling was carried out during 1993-95 with financial and technical
assistance from the Italian government. The Geological Survey of Ethiopia carried out further
drilling during 1997-98 using its own budget.
Three deep (maximum 2100m) and three shallow exploratory wells (about 500m) were drilled
during 1993-98 period. The three shallow exploratory wells are productive with a potential of at
least 3-5MW electric power generation.
Currently, well testing and reservoir engineering studies and geochemical monitoring of the
shallow geothermal reservoir is in progress towards the objective of carrying out the feasibility
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study followed by installation of small scale pilot power plant using the existing shallow
productive wells.
All electric power generated in the Afar region is from Diesel generators. Diesel fuel is imported,
and transported from the Port of Djibouti at high cost. Therefore, the proposed geothermal
resource exploration and development programme would provide power for the Dubti farm and
towns of Semera, Logiya, Dubti and Det Bahri.
PROJECT 2. Aluto - Langano Geothermal Pilot Power Plant Rehabilitation And
Development
The Aluto-Langano Geothermal field
The Aluto-Langano geothermal field is located on the floor of the Ethiopian Rift Valley about
200 km south east of Addis Ababa (Figure 1). In the Aluto-Langano geothermal field, eight deep
exploratory wells were drilled to a maximum depth of 2500m, between 1981 and 1985, out of
which four are potentially productive. The maximum reservoir temperature encountered in the
productive wells is about 350ºC. A new era of resource utilization started in 1998 by installing
the 7.2 MWe net capacity pilot power plant at Aluto-Langano. 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 (5MWe).
The project deals with expansion of the Aluto-Langano geothermal field to full potential field,
which has been estimated to be 30MWe.
PROJECT 3: Surface Exploration in Five Geothermal Prospects (Corbetti, Abaya, Tulu
Moye, Dofan and Fantale) and Development of Two selected Fields
The project deals with investigating five resource prospects by surface exploration techniques.
The selection of the five prospects was based on economic criteria and their strategic locations
with respect to proximity to the existing grid and to regions of high population density. Past
exploration information was the basis for selecting these prospects among several others that
could be considered. Greater distance to the grid has precluded the selection of several equally
attractive prospects located in the Southern, Central and Northern Afar regions.
The project will be implemented into two phases: Phase 1: Surface exploration in the selected
geothermal prospect areas; and Phase 2: Exploration drilling and power development at the two
selected prospects.
The following five selected geothermal prospect areas are presently at various stages of surface
exploration.
The Corbetti Geothermal Prospect area
The Corbetti geothermal prospect area (Figure 1) is located about 250 km south of Addis Ababa.
Eight temperature gradient wells have been drilled to depths ranging from 93-178m. A maximum
temperature of 94C was recorded. The data show the probable existence of a deep reservoir
with temperatures exceeding 250 C.
A 132 KV power transmission line passes within 15 kms of the prospect and is the main trunk
line to Southern Ethiopia, to towns along the two branch of the highway to Kenya.
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The Abaya Geothermal Prospect area
Abaya is located on the northwest shore of Lake Abaya, about 400 km south by road from Addis
Ababa. Spring temperatures are as high as 96 C with a high flow rate. Integrated geoscientific
studies (geology, geochemistry, and geophysics) have identified the existence of a potential
geothermal reservoir with temperature in excess of 260C.
The 132 KV transmission line to Arba Minch to the south parts at the Wolayta Soddo substation
is located about 40 kms to the NNW of the prospect. This raises the prospect for development of
the resource once it is adequately explored, including by drilling.
The Tulu Moye-Gedemsa Geothermal Prospect area
During 1998-2000, integrated geological, geochemical and geophysical studies including shallow
temperature gradient surveys (150-200m) , confirmed the existence of geothermal reservoir with
a temperature of about 200C and target areas for further deep exploration wells were delineated.
This prospect area is located close to the Koka and Awash II and III hydro-electric power
stations, the associated 230 and 132 KV substations and transmission lines.
The Dofan Geothermal Prospect Area
The presence of several hydrothermal manifestations (fumaroles and hot springs) within the
graben, together with an impervious cap, needs to be regarded with high priority for further detail
exploration and development. The area is located about 40 kms distance from the high voltage
substation in Awash town.
The Fantale Geothermal Prospect Area
The Geological Survey of Ethiopia has carried out detail geological, geochemical and
geophysical investigations in order to delineate and select target areas for deep exploration wells.
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