BARO AND KARADOBI HYDROPOWER PROJECTS
Under the Nile Basin Initiative (NBI), and the Eastern Nile Subsidiary Action Programme (ENSAP) the basin countries have identified development of regional electricity markets as an important component of their strategy to promote economic development and cooperation in the region. In 2001, the Eastern Nile Council of Ministers (ENCOM) decided that funding should be sought for studies on selected projects. Therefore, from Ethiopia , the Baro and Karadobi Projects have been selected for further study and development.
In light of the shared vision program of the NBI the projects are intended to provide income and improvements in the region in several areas and create win - win situations for the countries involved ( Ethiopia , Sudan & Egypt ). In addition to sale and export of electricity, the Baro and Karadobi projects are expected to provide improvements to the downstream riparian countries with regards to flooding, siltation, irrigation and water conservation. The projects are therefore studied as multi- purpose regional projects.
Hence, both projects are foreseen to be developed with the participation of private investors. In addition to the basic soundness and economic viability of a project, potential investors are interested in the risk elements. For hydropower projects. these are mainly be centered on the geology, hydrology and environmental conditions. These areas therefore were given particular emphasis in the studies.
For the feasibility study of Baro and the pre-feasibility Study of Karadobi multi-purpose Hydropower Projects, the Government of Ethiopia has received a grant of 40 million Norwegian Kroner (NOK) from the Government of Norway.
The Baro project is located on the Baro River between Gore and Bonga approximately 600km by road west of Addis-Ababa (400km air distance). A pre-feasibility study of the project was conducted by Norplan in association with Norconsult in 1999.
The Karadobi hydropower project is located on the Abbay River ( Blue Nile ). The proposed dam site is located 1.7km down stream of its confluence with Guder River at about 135km (air distance) north west of Addis-Ababa. The project was studied at reconnaissance level in the Abbay River Master Plan Project by BCEOM, in 1998.
The objective of the feasibility study of Baro project is to produce a bankable report that will analyze and document all-important aspects required for the formal approval of the project by MoWR and other governmental authorities of Ethiopia . and consideration of priority among ENSAP project by ENCOM.
The objective of the pre-feasibility study of Karadobi project is to produce a report that will analyze all important aspects in relation to the project to a preliminary level and indicates technical, economic, social and environmental viability of the project. It shall serve as basis for the government of Ethiopia , the government of Norway who pledged the study fund and ENCOM to decide further action to be taken with respect to the project.
The Ministry of Water Resources had entered an agreement and signed a contract with the international consultants, Norplan-Norconsult- Lahmeyer (with local associates) on May 10, 2004, to undertake pre-feasibility and feasibility studies of Karadobi and Baro hydropower projects respectively.
The consultants have commenced the investigation work on June 1, 2004 and by now they have completed the feasibility study of the Baro and the pre-feasibility studies of the Karadobi Multi-purpose project and have submitted the Final Study Reports.
According to the present feasibility studies, full development of the Baro scheme (Baro-1, Baro-2 & Genji Diversion) will have a power generation with an installed capacity of 896 MW.
The present pre-feasibility study of the Karadobi Multi-Purpose Project indicate a rolled concrete gravity dam of maximum structural height of 260m and length of about 684 m at the crest, with a corresponding installed capacity of 1600 MW. The reservoir area full level has an area of 445km 2 with a capacity of. 40,200 Mm 3 .
Project Design (Goal, Outcomes, and 0utputs) of the feasibility study of the Baro & Pre-feasibility study of the Karadobi
The goal of the Project is to:
- Promote regional economic development through provision of more renewable hydropower energy at a reasonable cost
- To promote regional Co-operation in the power sector and increase power trade via future interconnected transmission networks in the Eastern Nile countries ( Ethiopia , Sudan & Egypt )
- To protect the Environment by providing environment friendly energy resources
- • To create a source of foreign currency revenue for Ethiopia .
The output of the Norwegian contribution is a feasibility study report for the Baro hydropower Project and a pre-feasibility report for the Karadobi hydropower Project.
The location of the Baro Multi-Purpose Project & the Karadobi Multi-Purpose Project (MPP) are shown on the enclosed figures (fig 1, 2 & 3)
Image 1 Location Map of Baro-Karadobi Project
Image 2 Karadobi Project Dam Site
FEASIBILITY STUDY OF WABE-SHEBELLE (WS18) MULTIPURPOSE PROJECT
Wabe-Shebelle (WS18) Multipurpose Project site is located in the middle of the Wabe-Shebelle River Basin about 785 km South-East of Addis Ababa and 255 km South-West of Jijiga town. The access is asphalt road up to Harar (526 km), all weather /gravel/ road from Harer up to Fik (173 km), dry weather road from Fik to Hamero (50 km) and the rest (36 km) is trail. The geographical location of the dam site is 42 0 07'00”N and 07 0 27'00”E.
The project has 2238.19 Mm 3 live storage between 580m and 535.41m, and generates energy in the surface power station. The power system has a rock-fill dam with a central core clay, 111 m high. The surface powerhouse has a size of 120mx31mx39.2m. The system has a steel penstock of 8m diameter and 420m length connected with 3 Francis turbines with a total installed capacity of 87.75MW. The power from WS18 project can be evacuated though 1no. Double circuit 230 KV transmission line connected to Bale Robe substation.
Image 3 Shebelle Project Dam Site
The objective of the study is to recommend the optimum utilization of the potential of the WS-18 Site for the purpose of irrigation development and power generation. 14 potential irrigation projects have been identified in 1973 by BCEOM study of the lower valley. The total net area of these projects identified by BCEOM is 92,000ha. As the first priority for the development, Ilo-Uen /net area =15,000ha/ and Bul-Doho /net area =17,000ha/ will be studied during the current Multipurpose feasibility study.
FEASIBILITY STUDY OF GENALE (GD-6) HYDROPOWER PROJECT
Genale GD-6 is one of the most attractive hydropower projects identified and studied at pre-feasibility level in the ongoing Genale-Dawa River Basin Integrated Resources Development Master Plan Study Project.
The project is located approximately 50 km South-East of Negelle Town . The UTM coordinates of the dam site are 646650 E / 594090 N. The powerhouse is located in Filtu Wereda, Liben Zone of the Somali National Regional State , whereas the dam is in the Oromia National Regional State . The dam site can be accessed from the main Road 44 approximately 1km east of the village Hayadimtu turning towards North West on an improved trail. After approximately 26km a steep slop permits the passage only during dry weather. The total length of the track ranges about 36km from the road to the Genale River . The project design consists of a 39m high RCC dam, a head-race tunnel of about 18km length and a penstock of 1.1km, connected to the open-air powerhouse with 3 Francis turbines with a total installed capacity of 257MW and a generation of 1231GWh p.a.
Image 4 Genale Project Dam Site
PREFEASIBILITY STUDY OF BORDER AND MANDAYA HYDROPOWER PROJECTS
Assessment of the Abay River basin by the USBR in 1964 identified four hydropower sites in the main Abay River course, Karadobi, Mabil, Mandaya and Border . Karadobi is the most upstream of all the identified sites located some 60 kilometres downstream of the Kessie Bridge . The Mabil site is located downstream of Karadobi and upstream of Mandaya site. Border is the most downstream of all the hydropower sites of the Abay river identified within Ethiopia .
Under the Nile Basin Initiative a number of hydropower sites including Border and Mandaya are proposed to be developed in Ethiopia for the benefit of the Eastern Nile basin countries ( Egypt , Ethiopia and Sudan ). The Eastern Nile Technical Regional Office (ENTRO) hired a consultant, EDF/SW, to conduct The Eastern Nile Power trade program study. This study includes feasibility study of interconnection between the Eastern Nile countries and Pre Feasibility studies of the Border and Mandaya Hydropower sites in Ethiopia and DalI hydropower site in Sudan .
Previous studies conducted on the Border and Mandaya sites were at reconnaissance level. The pre feasibility studies of the Border and Mandaya hydropower sites are at preliminary stage and a brief summary of the findings and their characteristics will be presented as follows.
MANDAYA HYDROPOWER SITE
The Mandaya site is the most upstream of the hydropower sites under consideration in the study of the Eastern Nile power trade program study. The site is only accessible by helicopter as there appears to be no roads or tracks within 50 km. The topography at the site is well suited for the development of a major dam. The USBR (1964) reconnaissance study recommended a dam some 150 metres in height (FSL 741 m) with a reservoir extending upstream to the next identified site at Mabil. Preliminary investigation of the present study shows that the Mandaya site is capable of accommodating a dam of up to 260 metres in height (FSL 860 m) or thereabouts, obviating the need for the Mabil project and with the reservoir extending upstream close to the Karadobi site.
The reservoir area and volumes have yet to be established. However, it is clear that the reservoir will provide a high degree of regulation of inflows and flood mitigation as well as having a sufficiently large volume to ensure a long period of life prior to significant storage losses due to sediment deposition.
River flows at Mandaya are approximately 60% greater than Karadobi. As a consequence the installed capacity of the Mandaya project is preliminarily estimated as some 2400 – 2800 MW with potential energy generation estimated as some 16,000 to 18,000 GWh/year. A more detailed study of reservoir modelling will confirm the firm and average energy output and installed capacity.
From field observations it appear that there are few permanently resident population within the reservoir area.
The Mandaya project offers high potential for multi-purpose benefits through integrated planning taking account of potential for flood alleviation and regulation of flows.
Image 5 Mendaya Project Dam Site
The Border site is the most downstream of the hydropower sites under consideration within Ethiopia . The topography at the site is well suited to development of a dam of moderate height of some 80 m. The USBR (1964) study recommended a dam some 80 metres in height (FSL 575 m) with a reservoir extending upstream close to the Mandaya site. This development appears near-optimal for the site since higher levels would appear to require extensive saddle dams to contain the reservoir. Observations at the site confirm the presence of good foundation rock which would be suitable for concrete aggregate or rockfill.
There would be some multi-purpose benefits of river regulation and flood alleviation downstream, associated with the integrated development of the Border reservoir but not to the same extent as for Mandaya. There is likely to be some loss of flood recession agriculture along the Nile downstream in Sudan and there would be a substantial reduction in sediment delivered to Roseires reservoir.
The installed capacity would be of the order of 800 MW and annual energy generation would be of the order of 7000 – 8000 GWh/yr.
A number of villages are present along the Nile river valley and would need to be resettled to nearby areas along the reservoir perimeter. The preliminarily estimated population that would be displaced by reservoir amounts to some 2000 – 5000 people.
Image 6 Border Project Dam Site
DETAIL DESIGN OF KESEM HYDROPOWER PROJECT
Ethiopia has high potential for production of sugar for both internal and export markets. This is because of its geographical location (just north of the equator), a wide variety of ecological regions, topography & climate.
The project site is situated at about 220 Km from Addis Ababa along the Addis Ababa-Mille Road . Geographically the area is located 39° 54' E and 09° 09' N.
With the objective of raising sugar production, agreement has been signed in August 2004 between the Ministry of Water Resources and the Water Works Design and Supervision Enterprise (Consultant) to prepare a detail design of Kesem irrigation project. The agreement was meant for the development of sugarcane in the kesem and bolhamo areas. Most of the design works are now completed and construction activities are started.
The study proposes a rock fill dam with reservoir capacity of 500 MCM located upstream of existing Awara Melka weir for regulation. A weir about 10 kms downstream of the dam was proposed for diverting the regulated water to irrigate the left and right banks of the Kesem River .
In order to make the kesem Irrigation project more attractive, the Ministry of Water Resources suggested incorporating the development of hydropower plant in the system to utilize the flowing water to the irrigation field. The hydropower potential is dictated by downstream irrigation requirement. The layout of the project will allow producing 10 to 15MW of power with only additional cost of electromechanical equipments. The plant would have to operate over a wide range of head and discharge. The capacity will be even more with the current pattern of irrigation demand.
Image 7 Kesem Project Dam Site