The document summarizes a study on identifying feasible sites for micro hydropower generation in the Jimma area of Ethiopia. Six potential sites located along rivers were proposed. After evaluation based on technical, economic and social criteria, the Kersa-1 and Wanja sites were selected as the most attractive pilot project sites. Key details of the two sites like available flow, head, power potential, infrastructure requirements and proposed hydraulic designs are provided. The study aims to upgrade existing traditional watermills to small hydropower schemes for rural electrification through a collaboration between Jimma University and GIZ.

1. Identification and study of feasible watermill sites for
Micro Hydropower Generation in Jimma Area
Seminar Presentation
Frezer Seid Awol
30.10.2012

2. Watermills
• Constructed by diverting water from river to hit a wheel which is connected
to a mill
• Water driven mills used to grind grains
• History in Ethiopia traced back to mid 19th century
• Distributed in rural areas where electricity and diesel not reached
• Privat or public
 Substitute hand-driven mills
 Small scale industry
 Multipurpose use of river
X Slow operation
X Flooded in rainy seasons
X Inefficient water use
 Hence, upgrading to small hydropower scheme was advocated and requested.

3. Classification of Hydropower
By capacity By design head
Large >100 MW Low-head <15 m
Medium 15-100 MW Medium-head 15-50 m
Small 1-15 MW High-head >50 m
Mini 100 KW – 1 MW
By grid type
Micro 5 – 100 KW
Off-grid
Pico <5 KW In-grid
By design type
By Power supply system
Run-of-river (Ethiopian context)
Pumped-Storage
Inter-Connected System (ICS)
Storage Self-Contained System (SCS)
Tidal
 The investigation sites are off-grid, low to medium head, micro, self-
contained system run-of-river hydropower plants.

4. MoU for Rural Electrification
• Memorandum of Understanding signed between Deutsche Gesellschaft für
Internationale Zusammenarbeit (GIZ) GmbH and Jimma University :
– To actively involve stakeholders in hydropower development secter
– To select and implement 2 joint pilot projects in Jimma area from proposed 6 sites for
demonstration and know how transfer
– To establish a center of Excelence for research and capacity building
• 2nd largest University • BMZ and BMF
• Started as a college in • Since 1964 in Ethiopia
1952 • Energy Coordination
• Institute of Office
Technology • Policy & stategy advice
• Courses & Researchs • Energy efficient
• Proposal on technology promotion
hydropower projects • Rural electrification
• Feasibility study for • Pilot projects evaluation
pilot projects
• Funding
• Jimma Hydropower
Center of Excelence

5. Jimma Hydropower Center of Excelence
Source: Abera Melese, JHPCE, J uly 2 010
• Hydro – Scout
• Consultancy and support • Concept note and proposal
• Customized training and lectures • Awareness and promotions
• Feasibility study and design • Community setup
• Research and thesis • Supervision
• 2 Pilot projects design and execution • Documentation

6. Activities
 Team assigned to select 2 most technically & socio-economically attractive watermills
sites from the proposed 6 sites and design the HP scheme
• Desk study Desk Study
- To be familiar with hydrologic and topographic profile
• Reconnaissance Visit of the project sites
- To be aware of rough location (distance) &
• Pre – feasibility study accessibility
Reconnaissance visit
• Feasibility study - Short Visit to the proposed sites
• Detailed design - Identify if there is watermills at the sites & which are
functional or not
- Identifying ownership & social structures
- Nominate contact persons
Feasibility Study
- The final decision for or against the
recommended sites Pre feasibility study
- Best 2 pilot projects selection and re- - Available flow at dry season
assessment - Available head
- Design of civil and electromechanical structures - Topographic maps
- Socio economic analysis - Access to project site
Detail Design - Availability of local construction material at project
- Preparation of the detailed layout of the Civil & sites
Electro Mechanical scheme - To determine which sites are most attractive
- Cost-Benefit analysis - Development options , conclusions and
recommendations are made

7. Proposed sites

8. Proposed sites
Site Name: Kersa-1 Watermills: 1 traditional
Distance (From Jimma): 23km Discharge: 120-160l/s
GPS location: N 07o 44’05.2’’ Head: 11m
E 37o 0’51.62’’ Accessibility: Good
Elevation: 1760masl Power Potential: 11 KW
Remark: Attractive

9. Proposed sites
Site Name: Kersa 2 Watermills: NO
Distance (From Jimma): 26km Discharge: 200l/s
GPS location: N 07o 44’ 53.9’’ Head: 4-5m
E 36o 57’ 41.8’’ Power potential : 5.5-6.9KW
Elevation: 1750masl Accessibility: Bad
Remark: Not Attractive for
MHP

10. Proposed sites
Site Name: Kelecha Watermills: 1 Not functional
Distance (From Jimma): 25km Discharge: 100 l/s
GPS location: N 7°39'30.40" Head: 5m
E 37° 1'50.71“ Power output: 3.4KW
Elevation: 1702masl Accessibility: Medium
Remark: Not Attractive for
MHP

11. Proposed sites
Site Name: Melka Qiltu Watermills: 1 Not functional
Distance (From Jimma): 24km Discharge: 80 l/s
GPS location: 7°46'30.71"N Head: 15m
36°38'35.16"E Power output: 8.24KW
Elevation: 1930masl Accessibility: Medium
Remark: Not Attractive for MHP

12. Proposed sites
Site Name: Fechie Watermills: 1 Not functional
Distance (From Jimma): 23km Discharge: 90 l/s
GPS location: 7°44'8.11"N Head: 14m
36°40'49.06"E Power output: 8.65KW
Elevation: 2017masl Accessibility: Bad
Remark: Not Attractive for MHP

13. Proposed sites
Site Name: Wanja Watermills: 1 traditional
Distance (From Jimma): 38km Discharge: 250l/s
GPS location: N 07o 52’02.5’’ Head: 35m
E 36o 42’03.8’’ Accessibility: Good
Elevation: 1520masl Remark: Irrigation scheme is being
constructed on the river
without affecting the
watermill, attractive

14. Proposed sites
Summary
Site Name Distance Discharge Head Power output Accessibility Existing Social
(km) (m³/s) (m) (KW) Watermills status
1 Kersa 1 23 0,14 12 11,5 Accessible 1 Operational Active
2 Kersa 2 26,03 0,2 4 5,5 Not accessible None Passive
3 Wanja 38 0,25 35 60,1 Accessible 1 Operational Active
Mostly
4 Kelecha 25 0,1 5 3,4 1 Abandoned Passive
Accessible
5 Melka Qiltu 24 0,08 15 8,24 Accessible 1 Abandoned Passive
6 Fechie 23 0,09 14 8,65 Not accessible 1 Abandoned Passive

15. Selection Criteria
Technically attractive sites fulfills ideally most of the following criteria
• Available flow and head are substantial.
• Topography is favorable.
• Ratio of water head to canal length is 10% or better.
• Firm capacity is more than demand estimate.
• Low degree of difficulties / risks.
• Distance of powerhouse to load center is less than 1 km per 100 kW
installed capacity.
• Consumer density is greater than 30 connections per 1Km of
transmission and distribution lines.
 Technically attractive projects are not necessarily promising projects and vise-versa!
Source : GIZ guide lines, MHP assessment standards

16. Selection Criteria
Non-technical aspects should be considered equally.
• Synergies with other projects or installations e.g. irrigation, water supply…
• Large part of the equipment can be manufactured & maintained locally.
• Limited number of technically critical parts.
• Country's feed-in-tariff policy is encouraging.
• Substantial equity contribution to project cost is available.
• Broad political support at all relevant levels can be secured.
• No social conflicts due to project implementation expected.
• No major adverse environmental impacts to be expected.
 Kersa-1 and Wanja sites are selected.
Source : GIZ guide lines, MHP assessment books, JU C ivil Eng’g student thesis

17. Selected sites
Kersa-1
• 124 households
• Power Consumption: 45.276 KWh/household/month
• Good access for transportation
• Local construction material
• Village out of gird line
• Traditional weir of 6m length at 40o CCW
• Main river 160 l/s, diverted canal 120l/s
• 1200m earth canal

18. Selected sites
Kersa-1
• Development option
Option 1. At the existing watermill- To modify the existing site to get 11m
head and upgrade the trash-rack, forebay, penstock and powerhause
Option 2. 50m upstream of the watermill- To construct new Civil and
Electro-mechanical structures,
• Diverting water completely and using T-14 cross flow turbine(η = 70%),
has power potential of:
Power = ηγQH
= 0.7*9810 N/m*0.14 m³/s*12 m
= 11.5 KW

19. Selected sites
Wanja
• 688 households
• Power Consumption: 99.176 KWh/household/month
• Site is easily accessible for transportation
• Community is in remote area
• Head - 35m
• Discharge - 250 l/s
• Ratio of water head to canal length about 16%
• Synergy with Irrigation scheme
• Local construction materials available
• Power potential = 60 KW
• the most attractive & promising feasible site

20. Rough layout
Kersa 1 Wanja

21. Hydraulic design
Wanja Site
Intake structure – Weir

22. Hydraulic design
Wanja Site
Diversion canal Forbay tank
P enstock
Length – 220m

23. Hydraulic design
Wanja Site
Penstock – Slide block
• Length = 67m
• Type - Welded steel
• Internal Diameter = 0.35m
• Wall thickness = 6 mm
• Anchor block size = 2.34 m3
• Slide block spacing = 8m
Slide block

24. Hydraulic design
Kersa-1 Site
Intake structure – Weir
• Type – Diagonal Ogee-crested weir @ 40o
• Calculation according to USACE and Chow,
1959
• HQ50 = 58 m³/s
• Length – 7.5m
• Upstream height – 1m
• Downstream height – 1.66m
• Bottom Width – 2.66m

25. Hydraulic design
Kersa-1 Site
Diversion Canal
• Modify the traditional canal
• Length = 1150 m
• Type - unlined earth
• Total depth = 0.5m
• Base width = 0.7m
• Channel bed slope = 0.002 m/m

26. Hydraulic design
Turbine Selection
T-15 Crossflow turbine is selected for both plants

27. Hydraulic design
Turbine sizing – Wanja site
• Design head 36.47m
• Design discharge 230 l/sec
• Diameter of the runner 0.3m
• Calculated width of the runner = bo = 159mm
• Calculated turbine speed = 765 rpm
• Run away speed = 1377 rpm
• Specific speed = 24.7
• Generator, belt and transmission efficiency = 85 %
• Electrical power output = 54.28 KW
L oc ally manufactured T-15 turbine @ Ererte site, a G IZ project

28. Thank you!