Volume 1 Main Report
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THE FEDERAL DEMOCRATIC REPUBLIC OF ETHIOPIA MINISTRY OF WATER RESOURCES GENALE GD-6 HYDROPOWER PROJECT FEASIBILITY STUDY Final Report Volume 1 Main Report May 2009 in association with Federal Democratic Republic of Ethiopia – Ministry of Water Resources Volume 1 Feasibility Study of Genale GD-6 Hydropower Project Page i Structure of the Feasibility Report Volume 1 Main Report Volume 1 is the Main Report, a stand-alone volume that gives the reader a complete picture of the recommended project and the main results of the study. Volume 1 starts with an Executive Summary. Details and data sheets of studies and analyses within the various fields (geology, hydrology, sediments, simulations, hydraulic analysis, economic analyses, etc.) are given in separate volumes/annexes. Volume 2 Project Drawings of Genale GD-6 HPP Series A: General drawings Series B: Civil project structures Series C: Mechanical and electrical equipment Series D: Transmission lines and power system Series E: Geology and ground conditions Series F: Construction schedule Series G: Access roads Volume 3 Supporting Documents Part 1 - Various analyses Annex 3 A: Reservoir operation and power production Annex 3 B: Hydrology and sediment transport Annex 3 C: Hydraulic analyses. Optimisation. Annex 3 D: Access roads Annex 3 E: Power system and transmission lines Annex 3 F: Surveying and mapping Annex 3 G: Detailed cost estimate Annex 3 H: Economic and financial analyses Volume 4 Supporting Documents Part 2- Geology and Geotechnics. Ground conditions and ground engineering. Annex 4 A: Geological mapping – field report with photographs Annex 4 B: Rotary core drillings – core logs Annex 4 C: Core box photographs Annex 4 D: Field permeability tests Annex 4 E: Laboratory test results Annex 4 F: Seismic Hazard Assessment Report Volume 5 Environmental Impact Assessment GD-6 Feaisbility Report Final Volume 1.doc NORPLAN – NORCONSULT JV in Association with Shebelle Engineering Federal Democratic Republic of Ethiopia – Ministry of Water Resources Volume 1 Feasibility Study of Genale GD-6 Hydropower Project Page ii TABLE OF CONTENTS - VOLUME 1 LIST OF TABLES ................................................................................................................................ VIII LIST OF FIGURES ................................................................................................................................. XI LIST OF REFERENCES ...................................................................................................................... XIII LIST OF ABBREVIATIONS AND ACRONYMS .................................................................................. XIV 1 EXECUTIVE SUMMARY ........................................................................................................... 1-1 1.1 Introduction ................................................................................................................................. 1-1 1.2 Key results of study .................................................................................................................... 1-1 1.2.1 Power production and Cost .............................................................................................................1-1 1.2.2 Base Case, Economic and Financial analysis. ................................................................................1-4 1.2.3 Environmental impacts ....................................................................................................................1-6 1.3 Genale GD-6 - Brief description of the recommended project ................................................... 1-8 1.3.1 Project location................................................................................................................................1-8 1.3.2 Civil structures and reservoir ...........................................................................................................1-9 1.3.3 Electromechanical equipment ....................................................................................................... 1-10 1.3.4 Small Hydropower Plant ................................................................................................................ 1-11 1.4 Key project characteristics for Genale GD-6 ........................................................................... 1-12 2 STUDY BACKGROUND ............................................................................................................ 2-1 2.1 Project location ........................................................................................................................... 2-1 2.2 Previous studies on Genale GD-6 Hydropower Project,............................................................ 2-2 2.3 Objective for the present study .................................................................................................. 2-2 3 GENALE GD-6 – PROJECT DESCRIPTION ............................................................................ 3-1 3.1 Genale GD-6 - Arrangement of project structures ..................................................................... 3-1 3.2 Genale GD-6. Layout changes. ................................................................................................. 3-2 3.3 Genale GD-6 - Dam and reservoir ............................................................................................. 3-3 3.3.1 Dam axis selection ..........................................................................................................................3-3 3.3.2 Dam height ......................................................................................................................................3-4 3.3.3 Dam type and sealing concept ........................................................................................................3-5 3.3.4 Reservoir features ...........................................................................................................................3-7 3.4 Genale GD-6 - Spillway ............................................................................................................ 3-11 3.4.1 Spillway type and dimensions ....................................................................................................... 3-11 3.4.2 Spillway design for flood discharge ............................................................................................... 3-12 3.4.3 Stepped spillway option .................................................................................................................3-15 3.4.4 Spillway capacity ........................................................................................................................... 3-15 3.5 Genale GD-6 - Power waterways, powerhouse and associated structures ............................ 3-17 3.5.1 General layout ............................................................................................................................... 3-17 3.5.2 Power intake and headrace waterway ...........................................................................................3-17 3.5.3 Powerhouse complex .................................................................................................................... 3-19 3.5.4 Tailrace waterway and outlet ......................................................................................................... 3-20 3.6 Genale GD-6 - River diversion during construction ................................................................. 3-21 3.7 Genale GD-6 - Access roads and camps ................................................................................ 3-22 3.7.1 Access roads ................................................................................................................................ 3-23 3.7.2 Camps ........................................................................................................................................... 3-27 3.8 Genale GD-6 - Mechanical equipment ..................................................................................... 3-29 3.8.1 General ......................................................................................................................................... 3-29 GD-6 Feasibility Report Final Volume 1.doc NORPLAN – NORCONSULT JV in Association with Shebelle Engineering Federal Democratic Republic of Ethiopia – Ministry of Water Resources Volume 1 Feasibility Study of Genale GD-6 Hydropower Project Page iii 3.8.2 Turbine selection ........................................................................................................................... 3-29 3.8.3 Main turbine data .......................................................................................................................... 3-30 3.8.4 Turbine design .............................................................................................................................. 3-32 3.8.5 Main inlet valves ............................................................................................................................3-32 3.8.6 Governors and oil pressure system ............................................................................................... 3-34 3.8.7 Stability and surges ....................................................................................................................... 3-34 3.8.8 Machine hall crane .......................................................................................................................