No.
THE FOLLOW-UP STUDY
ON
THE REHABILITATION OF HYDROPOWER STATIONS IN THE
KELANI RIVER BASIN FOR
HYDROPOWER OPTIMIZATION IN
SRI LANKA
FINAL REPORT Vol. I
MAIN REPORT
JULY 2005
JAPAN INTERNATIONAL COOPERATION AGENCY ECONOMIC DEVELOPMENT DEPARTMENT
ED JR 05 - 053
PREFACE
In response to a request from Government of the Democratic Socialist Republic of Sri Lanka, the Government of Japan decided to conduct the Follow-up Study on the Rehabilitation of Hydropower Stations on the Kelani River Basin for the Study on Hydropower Optimization in Sri Lanka and entrusted the study to the Japan International Cooperation Agency (JICA).
JICA sent a study team led by Mr. Tsuyoshi Nakahata and organized by Electric Power Development Co., Ltd. to Sri Lanka five times from July 2004 to May 2005.
The study team held discussions with the officials concerned of the Government of Sri Lanka, and conducted field studies in Sri Lanka. After its return to Japan, the team conducted further studies and compiled the results in this report.
I hope this report will contribute to the promotion of rehabilitation of hydropower stations in the Kelani River basin and to the enhancement of friendly relations between our two countries.
I wish to express my sincere appreciation to the persons concerned for their close cooperation throughout the study.
July 2005
Tadashi Izawa Vice-President Japan International Cooperation Agency
July, 2005 Mr. Tadashi Izawa Vice-President Japan International Cooperation Agency Tokyo, Japan
Dear Mr. IZAWA,
Letter of Transmittal
We are pleased to submit our report on the Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for the Study on Hydropower Optimization in Sri Lanka.
This study was conducted for the purposes of carrying out inspections of troubles in the five hydropower stations in the Kelani River basin, of making the rehabilitation plan such as repair and replace with a feasibility study level for them and of giving suggestions of the maintenance manuals for hydropower in Sri Lanka.
During the study period, we made our best effort to establish the optimum plans from the technical, economic and environmental points of view.
We wish to take this opportunity to express our sincere gratitude to your Agency, the Ministry of Foreign Affairs, and the Ministry of Economy, Trade and Industry. We also wish to express our deep gratitude to the Ceylon Electricity Board, the Embassy of Japan in Sri Lanka, the JICA Sri Lanka Office, and other agencies concerned in Sri Lanka for the close cooperation and assistance extended to us during our study period.
Very truly yours,
Tsuyoshi Nakahata Team Leader The study team of the Follow-up Study on the Rehabilitation of the Kelani River Basin for the Study of Hydropower Optimization in Sri Lanka
Laxapana Fall
Castlereagh Dam
Laxapana Hydropower Station (Old and New Laxapana Hydropower Station)
Wimalasurendra Hydropower Station
Turbines and Generators in Old Laxapana Hydropower Station
Efficiency test in New Laxapana Hydropower station
Intake Guard Valve House of Canyon Hydropower Station
Water Leakage from Turbine in Polpitiya Hydropower Station The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin The Study of Hydropower Optimization in Sri Lanka
CONTENTS
CONCLUSION AND RECOMMENDATION...... CR-1 Conclusion ...... CR-1 Recommendation ...... CR-4
1. INTRODUCTION ...... 1-1 1.1 Background of the Study ...... 1-1 1.1.1 Social and Economic Background ...... 1-1 1.1.2 Necessity of Rehabilitation of Hydropower Stations in the Kelani River Basin and Request for Technical Assistance...... 1-1 1.2 Purposes of the Study ...... 1-2 1.3 Contents of Each Study Stage...... 1-2 1.4 Persons involved in the Study (Positions as of the time of the Study) ...... 1-4
2. GENERAL FEATURES OF SRI LANKA...... 2-1 2.1 Topography...... 2-1 2.2 Climate ...... 2-2 2.3 Government ...... 2-2
3. SOCIO-ECONOMY...... 3-1 3.1 Population...... 3-1 3.1.1 Census Population...... 3-1 3.1.2 Labor Force...... 3-1 3.1.3 Ethnic Group...... 3-1 3.2 Macro Economic Features...... 3-1 3.2.1 National Accounts...... 3-1 3.2.2 Economic Sector Profile ...... 3-2 3.2.3 External Trade and Balance of Payment ...... 3-2 3.2.4 Government Finance...... 3-3 3.2.5 External Debt and Outstanding ...... 3-3 3.2.6 Price Indices and Exchange Rates...... 3-4 3.3 Projection of Socio-Economic Structures...... 3-4 3.3.1 Population and GDP Projection ...... 3-4
4. PRESENT SITUATION OF POWER SECTOR IN SRI LANKA...... 4-1 4.1 Energy Situation ...... 4-1 4.2 History and Formation of Power Sector...... 4-1 4.3 Power Demand and Supply Balance ...... 4-5 4.4 Electricity Generation...... 4-7 4.5 Electricity Tariff ...... 4-8 4.6 Existing Power Plants...... 4-11 4.7 Introduction of Independent Power Producers (IPPs) ...... 4-12 4.8 Present Status of Transmission and Distribution Lines ...... 4-13
Final Report i The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin The Study of Hydropower Optimization in Sri Lanka
4.9 Forecast of Power Demand and Supply ...... 4-13 4.10 Power Development Plan ...... 4-14 4.11 History and Difficulties of Power Development Plan ...... 4-18 4.12 Transmission and Distribution Lines Expansion Plan...... 4-19 4.13 Present Situation of Hydropower Stations in Kelani River Basin...... 4-20
5. CIVIL STRUCTURES...... 5-1 5.1 Present Status and Rehabilitation Plan for Wimalasurendra Hydropower Plant ...... 5-3 5.1.1 Castlereagh Reservoir...... 5-3 5.1.2 Castlereagh Dam...... 5-3 5.1.3 Intake...... 5-5 5.1.4 Headrace Tunnel ...... 5-5 5.1.5 Surge Tank...... 5-5 5.1.6 Penstock ...... 5-5 5.1.7 Powerhouse ...... 5-5 5.1.8 Tailrace...... 5-5 5.2 Present Status of and Rehabilitation Plan for Old Laxapana Hydropower Plant .....5-7 5.2.1 Norton Bridge Pondage...... 5-7 5.2.2 Norton Bridge Dam...... 5-7 5.2.3 Intake...... 5-11 5.2.4 Headrace Tunnel ...... 5-11 5.2.5 Surge Tank Turbulence and Explosive Noise...... 5-11 5.2.6 Penstock ...... 5-12 5.2.7 Powerhouse ...... 5-12 5.2.8 Tailrace...... 5-12 5.3 Present Status of and Rehabilitation Plan for Canyon Hydropower Plant ...... 5-13 5.3.1 Maussakelle Reservoir...... 5-13 5.3.2 Maussakelle Dam...... 5-13 5.3.3 Intake...... 5-13 5.3.4 Headrace Tunnel ...... 5-14 5.3.5 Surge Tank...... 5-14 5.3.6 Penstock ...... 5-14 5.3.7 Powerhouse ...... 5-14 5.3.8 Tailrace...... 5-14 5.4 Present Status of and Rehabilitation Plan for New Laxapana Hydropower Plant..5-16 5.4.1 Canyon Pondage...... 5-16 5.4.2 Canyon Dam...... 5-16 5.4.3 Intake...... 5-17 5.4.4 Headrace Tunnel ...... 5-17 5.4.5 Surge Tank...... 5-17 5.4.6 Penstock ...... 5-20 5.4.7 Powerhouse ...... 5-20 5.4.8 Tailrace...... 5-20
Final Report ii The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin The Study of Hydropower Optimization in Sri Lanka
5.5 Present Status of and Rehabilitation Plan for Polpitiya Hydropower Plant ...... 5-22 5.5.1 Laxapana Pondage...... 5-22 5.5.2 Laxapana Dam...... 5-22 5.5.3 Intake...... 5-24 5.5.4 Headrace Tunnel ...... 5-25 5.5.5 Surge Tank...... 5-25 5.5.6 Penstock ...... 5-25 5.5.7 Powerhouse ...... 5-25 5.5.8 Tailrace...... 5-26 5.6 Others ...... 5-27 5.6.1 Drainage Relief Holes...... 5-27 5.6.2 Removal of Vegetation...... 5-27 5.6.3 Allocation of Civil Engineer ...... 5-27 5.6.4 Periodic Inspection...... 5-27 5.7 Surging Analysis of the Old Laxapana Hydropower Plant...... 5-28 5.7.1 General...... 5-28 5.7.2 Methodology and Conditions...... 5-28 5.7.3 Results...... 5-29 5.7.2 Conclusions...... 5-33
6. HYDRO-MECHANICAL EQUIPMENT...... 6-1 6.1 Wimalasurendra Hydropower Station ...... 6-6 6.1.1 Site Survey ...... 6-6 6.1.2 Penstock ...... 6-6 6.1.3 Flashboard of Spillway ...... 6-7 6.1.4 Intake Gate and Trashrack...... 6-8 6.1.5 Bottom Outlet Works ...... 6-8 6.1.6 Tailrace Gate...... 6-13 6.2 Old Laxapana Hydropower Station ...... 6-13 6.2.1 Site Survey ...... 6-13 6.2.2 Penstock ...... 6-13 6.2.3 Spillway ...... 6-15 6.2.4 Intake Gate and Trashrack...... 6-15 6.2.5 Bottom Outlet Works ...... 6-16 6.2.6 Tailrace Gate...... 6-16 6.3 Canyon Hydropower Station ...... 6-17 6.3.1 Site Survey ...... 6-17 6.3.2 Penstock ...... 6-17 6.3.3 Spillway ...... 6-18 6.3.4 Intake Gate and Trashrack...... 6-18 6.3.5 Bottom Outlet Works ...... 6-18 6.3.6 Intake Guard Valve...... 6-19 6.3.7 Tailrace Gate...... 6-19
Final Report iii The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin The Study of Hydropower Optimization in Sri Lanka
6.4 New Laxapana Hydropower Station...... 6-20 6.4.1 Site Survey ...... 6-20 6.4.2 Penstock ...... 6-20 6.4.3 Spillway gate...... 6-21 6.4.4 Intake Gate and Trashrack...... 6-21 6.4.5 Bottom Outlet Works ...... 6-22 6.4.6 Sedimentation...... 6-22 6.5 Polpitiya Hydropower Station ...... 6-23 6.5.1 Site Survey ...... 6-23 6.5.2 Penstock ...... 6-23 6.5.3 Spillway Gate...... 6-24 6.5.4 Intake Gate and Trashrack...... 6-25 6.5.5 Bottom Outlet Works ...... 6-26 6.5.6 Sedimentation...... 6-27
7. ELECTRO-MECHANICAL EQUIPMENT...... 7-1 7.1 General ...... 7-1 7.2 Present Status of and Rehabilitation Plan for Wimalasurendra Hydropower Station...... 7-4 7.2.1 Mechanical Equipment...... 7-4 7.2.2 Electrical Equipment...... 7-6 7.2.3 Control Equipment...... 7-9 7.3 Present Status of and Rehabilitation Plan for Old Laxapana hydropower station ...... 7-13 7.3.1 Mechanical Equipment...... 7-13 7.3.2 Electrical Equipment...... 7-19 7.3.3 Control Equipment...... 7-22 7.4 Present Status of and Rehabilitation Plan for Canyon hydropower station ...... 7-26 7.4.1 Mechanical Equipment...... 7-26 7.4.2 Electrical Equipment...... 7-28 7.4.3 Control Equipment...... 7-29 7.5 Present Status of and Rehabilitation Plan for the New Laxapana hydropower station ...... 7-31 7.5.1 Mechanical Equipment...... 7-31 7.5.2 Electrical Equipment...... 7-33 7.5.3 Control Equipment...... 7-35 7.6 Present Status of and Rehabilitation Plan for Polpitiya hydropower station...... 7-39 7.6.1 Mechanical Equipment...... 7-39 7.6.2 Electrical Equipment...... 7-43 7.6.3 Control Equipment...... 7-45
8. REHABILITATION PLAN...... 8-1 8.1 General ...... 8-1
Final Report iv The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin The Study of Hydropower Optimization in Sri Lanka
9. MAINTENANCE MANAGEMENT...... 9-1 9.1 Civil Structures...... 9-1 9.1.1 Present Status ...... 9-1 9.1.2 Recommended Inspection Manual...... 9-1 9.2 Hydromechanical Equipment...... 9-3 9.2.1 Present Status ...... 9-3 9.2.2 Recommendations for Maintenance...... 9-3 9.2.3 Technical Documents on Maintenance ...... 9-4 9.3 Electro-mechanical Equipment...... 9-6 9.3.1 Present Status ...... 9-6 9.3.2 The Issue of the Maintenance Work for Electro-mechanical Equipment...9-7 9.3.3 Recommended Frequency and Items for Maintenance Works...... 9-8
10. ECONOMIC AND FINANCIAL ANALYSIS ...... 10-1 10.1 Economic Analysis ...... 10-1 10.1.1 Estimate of Economic Benefits...... 10-2 10.1.2 Estimate of Economic Costs ...... 10-4 10.1.3 Result of Economic Evaluation...... 10-5 10.2 Sensitivity Analysis of EIRR...... 10-5 10.2.1 Sensitivity of Project Costs ...... 10-5 10.2.2 Sensitivity of Fuel Price...... 10-6 10.2.3 The Limiting Time of without Project ...... 10-6 10.3 Financial Analysis ...... 10-9 10.3.1 Estimate of Financial Benefit...... 10-9 10.3.2 Estimate of Financial Cost ...... 10-9 10.4 Result of Financial Evaluation ...... 10-10 10.5 Sensitivity Analysis of FIRR...... 10-10 10.5.1 Sensitivity of Project Costs ...... 10-10 10.5.2 Sensitivity of Electricity Price ...... 10-10 10.6 ODA Finance...... 10-11 10.6.1 Analysis of ODA Finance ...... 10-11 10.7 Sensitivity Analysis of ODA Finance...... 10-12 10.7.1 Sensitivity Analysis of Electricity Price...... 10-12 10.7.2 Sensitivity Analysis of Foreign Loan Condition...... 10-12
11. ENVIRONMENTAL IMPACT ASSESSMENT...... 11-1 11.1 Awareness of Environmental and Social Issues in Sri Lanka...... 11-1 11.2 Institutional and Legal Framework in Sri Lanka...... 11-1 11.2.1 Governmental Institutions...... 11-1 11.2.2 Environmental Laws and Regulations ...... 11-2 11.3 Procedure of Environmental Impact Assessment ...... 11-2 11.4 Environmental Impact Assessment for the Rehabilitation of Hydropower Stations in the Kelani River Basin...... 11-5
Final Report v The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
LIST OF TABLES
Table 3.1 Gross National Product at Current Factor Cost Price Table 3.2 Balance of Payments: 1998- 2003 Table 3.3 Summary of Governmental Fiscal Operations Table 3.4 Net Receipt of Foreign Assistance: 1997-2003 Table 3.5 Outstanding Foreign Debt : 1997-2003 Table 3.6 Ownership of Outstanding Foreign Debt : 1997-2003 Table 3.7 Sri Lanka Consumer's Price Index Table 3.8 Foreign Exchange Rates: 1990-2003
Table 4.1 Demand and Supply Balance Table 4.2 Electricity Generation 1989 - 2003 Table 4.3 Gross System Losses and Load Factor Table 4.4 Ceylon Electricity Board Tariff (effective from 1st August 2002) Table 4.5(1) Existing Hydropower Plants (connected to the national grid, as Jan. 2005) Table 4.5(2) Existing Thermal Plants (connected to the national grid, as of Jan. 2005) Table 4.6 Features of Existing IPP Plants Table 4.7 Length of CEB Transmission and Distribution Lines Table 4.8 Number and Capacity of Substations Table 4.9 Load Forecast from 2004to 2024 (Base Case) Table 4.10 Generation Expansion Plan Sequence Table 4.11 Generation Expansion Plan and Reserve Margin Table 4.12 Generation Expansion Plan (in 1993)
Table 5.1 Summary of Investigation Results Table 5.2 Water Quality Test Result (carried out on August 26, 2004) Table 5.3 Measurement Result of Leakage Table 5.4 Annual Loss by Leakage Table 5.5 Financial Analysis Result Table 5.6 Water Quality Test Result at near Surge Tank of New Laxapana Power Plant Table 5.7 Annual Loss due to Leakage Table 5.8 Financial Analysis Result Table 5.9 Number of Rain Gauge Stations Table 5.10 Cost of Rain Gauge Stations Table 5.11 Conditions of Analysis Table 5.12 Case of Analysis
Final Report LT - 1 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Table 5.13 Results of the Analysis
Table 6.1 Main Furthers of Hydro-mechanical Equipment Table 6.2 Rehabilitation Work Cost of Hydro-mechanical Equipment Table 6.3 Measurement Instrument Table 6.4 Comparison Table of SR Gate, Rubber Dam and Steel Gate Table 6.5(1) Measurement Result: Power Station: Wimalasurendra Station Table 6.5(2) Measurement Result: Power Station: Old Laxapana Station Table 6.5(3) Measurement Result: Power Station: Canyon Station Table 6.5(4) Measurement Result: Power Station: New Laxapana Station Table 6.5(5) Measurement Result: Power Station: Polpitya Station
Table 7.1 CEB's Rehabilitation Plan Table 7.2 Facility Data of the Hydropower Stations in Kelani River Basin Table 7.3 Insulation Resistance of Generator Stators at the Wimalasurendra Hydropower Station Table 7.4 Insulation Resister of No. 1 Transformers at the Wimalasurendra Hydropower Station Table 7.5 Insulation Resister of No. 2 Transformers at the Wimalasurendra Hydropower Station Table 7.6 Insulation Resister of Generator Stators at the Old Laxapana Hydropower Station Table 7.7 Insulation Resistance of Generator Transformers for Units 1, 2, and 3 at the Old Laxapana Hydropower Station Table 7.8 Insulation Resistance of Unit 4 Generator Transformers at the Old Laxapana Hydropower Station Table 7.9 Insulation Resistance of Unit 5 Generator Transformers at the Old Laxapana Hydropower Station Table 7.10 Insulation Resister of Generator Stators at Canyon Hydropower Station Table 7.11 Insulation Resistance of Generator Transformers at the Canyon Hydropower Station Table 7.12 Insulation Resistance of Generator Transformers at the Canyon Hydropower Station Table 7.13 Insulation Resistance of Generator Stators at the New Laxapana Hydropower Station Table 7.14 Insulation Resistance of Generator Transformers at the New Laxapana Hydropower Station Table 7.15 Insulation Resistance of Generator Transformers at the New Laxapana Hydropower Station Table 7.16 Turbine Repair Record Table 7.17 Bearing Oil Cooler Repair Record
Final Report LT - 2 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Table 7.18 Insulation Resistance of Generator Stators at the Polpitiya Hydropower Station Table 7.19 Insulation Resistance of No.1 Transformers at the Polpitiya Hydropower Station Table 7.20 Insulation Resistance of No.1 Transformers at the Polpitiya Hydropower Station
Table 8.1 Present Condition of Each Hydro Power Station of the Laxapana Complex (Including Civil and Hydro-mechanical Equipment) Table 8.2 Cost of the Rehabilitation Plan (Including civil and hydro-mechanical equipment) Table 8.3 Schedule of the Rehabilitation Plan (Case 1) Table 8.4 Schedule of the Rehabilitation Plan (Case 2)
Table 10.1 Adjustment Factor, Power Value and Energy Value Table 10.2 Power Value and Energy Value Table 10.3 Outage Term (1) Table 10.4 Outage Term (2) Table 10.5 Pure Construction Cost & Economic Cost Table 10.6 O & M Cost of Wimalasurendra P/S Table 10.7 O & M Cost of Old Laxapana P/S Table 10.8 O & M Cost of New Laxapana P/S Table 10.9.1 Calculation of Economic Evaluation Indices Wimalasurendra P/S Case 1 （Repair as Required） Table 10.9.1 Calculation of Economic Evaluation Indices Wimalasurendra P/S Case 2 （Scheduled Replace） Table 10.10 Calculation of Economic Evaluation Indices Old Laxapana Stage I P/S Table 10.11 Calculation of Economic Evaluation Indices New Laxapana P/S Table 10.12.1 Calculation of Economic Evaluation Indices Wimalasurendra P/S Case 1 （Repair as Required）with special repair 1 Table 10.12.2 Calculation of Economic Evaluation Indices Wimalasurendra P/S Case 1 （Repair as Required）with special repair 2 Table 10.13 Economical Sensitivity of Construction Cost Table 10.14 Economical Sensitivity of Fuel Price Table 10.15 Outage Term (3) (Replace After Crash) Table 10.16 Cost of Energy Not Served Wimalasurendra P/S Table 10.17 Cost of Energy Not Served Old Laxapana Stage I P/S Table 10.18 Cost of Energy Not Served New Laxapana P/S Table 10.19.1 Calculation of Economic Evaluation Indices Wimalasurendra P/S Replace after Crash(1)
Final Report LT - 3 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Table 10.19.2 Calculation of Economic Evaluation Indices Wimalasurendra P/S Replace after Crash(2) Table 10.20.1 Calculation of Economic Evaluation Indices Old Laxapana Stage I P/S Replace after Crash(1) Table 10.20.2 Calculation of Economic Evaluation Indices Old Laxapana Stage I P/S Replace after Crash(2) Table 10.21.1 Calculation of Economic Evaluation Indices New Laxapana P/S Replace after Crash(1) Table 10.21.2 Calculation of Economic Evaluation Indices New Laxapana P/S Replace after Crash(2) Table 10.22 Pure Construction Cost & Financial Cost Table 10.23.1 Calculation of Financial Evaluation Indices Wimalasurendra P/S Case 1 (Repair as Required） Table 10.23.2 Calculation of Financial Evaluation Indices Wimalasurendra P/S Case 2 (Scheduled Replace） Table 10.24 Calculation of Financial Evaluation Indices Old Laxapana Stage I P/S Table 10.25 Calculation of Financial Evaluation Indices New Laxapana P/S Table 10.26 Financial Sensitivity of Hydro Power Construction Cost Table 10.27 Financial Sensitivity of Electricity Tariff Table 10.28 Consolidated Loans and Sources to CEB at End of 1999 Table 10.29.1 Cash Flow Statement: Case of ODA Finance Wimalasurendra PS Case1 Table 10.29.2 Cash Flow Statement: Case of ODA Finance Wimalasurendra PS Case2 Table 10.30 Cash Flow Statement: Case of ODA Finance Old Laxapana StageI P/S Table 10.31 Cash Flow Statement: Case of ODA Finance New Laxapana P/S Table 10.32 Loan Finance Sensitivity of Electricity Tariff Table 10.33 Loan Finance Sensitivity of Foreign Loan Condition
Final Report LT - 4 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
LIST OF FIGURES
Figure 1.1 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Figure 2.1 Administrative Boundary Map Figure 2.2 Administrative Structure of Sri Lanka
Figure 4.1 Organisation Structure of CEB Figure 4.2 Daily Load Curve over the Year Figure 4.3 Growth Rate of GDP and Electricity Sales Figure 4.4 Mechanism of CEB's Cross Subsidy to Domestic Use (1995) Figure 4.5 Expansion Plan and Peak Demand Figure 4.6 Location Map of Power Stations in Sri Lanka Figure 4.7 Longitudinal Section of Kelani River Basin Figure 4.8 Laxapana Complex
Figure 5.1 Sampling Point of Water Quality Test Figure 5.2 Correlation between IRR and Remedial Works Cost Figure 5.3 Sampling Location and Electrical Conductivity Values Figure 5.4 Correlation between IRR and Remedial Works Cost Figure 5.5 Water Level Fluctuation in Surge Tank（Case 3） Figure 5.6 Water Level Fluctuation in Surge Tank（Case 8） Figure 5.7 Water Level Fluctuation in Surge Tank（Case 9） Figure 5.8 Water Level Fluctuation in Surge Tank（Case 10）
Figure 6.1 SR Gate（Obermeyer type） Figure 6.2 Rotary type trash rake machine Figure 6.3 Wire rope type rotary rake machine
Figure 7.1 Control System Configuration for Wimalasurendra Hydropower Station Figure 7.2 SCADA System Connected to the Old Laxapana Hydro Power Station (HPS) Figure 7.3 Control System Configuration of New Laxapana Hydropower Station
Figure 9.1 Image of Deterioration Curve
Figure 10.1 Comparison of Scheduled Replace and Replace after Crash
Final Report LF - 1 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
LIST OF PICTURES
Picture 5.1 Castlereagh Dam Picture 5.2 Flashboard Picture 5.3 Plugged Drainage Relief Hole Picture 5.4 Excessive Turbulence Picture 5.5 Norton Bridge Dam Picture 5.6 Leakage at Right Bank Picture 5.7 Surge Tank Picture 5.8 Inside of the Surge Tank Picture 5.9 Maussakelle Dam Picture 5.10 Valve House Picture 5.11 Anti-Negative Pressure Valve Picture 5.12 Displacement of Retaining Wall Picture 5.13 Sedimentation Picture 5.14 Downstream of Canyon Dam Picture 5.15 Dam Toe Picture 5.16 Leakage near Surge Tank Picture 5.17 Erosion in Concrete Picture 5.18 Spillway of Laxapana Dam Picture 5.19 Vortex at Intake Picture 5.20 Land slide Area at Laxapana Dam Picture 5.21 Landslide Area at Polpitiya Picture 5.22 Erosion in Concrete Wall
Picture 6.1 Panorama view of penstock Picture 6.2 Ring girder support with wheels Picture 6.3 Repairing of Intake Equipment Picture 6.4 Leakage from needle valve Picture 6.5 Panorama view penstock Picture 6.6 Spigot & socket (1st stage) Picture 6.7 Blasting machine Picture 6.8 Painting machine Picture 6.9 Spillway of Norton Dam Picture 6.10 Measuring for plate thickness Picture 6.11 Check for slide shoe Picture 6.12 Leakage from the expansioin joint
Final Report LP - 1 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Picture 6.13 Intake guard valve house Picture 6.14 Repairing the tailrace gate by CEB Picture 6.15 Panorama view Picture 6.16 Touch up paint for welding joint by CEB Picture 6.17 Repair work of drain Picture 6.18 Filler material of concrete saddle Picture 6.19 Sedimentation of reservoir Picture 6.20 Plan for dredging by grab Picture 6.21 Panorama view of penstock Picture 6.22 Mechanical joint Picture 6.23 Outside surface of welded joint Picture 6.24 Outside surface of bottom Picture 6.25 Trunnion requires access facility Picture 6.26 Arm requires drain holes Picture 6.27 Gate operation Picture 6.28 Gate operation table (manual operation) Picture 6.29 Intake equipment Picture 6.30 Vortex on the Surface
Picture 7.1 Present Status of the Unit 1 Stator Picture 7.2 Turbine and Generator of Old Laxapana Stage I (Unit 2) Picture 7.3 Diffuser and Needle of Old Laxapana Stage I Picture 7.4 Repairing of Runner Crack of Old Laxapana Stage I Picture 7.5 Repaired Runner Bucket of Old Laxapana Stage I Picture 7.6 Indication of Runner Crack at Old Laxapana Stage I Picture 7.7 Slipped iron piece Picture 7.8 Crack in Guide Ring for Wicket Gate Operating Mechanism of Polpitiya Turbine Picture 7.9 Repair Welding of Polpitiya Runner
Final Report LP - 2 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin The Study of Hydropower Optimization in Sri Lanka
ABBREVIATIONS
Organizations
ADB Asian Development Bank BOI Bureau of Investmrnt BII Bureau of Infrastructure Investment CEA Central Environmental Authority CBSL Central Bank of Sri Lanka CEB Ceylon Electricity Board CECB Central Engineering Consultancy Bureau DGEU Department of Government Electricity Undertakings EPDC (J-POWER) Electric Power Development Company, Ltd. ERD External Resources Department ESC Energy Supply Committee IAEA International Atomic Energy Agency IBRD International Bank for Reconstruction and Development JBIC Japan Bank for International Cooperation JICA Japan International Cooperation Agency LECO Lanka Electricity Company MOF Ministry of Finance MPE Ministry of Power and Energy NGO Non-Governmental Organization OECF Overseas Economic Cooperation Fund OECD Organization for Economic Cooperation and Development OPEC Organization of the Petroleum Exporting Countries
Technical terms
ASTM American Society for Testing and Material CPI Consumer Price Index CRT Cathode – Ray Tube DSCR Debt Service Coverage Ratio DSM Demand-Side Management EEI Energy Efficiency Improvement EER Energy Efficient Ratio EIA Environmental Impact Assessment EIRR Economic Internal Return Ratio EL. Elevation
Final Report AB - 1 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin The Study of Hydropower Optimization in Sri Lanka
ENEPEP Energy and Power Evaluation Programme ESCO Energy Service Company FIRR Financial Internal Return Ratio GDP Gross Domestic Product GPS Global Positioning System GVA Gross Value Added H.P.S Hydropower Station IPP Independent Power Producer IPZ Investment Promotion Zone IRR Internal Return Ratio JIS Japanese Industrial Standard LGB Lower Guide Bearing LOLP Loss of Load Probability LBP Laser Beam Printer LLCR Loan Life Coverage Ratio LTGEP Long-Term Generation Expansion Plan LCU Local Control Unit NEA National Environmental Act NPV Net Present Value O&M Operation and Maintenance ODA Official Development Assistance OPGW Optical Ground Wire PAA Project Approving Agency PCB Polychlorinated - Biphenyl PIO Process Input Output ROA Return on Asset ROE Return on Equity ROI Return on Investment SCADA Supervisory Control and Data Acquisition SOE Sequence of Event Printer TGB Turbine Guide Bearing T&UGB Thrust and Upper Guide Bearing UPS Uninterrupted Power Supply WPI Wholesale Price Index
Final Report AB - 2 CONCLUSION AND RECOMMENDATION The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin The Study of Hydropower Optimization in Sri Lanka
CONCLUSION AND RECOMMENDATION
CONCLUSION
The conclusions described hereunder are based on the results of the Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for the Study of Hydropower Optimization in Sri Lanka (hereinafter referred as “the Study”), conducted from July 2004 to July 2005.
1. Rehabilitation for the Existing Hydropower Stations]
Wimalasurendara Hydropower Station
Repair of Headrace Tunnel
A collapse in the headrace tunnel has been worried since muddy water from outlet of powerhouse was recognized in the past. The CEB carried out the dewatering and inspection of the tunnel in February 2005, and the Study Team also participated in the inspection. Through the inspection, a cause of the muddy water was suspected most likely due to a tunnel collapse, and the Study Team proposed the repair plan of it. Since the scale of the collapse was fortunately small, the CEB conducted repair works after the inspection and finished the works by April 2005, and the power station restarted its operation after filling water into the tunnel.
Replace of Generators
Downward movement of stator coil caused by loosening of the wedges in the Unit 1 generator was recognized and that in the Unit 2 has been worried. Two alternatives, one is to replace the stator coils and the iron cores and the other is to replace the whole generators, are recommendable.
It was recognized that the insulation resistance values in the most of transformers are largely decreasing. Therefore, it is recommended to replace all the transformers urgently to avoid earth fault and short circuit fault which may occur in case the power plants are operated continuously. In addition, the control equipment of the plants has some troubles due to degrading and it also has entered an era of replace.
Old Laxapana Hydropower Station
Replace of Turbines and Generators
The Stage I plants (Units 1 to 3 with capacity of 8.33MW for each) of the Old Laxapana Hydropower Station has been operated for more than 54 years. It is recommended to replace all the turbines and generators, because the efficiency of the turbines has decreased by more than 10% than the original and supply of the spare parts of the plants can not be expected because the original manufacturer closed its business.
Incremental capacity from 8.33MW to 9MW due to improvement of their efficiencies is expected in case of the replacement.
It is desired for the CEB to continue to monitor the deterioration degree of the Stage II plants (Units 4 and 5 with capacity of 12.5MW for each).
Final Report CR - 1 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin The Study of Hydropower Optimization in Sri Lanka
Canyon Hydropower Station
Improvement of Anti-negative Pressure Valve
Anti-negative pressure valves locate in headrace just downstream of the dam. The valves operated and water belched out twice in the past under conditions where the reservoir water level was almost near the minimum operation level and the discharge for the turbines was almost the maximum, and .there was much difficulty in stopping water.
Since a drastic improvement of the waterway structure to prevent occurrence of negative pressure will be huge works and the operation of the valves is not so often, it will be better to relocate the valves from inside to outside of the valve house to avoid the effect of spring water to other surrounding equipment and to make the operation of intake valves, which locate just upstream, easy.
New Laxapana Hydropower Station
Water Leakage from headrace Tunnel
Water, which seems to be from the headrace tunnel near the surge chamber, has been observed since commissioning of the power station. During the Study, it was confirmed that water has been coming from the tunnel. Anti-negative pressure valves locate in headrace just downstream of the dam.
It is recommended to specify the location of leakage points and to take measures to shut out them if an opportunity of dewatering occurs, because it is considered that immediate land slide nearby caused by the water leakage is unlikely.
Replace of Generators
As well as the Wimalasurendra Hydropower Station, downward movements of stator coil caused by loosening of the wedges were recognized and urgent measures are required for them. In spite that two alternatives, one is to replace the stator coils and the iron cores and the other is to replace the whole generators, also are recommendable, the latter, which can shorten the operation stop period, will be more practical because the New Laxapana Station has a function of frequency control of the Sri Lankan system and it is difficult to stop operation over the long term.
In addition, the control equipment of the plants has some troubles due to degrading and it also has entered an era of replace.
Polpitiya Hydropower Station
Vibration in Turbines
In spite the Polpitiya Station is having a restriction on its operation due to vibration in the turbines under low load, the Study Team could not get a conclusion of replacement of the turbines during the Study. . Further detailed investigation is required.
2. Environmental Impact Assessment for Rehabilitation
EIA will not be required for the above-mentioned rehabilitation works because they do not introduce a large scale change in original lands, and replacement works of turbine and generator can be done in the existing powerhouses.
But, development works within a distance of 100m from full supply level of existing reservoir belong to the projects which are necessary to obtain an approval of project implementation by the Project
Final Report CR - 2 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin The Study of Hydropower Optimization in Sri Lanka
Approving Agency (PAA) based on the National Environmental Act. The rehabilitation works of the hydropower stations in the Kelani River basin correspond to such projects.
Therefore, it is essential to inquire of the Central Environmental Authority (CEA) about the necessity of EIA procedure before project implementation.
3. Schedule of Rehabilitation Implementation
Since shut-down of the existing power station is inevitable for the rehabilitation works under the circumstances that the power balance of the country is so tight, it is importance to weigh the timing of the works.
Although dewatering and internal inspection of the tunnel of the Wimalasurendra Hydropower Station had originally been scheduled to do in 2004 and postponed, fortunately they were carried out during the Study Period (in February 2005). Also just before, the dewatering was likely to be postponed again.
In this way, the power balance in the country is so fragile and development of new power stations is expected before the rehabilitation works. It is very importance especially for the rehabilitation of the New Laxapana Station to weigh the timing of the works, because the function of frequency control equipped with it must be transferred to other power stations before shut-down, and the capacity of 100MW is relatively large and generator with 50 MW capacity must be shut-down even if two generators are schedule to be replaced one by one.
Final Report CR - 3 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin The Study of Hydropower Optimization in Sri Lanka
RECOMMENDATION
In Sri Lanka, more than 55% of the potential hydropower has already been harnessed, and the remaining potential hydropower that is economically efficient and environmentally acceptable is very limited. Therefore, as described in the Long-Term Generation Expansion Plan, large-scale thermal power stations will be constructed to meet the increases in demand in the future, and the composition of power sources will change from “hydropower dominated” to “thermal power dominated”. In parallel with this change, the role of hydropower stations, regardless of whether they are existing or newly constructed, should also change.
Amid call for necessity of large scale thermal power station, it is very difficult to develop any types of new power station and the power balance become fragile, then shut-down of existing power stations for inspection or repair works become more and more difficult.
Rehabilitation of the Existing Hydropower Stations
As the result of the Study, it was recognized that all hydropower stations in the Kerani River basin has been deteriorated badly and some of them are likely to be shut-down at any time.
Stoppage of existing power station under the condition of tight power balance leads to increase of loss of load probability (LOLP) or power cut in some area. In case the shut-down lasts for long period, the CEB will prepare some emergency power with commonly high generation cost, which accelerates the financial balance of the CEB worse.
Although development of new power station is essential for the CEB, continuous proper operation of the existing hydropower stations is as important as, or more than that.
As stated above, the CEB should implement the rehabilitation works of hydropower stations in the Kelani River basin after designing a schedule of appropriate planned outage taking into account the power balance of the system in the future.
Maintenance Management
The CEB has been very well operating and maintaining all the existing hydropower stations in spite of limited budget and constrain on outage under the tight power balance situation. Especially as for electro-mechanical equipment, the CEB's staffs have repaired some equipment by themselves without any supply of spare parts from the original manufacturer.
The tight power balance set off a vicious cycle; i.e., the tight power balance creates a difficulty in having outage of power plants for inspection and repair, which leads to derogation of reliability in stable operation of power plants, and which make the power balance tight.
As for civil structures, daily visual inspection is most effective to find defect early. It is desired to make monthly patrol inspection by civil engineer in the CEB headquarter even though daily inspections has no alternative but to be made by other engineer on behalf of civil engineer because no civil engineer is allocated to the Laxapana Complex. Furthermore, tunnel inspection after dewatering is also required every ten or twenty years.
In spite that periodic inspections for hydro-mechanical and electro-mechanical equipment have been done so frequently, deterioration degree cannot be estimated accurately because different methods has been applied in each case. Therefore it is recommended to standardize the frequency and method of measurements. Furthermore, it is recommended to make an overhaul for all the plants too because it has never been made for more than twenty-five years since their commissioning.
Final Report CR - 4 1. INTRODUCTION The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
1. INTRODUCTION
1.1 Background of the Study
The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for the Study of Hydropower Optimization in Sri Lanka (hereinafter referred to as the Study) was conducted under the Minutes of Meetings and the Scope of Work signed by the Department of External Resources (on behalf of the Ministry of Finance and Planning), Ministry of Power and Energy, the Ceylon Electricity Board (hereinafter referred to as the CEB) and the Japan International Cooperation Agency (hereinafter referred to as JICA) on April 28, 2004.
1.1.1 Social and Economic Background
In Sri Lanka, no fossil fuel deposits have been found except a small amount of peat to the north of Colombo, and analysis of the peat shows its unfitness for the purpose of thermal power generation. Therefore, hydropower and biomass such as firewood are the main domestic energy sources in the country.
The economy of Sri Lanka has had an expanding tone since it escaped the stagnation of the 1980s. The country remained nearly unaffected by the economic crisis that hit almost all countries in Asia, and its annual growth rate of GDP exceeded 5% in the 1990s. Electric power generation has also increased in proportion to the growth of the economy, and power demand elasticity (power demand growth rate/GDP growth rate) has been close to 2.0. This indicates that power demand has been increasing at a high rate in recent years, and an active growth rate exceeding 7 to 8% a year is predicted in the 20-year power demand forecast.
However, the circumstances surrounding the development of new power projects, regardless of whether they are hydropower or thermal power projects, have been worsening mainly because of environmental concerns. Therefore, since 1997, the CEB has had no choice but to purchase relatively expensive electricity from IPPs. Moreover, combined with the effects of droughts, the power supply had not been able to meet the demand in the past few years, in the late 1990s and early 2000s, and scheduled power cuts had to be introduced. Furthermore, these circumstances, in which a stable power supply is not ensured, could cast a shadow on the economic growth of the country.
Development of new power plants is one of the crucial issues for the Government of Sri Lanka, and inauguration of large-scale thermal power plants in particular is expected. On the other hand, development of hydropower resources is also an important issue to ensure energy security for the country, which heavily depends on overseas sources for fossil fuel.
1.1.2 Necessity of Rehabilitation of Hydropower Stations in the Kelani River Basin and Request for Technical Assistance
As of January 2004, the total capacity of generating facilities owned by the CEB was 1,680MW, which consisted of 1,205MW at 16 hydropower stations and 475MW at five thermal power stations. Annual output in 2003 by hydropower generation and that by thermal power generation were 3,314GWh and 4,293GWh, respectively. In addition to the CEB’s facilities, IPPs have, as of 2003, 26 small scale hydropower stations with total capacity of 40MW and seven thermal power stations with a total capacity of 434.5MW. As shown by these figures, the Sri Lankan power sector depends on hydropower, which accounts for over 70% of the total generating capacity of the CEB as of 2003.
According to the Long Term Generation Expansion Plan worked out in 2004, the growth rates of maximum power demand over the next 20 years are predicted to be 7 to 8% annually. However, expectations for future development of hydropower are low because of economic efficiency and environmental constraints. Thus, it is obvious that thermal power generation will necessarily take a major role in the long term.
Final Report 1 - 1 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
To cope with these problems, the role of hydropower in Sri Lanka should be altered from the power source for base demand to that for middle and/or peak demand. Although the potential hydropower in Sri Lanka is said to be around 2,000MW, more than 1,100MW has already been developed, and the number of remaining project sites that have potential from the viewpoints of economic efficiency and the natural/social environment is limited. However, development of hydropower is strongly expected from the viewpoint of the energy security of the country, which has limited domestic energy resources.
In these circumstances, the Government of Sri Lanka in September 1999 requested the Government of Japan to conduct a feasibility study regarding the optimization of hydropower in Sri Lanka. In response to the request, the Government of Japan conducted a project formation study in December 2000 and a preliminary study in November 2001, and the Scope of Work was determined between the CEB and JICA on November 16 of the same year.
The Study on Hydropower Optimization completed in March 2004, and serious deterioration degrees were found in the existing hydropower stations in Sri Lanka, especially those five stations in the Kelani River Basin. Since the power development plan has been made by the CEB under the condition that the existing hydropower stations will be operated properly, shutdown of the existing hydropower stations due to some troubles may leads to review of its power development plan. As a result, the CEB requested JICA to conduct the follow-up study on the rehabilitation of hydropower stations in the Kelani River basin.
1.2 Purposes of the Study
According to the above-mentioned Scope of Work, the purposes of the Study are:
- to comprehend the situations of the existing hydropower stations,
- to establish the rehabilitation program based on the problems found in the above at a feasibility study level, and
- to recommend the methods of deterioration assessment and maintenance inspection to the CEB.
Specifically, the purposes of the Study are in two categories as described below.
The first purpose is to comprehend problems in the existing hydropower stations and to classify these problems into those requiring measures immediately and those requiring measures gradually. Priorities (deterioration degree) are to be given for each problem, and rehabilitation plans with a feasibility study level are to be recommended.
The second purpose is to comprehend the present situations of maintenance and inspection of the CEB and to recommend a realistic operation and maintenance manual excluding overloaded inspection to the CEB.
The entire study flow with the above-mentioned purposes is shown in Figure 1.1.
1.3 Contents of Each Study Stage
(1) The First Study Period in Sri Lanka (July 25 - September 4, 2004)
At the beginning of the first study period, the Study Team submitted the Inception Report to the CEB and made a presentation, and obtained the CEB’s consent regarding the method of the Study.
Following the presentation, the Study Team carried out the following:
Final Report 1 - 2 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
- Recognition of problems and inspection of their degrees of deterioration for each hydropower station and structure (civil structure, hydro mechanical equipment, and electro-mechanical equipment) under support of the CEB’s engineers based in Laxpapana Complex, where the existing five stations are all operated and controlled, as the home base of the Study.
- Information-gathering on past inspection records and related documents and interviews of relevant persons for judging deterioration.
- Preparation of bidding documents and calling for bids on local contracts for topographic and geological surveys.
- Surveys and interviews of relevant persons under EIA procedures by the member in charge of the environment.
- Geological site reconnaissance in the project area by the geologist.
- Data collection for economic and financial analysis by the member in charge.
(2) The First Study Period in Japan
Based on the outcome obtained in the first study period in Sri Lanka, the Study Team made the rehabilitation plan taking into consideration the location and degree of deterioration of each hydropower station and structure, and prepared the Progress Report.
(3) The Second Study Period in Sri Lanka (October 17 - 31, 2004)
The Study Team submitted the rehabilitation plan of the hydropower stations in the Kelani River Basin to the CEB based on the Progress Report that was prepared in the First Study Period in Japan, and the CEB and the Study Team had something in common on it.
The seminar was held with relevant persons from the Ministry of Power and Energy, the CEB, JICA, JBIC, etc., participating, and the problems and their deterioration degrees were introduced.
Moreover, the Study Team collected additional data missing in the first study period. In Sri Lanka.
The Study Team negotiated with the selected bidders for the topographic survey and geological investigation and concluded contracts.
At the start of the site work by the contractors, the team members in charge of these contracts went to the site with the contractors' engineers to give them detailed instructions.
(4) The Second Study Period in Japan
The Study Team made a conclusive rehabilitation plan in which items and their priorities, costs and schedules were included based on the result of the Second Study Period in Sri Lanka.
Maintenance manuals for structures and equipment were prepared.
The Progress Report, which included the above results, was prepared.
(5) The Third Study Period in Sri Lanka (January 30 – February 13, 2005)
The Study Team concluded the rehabilitation plan after negotiation with the CEB. Moreover, the maintenance manuals were introduced to the CEB and were understood by the CEB.
Final Report 1 - 3 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
The Study Team members in charge of the contract visited the site and accepted the results after confirming the site situations.
(6) The Forth Study Period in Sri Lanka (February 23 – March 9, 2005)
The Study Team carried out the tunnel site inspection of the Wimalasuendra hydropower station together with the CEB staff members after dewatering, and gave suggestions to the CEB about the method to repair the recognized problems such as the tunnel collapse.
(7) The Third Study Period in Japan
The Study Team prepared the Draft Final Report, in which some measures to be taken especially for civil structure problems, based on the results of topographic survey, geological investigation and the Fourth Study Period in Japan.
(8) The Fifth Study Period in Sri Lanka (May 23 – June 3, 2005, tentative schedule)
The Study Team will explain and confirm the content of the Draft Final Report. The Study Team will confirm the degree of understanding of the Study result transferred to the counterparts.
1.4 Persons involved in the Study (Positions as of the time of the Study)
(1) Ministry of Power & Energy
Mr. P. Weerahandi Secretary
(2) Ceylon Electricity Board
Mr. Ananda S. Gunasekara Chairman Mr. Wijeratne General Manager Mr. Ranjit F. Fonseka General Manager Mr. K. S. P. Jayawardena AGM, Generation Projects Mr. M. C. Wickramasekara DGM, Generation Projects Mr. C. P. W. Akarawita DGM, Laxapana Complex Ms. Kamani Jayasekera Chief Engineer, Generation Planning Mr. S. D. G. L. Jayatilaka Electrical Engineer, Generation Projects Mr. R.K.W. Wijeratne Environmental Officer Mr. H. M. Anura Herath Chief Engineer, Laxapana Power Station Mr. D. M. D. B. Dissanayake Mechanical Engineer, Laxapana Power Station Mr. S. K. S. Chandrasoma Mechanical Engineer, Laxapana Power Station Mr. Saumya Kumara Electrical Engineer, Wimalasurendra Power Station Mr. G. Athula Kumara, Electrical Engineer, Polpitiya Power Station Mr. Liyanage Electrical Engineer, Canyon Power Station Mr. K.K. Kithsiri Civil Engineer, Generation Projects
(3) Embassy of Japan
Mr. Koji Iwashita First Secretary
4) Japan Bank for International Cooperation (Representative Office in Colombo)
Mr. Shinya Ejima Chief Representative
Final Report 1 - 4 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
(5) Japan International Cooperation Agency (Sri Lanka Office)
Mr. Toshio Sugihara Resident Representative Mr. Takumi Ueshima Resident Representative Mr. Jituya Ishiguro Assistant Resident Representative Mr. Jiro Komatsu JICA Expert
(6) JICA Study Team
Mr. Tsuyoshi Nakahata Team Leader / Hydropower Facility /Power Development Plan Mr. Yoshiyuki Kaneko Civil Facility / Environmental Impact Assessment Mr. Nobuo Hoshino Geology Mr. Koichi Hakamatsuka Hydro mechanical Facility Mr. Joshiro Sato Hydro turbine Mr. Shinichi Inaba Generator Mr. Mototaro Okada Control facility for Power Station Mr. Toshiro Nakano Economic and Financial Analysis Mr. Koji Tabata Operation Coordination
Final Report 1 - 5 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
No. of Month 12345678910111213 Fis cal Year Year 1 (Fiscal Year 2004) Year 2 (Fiscal Year 2005) Calender month Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Preparatory Work 1st Study Period in Japan 2nd Study Period in Japan 3rd Study Period in Japan
1) Survey Method and Detailed Plan 1) Data Analysis 1) Drafting Short-Term and Long-Term 1) Drafting Short-Term Rehabilitation Plan 2) Preparation of Inception Report and 2) Drafting Short-Term Rehabilitation Rehabilitation Plan (Civil Structures) Questionnaire Plan (Elec-Mech) 2) Drafting Deterioration Assessment Plan 2) Preparation of Draft Final Report Work in Japan 3) Preparation of Progress Report 3) Planning 4th Work Period in Sri Lanka
1st Study Period in Sri Lanka 2nd Study Period in Sri Lanaka 3rd Study Period in Srilanka 4th Study Period in Sri Lanaka 5th Study Period in Sri Lanaka
1) Presentation of Inception Report 1) Presentation of Progress Report 1) Discussion on Short- and Long- 1) Deterioration 1) Presentation of Draft Final Report 2) Collection of Existing Data 2) 1st Workshop Term Rehabilitation Plan Assessment 2) Confirmation of Technical Transfer 3) Geological Survey 2) Discussion on Deterioration (Civil Structures) 4) Deterioration Assessment Assessment Plan Work in Sri Lanka 5) Contract on Site Investigations 3) Advice on Improvement of O&M Organisation 4) Preparation of Interim Report 5) Presentation of Interim Report 6) 2nd Workshop (Discussion)
Geological Investigation Site Survey
Technical In S ri Lank a Tr a n s f e r In Japan Submission of Report Ic/R P/R It/R Df/R F/R Workshop △ 1st Workshop △ 2nd Workshop(Discussion) 12345678910111213 Assignment Year 1 (Fiscal Year 2004) Year 2 (Fisical Year 2005) Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Team leader Hydropower Equipment Hydropower Planning Civil Works/Environmental and S ocial considerations Geology
Hydro-Mechanical
Turbine
Generator
System Control Economic and Financial Analysis Operation Coodination
Figure. 1.1 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Final Report 1 - 6 2. GENERAL FEATURES OF SRI LANKA The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin The Study of Hydropower Optimization in Sri Lanka
2. GENERAL FEATURES OF SRI LANKA
2.1 Topography
The Democratic Socialist Republic of Sri Lanka (hereinafter referred to as “Sri Lanka”) is an island country in the Indian Ocean, located to the south of the Indian subcontinent. The main island lies between 5°55´ and 9°55´ north latitude and between 79°42´ and 81°52´ east longitude, and stretches for about 240km in the east-west direction and 435km in the north-south direction. The area of the country is 67,095km2 including internal waters of 1,170km2.
The administrative capital was relocated from Colombo to Sri Jayewardenepura in 1984, on the outskirts of Colombo. However, in practice, capital city functions remain in Colombo.
The topographic features of Sri Lanka are categorized in three zones on the basis of elevation: a central mountainous area called as the Central Highlands, the plains, and the coastal belt.
The Central Highlands area is in the south-central part of Sri Lanka. The core of this area is a high ridge, running north-south for approximately 65km. This area includes some of Sri Lanka’s highest mountains. Mt. Pidurutalagala is the highest at 2,524m. At the plateau’s southern end, mountain ranges stretch 50km to the west toward Adams Peak (2,243m) and 50km to the east toward Mt. Namunakuli (2,036m). Flanking the high central ridges are two plateaus. On the west is the Hatton Plateau, a deeply dissected series of ridges sloping downward the north. On the east, the Uva Basin consists of rolling hills traversed by some deep valleys and gorges. To the north, separated from the main body of mountains and plateaus by broad valleys, lies the Knuckles Massif, with steep escarpments, deep gorges, and peaks rising to more than 1,800m. South of Adams Peak lies the parallel ridges of the Rakwana Hills, with several peaks over 1,400m.
Most of the island’s surface consists of plains between 30 and 200m above sea level. In the southwest, ridges and valleys rise gradually to merge with the Central Highlands, giving a dissected appearance to the plain. Extensive erosion in this area has worn down the ridges and deposited rich soil for agriculture downstream. In the southeast, a red, lateritic soil covers relatively level ground that is studded with bare, monolithic hills. The transition from the plain to the Central Highlands is abrupt in the southeast, and the mountains appear to rise like a wall. In the east and the north, the plain is flat, dissected by long, narrow ridges of granite running from the Central Highlands.
A coastal belt about 30m above sea level surrounds the island. Much of the coast consists of sandy beaches indented by coastal lagoons. In the Jaffna Peninsula, limestone beds are exposed to the sea as low-lying cliffs in a few places. In the northeast and the southwest, where the coast cuts across the stratification of the crystalline rocks, rocky cliffs, bays, and offshore islands can be found: these conditions have created natural harbors at Trincomalee on the northeast coast and Galle on the southwest coast.
The rivers of Sri Lanka radiate from the Central Highlands to the sea. There are 16 principal rivers longer than 100km in length, with 12 of them carrying about 75 percent of the mean river discharge in the country. The longest river is the Mahaweli Ganga (335km), and the Aruvi Aru (164km) follows. In the Highlands, river courses are frequently broken by discontinuities in the terrain, and where they encounter escarpments, numerous waterfalls and rapids have eroded a passage. Once they reach the plain, the rivers slow down and the waters meander across flood plains and deltas. The upper reaches of the river are wild and usually unnavigable, and the lower reaches are prone to seasonal flooding.
Final Report 2 - 1 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin The Study of Hydropower Optimization in Sri Lanka
2.2 Climate
The climate of Sri Lanka is categorized as tropical as a whole. The annual average temperature in Colombo is about 27°C. At higher elevations, however, it is quite cool, and the annual average temperature goes down to about 15°C in Nuwara Eliya at about 1,800m above sea level.
The rainfall pattern is influenced by the monsoon winds of the Indian Ocean and Bay of Bengal and is marked by four seasons. The first season is from mid-May to October, when winds originate in the southwest, bringing moisture from the Indian Ocean. When these winds encounter the slopes of the Central Highlands, they unload heavy rains on the mountain slopes and the southwestern sector of the island. However the leeward slopes in the east and northeast receive little rain. The second season occurs in October and November, the inter-monsoon season. During this season, periodic squalls occur and sometimes tropical cyclones bring overcast skies and rains to the southwest, northeast and eastern parts of the island. During the third season, December to March, monsoon winds come from the northeast, bringing moisture from the Bay of Bengal, unloading heavy rains on the northwestern slopes of the mountains. Another inter-monsoon period occurs from March to mid-May.
Monthly mean temperatures and monthly total precipitation in Colombo and Nuwara Eliya are shown below.
Monthly Mean Temperature (°C) Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Colombo 26.4 26.7 27.6 28.0 28.0 27.6 27.3 27.3 27.4 26.8 26.4 26.3 Nuwara Eliya 14.2 14.3 15.1 16.2 16.9 16.0 15.5 15.7 15.7 15.8 15.5 14.7
Monthly Total Precipitation (mm) Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Colombo 79.7 81.8 113.7 255.8 368.7 199.5 147.0 90.1 233.7 372.2 319.0 175.1 Nuwara Eliya 116.1 89.6 68.9 168.9 184.7 215.0 185.0 160.1 177.1 245.0 221.9 212.9
2.3 Government
The president, who is elected directly for a six-year term, serves as the head of state. In Sri Lanka, the president also serves as the head of government and appoints cabinet ministers in consultation with the prime minister. As of the end of 2001, there were 25 ministries of cabinet rank; the CEB belongs to the Ministry of Power and Energy.
The legislative branch of the government is unicameral and the Parliament consists of 225 seats. The members of Parliament are elected by popular vote on the basis of a modified proportional representation system and serve six-year terms.
The administrative divisions of the country consist of nine provinces and 25 districts under these provinces. The smallest administrative unit is the Assistant Government Agent of Divisions (AGA Division), and there are 247 AGA Divisions in the country. The Broadlands Hydropower Project is located on the boundary between Nuwara Eliya District in Central Province and Ratnapura District in Sabaragamuwa Province.
Figure 2.1 and 2.2 show these administrative boundaries and administrative structures.
Final Report 2 - 2 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin The Study of Hydropower Optimization in Sri Lanka
Jaffina
Northern Province
Kilinochchi
Mannar
Vavuniya Mannar
Anuradhapura Trincomalee
North-Central Province Eastern Province Polonnaruwa North-Western Puttalam Province Batticaloa
Kirunegala Matale
Kandy Central Province Amparai Kegalla Gamp ah a
Nuwara Baddula Eliya Western Colombo Uva Province Province Sabaragamuwa Province Moneragala Kalutara Ratnapura
Galle Hambantota Matara
Southern Province Legend Provincial Boundary District Boundary
Figure 2.1 Administrative B oundary M ap
Final Report 2 - 3 Sri Lanka
Nothern Province North-Central Province North-Western Province Province of Uva Province of Sabaragamuwa Central Province Eastern Province Westrn Province Southern Province
Jaffna Anuradhapura Puttalam Monaragala Kegalla Matale Trincomalee Gampaha Galle District District District District District District District District District Kilinochchi Polonnaruwa Kurunegala Badulla Ratnapura Kandy Batticaloa Colombo Matara Mullaittivu Nuwara Eliya Ampara Karutara Hambantota Vavuniya Consists of: Consists of: Consists of: Consists of: Mannar Medirigiriya, Giribawa, Mahiyanganawa, Eheliyagoda, Consists of: Consists of: Consists of: Consists of: Lankapura, Galgamuwa, Ridimaliyadda, Kuruwita, Kotmale, Padiyatalawa, Panadura Totamuna, Katuwana, Consists of: Hingrakgoda, Polpitigama, Migahakivula, Ratnapura, Uda Hewaheta, Maha Oya, Bandaragama, Wiraketiya, Mannar, Elahera, & Mahawa, Kandaketiya, Imbulpe, Walapane, Uhana, Rayigam Korale East, Angunakolapelessa, Mantai West, Tamankaduwa. Nikaweratiya, Uva Paranagama, Balangoda, Nuwara Eliya, & Sammanturai, Bulatsinhala, Ambalantota, Nanaddan, & Kobeigane, Haliela, Pelmadulla, Amabagamuwa Korale. Kalmunai, Dodangoda, Hambantuta, Musali. Consists of: Wariyapola, Soranatota, Nivitigala, Nintavur, Karutala Totamuna North, Tissamaharama, Padawiya, Ibbagamuwa, Passara, Ayagama, Consists of: Addalachcherai, Karutala Totamuna South, Tangalla, & Consists of: Kebitigollewa, Ridigama, Baddula, Kalawana, Pujapitiya, Akkaraipattu, Pasdun Korale, Belitta. Nedunkerni, Medawachchiya, Mawatagama, Ella, Atakalann Korale, Akurana, Damana, Pasdun Korale East, & Vavuniya South (Tamil), Nuwaragampalata Central, Kurunegala, Bandarawela, Weligepola, & Pata Dumbara, Tirrukkovil, Pasdun Korale South. Consists of: Vavuniya South (Sinhara), & Nochchiyagama, Hettipola, Haputale, Kolonna Korale. Panwila, Pottuvil, & Morawak Korale West, Cheddikulam. Rambewa, Bingiriya, Welimada, & Uda Dumbara, Lahugala. Consists of: Morawak Korale East, Kahatagasdigiliya, Kuliyapitiya, Haldummulla. Consists of: Minipe, Colombo Kandabada Pattuwa West, Consists of: Horowupotana, Weerambugedara, Rambukkana, Meda Dumbara, Consists of: Kolonnawa, Weligam Korale North, Tunukkai, Huruluwewa, & Polgahawera, Consists of: Mawanella, Kundasale, Korale Pattu, Kaduwela, Weligam Korale South, Puthukkudiyiruppu, Mihintale. Alawwa, & Madulla, Aranayaka, Kandy, Korale Pattu North, Homagama, Gangabada Pattuwa North, Mullaittivu, & Pannala. Wellassa, Galigamuwa, Harispattuwa, Eravur Pattu, Avissawella, Kandabada Pattuwa East, Pandiyankulam. Medagama, Kegalla, Tumpane, Manmunai North, Maharagama, Wellabada Pattuwa East, Consists of: Badalkumbura, Warakapola, Yatinuwara, Manmunai West, Nugegoda, Gangabada Pattuwa South, Consists of: Vanathavillu, Monaragala, Ruwanwella, Udunuwara, Manmunai South West, Moratuwa, & Weligam Korale West, Pachchilaipalli, Karuwalagaswewa, Siyambaranduwa, Yatiyantota, Pata Hewaheta, Eravil & Manmunai South, & Kesbewa. Matara Four Gravets, & Karachchi, & Kalpitiya, Buttala, Deraniyagala, & Udapalata, Porativu. Wellabada Pattuwa West. Punakari. Puttaram, Wellawaya, & Dehiowita. Ganga Ihara Korale, & Consists of: Kirimetiyawa, Tanamalwila. Pasbage Korale. Consists of: Negombo, Consists of: Consists of: Anamaduwa, Padawi Siripura, Katana, Bentota, Delft, Arachchikattuwa, Consists of: Kuchchaveli, Divulapitiya, Elpitiya, Kayts, Chilaw, Galewela, Gomarankadawara, Mirigama, Niyagama, Chankanai, Natt&iya, & Dambulla, Morawewa, Attanagalla, Tawalama, Sandilippai, Wennappuwa. Naula, Town & Gravets Minuwangoda, Neluwa, Tellippalai, Pallepola, Tampalakamam, Wattala, Nagoda, Kopay, Yatawatta, Kinniya, Ja-ela, Karandeniya, Vadamarachchi, Matale, Mutur, Gampaha, Ambalangoda, Point Pedro, Ambanganga Korale, Seruwawila, & Mahara, Balapitiya, Uduvil, Laggala, Kantale. Weke, Hikkaduwa, Velanai, Wilgamuwa, Biyagama, & Baddegama, Jaffna, Rattota, & Kelaniya. Yakkaramulla, Nallur, & Ukuwela. Akmimana, Chavakachcheri. Bope Podala, Galle Four Gravets, & Habaraduwa. Legend : Province
District
Assistant Government Agent (AGA) Divion.
Source : CEB Figure 2.2 Administrative Structure of Sri Lanka
2 - 4 3. SOCIO-ECONOMY The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
3. SOCIO-ECONOMY
3.1 Population
3.1.1 Census Population
As the following table showing, the population of 19 million in 2003 increased from 18 million in 1998, and it has been rising at annual rate of about 1.3%.
Population of Sri Lanka Units 19981999 2000 2001 2002 2003 Mid-year Population Million 17.94 18.21 18.47 18.73 19.01 19.25 Growth Rate % 1.3 1.5 1.4 1.4 1.5 1.3 Source: Annual Report of Central Bank of Sri Lanka 2003
3.1.2 Labor Force
A labor force was amounted as 7.6 million persons as of 2003, of which around 91.5% was actually employed. Thus, an unemployed rate was 8.5 % in the same year. Since the unemployment rate was more than 12% in 1995, the rate has been improved by around 8% after 2000.
Among the labor market at 2003, "agriculture" sector absorbed 35% of the overall employed workforce, it is the still largest rate in the major economic sectors. As the second position in the labor market, "personal services" sector absorbed 22% of the total people employed. Following them, "manufacturing" sector had 16%, and "trade and hotel" sector, 14%, as shown in the table. Other than "agriculture" sector, these major sectors above seem to increase the labor force into their work fields.
3.1.3 Ethnic Group
Sri Lanka is essentially composed of three ethnic groups, that is, the Sinhalese, Tamil and Muslim. They make up more than 99% of the country population. These groups are corresponding to religious and linguistic distinctions. The Sinhalese account for nearly three-fourths of the people.
3.2 Macro Economic Features
3.2.1 National Accounts
The gross domestic product (GDP) in Sri Lanka was Rs.1,561 billion at current factor cost prices in 2003, as shown in Table 3.1. Among major economic sectors, “wholesale, retail trade” sector recorded the largest gross value added (GVA) of Rs.314 billion, the highest contribution to the national economy.
An economic sector of "agriculture, forestry and fishing" accounted for Rs.297 million. And "manufacturing" sector occupied the third position, accounting for Rs.242 million.
As the following table showing, GDP per capita has grown continuously after US$841 in 2001 and recorded US$947 in 2003.
Final Report 3 - 1 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
GDP Growth Rate and Per Capita GDP Units 1999 2000 2001 2002 2003 Growth Rate % 4.3 6.0 -1.5 4.0 5.9 Per Capita GDP US$ 863 899 841 870 947 Source: Annual Report of Central Bank of Sri Lanka 2003
3.2.2 Economic Sector Profile
In terms of economic performance, “trade” sector recorded the largest contribution to GDP as 20 % in 2003, as shown in Table 3.1. The second largest contributing sector was “agriculture, forestry, fishing” sector, accounting for 19% in the same year. The third one was the manufacturing sector accounting for 16% in 2003.
Around 85% of "manufacturing" sector is composed with industrial production except processing tea, rubber and coconut. Among them, industrial category of "textile, wearing apparel & leather products" had the highest share as around 43 % to the total production in 2003. And the category of "food, beverages, tobacco" was the second one as around 25 % in 2003. The third one was the category of "chemical, petroleum, plastic products" as around 17% to the total production. These top three industrial categories accounted for 85% of the total production in 2003.
Most large-scale industries are now owned by the government, and manufacturing industries in the private sector produce mainly consumer goods and some capital tools such as machine tools and building materials. An investment promotion zone (IPZ) was established in the north of Colombo in the 1970’s to attract foreign investment through various tax exemptions.
"Services" sector including trade, hotels, transport, banking, public and private services are the largest sector among the major sectors, and absorb around one-third of the total labor force, which recorded 7.7% GDP growth. It supports stable growth of Sri Lanka economy. Among these sub-sectors, "transport and communication" and "banking, insurance and real estate" sub-sectors recorded the largest growth of 10.2% and 10.6% respectively in 2003.
3.2.3 External Trade and Balance of Payment
Sri Lanka has run a deficit in current account for many years by 2000 as shown in Table 3.2. The cause of this is deficit of a trade balance. Capital account has exhibited a surplus. Financial account, as shown in Table 3.2, long-term financial accounts surplus have covered short-run financial accounts deficit in some years. As the result, capital and financial account has kept a surplus.
Then, the over-all balance of external trade by current account and capital and financial account has been keeping a surplus since 2001 to 2003, and it recorded US$500 million surplus in 2003.
The Sri Lanka’s external trade has kept the balance in deficit as indicated above. Its trade structure has kept a traditional pattern. That is, the main product for exporting are tea, rubber, coconuts, etc., and textiles, garments, petroleum products, etc., for light industrial products, and for importing consumer goods like rice, wheat, sugar, etc., intermediate goods like petroleum, fertilizer, chemicals, etc., and investment goods like machinery, transport equipment, etc. It is said that this external trade is a typical external trade structure of developing countries. Therefore, the external environment in international markets for commodities and industrial products is a potent influence not only to Sri Lanka’s external trade but also to the national economy.
Final Report 3 - 2 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
(Unit: Rs. Billion) Item 1998 1999 2000 2001 2002 2003 Merchandise Export 310 325 411 431 450 495 Merchandise Import 380 422 554 533 585 643 Trade Balance -70 -97 -143 -103 -135 -148 Note: Figures in FOB for export and CIF for import
3.2.4 Government Finance
In Sri Lanka, a fiscal year starts from January 1 and ends on December 31 in the same year, i.e., the same as calendar year. In 2002 and 2003, the Government finances of Sri Lanka amounted to Rs.261.9 billion and Rs.276.5 billion in revenue and Rs.403.0 billion and Rs.417.7 billion in expenditure, as shown in Table 3.3. Thus, the balance of these fiscal operations was resulted in deficit as -141.1 billion in 2002 and -141.2 billion in 2003. These deficits were financed by borrowings, grants and proceeding privatization.
Taxes share at 85 % and 84 % of the total revenue in 2002 and 2003 respectively, and do not show distinguished changing in these several years.
3.2.5 External Debt and Outstanding
(1) The foreign assistance
Economic assistance from industrialized countries, member nations of OECD, and multilateral agencies is shown in Table 3.4, Table 3.5 and Table 3.6. Table 3.4 shows net receipt of foreign assistance from 1997 to 2003, and Table 3.5 and Table 3.6 show outstanding foreign debt. Sri Lanka has received most grants from Japan, has built important relationship between Japan in loan and grants assistance. It is still continued for a long time until now.
(2) The external debt
The total external debt of the country increased by 14% from 2002, it was US$10.6 billion in 2003. It corresponds to 58.4% of the GDP. On the other hand, the improvement is found in Debt Service Ratio (DSR) 11.6% in 2003 from 13.2% in 2002. Usually, from 20% or less of this index is desirable, thus Sri Lanka has an enough capability to repay the external debt.
(Unit; US$ million) Item 1999 2000 2001 2002 2003 Debt Outstanding of Long-Term Debt 8,613 8,456 7,839 8,732 10,025 Total Debt Service 9,088 9,031 8,372 9,333 10,644 Debt Service Payment 846 953 813 788 757 Interest Payment 296 332 254 216 229 Exports of Goods and Services 6,801 7,787 7,436 7,330 8,099 Debt Service Ratio (DSR) 15.2 14.7 13.2 13.2 11.6
Final Report 3 - 3 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
3.2.6 Price Indices and Exchange Rates
(1) Price Indices
Table 3.7 shows price indices from the year 2000 to 2003 covering consumer prices. The consumer price index (CPI) in Sri Lanka increased to 158 (base: 1995 to 1997 =100) in 2003. While, the wholesale price index (WPI) in Sri Lanka increased to 147 (base: 1996=100) in 2003. Especially the main causes are non-metallic product like ceramic that has increased to 3,344, and fuel to 143.
(2) Foreign Exchange Rates
Table 3.8 shows the foreign exchange rate of Rupees per US$ and JP¥ from 1990 to 2003 at the end of each period and the annual average. The value of Rupee dropped from Rs.40.27 per US$1 in 1990 to Rs.96.52 in June 2003. Also the value of Rupee dropped from Rs.0.292 per JP¥1 in 1990 to Rs.0.833 in June 2003.
3.3 Projection of Socio-Economic Structures
3.3.1 Population and GDP Projection
The table below shows the projections of population and GDP growth rate, which are reported in Annual Report 2003 of Central Bank of Sri Lanka.
Projection Item 2003 2004 2005 2006 2007 GDP (%) Growth Rate 5.9 5.5 6.5 7.0 7.2 Population（million） 19.3 19.4 19.6 19.8 20.0
Final Report 3 - 4 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Table 3.1 Gross National Product at Current Factor Cost Price
(Unit: Rs Billion) (share of (Rate of GDP Increse SECTOR 1999 2000 2001 2002 2003 at 2003) 2002-2003) 1. Agriculture 205 224 250 288 297 19% 1.5% Agriculture, Forestry, Fishing 205 224 250 288 297 19% 1.5% Agriculture 163 177 199 233 237 15% 3.0% Tea 12 16 16 17 17 1% -2.2% Rubber 2 3 2 3 5 0% 1.7% Coconut 18 13 13 20 19 1% 7.1% Paddy 30 32 35 42 41 3% 7.4% Other 101 114 133 150 156 10% 1.8% Forestry 16 17 19 20 25 2% 1.4% Fishing 26 29 31 34 34 2% -6.9%
2.Industry 271 307 334 369 410 26% 5.5% Mining, Quarrying 18 22 24 26 27 2% 3.6% Manufacturing 163 189 199 222 242 16% 4.4% Processing of Tea, Rubber, Coconut 25 28 29 35 36 Factory Industry, Small Industory 138 161 170 187 206 Construction 75 83 95 101 112 7% 5.5% Electricity, Gas, Water 14 13 16 20 28 2% 21.7%
3.Servises 518 594 662 746 854 55% 7.7% Transport, Communication 114 132 150 174 213 14% 10.2% Wholesale, Retail trade 211 254 263 288 314 20% 7.3% Banking, Insurance, Real estate 81 86 106 135 170 11% 10.6% Ownership of Dwelling 18 20 22 24 25 2% 1.3% Public Administration, Defense 52 58 69 69 69 4% 0.6% Private service 41 45 51 56 63 4% 7.2% GDP 994 1,125 1,245 1,402 1,560 100% 5.9% Net factor income from abroad -18 -23 -24 -25 -19 GNP 977 1,102 1,221 1,377 1,542 6.4%
Source : Annual Report 2003, Central Bank of Sri Lanka
Final Report 3 - 5 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Table 3.2 Balance of Payments: 1998- 2003
(Unit: US$ Million) Item 1998 1999 2000 2001 2002 2003
Current Account -227 -562 -1,066 -215 -237 -101 Goods, Services and Income (net) -1,127 -1,475 -2,064 -1,221 -1,365 -1,335 Trade Balance -1,091 -1,369 -1,798 -1,158 -1,407 -1,539 Services (net) 144 148 38 204 295 396 Income (net) -180 -254 -304 -267 -253 -192 Transfers (net) 900 913 998 1,006 1,128 1,234 Private Transfers (net) 848 887 974 984 1,097 1,205 Other Transfers 52 26 24 22 31 29
Capital & Financial Account 412 373 443 563 444 702 Capital Account 79 81 50 198 66 61 Capital Transfers (net) 79 81 50 198 66 61 Financial Account 333 292 393 365 379 641 Long-term: 397 435 305 164 326 717 Direct Investment 193 177 176 172 185 201 Private Long-term (net) 1 196 82 -257 -21 -33 Government, Long-term (net) 203 62 47 249 162 548 Short-term: -64 -143 88 201 53 -76
Errors & Omissions -151 -73 101 -129 130 -99
Overall Balance 34 -262 -522 219 338 503
Source : Annual Report 2003, Central Bank of Sri Lanka
Final Report 3 - 6 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Table 3.3 Summary of Governmental Fiscal Operations
Rs.Million Item 2000 2001 2002 2003
Total revenue 211,282 234,296 261,887 276,516 Tax reveue 182,392 205,840 221,837 231,648 Non tax reveue 28,890 28,456 40,050 44,868
Expenditure and lending minus repayments 335,823 386,519 402,989 417,672 Current 254,279 303,362 330,847 334,693 Capital and net lending 81,544 83,157 72,142 82,979 Public investment 80,955 82,491 72,177 87,409 Other net lending 589 666 -35 -4,430
Overall deflict (before grants) -124,541 -152,223 -141,102 -141,156
Financing 124,541 152,222 141,101 141,155 Foreign financing 5,640 20,038 9,057 51,022 Net borrowings 495 14,538 1,978 43,066 Grants 5,145 5,500 7,079 7,956 Domestic financing 118,500 123,595 126,351 79,660 Market borrowings 115,325 122,848 127,167 79,830 Other borrowings 3,175 747 -816 -170 Domestic grants 250 Privatization proceeds 401 8,589 5,693 10,223
Source: Annual Report 2003, Central Bank of Sri Lanka
Final Report 3 - 7 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Table 3.4 Net Receipt of Foreign Assistance: 1997-2003
Rs.Million Item 1997 1998 1999 2000 2001 2002 2003
1.Loans 14,638 19,420 8,604 10,070 19,396 10,113 53,213 ADB 4,499 6,917 5,645 4,343 5,295 11,878 17,231 China 146 407 319 -90 1,478 1,691 2,206 IDA 3,986 5,415 2,542 2,236 677 5,663 15,950 India 584 252 -128 -147 -177 912 4,003 Japan 3,629 7,780 4,927 7,353 10,011 6,309 21,655 USA 293 -841 -1,744 -1,653 -2,532 -2,782 -2,977 Others 1,501 -510 -2,957 -1,972 4,644 -13,558 -4,855
2.Grants 7,329 7,200 6,761 5,145 5,500 7,079 7,956 ADB 160 116 350 420 482 513 317 Germany 299 54 510 324 208 920 1,167 Japan 2,428 3,280 3,380 2,826 2,135 2,287 1,643 Others 4,442 3,750 2,521 1,575 2,675 3,359 4,829
Total 21,967 26,620 15,365 15,215 24,896 17,192 61,169
Source: Annual Report 2003, Central Bank of Sri Lanka
Table 3.5 Outstanding Foreign Debt : 1997-2003
Rs.Million Item 1997 1998 1999 2000 2001 2002 2003
1.Project Loans 320,867 400,284 444,423 477,845 542,942 640,354 769,559
2.Non Project Loans 55,464 60,989 63,443 64,195 93,799 81,603 74,322 Commodity 53,816 59,626 62,182 63,009 67,563 68,050 68,891 Other 1,648 1,363 1,261 1,186 26,236 13,553 5,431
Total 376,331 461,273 507,866 542,040 636,741 721,957 843,881
Source: Annual Report 2003, Central Bank of Sri Lanka
Table 3.6 Ownership of Outstanding Foreign Debt : 1997-2003
Rs.Million Item 1997 1998 1999 2000 2001 2002 2003
1.Multilateral 173,428 211,730 228,736 250,096 289,686 341,326 405,156 ADB 76,186 94,583 104,150 115,353 136,064 164,017 195,895 IDA 92,481 111,771 119,045 129,403 146,853 169,336 199,782 Others 4,761 5,376 5,541 5,340 6,769 7,973 9,479
2.Bilateral 188,576 234,585 267,383 277,317 305,511 349,007 398,925 Germany 25,652 30,132 27,656 28,338 32,953 39,545 46,657 Japan 98,738 132,374 154,801 172,932 185,081 217,151 255,277 USA 41,927 45,789 47,268 51,053 58,064 57,937 55,229 Other 22,259 26,290 37,658 24,994 29,413 34,374 41,762
3.Financial Market 14,327 14,958 11,747 14,627 41,544 31,624 39,801
Total 376,331 461,273 507,866 542,040 636,741 721,957 843,882
Source: Annual Report 2003, Central Bank of Sri Lanka
Final Report 3 - 8 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Table 3.7 Sri Lanka Consumer's Price Index (1995-1997 = 100) Item 2000 2001 2002 2003
All Items 125.1 140.1 154.4 158.4
Food & Drinks 124.2 139.2 153.3 154.8 Clothing & Footwear 115.6 119.9 131.4 141.9 Housing , Water, Electricity, Gas & other fuels 122.8 136.9 147.5 156.9 Household Equipment & Maintenance of House 115.0 132.7 149.1 153.2 Health 171.6 192.8 238.1 240.7 Transportation & Communication 134.1 160.8 166.7 180.2 Leisure, Entertainment and Culture 125.4 130.7 136.9 136.9 Education 135.9 147.5 163.7 170.4 Miscellaneous Goods & Service 124.1 147.9 169.3 182.9
Source: Annual Report 2003, Central Bank of Sri Lanka
Final Report 3 - 9 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Table 3.8 Foreign Exchange Rates: 1990-2003
(Unit: Rupees at Average Exchange Rate) Month 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Rupees per US Dollar January 40.000 40.380 42.660 46.400 49.535 50.130 54.155 56.910 61.472 67.948 72.358 83.662 93.505 96.768 February 40.000 70.700 42.980 46.700 49.202 50.170 54.184 57.393 61.826 68.477 72.834 86.976 93.628 96.862 March 40.000 70.760 43.250 47.450 49.065 49.930 54.161 57.782 62.300 69.121 73.086 85.811 95.642 96.931 April 40.000 70.920 43.550 47.970 49.035 49.760 54.197 58.412 63.094 69.685 73.263 87.883 96.137 96.981 May 40.000 41.100 43.730 48.111 49.538 50.050 54.414 58.797 63.864 70.195 73.803 90.682 96.200 97.213 June 40.000 41.170 43.980 48.452 49.305 50.560 54.969 58.968 64.509 70.627 75.748 90.439 96.097 97.230 July 40.000 41.500 44.080 48.972 49.395 50.968 55.508 59.194 65.247 71.097 77.540 90.264 96.287 97.140 August 39.920 41.870 44.140 49.100 49.510 51.978 55.797 59.504 65.984 71.062 77.540 89.926 96.260 96.968 September 39.990 42.020 44.340 49.153 49.530 52.248 56.196 59.672 66.064 71.212 77.540 90.175 96.276 95.456 October 40.400 42.240 44.510 49.267 49.230 53.098 56.526 59.939 66.287 71.404 77.540 90.850 96.375 94.512 November 40.290 42.500 44.630 49.423 49.430 58.783 56.513 60.329 66.943 71.821 78.373 92.554 96.593 95.777 December 40.240 42.580 46.000 49.562 49.980 54.048 56.643 61.024 67.526 72.058 79.704 93.132 96.725 96.414 Average 40.070 48.978 43.988 48.380 49.396 51.810 55.272 58.994 64.593 70.392 75.777 89.363 95.810 96.521
Rupees per J apanes e Yen January - 0.308 0.339 0.372 0.451 0.509 0.513 0.484 0.475 0.601 0.689 0.717 0.704 0.814 February - 0.536 0.332 0.397 0.472 0.517 0.512 0.466 0.491 0.587 0.666 0.748 0.699 0.812 March - 0.502 0.325 0.408 0.476 0.559 0.511 0.471 0.484 0.578 0.685 0.708 0.718 0.817 April - 0.516 0.326 0.432 0.478 0.594 0.505 0.465 0.478 0.582 0.695 0.710 0.751 0.810 May - 0.298 0.341 0.452 0.474 0.602 0.511 0.493 0.473 0.576 0.683 0.744 0.773 0.828 June - 0.299 0.350 0.454 0.498 0.598 0.505 0.516 0.460 0.584 0.713 0.740 0.804 0.823 July 0.271 0.301 0.347 0.462 0.495 0.576 0.507 0.515 0.464 0.593 0.719 0.725 0.803 0.819 August 0.277 0.305 0.359 0.471 0.497 0.525 0.518 0.505 0.457 0.626 0.717 0.740 0.816 0.816 September 0.290 0.316 0.360 0.467 0.503 0.532 0.512 0.494 0.491 0.662 0.726 0.760 0.792 0.830 0.312 0.323 0.361 0.455 0.506 0.522 0.503 0.495 0.549 0.674 0.715 0.750 0.787 0.863 October November 0.302 0.327 0.358 0.454 0.500 0.579 0.503 0.483 0.556 0.686 0.720 0.757 0.790 0.877 December 0.299 0.340 0.369 0.443 0.501 0.526 0.498 0.471 0.576 0.702 0.712 0.731 0.807 0.893 Average 0.292 0.364 0.347 0.439 0.488 0.553 0.508 0.488 0.496 0.621 0.703 0.736 0.770 0.833
Source: Annual Report 1995-2003, Central Bank of Sri Lanka International Financial Statistics, June 2002, IMF Note: *1 Figures in italics are quoted from "International Financial Statistics, IMF".
Final Report 3 - 10 4. PRESENT SITUATION OF POWER SECTOR IN SRI LANKA The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
4. PRESENT SITUATION OF POWER SECTOR IN SRI LANKA
4.1 Energy Situation
In Sri Lanka, no fossil fuel deposits have been found except a small amount of peat to the north of Colombo, and analysis of the peat has proved its unfitness for the purpose of thermal power generation. Therefore, hydropower and biomass such as firewood are the main domestic energy sources in the country.
The primary energy sources of Sri Lanka in 2001 are 50% biomass, 41% petroleum and 9% hydro.
On the other hand, total energy consumption including both commercial and non-commercial energy demand in 2002 amounted to 7,282ktoe and non-commercial energy accounted for two-thirds of the total. Energy consumption in the power sector accounted only for 6.2%. Sectoral energy consumption breaks down into 19% for industrial-sector use, 28% for transport use, and 53% for household, commercial and other use.
The energy situation of Sri Lanka can be summarized as follows:
- There is no domestic fossil fuel in Sri Lanka. The only indigenous source is biomass including fuel wood, and hydro.
- Estimated total hydro potential in Sri Lanka is about 2,000MW, of which about 1,205MW is already utilized.
4.2 History and Formation of Power Sector
Sri Lanka’s electric power industry began in 1895 when a hydropower station was installed in Colombo. In 1922 the Colombo Railway and Electric Light Company was established to supply power to limited areas such as governmental and commercial buildings. In 1927 the Department of Government Electricity Undertakings (DGEU) was established and since then the electric power industry has been operated by administrative bodies.
In 1951 the Electricity Act was enacted to regulate power sector. The DGEU took charge of generation and transmission and local governments handled distribution and power supply.
Following the Ceylon Electricity Board Act in 1969, the Ceylon Electricity Board (CEB) was organized under the jurisdiction of the Ministry of Power and Energy and took over the generation and transmission functions of the DGEU.
Lanka Electricity Company (LECO), which was established in 1983, assumed part of the distribution business from local governments near Colombo. Around a sixth of total electricity sales has been distributed by LECO. Distribution in other areas was gradually transferred from local governments to the CEB and the transition was completed in 1998.
The Ministry of Power and Energy is responsible for the formulation of policy related to the power and energy sector, as a main agency.
At present, a power sector reform program to promote private investment in the power sector and to reduce electricity tariffs competitively is on-going under the assistance of the IBRD and ADB. Specifically, the CEB will be unbundled into generation (hydropower and thermal power), transmission and five distribution companies in the first half of 2005.
Final Report 4 - 1 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
(1) Ministry of Power and Energy (MPE)
The MPE is the main government body handling power and energy policy in Sri Lanka. The MPE has imposed legal control over power-related organizations based on the Electricity Act enacted in 1951. The MPE and the Mahaweli Authority, excluding its land component, were unified, and the Ministry of Irrigation and Power was established during the restructuring of ministries in 1994. But the Ministry was divided into the MPE and the Ministry of Irrigation and Water Resource Development in the organizational reform in October 2000.
(2) Ceylon Electricity Board (CEB)
The CEB is a state-owned vertically integrated organization handling generation, transmission and distribution functions. There are seven divisions: the generation, transmission, distribution and operation, distribution development, commercial, headquarters, and finance manager divisions, under the board members such as the Chairman and General Manager (refereed to Figure 4.1). Though the CEB has been established as an independent body, executives are to be the assigned by the Ministry of Power and Energy, and approval by the Government is required for investments and setting tariffs.
(3) Lanka Electricity Company Limited (LECO)
LECO is a distribution company financed and established by the CEB, Urban Development Corporation and local governments, and the CEB holds 54% of LECO’s stock. The supply area of LECO is mainly in coastal areas such as the Western Division and Southern Division, and covers about 10% of Sri Lanka. However, these areas are not contiguous but are scattered. Total electricity sales of Sri Lanka in 2003 amounted to 846.2GWh, of which about 14% is supplied by LECO. LECO’s customers include about 380,000 households. The electrification ratio of the area supplied by LECO is higher than the national average.
(4) Ministry of Finance and Planning
The External Resources Department (ERD) is a operation organization for external resources, and the National Planning Department (NPD) assesses all projects requested to a foreign country from a national point of view and on a technical basis, and determines aid for projects in the Ministry of Finance and Planning. There are three divisions in the ERD – the Policy Division, Japan Division and Technical Assistance Division. The Policy Division is an organization that functions as a corresponding clerk to the NPD and is in charge of assembling assistance requests from each implementing ministry. The Japan Division is in charge of technical assistance excluding JICA expert dispatch and JICA training, the JICA grant aid program and yen loans. The Technical Assistance Division is in charge of JICA technical assistances such as JICA expert dispatch and JICA training. JICA dispatches experts to the Japan Division in order to assist the ERD in implementing projects.
(5) Energy Supply Committee
The Energy Supply Committee (ESC) under the Ministry of Power and Energy was set up in March 2002, based on the Energy Supply Act No. 2 of 2002, with a two-year mandate to find immediate solutions to the existing problems of the energy sector. The ESC consists of the Secretaries of Finance, Power and Energy, and Industrial Development, and the Chairmen of the CEB, Ceylon Petroleum Corporation, and the Board of Investment (BOI), and other appointed members. The ESC discharges these functions, among others:
- tendering advice to the Government on all matters concerning (i) the generation, transmission, distribution, supply and use of electrical energy; and (ii) the importation, exportation, storage, distribution and supply of petroleum and petroleum products;
Final Report 4 - 2 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
- supervision and issue directives to the CEB and to the CPC; - regulating and fixing tariffs and other charges from time to time for the supply of electricity.
(6) Public Utilities Commission (PUC)
The power sector is regulated by the Public Utilities Commission (PUC). Five PUC members were appointed in July 2003. Sectors covered by the PUC are the power sector and water supply sector. The functions of the PUC in regard to the power sector are to act as the economic, technical and safety regulator for the electricity industry.
(7) Strategic Enterprise Management Agency (SEMA)
The SEMA facilities and ensures the efficient management of 12 strategic enterprises including the CEB in Sri Lanka. The aim is to improve the efficiency and effectiveness of the Sri Lanka economy by putting these enterprises on par with their private sector counterparts, while retaining state ownership. The functions of the SEMA include re-engineering of the strategic state-owned enterprises (SSOEs) to be capable of generating investment surpluses. The SEMA is also tasked with ensuring that each of the SSOEs will have commercially sound corporate structures. The 12 enterprises fall into six clusters – banking, energy, port services, transport, trading and manufacturing, and water supply and sanitation.
(8) National Procurement Agency (NPA)
The NPA is an independent regulatory body established to oversee procurement monitoring, capacity building and policy-related matters and to strengthen and streamline the Government procurement system. It is mandated to prevent delays and inefficiencies through the formulation of simplified and harmonized procurement policies, guidelines and standards. In addition, the NPA engages in capacity building and monitoring to ensure accountability and transparency in procurement practices.
(9) Board of Investment (BOI)
The Board of Investment (BOI) was established in 1978, and is structured to function as a central facilitation point for foreign and local private investors. It operates as an autonomous statutory body, and has authority to sign agreements for granting special concessions – such as exemptions of taxes and free repatriation of profits, dividends and capital proceeds – with companies satisfying specific eligibility criteria that are designed to meet strategic economic objectives of Sri Lanka. Infrastructure development is one of the eligible sectors for BOI concessions, and the BOI has a separate division of the Bureau of Infrastructure Investment (BII) to coordinate and facilitate private-sector investments relating to infrastructure.
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DGM (Energy Sales) DGM (Corporate Affairs) DGM (Thermal Complex) ORGANISATION STRUCTURE DGM (Mahaweli Complex) CEYLON ELECTRICITY BOARD DGM (Laxapana Complex) AGM as at 31.12.2003 DGM (Mechanical) GENERATION DGM (Generation Projects) DGM (Other Hydro) DGM (Electrical Maintenance) DGM (Environment Civil Maintenance & Dam Safety) AFM (Generation) DGM (Energy Purchase)) DGM (Transmission & Generation Planning) DGM (Transmission & Design & Environment) DGM (Corporate & Regulatory Relations) AGM DGM (Information Technology) DGM (Transmission Operation & Maintenance) TRANSMISSION DGM (Asset Management) DGM(Transmission Projects) DGM (System Control) DGM (Communication) DGM (Energy Marketing) *CHIEF AFM (Transmission & Bulksupply) INTERNAL AUDITOR DGM (Commercial & Corporate) DGM (Project & Heavy Maintenance) AGM DGM (Planning & Development) DISTRIBUTION DGM (Colombo City) REGION 1 DGM (North Western Province) DGM (North Central) AFM (Distribution Region 1)
CHAIRMAN *GENERAL DGM (Commercial & Corporate) AND BOARD OF DGM (Project & Heavy Maintenance) MANAGER AGM DGM (Planning & Development) DIRECTORS DISTRIBUTION DGM (Central Province) DGM (Western Province North) REGION 2 DGM (East) AFM (Distribution Region 2)
DGM (Commercial & Corporate) DGM (Project & Heavy Maintenance) AGM DGM (Planning & Development) SECRETARY TO DISTRIBUTION DGM (Western Province South II) THE BOARD DGM (Sabaragamuwa) REGION 3 DGM (Uva) AFM (Distribution Region 3)
DGM (Commercial & Corporate) AGM DGM (Project & Heavy Maintenance) DISTRIBUTION DGM (Planning & Development) REGION 4 DGM (Western Province South I) DGM (South) AFM (Distribution Region 4) PROPOSED DISTRIBUTION DGM (North) REGION 5 AFM (Distribution Region 5)
PROPOSED Secretary Pension Fund Secretary Provident Fund COMPANY X DGM (CW&B) PROPOSED DGM (WS&AS) Project Director (Upper Kothmale Power Project) COMPANY Z Project Director (Colombo City Electricity Distribution Development Project)
*FINANCE *AFM (Headquarters) *AFM (Corporate) LEGEND MANAGER AGM - Additional General Manager *DGM (Personnel) DGM - Deputy General Manager *DGM (Medium Voltage Construction & Maint.) AFM - Additional Finance Manager *DGM (Distribution Project) *DGM (procurement) Source: CEB Annual Report 2003) Manager Investigations Chief Legal Officer Figure 4.1 Organisation Structure of CEB Manager Security
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4.3 Power Demand and Supply Balance
In 2003, the total generated electricity in Sri Lanka at the generating end amounted to 7,612GWh (excluding captive power). Electricity sales amounted to 6,209GWh and the remaining electricity was station use and losses at transmission and distribution lines and so on.
In 1996, the maximum peak demand (968.4MW) in the country decreased compared to that in the previous year due to the effect of drought, but since then it has been growing steadily. The recorded maximum demand in 2003 was 1,516MW. The average growth rate over the five years up to 2003 was about 7% per annum. Then, rotating power cuts were conducted due to insufficient power supply capability in 2001 and in 2002. In 2003, rotating power cuts were not carried out due to high water flow. In spite of the fact that total annual electricity sales increased in 2002, the maximum peak demand in 2002 was 1,422MW, down 1.6% from the previous year. The reason for this phenomenon has not yet been specified. The tariff for domestic use for lighting and televisions, which is the main factor in peak demand, was greatly increased after April 2002, and might function as a demand-side management effect.
Since the drought in 1996, the proportion of hydropower has been decreasing year by year, and electricity generated by the CEB’s facilities has also been decreasing since the emergence of IPPs in 1997.
Table 4.1 Demand and Supply Balance 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Hydro 4,089 4,514 3,249 3,443 3,909 4,152 3,154 3,045 2,589 3,190 Thermal 275 269 1,126 1,450 1,264 1,396 2,569 2,237 2,866 2,587 Wind - - - - - 3 3 3 4 3 Hydro Generation - - 3 5 6 18 43 65 104 120 （GWh） (IPP) Thermal - - - 13 390 507 916 1,170 1,248 1,711 (IPP) Captive 22 17152 235 114 108 167 105 141 - Total 4,387 4,800 4,529 5,146 5,683 6,185 6,853 6,625 6,951 7,612 Industrial 1,406 1,527 1,361 1,430 1,614 1,613 1,731 1,719 1,866 2,159 Sectoral Commercial 582 631 592 689 758 829 895 859 921 1,042 Electricity Sales Domestic 928 1.034 1,046 1,213 1,378 1,555 1,755 1,798 1,821 2,030 （GWh） Others 649 723 589 707 771 812 877 862 894 977 Total 3,565 3,915 3,588 4,039 4,521 4,809 5,258 5,236 5,502 6,209 Peak（MW） 910 980 968 1,037 1,137 1,291 1,405 1,445 1,422 1,516 Source: CEB Statistical Digest 2003
Daily peak demand occurs from the evening until 10 p.m. because of lighting requirements. The disparity between the daily peak and the base load is around 2.4 to 1. In Sri Lanka, seasonal changes in load are minimal as are temperature variations. The maximum demand has been recorded month by month (refer to the figure below).
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Source: CEB Report on Long Term Generation Expansion Planning Studies 2005-2019
Figure 4.2 Daily Load Curve over the Year
As indicated in the relationship between the gross domestic product (GDP) growth rate and the growth of electricity sales, electricity generation has been growing in proportion to economic growth. The electricity elasticity (power generation growth rate/GDP growth rate) is almost 2, which implies that the growth of demand for electricity in the country exceeds economic growth.
(%) (Elasiticity) 20 3
2.5 15 2.0 2 1.8 1.8 1.8 1.6 1.5 1.6 1.5 1.4 1.3 1.4 1.3 1.2 1.1 10 0.9 1
0.3 5 0
0 -1 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03
-5 -2 -2.2
-10 -3 GDP Growth Rate Demand Growth Rate Electricity Elasticity
Source: Central Bank of Sri Lanka: Economic and Social Statistics of Sri Lanka 2003. CEB: Sales & Generation Data Book 2003.
Figure 4.3 Growth Rate of GDP and Electricity Sales
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4.4 Electricity Generation
Electricity generation in Sri Lanka has been growing steadily except for in dry years. The annual growth rate of electricity generation averaged 6.7% during the last 10 years (from 1993 to 2003). Taking into account the fact that the electricity generation in 2002 includes rotating power cuts equivalent to 525GWh, the average annual growth could be close to 8%.
As for the composition of generation by source, dependence on hydropower has been eased since the power crisis in 1996 due to drought, and the share of hydropower is less than 50% at present. In the country the share of hydropower had been about 80% until 1995. Many hydropower plants were incidental facilities to multipurpose dams with irrigation functions. Therefore, the CEB was sometimes obliged to cut power generation in times of drought.
Since 1997, the CEB has made efforts to avoid power cuts by introducing IPPs and encouraging installation of self-generation plants with incentive schemes. Annual precipitation recovered in 1997 and electricity generation growth has been high since that year.
However, in 2001 the CEB again failed to meet the potential demand in the country and was obliged to implement rotating power cuts. Electricity generation dropped because of the delay in new power development and drought conditions. In 2002, the situation of power cuts could not be improved. Amounts of power cuts in 2001 and 2002 are estimated to be 289GWh and 525GWh, respectively. In 2003, rotating power cuts were avoided because of high water flow and the commencement of the Kelanitissa combined cycle power station in August 2002 by using Japanese yen loan.
Table 4.2 Electricity Generation 1989 - 2003 Hydro Thermal Self Growth Total Year Generation Generation Generation Rate (GWh) (GWh, %) (GWh, %) (GWh, %) (%) 1989 2,801 (98.0) 57 (2.0) - 2,858 2.1 1993 3,796 (95.4) 183 (4.6) - 3,979 12.4 1994 4,089 (93.2) 275 (6.3) 22 (0.5) 4,386 10.2 1995 4,514 (94.0) 269 (5.6) 17 (0.4) 4,800 9.4 1996 3,249 (71.8) 1,126 (24.9) 152 (3.4) 4,527 -5.7 1997 3,448 (67.0) 1,463 (28.4) 235 (4.6) 5,146 13.7 1998 3,915 (68.9) 1,654 (29.1) 114 (2.0) 5,683 10.4 1999 4,175 (67.6) 1,901 (30.8) 97 (1.6) 6,173 8.6 2000 3,197 (46.7) 3,486 (50.9) 158 (2.4) 6,841 10.8 2001 3,113 (47.0) 3,407 (51.4) 105 (1.6) 6,625 -3.2 2002 2,696 (38.8) 4,114 (59.2) 136 (2.0) 6,946 4.8 2003 3,314 (43.5) 4,298 (56.5) - 7,612 9.6 Note: Total generation figures since 2000 exclude wind power. Source: CEB Report on Long Term Generation Expansion Planning Studies 2005~2019
Total system losses, which include technical losses in generation, transmission and distribution, and other non-technical losses, and load factors in the past year are shown in the table below. The CEB could not install meters for new consumers due to its financial difficulties and the system losses in the past three years, from 1998 to 2000, which included consumed electricity at non-metered connections, increased remarkably.
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Table 4.3 Gross System Losses and Load Factor Generation* Sales* Peak Losses Load Factor* Year (GWh) (GWh) (MW) (%) (%) 1989 2,858 2,353 617.9 17.7 52.8 1990 3,150 2,608 639.7 17.2 56.2 1991 3,377 2,742 685.1 18.8 56.3 1992 3,540 2,869 742.0 19.0 54.5 1993 3,979 3,270 812.0 17.8 55.9 1994 4,365 3,565 910.0 18.3 54.8 1995 4,783 3,915 979.7 18.1 55.7 1996 4,377 3,588 968.4 18.0 51.6 1997 4,911 4,039 1,037.0 17.8 54.1 1998 5,569 4,521 1,136.5 18.8 55.9 1999 6,076 4,809 1,291.0 20.9 53.7 2000 6,687 5,258 1,404.0 21.4 54.2 2001 6,520 5,236 1,444.5 19.7 51.5 2002 6,810 5,502 1,421.8 19.2 54.7 2003 7,612 6,209 1,515.6 18.4 57.3 Generation, Sales and Load Factor exclude self generation. Losses include those at all levels, generation, transmission and distribution and any non-technical losses. (Sources: CEB Report on Long Term Generation Expansion Planning Studies 2005~2019 and Statistical Digest 2003)
4.5 Electricity Tariff
The electricity tariff system in Sri Lanka consists of two parts, demand plus fixed charge and energy (unit) charge. A time-of-day tariff is applicable to industrial-sector use. Even though the tariff for domestic use has been held down in consideration of the lower-income groups, the electricity tariff is high compared to those in other Southwest Asian countries.
The expansion of thermal generation since 1996 has had a great impact on the financial situation of the CEB. The total fuel cost in 1995 was only Rs.0.9 billion, but in 1996 it amounted to Rs.4 billion and in 2000, 2001, 2002 and 2003 it was Rs.10.7 billion, Rs.11.9 billion, Rs.14.6 billion (Rs.9.7 billion for the thermal power plants owned by CEB and Rs.4.9 billion for the hired plants) and Rs.13.8 billion (Rs.11.3 billion for the thermal power plants owned by the CEB and Rs.2.5 billion for the hired plants), respectively. Although the main reason for the decrease in fuel cost seems to be only because of fuel cost saving for hired plants, another reason is efforts made by the CEB. In 2003, in spite the total annual energy generated by the CEB's thermal power stations increased by 12.3%, the total fuel volume consumed decreased by 0.5%. This is attributed to the fact that the CEB cut the plant factor of the power stations with low efficiency and increased the plant factor of the power stations with high-efficiency improvements such as the Kelanitissa combined cycle power station.
In order to raise funds for the expansion of thermal generation and construction of new projects to resolve the power shortage, the electricity tariff was increased in September 1997, with the average tariff rising 11%, from Rs.4.05 per kWh to Rs.4.52 per kWh. The increase rate for industrial use was kept lower at 9%, compared with other uses. The increase rates for domestic use and commercial use were 14.6% and 12.8%, respectively. Owing to not only the increased tariff but also a sharp upturn in electricity sales, revenue from electricity sales in 1997 amounted to Rs16.78 billion, up 16.5% from the previous year.
As mentioned, the financial situation of the CEB was improved temporarily, but the rates of return in 2000 and 2001 became negative because of the increase in fuel costs due to the sudden rise in oil prices, and due to expensive power purchases from IPPs. Therefore, the electricity tariff was raised repeatedly in June 2000, March 2001 and April 2002.
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The government has provided no subsidies to the CEB related to the electricity tariff. As a result, cross subsidies from industrial and commercial uses to domestic use must be made by the CEB as a relief measure for lower-income groups. The tariffs for commercial use and industrial use were 1.6 times and 1.15 times the average tariff in 2001. On the other hand, the tariffs for domestic use and the bulk supply to LECO are only 72% and 67% of the average, and the tariff for commercial use is more than twice the average tariff. The details of cross subsidies in 1995 are shown in Figure 4.4.
Though the CEB intended to abolish the cross subsidies by 2001 with step-by-step adjustment, this has not yet been done.
Table 4.4 Ceylon Electricity Board Tariff (effective from 1st August 2002) Fixed Charge Unit Charge (Rs/month) (Rs/kWh) 1~30 31~60 61~90 91~180 180< Domestic 30.0 3.0 4.0 4.4 10.6 15.8 Religious Purpose 30.0 2.5 2.7 4.0 7.2 Fixed Charge Demand Charge Unit Charge (Rs/month) (Rs/kVA) (Rs/kWh) Contract Demand 30.0(~10kVA) － 10.9 Low Voltage General <42kVA ( ) (400/230V) 230 10kVA< Purpose >=42kVA 800 480 10.8 High Voltage (11/33/132kV) 800 460 10.7 Contract Demand 30.0(~10kVA) － 7.5 Low Voltage <42kVA 230(10kVA<) Industrial (400/230V) >=42kVA 800 400 7.1 High Voltage (11/33/132kV) 800 380 7.0 Industrial Contract Demand 30.0(~10kVA) － 15.0 (peak) (time-of- Low Voltage <42kVA 230(10kVA<) 6.9 (off peak) day) (400/230V) >=42kVA 800 380 14.7 (peak) 6.5 (off peak) 800 360 14.0 (peak) High Voltage (11/33/132kV) 6.1 (off peak) Low Voltage － 240 7.2 (400/230V) Bulk Supplies to LECO High Voltage － 220 5.4 (11/33/132kV) Street Lighting － － 7.8 Source: CEB Statistical Digest 2003
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Cross Subsidies between Customer Cla sses in CEB
2,337 General Purpose
1,335 1,481 Households 3,830 & 2,448 Religious
966 2,530 11 1,102 Li c en sees
5,656 Industries
148 St r e et million 14,501 Rs Requirement Revenue CEB Lighting
Subsidy provided to other customers Subsidy received Revenue “Responsibility”
Note: The information is in Rs Million, for year 1995. The revenue” responsibility ” of each class of customer is considered to be equal on an price/ kWh basis. Responsibility at LRMC levels is presented elsewhere.
Source: Institute of Policy Studies, Electricity Pricing Policy in Sri Lanka
Figure 4.4 Mechanism of CEB’s Cross Subsidies of Domestic Use (1995)
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4.6 Existing Power Plants
The CEB’s existing generating power plants in January 2005 consist of 16 hydropower plants with a total capacity of 1,205MW and five thermal power plants with a total effective capacity of 475MW; the total capacity is 1,680MW. In January 2003, 3×16MW gas turbines (Old) and 2×22MW steam turbines at Kelanitissa, with a total capacity of 88MW, were retired and a new 61MW plant, the steam turbine portion of the Kelanitissa Combined Cycle power plant funded by JBIC, was commissioned in October 2002. The existing power plants, with the remaining 3×17MW gas turbines (Old) at Kelanitissa and 4×18MW diesel plants at Sapugaskanda, are scheduled to retire in 2010 and 2013, respectively.
Table 4.5 (1) Existing Hydropower Plants (connected to the national grid, as of Jan. 2005) Annual Plant Storage Hydro Project Capacity Energy Factor Capacity Commissioning (MW) (GWh) (%) (MCM) Laxapana (KM*) Complex Canyon 60 (30 x 2) 160 30 123.4 #1 Mar.’83, #2 ‘88 Wimalasurendra 50 (25 x 2) 112 26 44.8 Jan.’65 Old Laxapana 50 (8.33 x 3 286 65 0.4 8.33MW x 3 Dec.’50 + 12.5 x 2) 12.5MW x 2 Dec.’58 New Laxapana 100 (50 x 2) 552 63 1.2 #1 Feb.’74, #2 Mar.’74 Polpitiya 75 (37.5 x 2) 453 69 0.4 Apr.’69 Laxapana Total 335 1,432 Mahaweli Complex Victoria 210 (70 x 3) 865 47 721.2 #1 Jan.’85, #2 Oct.’84, #3 Feb.’86 Kotmale 201 (67 x 3) 498 28 172.6 #1 Apr.’85, #2,3 Feb.’88 Randenigala 122 (61 x 2) 454 42 875.0 Jul.’86 Ukuwela 38 (19 x 2) 154 46 1.2 #1 Jul.’76, #2 Aug.’76 Bowatenna 40 (40 x 1) 54 15 49.9 Jun.’81 Rantambe 49 (24.5 x 2) 239 56 21.0 Jan.’90 Mahaweli Total 660 2,258 Other Hydro Samanalawewa 120 (60 x 2) 344 32 278.0 Oct.’92 Kukule 70 (35 x 2) 300 49 1.7 Jul.'03 Other Hydro Total 190 644 Small Hydro Plants Inginiyagala 11 (2.475 x 2 Jun.’63 + 3.15 x 2) Uda Walawe 6 (2 x 3) Apr.’69 Nilambe 3 (1.6 x 2) Jul.’88 Small Hydro Total 20 Hydro Total 1,205 4,465 *KM: Kehelgamu Oya - Maskeliya Oya Source: CEB, Report on Long Term Generation Expansion Planning Studies 2005~2019
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Table 4.5(2) Existing Thermal Power Plants (connected to the national grid, as of Jan. 2005) Capacity used Annual Name Plate for Max. Thermal Power Plant Commissioning Capacity Studies Energy (MW) (MW) (GWh) Kelanitissa Power Station Gas Turbine (Old) 60 (20x3) 51 (17x3) 328 Dec.’81, Mar.’82, Apr.’82 Gas Turbine (New) 115 (115x1) 115 (115x1) 707 Aug.’97 Combined Cycle (JBIC) 165 (165x1) 165 (165x1) 1,290 Aug.’02 Kelanitissa Total 340 331 2,325 Sapugaskanda Power Station Diesel 80 (20x4) 72 (18x4) 472 May.’84, May.’84, Sep.’84, Oct.’84 Diesel (Extension) 80 (10x8) 72 (9x8) 504 4 Units Sep.’97, 4 Units Oct.’99 Sapugaskanda Total 160 144 976 Total Thermal 500 475 3,301 Source: CEB, Report on Long Term Generation Expansion Planning Studies 2005~2019
4.7 Introduction of Independent Power Producers (IPPs)
The national policy of Sri Lanka gives social infrastructure and education higher priority in the distribution of soft loans from abroad, and the government expects power development in the future to be implemented mainly under private finance. As of 2004, IPPs have in operation seven thermal power plants with a total capacity of 434.5MW and as of 2003, 26 small scale hydropower plants with a total capacity of 40MW. The features of seven thermal power plants operated by IPPs are shown in the table below.
Table 4.6 Features of Existing IPP Plants Name Plate Capacity used Annual Contract Plant Name Capacity for Studies Energy Commissioning Period (MW) (MW) (GWh) (Years) IPPs Lakdhanavi 22.5 22.5 156 1997 15 Asia Power 51 41 330 1998 20 Colombo Power 64 60 420 Mid. '00 15 Diesel Plant Matara 24.8 20 167 Mar. '02 10 Diesel Plant Horana 24.8 20 167 Dec. '02 10 Kelanitissa AES CCY 163 163 1,314 GT-Jan. '03 20 Steam-May '06 Heladanavi 100 100 698 Oct.’04 10 IPPs Total 450.1 434.5 3,252 Source: CEB, Report on Long Term Generation Expansion Planning Studies 2005~2019
To promote the introduction of IPP schemes, the Ministry of Finance & Planning and the CEB have each made guidelines for BOT projects. According to the guidelines, all thermal power plants in the future will, in principle, be constructed under BOO/BOT schemes with competitive bidding.
As for hydropower plants, those with a capacity of 10MW and above are to be operated by the CEB from the viewpoint of multiple utilization of water resources, while hydropower plants of less than 10MW capacity are expected to be developed by IPPs. The CEB intends to purchase power from these small-scale hydropower plants for the tariff based on “avoided cost,” and connect them to the national grid. Although the ESC recently encouraged private investors to participate in hydropower plants of less than 50MW, a clear consensus among related organizations including the CEB has not yet been obtained.
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4.8 Present Status of Transmission and Distribution Lines
In Sri Lanka, the voltage of main transmission lines is 220kV or 132kV. All the 66kV transmission lines installed in the 1950s have been upgraded to 132kV. In 2003, the total length of transmission lines was about 1,800km (excluding 242 route km of 132kV transmission lines in the North and East), and about 80% of the total was 132kV lines and 220kV lines connecting hydropower plants in the Mahaweli River basin with industrial areas near Colombo.
The voltage of distribution lines is 33kV or 11kV for medium-voltage lines, and it is stepped down to 400V or 230V lines for distributing power to consumers. There were 14,938 substations as of 2003.
Gross system losses amounted to 18.4% in 2003, down a significant 0.8% from the amount in 2002. The main factor in the dramatic reduction in the system losses may be that the CEB has started to install meters for non-metered consumers, which rose from 1998 to 2000.
Table 4.7 Length of CEB Transmission and Distribution Lines (Unit: km) 220kV 132kV 33kV 11kV 400/230V 2002 315 1,501 17,784 2,420 68,810 2003 315 1,531 18,639 2,390 74,478 Note: Excludes 242 route km of 132kV transmission lines in the North and East Source: CEB, Statistical Digest 2003.
Table 4.8 Number and Capacity of Substations 220/132/33kV 220/132kV 132/33kV 132/11kV 33/11/3.3kV 33/11/LV Number 5 1 33 2 125 14,772 Capacity (MVA) 2,100/500 105 2,154 180 1,056 3,657 Source: CEB, Statistical Digest 2003.
4.9 Forecast of Power Demand and Supply
The CEB’s Generation Planning Branch releases the “Report on the Long-Term Generation Expansion Plan (LTGEP)” every year. In the LTGEP published in 2004 in forecasting future demand for electricity, the CEB prepared scenarios having medium (7.8%), low (7.0%) and high (8.7%) growth rates and made power development plans for each case.
The CEB categorizes demand into three sectors: domestic, industrial and commercial, and others (including consumption for religious activities and for street lighting). It then predicts them separately and combines them to determine total future demand. Domestic-sector use is estimated based on the demand in the category and number of consumers in the previous year. Industrial and commercial use is based on the expected GDP in the year, and the GDP and the demand in the categories in previous year. Other uses are based on demand growth rates in the past years.
In the above demand forecasts, demand in the North and East is excluded.
After preparing the demand forecast, the expected energy generation and peak demand were calculated based on the predicted gross system losses, which were expected to decrease gradually and reach a constant 14.1% after 2008, while those in 2003 were 18.4%, and on the load factor, which was expected to be constant throughout the planning period at 55%. Loss reduction in the distribution system was expected to contribute to the achievement of the planned loss reduction scheme, for the most part.
As shown in Table 4.3, the sequence of the load factors over the past 16 years shows a declining trend. That is, a decrease in peak demand is seen over the long term, albeit with some fluctuations. In 2002,
Final Report 4 - 13 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka negative annual growth in peak demand and a sudden increase in the load factor were recognized when a large-scale rotating power cut, which amounted to 525 GWh, was carried out, but the reasons have not been specified yet. It would be rash to conclude that the decline in peak demand has ceased. It is not certain that the load factor in 2003 hit the large figure of 57.3% despite the fact that the figures in 1996 (51.6%) and 2001 (51.5%), when power cuts took place, are relatively small. Therefore it is better to carefully watch the load factor trend for a while.
Although a scenario that the leveling of the load curve will succeed due to the effect of demand-side management has also prepared in the sensitive analysis of the demand forecasts, it is necessary to consider that the period of rural electrification has made the load curve sharper.
Table 4.9 Load Forecast from 2004 to 2024 (Base Case) Gross* Demand Growth Rate Generation Load Factor Peak Year Losses (GWh) (%) (GWh) (%) (MW) (%) 2004 6,573 5.9 18.2 8,038 55.0 1,668 2005 7,032 7.0 17.3 8,506 55.0 1,765 2006 7,567 7.6 15.3 8,937 55.0 1,855 2007 8,149 7.7 14.8 9,565 55.0 1,985 2008 8,804 8.0 14.1 10,245 55.0 2,126 2009 9,515 8.1 14.1 11,072 55.0 2,298 2010 10,284 8.1 14.1 11,967 55.0 2,484 2011 11,112 8.1 14.1 12,931 55.0 2,684 2012 12,005 8.0 14.1 13,970 55.0 2,900 2013 12,965 8.0 14.1 15,087 55.0 3,131 2014 13,995 7.9 14.1 16,286 55.0 3,380 2015 15,100 7.9 14.1 17,571 55.0 3,647 2016 16,283 7.8 14.1 18,948 55.0 3,933 2017 17,556 7.8 14.1 20,429 55.0 4,240 2018 18,920 7.8 14.1 22,017 55.0 4,570 2019 20,383 7.7 14.1 23,719 55.0 4,923 2020 21,949 7.7 14.1 25,541 55.0 5,301 2021 23,627 7.6 14.1 27,494 55.0 5,707 2022 25,429 7.6 14.1 29,591 55.0 6,142 2023 27,361 7.6 14.1 31,839 55.0 6,608 2024 29,431 7.6 14.1 34,248 55.0 7,108 * Gross losses include those at all levels: generation, transmission and distribution and any non-technical losses. Source: CEB, Report on Long Term Generation Expansion Planning Studies 2005~2019
4.10 Power Development Plan
To meet growing power demand in the future, the CEB has made efforts a) to promote the best mixture of power sources without excessive dependence on hydro power, b) to encourage private investment in the power sector, c) to implement demand-side management under effective energy conservation programs, d) to establish investment plans in accordance with economic needs, and e) to reduce distribution line losses.
According to the latest LTGEP, the power development plan up to 2019 is as shown in Table 4.10. Power generation facilities with a total capacity of 4,180MW are planned to be commissioned over the next 15 years. The total present value cost for all projects up to 2024 is estimated to be US$ 4,865 million (Rs471,195 million). The CEB uses the latest version of the Energy and Power Evaluation
Final Report 4 - 14 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Program (ENEPEP) developed by the International Atomic Energy Agency (IAEA), for planning the optimal power development plan. In the optimal power development plan, the Loss of Load Probability (LOLP) is targeted to be less than 0.82%, less than three days annually.
The relationship of LTGEP, peak demand, reserve margin and LOLP is shown in Table 4.11. The target figure of LOLP will be attained after 2005 according to the LTGEP, but a key question is whether new power generation projects will be able to be started in accordance with the LTGEP or not. The relationship between the LTGEP and peak demand is shown in Figure 4.5.
Table 4.10 Generation Expansion Plan Sequence
Hydro Capacity Year Thermal Additions Thermal Retirements Present Status Additions (MW) 2005 Heladhanavi Diesel Power 100 Commissioned in Plants at Puttalam October 2004 ACE Power Diesel Power Plant 100 Under construction at Embilipitiya Expected in March 2005 2006 2007 GT part of Kelawalapitiya CCY 200 Under Evaluation 2008 ST part of Kelawalapitiya CCY 100 Under Evaluation Gas Turbines 105 2009 Gas Turbines 140 2010 Upper 150 JBIC Pledged Kotmale Coal Steam 300 Kelanitissa Gas -51 Turbine (Old) 2011 Coal Steam 300 2012 Coal Steam 300 Lakdhanavi plant -22.5 Matara diesel plant -20 2013 Coal Steam 300 Sapugaskanda diesel -72 plant Horana diesel plant -20 2014 Coal Steam 300 2015 Gas Turbines 285 Colombo power barge -60 plant Medium-term Diesel -200 Power Plants 2016 Coal Steam 300 2017 Coal Steam 300 Kelanitissa Gas -115 Turbine (New) 2018 Coal Steam 300 Gas Turbines 180 Asian power plant -49 2019 Gas Turbines 420 Source: CEB Data
Final Report 4 - 15 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Table 4.11 Generation Expansion Plan and Reserve Margin Year Total Installed Peak Demand Reserve Capacity Reserve Margin LOLP Capacity (MW) (MW) (MW) (%) (%) 2005 2,194.5 1,668 526.5 31.6 0.245 2006 2,194.5 1,765 429.5 24.3 0.850 2007 2,394.5 1,855 539.5 29.1 0.465 2008 2,599.5 1,985 614.5 31.0 0.515 2009 2,739.5 2,126 613.5 28.9 0.740 2010 3,138.5 2,298 840.5 36.6 0.124 2011 3,438.5 2,484 954.5 38.4 0.064 2012 3,696.0 2,684 1,012.0 37.7 0.061 2013 3,904.0 2,900 1,004.0 34.6 0.093 2014 4,204.0 3,131 1,073.0 34.3 0.080 2015 4,229.0 3,380 849.0 25.1 0.509 2016 4,529.0 3,647 882.0 24.2 0.545 2017 4,829.0 3,933 896.0 22.8 0.660 2018 5,145.0 4,240 905.0 21.3 0.717 2019 5,565.0 4,570 995.0 21.8 0.618
Final Report 4 - 16 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
5,000
Total Installed Capacity Peak Demand Colombo Gas Turbine Gas － ACE Power
4,500 － Coal 300MW Coal Coal 300MW Coal Power ACE Power Sapugaskanda － －
4,000 300MW Coal Lakdanavo － Gas Turbine
3,500 300MWCoal s Coal 300MWCoal Capacity (MW) 3,000 Small GasTurbine － Y Upper Kotmale
2,500 Coal 300MW Coal Kerawalapitiya CC Medium TermMedium Diesel and Plants at Puttalam
2,000
1,500 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 Year
Figure 4.5 Expansion Plan and Peak Demand
Final Report 4 - 17 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
4.11 History and Difficulties of Power Development Plan
In spite of the fact that the balance between power demand and supply in Sri Lanka had been satisfied up to 2002, other than during an extreme drought year in 1996, power supplies were restricted in 2001 and 2002. Power demand before the year 2000 had been satisfied, as a result, which does not mean that the power development plans drawn up by the CEB had proceeded on schedule. To indicate the difficulties of new power plant development in the past, the LTGEP prepared by the CEB in 1993 for the years from 1994 to 2008 is shown in Table 4.12 as a reference.
As of 1993, the commissioning of a 66MW gas turbine plant and a 40MW diesel extension plant in 1996, and a 110MW diesel plant in 1997 and a 40MW diesel plant in 1998, totaling 256MW capacity, was planned to provide emergency power sources. In addition, two hydro power plants, Kukule (70MW capacity) and Upper Kotmale (123MW capacity), large-scale coal thermal power plants with a total capacity of 300MW, and refurbished 60MW gas turbine were expected to start operation. According to the 1993 power development plan, required power generation facilities until 2004 amounted to 809MW. In fact, the need for large-scale thermal power plants from the aspect of stable power supply and of hydro power development utilizing limited domestic resources was recognized, and coal was considered the most promising fuel source for thermal plants because of its stable fuel price.
Table 4.12 Generation Expansion Plan (in 1993)
Capacity Year Hydro Additions Thermal Additions Thermal Retirements (MW) 1994 1995 1996 Gas Turbine 66 Diesel (Extension) 40 1997 Diesel 110 1998 Diesel 40 1999 Kukule 70 2000 Upper Kotmale 123 2001 Coal Steam (Trincomalee) 150 Kelantissa Oil Steam -44 2002 Coal Steam (Trincomalee) 150 Kelanitissa Gas Turbine -48 2003 Refurbished Gas Turbine 60 Kelanitissa Gas Turbine -48 2004 Refurbished Gas Turbine 60 Coal Steam (Trincomalee) 300 Sapugaskanda Diesel -32 2005 2006 Gin Ganga 49 Gas Turbine 22 2016 Coal Steam (Trincomalee) 300 2017 Gas Turbine 66 Sapugaskanda Diesel 32 Source: CEB Data
On the other hand, the existing power plants at the end of 2004 that were commissioned since 1994 have a total capacity of 856.5MW, and include the Kelanitissa New Gas Turbine plant (115MW), Kelanitissa Combined Cycle plant (165MW), Sapugaskanda Diesel Extension plants (72MW), Kukule Hydropower Station (70MW) and power purchases of 434.5MW from diesel plants of independent power producers. All of those power plants use oil as fuel and can be regarded as emergency generators, which have been causing an unfavorable financial situation for the CEB.
Final Report 4 - 18 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Regarding the present power development plan from 2005 to 2019, the originally planned hydro power and coal thermal power projects – coal thermal plants with 300MW capacity expected to be commissioned in 2010 and the 150MW Upper Kotmale hydro power plant in 2010 – have been delayed, except for the Kukule hydropower plant, which started operation in July 2003. Emergency power plants are still expected to be installed before 2010, as before.
In 1993, emergency power plant development was scheduled to meet short-term increasing demand and large-scale coal thermal power plants and hydro power plants to meet long-term increasing demand, but most of the long-term projects have been postponed. Subsequently, emergency power plant developments consisting mainly of diesel or gas turbine plants were scheduled to meet short-term demand again in 2005.
Reasons given for the delays in project implementation for large-scale coal thermal power plants and hydro power plants are, in short, the difficulty of finding suitable project sites or the CEB’s delays in project implementation, or a combination of these, and some are mentioned below.
(1) Environmental Issues
All power plans have some environmental problems when they are going to be implemented, and even during implementation, and the hydro power projects and coal thermal power projects in Sri Lanka have been delayed because of environmental problems. Inappropriate EIA procedures were pointed out for a certain project and another project has been suspended because of excessively strong opposition. The ethnic and religious diversity of the country and/or an unstable political situation sometimes leads to inappropriate correspondence to opponents.
(2) Introduction of Private Investment and Sector Reform
The introduction of private investors for power development and the unbundling of the CEB are described in the “Power Sector Policy Directions” established in 1997 with the cooperation of the World Bank. At about that time, the CEB’s power development strategy efforts surged, and this may lead to the delay of projects. Also, which organization was responsible for power development was not clear and it took much time to change the CEB’s course of power development from its own project implementation by finance from international banks to power purchasing from independent power producers. (3) Delays in Contract Procedures The CEB has implemented projects itself with the assistance of international bank financing, and sometimes there have been delays during the loan agreement procedure and during the evaluation of consultants and contractors. After accepting private investors for power generation projects with independent power producers, the negotiation and conclusion of contracts took a long time before and it is still taking a long time.
(4) Lack of Political Leadership
As mentioned above, one of the reasons given for the difficulty of new project implementation is environmental problems, but sometimes the environmental problems contain political problems as well. It is essential, for power development plans of the CEB to go ahead, that assistance be solicited not only from related government bodies but also from political power-holders.
4.12 Transmission and Distribution Lines Expansion Plan
The CEB’s transmission and distribution lines are experiencing significant losses and it is important for Sri Lanka to reduce these losses, especially in distribution lines. Therefore, the CEB is making efforts to maintain and expand transmission and distribution lines with the assistance of overseas funds.
Final Report 4 - 19 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
JBIC has contributed financing amounting to 7.1 billion yen for the transmission and substation projects, Transmission Grid Substation Development Project I and II, since 1997, which were completed in 2004, and a total of 6.0 billion yen for the transmission line expansion project, Medium Voltage Distribution Network Reinforcement Project.
Furthermore, JBIC has decided to contribute financing totaling 6.0 billion yen for the Colombo City Electricity Project which is expected to start soon, and a total of 2.9 billion yen for the transmission line between the power station developed by IPP and Kotugoda on the outskirts of Colombo, which has been delayed due to an open contract with the IPP. JBIC signed loan agreements of 1.3 billion yen with Sri Lanka to finance the Vavuniya-Kilinochchi Transmission Line Project to support reconstruction in northern Sri Lanka, a region ravaged by civil war.
4.13 Present Situation of Hydropower Stations in Kelani River Basin
There are five hydropower stations with a total capacity of 335MW in the Kelani River basin, which have the single purpose of power generation, and they are called the Laxapana Complex. Although facilities of the hydropower stations in Sri Lanka have been well maintained as a whole under the limited budget for overhaul and maintenance, many defects of the hydropower stations in the Kelani River basin have become obvious recently. These defects are causing a deterioration of power supply capability and inefficient power operation, which worsens power shortage.
The Kelani River radiates from the Central Highlands to the Indian Sea passing through the city of Colombo, located in western Sri Lanka. The catchment of the river system is 2,278km2. The river basin is located in a heavy rainfall zone, and especially the area in which the five hydropower stations lie is one of the rainiest part of Sri Lanka. Annual rainfall in the area exceeds 4,000mm and that at the most upstream of the area exceeds 5,000mm. The five hydropower stations are located about 80km east of Colombo, and are relatively close to that electric power consuming region. Therefore, the development of these hydropower stations started at an early stage. The history of hydropower development in Sri Lanka began with the construction of the Old Laxapana Hydropower Station in the Kelani River basin, which began commercial operation in 1950. The location of the five power stations in the Kelani River basin are shown in Figure 4.6 to 4.8.
Final Report 4 - 20 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Figure 4.6 Location Map of Power Stations in Sri Lanka
Final Report 4 - 21 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Figure 4.7 Longitudinal Section of Kelani River Basin
Figure 4.8 Laxapana Complex
Final Report 4 - 22 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
(1) Wimalasurendra Hydropower Station
This power station was constructed with the assistance of the International Bank for Reconstruction and Development (IBRD). In 2002, a muddy discharge was recognized at the outlet of the power station. The chief engineer of the power station is presuming that the reason is a collapse somewhere inside the pressure headrace tunnel. As a basis for this thinking, muddy water ceased under partial operation of the plants at 25MW, indicating that decreasing water velocity in the tunnel reduces the discharge. Although it is essential to stop the operation and to dewater the tunnel to inquire into the real cause of the muddy water, the plants have been operated according to the instruction of the CEB’s headquarters. No options are left for the investigation except dewatering, although the chief engineer is afraid of enlargement of the tunnel collapse. No other significant problems, which may cause a plant shutdown, have been recognized.
The Wimalasurendra power station started commercial operation in 1965. Its electrical and mechanical equipment has been operated for 39 years. Therefore it is recommended that the inspections to check for deterioration of electro-mechanical generating equipment be done periodically and their conditions be observed continuously. Nevertheless, while the CEB had already prepared the replacement plan for the control and protection system, the plan has not been implemented due to the financial difficulties.
(2) Old Laxapana Hydropower Station
This power station was constructed with the assistance of IBRD and others. Units 1, 2 and 3 started commercial operation in 1950 and have been operated for 53 years. Units 4 and 5 started operation in 1958 and have been operated for 45 years. No notable defects have found in civil structures.
The control and protection system of electrical equipment, exciter systems of generators, and governors of hydro turbines were replaced step by step, in the first stage (1994-1995) and the second stage (2003-2004), by the CEB. However, other equipment such as inlet valves, needle valves and oil lifters is still experiencing serious trouble and these problems have spoiled the plants’ sound operation. As with the above mentioned power station, the CEB had already prepared the replacement plan for inlet valve and runner which were installed at the first construction stage (for Units 1, 2, 3); however, the plan has not been implemented due to financial difficulties.
(3) Canyon Hydropower Station
This power station was constructed with the assistance of the Asian Development Bank (ADB) and Organization of Petroleum Exporting Countries (OPEC). According to interviews at the site, the capacity of the power station was increased from the original plan during construction. Therefore, the waterway structures of the power station were not suitably designed for a 60MW power station and heavy friction losses caused by their too-small waterway diameters are arising. Because the tunnel diameter between the intake and the portal of the headrace tunnel is especially small, negative pressure has been increasing. In spite of the fact that an anti-negative pressure valve has been installed to prevent a breakdown of the pipe caused by negative pressure, it has malfunctioned from time to time.
This power station was constructed in 1983 and has been operated for more than 20 years. So far, no serious problem in the machinery has been observed. It is noted that the hydro turbines, generators and main transformers were manufactured in Japan.
(4) New Laxapana Power Station
This power station was constructed with the assistance of the IBRD and others and has been operated since 1974. A considerable amount of water, 0.1 m3/s, is leaking from the vicinity of the
Final Report 4 - 23 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
surge chamber located at the downstream end of the headrace, and is flowing down the slope, which may cause not only economic losses but also a negative impact on slope stability if it remains uncorrected over the long term. Additionally, the cavity below the toe of the spillway of the Canyon Dam is recognized.
The governor of Unit 1 is experiencing trouble and this unit frequently balks at the start-up of generation. Therefore, the CEB has to keep this unit running even in light load periods at night. Because the governor trouble deprives Unit 1 of its frequency regulating function, frequency fluctuation has been stabilized only by Unit 2. The governor system of this station is quite old-fashioned. If the CEB requires the enhancement of frequency stabilizing capability of this station in the future, the governor system of both units should be replaced at the same time.
(5) Polpitiya Hydropower Station
This power station was constructed with Canadian assistance. There is fear that sediment originating from surface exfoliation of the unlined headrace tunnel has been flowing into the turbines, but this has not yet been confirmed.
The CEB conducted the replacement work of the control and protection system, governor and exciter system from 2003 to 2004. But both hydraulic turbines in the Polpitiya power station still have serious mechanical problems (vibration of turbines and turbine shaft), so output of the generator is allowed only at 5MW, 32MW, or 37.5MW per unit to prevent serious vibration. Detailed investigation and suitable countermeasures to solve the problems are required for those two units.
Final Report 4 - 24 5. CIVIL STRUCTURE The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
5. CIVIL STRUCTURES
To help understand the present status of respective hydropower plants and study rehabilitation programs for defects, a site investigation and interview was conducted in cooperation with the Laxapana Complex Chief Engineer, Mr. Herath, and his staff. The following table shows the performance records of sites visited during the 1st Study Period in Sri Lanaka. The investigation was conducted in the following manner: The first visit was aimed to grasp the general features of a hydropower plant. The second and third visits were aimed to understand and analyze specific problems addressed by CEB. The forth visit was aimed to inspect the headrace tunnel of Wimalasurendra hydropower plant. The summary of the investigation results is shown in Table 5.1.
Visit Period Attendants
Mr. Nakahata (Team Leader) August 9~10, Mr. Kaneko (Civil Engineer) 1st 2004 Mr. Hoshino (Geologist) 3 Engineers from CECB (Local Consultant)
Mr. Kaneko (Civil Engineer) August 16~18, 2nd Mr. Hoshino (Geologist) 2004 2 Engineers from CECB (Local Consultant)
Mr. Nakahata (Team Leader) August 26~27, Mr. Kaneko (Civil Engineer) 3rd 2004 Mr. Hoshino (Geologist) 2 Engineers from CECB (Local Consultant)
Mr. Nakahata (Team Leader) Mr. Kaneko (Civil Engineer) February 25, 4th Mr. Tabata (Operation Cordination) 2005 Mr. Komatsu (JICA Expert) 2 Engineers from CECB (Local Consultant)
Final Report 5 - 1 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Table 5.1 Summary of Investigation Results
Wimalasurendra Old Laxapana Canyon New Laxapana Polpitiya Hydropower Plant Hydropower Plant Hydropower Plant Hydropower Plant Hydropower Plant Reservoir No comment in No comment in No comment in Sedimentation Sedimentation /Pondage particular particular particular Modification of Leakage at right Installation of rain spillway bank No comment in Cavity in gauge station Dam Re-drilling of Installation of particular foundation rock Reinforcement of drainage relief flashboard spillway holes Improvement of No comment in No comment in Vortex at intake Intake anti negative Sedimentation particular particular Landslide pressure valve Headrace Small collapse in No comment in No comment in No comment in No comment in Tunnel tunnel particular particular particular particular Surge No comment in Turbulence and No comment in Leakage on slope No comment in Tank particular explosive noise particular near surge tank particular Erosion in Erosion in foundation of Erosion in No comment in No comment in foundation of anchor block foundation of Penstock particular particular anchor block concrete anchor block concrete Leakage at concrete expansion joint Landslide Power No comment in No comment in No comment in No comment in house particular particular particular particular Leakage in wall concrete Displacement in Excessive No comment in Erosion in concrete Erosion in concrete Tailrace retaining wall turbulence at outlet particular wall wall concrete Re-drilling of drainage relief holes Removal of vegetation near civil structures Common Allocation of civil engineer Periodic inspection
Final Report 5 - 2 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
5.1 Present Status and Rehabilitation Plan for Wimalasurendra Hydropower Plant
5.1.1 Castlereagh Reservoir
(1) Surrounding Landslides
The slopes surrounding reservoirs in Laxapana Complex were investigated using topographical interpretation of topographical maps, aerial photos and field inspection.
The Castlereagh Reservoir is surrounded by gentle slopes, which are used for tea plantation. Steep slopes and escarpments are distant from the shore of the reservoir. Gentle slopes are underlain by weathered gneiss. There were no landslide topographies observed.
(2) Sedimentation Picture 5.1 Castlereagh Dam No significant problem was reported.
5.1.2 Castlereagh Dam
(1) Modification of spillway
1) Present status
According to CEB, they hope to replace the flashboard, which has been provided at the top of each spillway for an increase in reservoir capacity, with a new gate system in order to secure the safety of the people living along the river and to prevent useless spillage of reservoir water.
The flashboard system consists of wooden plates, rubber sheets, steel supports and wire as shown in Picture 5.2. The flashboard system cannot regulate discharging water. Consequently, once discharge starts, it is impossible to stop the discharge until the water level lowers below the crest elevation of the spillway. There are two problems which occur during discharge:
♦ Sudden rise in water level in the downstream of the dam ♦ This may cause danger for people Picture 5.2 Flashboard living downstream. ♦ Loss of benefit in electricity generation ♦ Even after flooding, it is impossible to close the flashboard system.
Therefore, CEB wishes to install a mechanical gate system, able to regulate discharge.
This modification will cause changes in load conditions to the spillway piers. Further, deterioration of structures may cause additional stress upon structures that will exceed allowable thresholds. It is necessary to collect the as-built drawings for understanding the arrangement of reinforcement needed, and the design reports for the load conditions. However, this task
Final Report 5 - 3 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
remains difficult due to the improper storage of these documents by CEB. Therefore, the present status should be investigated in order to understand the arrangement of reinforcement, load conditions, and the degree of deterioration of structures prior to the spillway modification.
2) Rehabilitation plan
The rehabilitation plan is described in Chapter 6.
(2) Drainage relief holes
1) Present status
There are drainage relief holes in the dam gallery. These holes function to relieve uplift on the bottom of the dam. Some of the drainage relief holes are likely to be plugged judging from the fact that no water was discharging from the holes. This defect would lead to an unstable condition of the dam. Therefore, these holes should be drilled so that they will discharge water.
Apart from the dam stability, the outlets from the drainage relief holes to the downstream face of the dam are also plugged. These outlets should also be cleaned. Picture 5.3 Plugged Drainage Relief Hole
Further, in some locations of the gallery algae covers the floors. This should be cleaned as well.
2) Rehabilitation plan
The plugged drainage relief holes should be drilled so as to be able to reach the foundation rock in order to release uplift and keep the dam stable.
The plugged outlets and the floor covered with algae should be cleaned.
(3) Crack
No significant crack was observed in the upstream and downstream face of the dam. The dam concrete is in good condition. (4) Leakage
No leakage was observed in the dam concrete and both abutments.
Leakage at the needle valve of the dam was observed. This matter is described in Chapter 6.
(5) Wear
No significant wear was observed in the spillway concrete.
Final Report 5 - 4 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
5.1.3 Intake
The Intake structure was submerging during the JICA team visit. There are no significant defects such as cracks, sedimentation and so forth.
5.1.4 Headrace Tunnel
It was impossible to enter the tunnel. Therefore, no significant investigation was conducted.
(1) Collapse in Tunnel
1) Present status
According to CEB, it is considered that the collapse occurred in the pressurized headrace tunnel. During the operation in 2001 it was observed that turbid water was discharging at the outlet which may have caused the collapse. In order to make sure the present status of the tunnel, the tunnel must be dewatered. CEB conducted the dewatering of the tunnel and inspected the tunnel on February 2005. The summary of the results are shown below. For more details see the appendix. The location of the collapse did not occur at the location which was expected by the people attending the technical meeting in CEB. Instead the collapse occurred at TD3,350ft of the headrace tunnel. The collapse was quite smaller than that expected. Further, the headrace tunnel looks in sound condition as a whole.
Following the inspection, the remedial works was implemented by local contractor. It was completed by the middle of April 2005 and filled with water.
5.1.5 Surge Tank
No significant defects were reported.
5.1.6 Penstock
No significant defects were reported.
5.1.7 Powerhouse
No significant defects were reported.
5.1.8 Tailrace
(1) Crack
No significant defects were reported in the concrete structures.
(2) Wear
No significant defects were reported in the concrete structures.
Final Report 5 - 5 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
(3) Flow
The discharged water coming out from the tailrace to the outlet was forming excessive turbulence. Large amounts of trapped air and noise were being discharged from the outlet periodically.
In general the intake and the surge tank are possible entrance locations for air. The influence of the fluctuation of the pressure acting upon civil structures, caused by the periodic discharging of air from the outlet, is negligible small. In this connection, CEB did not regard this matter as a problem. However, it is necessary to confirm that Picture 5.4 Excessive Turbulence there is no problem in energy production due to the turbulence.
Final Report 5 - 6 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
5.2 Present Status of and Rehabilitation Plan for Old Laxapana Hydropower Plant
5.2.1 Norton Bridge Pondage
(1) Sliding at surroundings
Surrounding slopes at reservoirs in Laxapana Complex were investigated using topographical interpretation of topographical maps, aerial photos, and field inspection.
Norton Bridge Pondage is generally surrounded by gentle slopes of 20 to 30 degrees, which are underlain by talus deposits or weathered gneiss and are used for tea plantation. A movement of a small scale landslide was recognized on the left bank. However, no remarkable landslide topography was observed in the surroundings of the pondage.
(2) Sedimentation
In the past, CEB has removed sedimentation material from the pondage. Sedimentation is a chronic problem for the Norton Bridge Pondage.
5.2.2 Norton Bridge Dam
(1) Crack
The concrete structure was generally in good condition.
(2) Leakage
1) Present status
Norton Bridge dam is constructed on sound gneiss dipping toward the left bank at about 25 degrees. Leakage was discovered at the Picture 5.5 Norton Bridge Dam just downstream right bank of the dam on August 18, 2004 during the 2nd site visit. The amount of the leakage at that time was approximately 0.3~0.5m3/sec and its color was muddy as shown in Picture 5.6.
It was found that this muddy color was the same as the stream at the just upstream right bank of the dam. In general the following points should be studied carefully when leakage is found at dams.
♦ Expansion of leakage path ♦ Influence on slope stability Picture 5.6 Leakage at Right Bank ♦ Loss of electricity income
As for the first point concerning leakage path, muddy leakage are indications of a generally serious situation. This indicates that the leakage path is expanding due to erosion. However, it is an unlikely scenario in the Norton Bridge Dam site is taking in account of the following facts. First, muddy leakage was not observed during the 3rd site visit i.e. color of the leakage was almost clear. The muddy leakage observed during the 2nd visit is probably due to the muddy inflow at the right bank stream, named Agro Oya. Second, the leakage path exists in sound
Final Report 5 - 7 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
gneiss rock, not soil. Third, the electrical conductivity values shown in Table 5.2 i.e. the values at No. 1,2 and 3, are very close to those of No.9, 10 and 11. Also, leakage is likely to be directly connected with the Agro Oya stream.
The second point concerns that there is no influence on the slope stability due to the following reasons. The leakage path is considered to be in rock. And, there was no trace of a sliding at the surrounding area despite that the leakage has been present for more than 30 years according to a local person.
Lastly, the third point concerning loss of electricity income is shown in the following chapter 2) “Rehabilitation Plan”.
Table 5.2 Water Quality Test Result (carried out on August 26, 2004)
Sampling Water Electrical Characteristic of Sampling Point Point No. Temperature Conductivity （℃） （μＳ） 1Upstream of the stream 22.0 27.4 2Just downstream of the waterfall 21.8 26.7 3Just downstream of the waterfall 21.7 27.4 4Confluence of the stream and the reservoir 21.8 29.0 5Confluence of the stream and the reservoir 21.9 29.1 6Standing water at left bank 27.1 87.5 7Stream at left bank 23.0 29.9 8Just upstream of discharge point 21.7 29.6 9Discharge point 21.4 27.8 10Discharge point 21.4 27.8 11Discharge point 21.3 27.9 12Reservoir 23.3 44.7
Intake Stream
12
6 7 Norton Bridge Norton Bridge Reservoir Dam
8
5 9 10 11 4 3
2
1 Agro oya
Figure 5.1 Sampling Point of Water Quality Test
Final Report 5 - 8 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
2) Rehabilitation plan
Before studying the precise rehabilitation plan, it is necessary to assess the benefit of electrical sales income, obtainable from the rehabilitation that is suppressed by the leakage. In order to achieve this, the following matters should be carried out.
♦ To measure the amount of the leakage for the estimation of electricity income ♦ To specify the entrance location of the leakage for planning the rehabilitation
The leakage amount was clarified through the investigation works of the JICA Study Team. Details are shown in the appendix. As for specifying the entrance location of the leakage, it is necessary to perform another investigation by CEB.
Table 5.3, 5.4, 5.5 and Figure 5.2 show the measurement results of the leakage, the annual loss due to the leakage and the financial analysis results.
Table 5.3 Measurement Result of Leakage Quantity Norton RWL Date Time l/s EL. (m) 18-Jan-05 13:40 40 865.32 20-Jan-05 13:25 38 864.82 25-Jan-05 13:40 39 865.09 27-Jan-05 13:30 38 865.01 1-Feb-05 15:15 48 865.31 2-Feb-05 11:10 56 865.52 9-Feb-05 14:05 50 864.69 11-Feb-05 13:35 48 864.94 19-Feb-05 14:30 44 866.33 20-Feb-05 14:25 43 866.7 Average 44.4 865.37
Table 5.4 Annual Loss due to Leakage QHη P PF W Tariff Annual Loss (m3/s) (m) (%) (kW) (%) (kWh) (Rs/kWh) (Rs) Minimum 0.038 449 85 142 64 796,109 7.68 6,114,116 Maximum 0.056 449 85 209 64 1,171,738 7.68 8,998,945 Average 0.0444 449 85 166 64 930,662 7.68 7,147,487
Final Report 5 - 9 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Table 5.5 Financial Analysis Result
IRR 20.00% Discount rate 0.1 NPV (*1000Rs) 31,933
Item Note Unit 2006 2007 2008 2009 ~ 2056 123 50 1. Remedial Works ×1000 Rs 35,740 2. Income Electricity GWh 0.930.930.93 0.93 Income 7.68 Rs/kWh ×1000 Rs 7,147 7,147 7,147 7,147
Cash Out Remedial works ×1000 Rs 35,740000 0 Cash In Electricity sale ×1000 Rs 0 7,147 7,147 7,147 7,147 Inflow-Outflow ×1000 Rs -35,740 7,147 7,147 7,147 7,147
Leakage - Remedial Works Cost Old Laxapana Plant
100,000 y = 2E+06x + 328.89 2 90,000 R = 1 80,000 y = 1E+06x + 183.91 70,000 R2 = 1 60,000 Discount rate=20% 50,000 Discount rate=15% 40,000 Discount rate=10% 30,000 y = 801746x + 112.8 R2 = 1 20,000
Remedial Works Cost (*1000Rs) Cost Works Remedial 10,000 0 0.03 0.035 0.04 0.045 0.05 0.055 0.06 Amount of Leakage (m3/s)
Figure 5.2 Correlation between Amount of Leakage and Remedial Works Cost
Figure 5.2 shows the correlation between the amount of leakage and the cost of remedial works based on the following conditions.
The leakage will stop completely due to the remedial works. The annual loss of electricity is obtained from the average amount of the leakage. The remedial works cost is on the basis that the net present value NPV is 0 at the specified discount rate.
The figure states that the limit amount of investment in the remedial works would be 70 million Rs, assuming that the discount rate is 10% where discharge is the average value 0.044m3/s. Tax is included in the cost of the remedial works. Furthermore it is not necessary to take account of the loss of electricity income for the remedial works because the works would not impact the plant operation for generation.
Final Report 5 - 10 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
(3) Wear
No wear features were observed on the ogee surfaces.
(4) Modification of spillway
1) Present status
According to CEB, they hope to install a flashboard, which will be the same type as installed at the Castlereagh Dam, to increase reservoir capacity.
The flashboard system consists of wooden plates, rubber sheets, steel supports and wires as shown in Picture 5.2. Flashboards cannot regulate discharging water.
2) Rehabilitation plan
This modification will cause changes in load conditions to the spillway piers. Further, deterioration of structures may cause additional stress upon structures that will exceed allowable thresholds. It is necessary to collect the as-built drawings for understanding the arrangement of reinforcement needed, and the design reports for the load conditions. However, this task remains difficult due to the improper storage of these documents by CEB. Therefore, the present status should be investigated in order to understand the arrangement of reinforcement, load conditions, and the degree of deterioration of structures prior to the spillway modification.
In addition to this the environmental impact assessment, also called EIA arises further difficulty. According to the law, the government must approve CEB works which occur within a 100m area from reservoir. With the installation of the flashboard system, the supply water level of the reservoir will be raised. Also, the area that will be restricted in accordance with the law will expand. Therefore, it is concluded that EIA procedures are essential.
The rehabilitation plan is described in Chapter 6.
5.2.3 Intake
No significant defects were reported.
5.2.4 Headrace Tunnel
It was impossible to enter the tunnel. Therefore, no significant investigation was conducted.
5.2.5 Surge Tank Turbulence and Explosive Noise
(1) Present status
It is reported that turbulence and explosive noises are present sometimes at the entrance of the Stage I penstock during plant operations with full discharge. This was not observed during the 2nd site visit due to that the plant was not operating at full discharge.
The following is possible scenario for the turbulence and the noise. Picture 5.7 Surge Tank
Final Report 5 - 11 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
While the plant is operated with full discharge, as the surge tank water levels lower air, enters into the Stage I penstock with turbulence at the entrance. Air becomes accumulated somewhere in the penstock near the surge tank. The accumulated air then regurgitates toward the surge tank for some reason. Once it reaches the surge tank an explosive noise is emanated with heavy turbulence.
It is best that such phenomena do not happen in the surge tank. However, no serious impact was observed on the operation in terms of Picture 5.8 Inside of the Surge Tank electricity output and civil structures.
(2) Rehabilitation plan
Assuming that the above scenario is true, the followings are possible causes.
♦ Big head loss in the headrace causes a lower water level in the surge tank. ♦ The selected location of the surge tank is rather high. ♦ The allocated water level at the dam is lower.
However, the mechanism of turbulence and large noise has not been clarified yet. There is also no influence prominent caused by the problem on electricity generation. Therefore, mechanism cause and influence of the problem should be clarified through further investigation.
Surging analysis has been done in order to understand other possible phenomena in the surge tank. According to the analysis results it is possible for air to enter the penstock depending on operation conditions. Details are listed in chapter 5.7.
5.2.6 Penstock
No significant defects were reported.
5.2.7 Powerhouse
No significant defects were reported.
5.2.8 Tailrace
No significant defects were reported.
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5.3 Present Status of and Rehabilitation Plan for Canyon Hydropower Plant
5.3.1 Maussakelle Reservoir
(1) Sliding at surroundings
Surrounding slopes at reservoirs in Laxapana Complex were investigated using topographical interpretation of topographical maps, aerial photos and field inspection.
Maussakelle Reservoir is surrounded by gentle slopes that are used for tea plantation. Steep slopes and escarpments are distant from the shore of the reservoir, except those with high waterfalls near the reservoir’s southern end.
Gentle slopes are underlain by talus deposits or weathered gneiss. A few landslide topographies were observed on the gentle slopes of the west coast in the reservoir. However, movement is slow and will not generate dangerous waves in the reservoir. Steep slopes near the southern end of the reservoir seem stable due to the underlain strong gneiss dipping gently against the slope.
(2) Sedimentation
No significant defects were reported.
5.3.2 Maussakelle Dam
No significant defects were reported.
5.3.3 Intake
(1) Improvement on Anti-Negative Pressure Valve
1) Present status
An anti-negative pressure valve is located just downstream of the dam. The valve’s Picture 5.9 Maussakelle Dam function is to prevent the steel pipes from buckling, which is caused by negative pressure during shutdown course of the plant. The valve opens when internal pressure reaches to less than 3.5 bars at the valve. Since the plant has been commissioned, spurts of water have appeared twice from the valve where that the reservoir water level was low and simultaneously the plant was operating with full discharge. In order to stop the spurting at the anti-negative pressure valve, it was necessary to close the inlet valve located just upstream of the anti-negative pressure valve. Both valves are located in the valve house. However, it is very hard to approach Picture 5.10 Valve House the inlet valve while water was spurting from the anti-negative pressure valve. Therefore, CEB hopes to modify the anti-negative pressure valve so that easy approach will be possible to the inlet valve even while water is spurting from the anti-negative pressure valve.
Final Report 5 - 13 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
2) Rehabilitation plan
It is recommended that the anti-negative pressure valve should be modified with additional drainpipes to be connected from the valve to the outside of the valve house so that water spurting can outflow without any interference from the inlet valve operation. The rehabilitation cost is shown in Chapter 6.
(2) Crack
No significant defects were reported.
(3) Flow, Sedimentation Picture 5.11 Anti-Negative Pressure Valve
No significant defects were reported.
5.3.4 Headrace Tunnel
It was impossible to enter the tunnel. Therefore, no significant investigation was conducted.
5.3.5 Surge Tank
No significant defects were reported.
5.3.6 Penstock
(1) Crack in Anchor Block
It was reported that some erosion was present on the anchor block concrete. Surrounding gutters of the anchor block should be improved in the manner that the eroded portion can be trimmed to the proper shape and those portions should be covered with concrete to protect from further erosion.
5.3.7 Powerhouse
No significant defects were reported.
5.3.8 Tailrace
(1) Displacement of Retaining Wall
During the first visit, displacement was found as shown in Picture 5.12. It was reported that this displacement was observed from the construction stage and it was not caused by water level fluctuation during the operation stage. However, the displacement has not been monitored by measurement. Therefore, it is necessary to do so.
(2) Crack
No significant defects were reported. Picture 5.12 Displacement of Retaining Wall
Final Report 5 - 14 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
(3) Wear
No significant defects were reported.
(4) Flow
No significant defects were reported.
Final Report 5 - 15 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
5.4 Present Status of and Rehabilitation Plan for New Laxapana Hydropower Plant
5.4.1 Canyon Pondage
(1) Sliding at surroundings
Surrounding slopes at reservoirs in Laxapana Complex were investigated using topographical interpretation of topographical maps, aerial photos and field inspection. Slopes on the left bank of Canyon Pondage are steep and covered by forests whereas those on the right bank are gentle 20 to 30 degree slopes used for tea plantation. There were no landslide topographies observed.
(2) Sedimentation
1) Present status
As shown in Picture 5.13, there was significant sedimentation in the Canyon Pondage. In the past, sedimentation has been removed to disposal areas located around the pondage using an excavator and dump trucks. Locating disposal areas is difficult due to the steep landscape.
2) Rehabilitation plan
The rehabilitation plan is described in Sub-chapter 6.4.6. Picture 5.13 Sedimentation 5.4.2 Canyon Dam
(1) Erosion at Dam Toe
There is cavity in the foundation rock. It is supposed that the cavity has developed due to spilling water. The cavity should be filled with concrete material.
Picture 5.14 Downstream of Canyon Dam Picture 5.15 Dam Toe
Final Report 5 - 16 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
(2) Crack
Generally, the concrete structure is in good condition. No significant defects were reported.
(3) Leakage
No significant defects were reported.
(4) Wear
No significant defects were reported.
5.4.3 Intake
(1) Crack
No significant defects were reported.
(2) Flow, Sedimentation
Sedimentation issues are listed in the chapter 5.4.1. No significant defects were reported.
5.4.4 Headrace Tunnel
It was impossible to enter the tunnel. Therefore, no significant investigation was conducted.
5.4.5 Surge Tank
(1) Leakage
1) Present status
New Laxapana Surge Tank and its surroundings are located on slopes inclining at about 20 in mean degrees. The headrace tunnel connects the penstock at the valve house located at the foot of a cliff about 10 to 20m high. The upper part of penstock traverses on to a gentle slope. This area is underlain by gneiss dipping almost parallel to the slope and talus deposits containing large gneiss blocks.
Many springs are observed in this area. According to the “New Laxapana Tunnel water leakage technical report (2003)”, these springs Picture 5.16 Leakage near Surge Tank dried up or nearly dried up during the dewatering of the tunnel in 1998, and recovered when the tunnel was refilled. Electrical conductivity of the springs and their streams was measured by JICA Study members in August 2004 as shown in Table 5.6 and Figure 5.3. Electrical conductivity values of the springs were close to the water sampled at the outlet of New Laxapana Power Plant, however different from the streams on the slope. This indicates that the springs’ origin would be water flowing in the headrace tunnel.
Final Report 5 - 17 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Table 5.6 Water Quality Test Result at near Surge Tank of New Laxapana Power Plant
Sampling Electrical Data Temperature Point No. on Characteristics of Sampling Point Conductivity No. (°C) Fig-5.2 (µS) 1 - Outlet of New Laxapana PS 20.9 26.0 2 ③ Upper slope of road near surge tank 20.9 27.4 3 ③ same as above 20.7 26.2 Seepage point on upper slope of 4 ⑱ 20.8 25.9 road near surge tank Reference Data 5 - Tributary of Maussakelle 17.5 8.9 6 - Maussakelle Reservoir 21.9 26.1 7 - Castlereagh Reservoir 24.4 44.6
Figure 5.3 Sampling Location and Electrical Conductivity Values
2) Rehabilitation plan
To verify the water quality, precise water quality tests were conducted in this study. V notch weirs were also installed and the water flow volume was monitored in order to obtain the volume of leakage and its change. Topographical survey and geological mapping have been done to get a precise topographic map and understand the geological condition respectively. The results are listed in the APPENDIX A-1.
Water leakage in the vicinity of the surge chamber increases the groundwater level and may decrease the stability of slopes. However, other then a few small surface movements, the
Final Report 5 - 18 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
movement of slopes has not been deeply observed. A comparison study between energy loss due to leakage and costs for stopping leakage has been done based on the measurement results of the leakage. Table 5.7, 5.8 and Figure 5.4 show the measurement results of the leakage, the annual loss due to the leakage and the financial analysis result.
Table 5.7 Annual Loss due to Leakage
QHη P PF W Tariff Annual Loss (m3/s) (m) (%) (kW) (%) (kWh) (Rs/kWh) (Rs) Minimum 0.0143 519.4 85 62 53 287,854 7.68 2,210,716 Maximum 0.1262 519.4 85 546 53 2,534,969 7.68 19,468,560 Avera ge 0.07025 519.4 85 304 53 1,411,411 7.68 10,839,638
Table 5.8 Financial Analysis Result
IRR 20.00% Discount rate 0.1 NPV (*1000$) 48,430 Item Note Unit 2006 2007 2008 2009 ~ 2056 123 50 1. Remedial Works ×1000 Rs 54,200 2. Income Electricity GWh 1.41 1.41 1.41 1.41 Income 7.68 Rs/kWh ×1000 Rs 10,840 10,840 10,840 10,840
Cash Out Remedial works ×1000 Rs 54,200 0 0 0 0 Cash In Electricity sale ×1000 Rs 0 10,840 10,840 10,840 10,840 Inflow-Outflow ×1000 Rs -54,200 10,840 10,840 10,840 10,840
Final Report 5 - 19 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Leakage - Remedial Works Cost New Laxapana Plant
250,000 y = 2E+06x + 70.563 R2 = 1 200,000
y = 1E+06x + 23.065 150,000 Discount rate=20% R2 = 1 Discount rate=15% 100,000 Discount rate=10% y = 771224x + 21.492 50,000 R2 = 1 Remedial Works Cost (*1000Rs)Cost Works Remedial 0 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 Amount of Leakage (m3/s)
Figure 5.4 Correlation between Amount of Leakage and Remedial Works Cost
Figure 5.4 displays the correlation between the amount of leakage and the cost of remedial works based on the following conditions.
The leakage will stop completely due to the remedial works. The annual loss of electricity is obtained from the average amount of the leakage. The remedial works cost is on the basis that the net present value NPV is 0 at the specified discount rate.
The figure suggests that the limit amount of investment in the remedial works would be 105 million Rs, assuming that the discount rate is 10% where discharge is the average value 0.070m3/s. Tax is included in the cost of the remedial works. Furthermore it is necessary to take account of the loss of electricity income for the remedial works because the works need dewatering the headrace tunnel. However, the loss of electricity income can be disregarded in case the works are conducted during the period of overhaul.
5.4.6 Penstock
(1) Crack in Anchor Block
It is reported that there is some erosion in the anchor block concrete. The surrounding gutters near the anchor block should be improved in the manner that the eroded portions can be trimmed to the proper shape and then the portion should be covered with concrete to protect from further erosion.
5.4.7 Powerhouse
No significant defects were reported.
5.4.8 Tailrace
(1) Crack
Final Report 5 - 20 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
No significant defects were reported.
(2) Wear
Erosion in concrete was observed at the tailrace as shown in Picture 5.17. It should be filled with concrete material.
(3) Flow
No significant defects were reported. Picture 5.17 Erosion in Concrete
Final Report 5 - 21 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
5.5 Present Status of and Rehabilitation Plan for Polpitiya Hydropower Plant
5.5.1 Laxapana Pondage
(1) Sliding at surroundings
Surrounding slopes at reservoirs in Laxapana Complex were investigated using topographical interpretation of topographical maps, aerial photos and field inspection. The unstable condition in the area may be due to rain. In order to maintain stability measures to protect it from rain water infiltration must be taken. Also, it is better to specify the inspection route for the area and to reinforce the drainage system in the area. For details see the appendix.
(2) Sedimentation
It is reported that a significant amount of sedimentation might have accumulated. It is necessary to remove this sedimentation. The rehabilitation plan is described in Chapter 6.
5.5.2 Laxapana Dam
(1) Installation of Rain Gauge Station
1) Present status
It is reported that there was a heavy rain on May 6, 2004, which amounted to 264mm in 3 hours and the maximum inflow at the dam was 1,700m3/s. Furthermore, it is also reported that overtopping occurred in the past day. Regarding CEB’s dam operation rules, the total amount of discharge through the turbines and the spillway should equal that of the inflow into the pond during the flood. However, it is very difficult to comply with these dam operation rules due to less reservoir capacity and there being no effective rain gauge station upstream. Therefore, CEB hopes to install rain gauge stations upstream in order to prevent people from encountering floods in the downstream area.
2) Rehabilitation plan
Needless to say, it is better to provide rain gauge stations in the upstream area in order to forecast the amount of inflow.
According to Japanese River Laws, the number of rain gauge stations to be provided by a dam owner shall depend on the catchments area of the dam as shown in Table 5.9. This can be applied to the Kelani river basin.
Assuming that Japanese products are adopted to this matter, the costs are as shown in Table 5.10.
Table 5.9 Number of Rain Gauge Stations Number of rain gauge station Catchment area 1< < 200km2 2< 200<, < 600km2 3< 600km2<
Final Report 5 - 22 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Table 5.10 Cost of Rain Gauge Stations
Item Number/Unit Price (US$) Monitoring & Controlling System 1 unit 250,000 Water Level Monitoring Station 1 unit 70,000 Rain Gauge Station 3 units 160,000 Installation & Adjustment LS 90,000 Shipment LS 10,000 House LS 20,000 Consulting Fee 10% 60,000 Contingency 10% 70,000 Total 730,000
(2) Reinforcement of Spillway
1) Present status
In connection with the rain gauge stations, CEB is considering the possibility reinforcing the spillway.
2) Rehabilitation plan
There are two alternatives in this matter. The first alternative is to utilize the diversion tunnel, which was excavated at the construction stage, but has not been used. The second alternative is to construct a spillway on the right bank. However, the existing spillway has enough of a capacity to Picture 5.18 Spillway of Laxapana Dam cope with the PMF (Probable Maximum Flood) according to the investigation conducted in December 2003, which was founded by the World Bank. Furthermore, the overtopping that occurred in the past was caused by not an abnormal flood but was due to trouble in the spillway gate operation. In addition, both alternatives seem to be unpractical in terms of construction costs. In conclusion, it is necessary to monitor how effective the rain gauge stations are before doing any feasibility study on the alternatives.
(3) Drainage Relief Holes
All holes on the gallery floor were functional during the 2nd site visit.
(4) Crack
Generally, the concrete structure is in good condition. No significant defects were reported.
(5) Leakage
No significant defects were reported.
Final Report 5 - 23 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
(6) Wear
The concrete ogee face of the spillway is in good condition.
5.5.3 Intake
(1) Crack
No significant defects were reported.
(2) Flow
1) Present status
During the first site visit, a vortex was observed at the intake as shown in Picture-5.19. Generally, a vortex could cause the following.
♦ Reduction of conduit sectional area, which reduces the amount of energy generated. ♦ Occurrence of air hammering due to regurgitation of trapped air in the conduit toward intake. ♦ Inflow of sedimentation materials causing turbine wearing. Picture 5.19 Vortex at Intake 2) Rehabilitation plan
Regarding measures for the vortex, a raft is an effective method according to J-POWER's laboratory tests.
However, the influence of the vortex on the energy generation in the Polpitiya Power Plant is not clear. Therefore, it is recommended that the characteristics and the influence of the problem should be clarified through further investigation.
(3) Landslide
The intake of Polpitiya Power Plant is on the right bank just upstream of Laxapana Dam and also located at the foot of a slope of about 40 degrees. This slope is underlain by thick talus deposits and failed at intervals of about 10 years. The area of slope failure was 50m wide and 30m long and was located on the upper side of the slope toward the access road to Laxapana Powerhouse. The thickness of slide material seems to be about 5m.
On this slope, the area adjacent to the existing slope failure is likely to become unstable by rain water infiltration. Therefore, a topographical Picture 5.20 Land slide Area at survey and geological mapping are to obtain a Laxapana Dam precise topographic map helping to understand the geological condition, to detect the sign of instability and to study effective preventive works. Details are shown in APPENDIX A-1.
Final Report 5 - 24 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
5.5.4 Headrace Tunnel
It was impossible to enter the tunnel. Therefore, no significant investigation was conducted.
5.5.5 Surge Tank
No significant defects were reported.
5.5.6 Penstock
(1) Crack in Anchor Block
It was reported that there is some erosion in the anchor block concrete. Surrounding gutters near the anchor block should be improved in the manner that the eroded portion can be trimmed to a proper shape and then the portions should be covered with concrete to protect from further erosion.
5.5.7 Powerhouse
(1) Crack, Leakage
Some of the walls in the generator floor and the turbine floor were wet due to the seepage through the walls. It is recommended that they should be repaired.
(2) Landslide
The slope behind Polpitiya Powerhouse inclines at about 40 degrees. The lower part of this slope failed in the past. The area of this slope failure seems to be about 30 x 20m and is underlain by talus deposits. Concrete drainage channels are prepared on the upper slope area in order to prevent the inflow of rain water. Signs of future movement related to this slope failure would appear as deformations of drainage channels that can be easily detected by periodic slope inspections. A topographical survey and geological mapping have been carried out for the same purpose as the intake mentioned above. Details are shown in the Picture 5.21 Landslide Area appendix. at Polpitiya
(3) Leakage through Ceiling
It was reported that rain water was leaking through the concrete flat roof resulting in the getting the ground floor wet. CEB staff has informed that cracks have developed in the bituminous layer placed on the roof slab. It is recommended that it should be repaired.
Final Report 5 - 25 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
5.5.8 Tailrace
(1) Crack
Erosion in the concrete retaining wall was noticed at the toe of the embankment slope of the switchyard along the river. This should be monitored. (2) Wear
No significant defects were reported.
Picture 5.22 Erosion in Concrete Wall
Final Report 5 - 26 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
5.6 Others
5.6.1 Drainage Relief Holes
During the visit, the drainage relief holes in the gallery of Castlereagh and Laxapana Dams were inspected. It was found that some drainage relief holes were plugged in Castlereagh Dam but not in Laxapana Dam. Judging from the above fact, it is likely that there are further plugged holes in other dams. Therefore, it is recommended that all drainage holes at every dam should be inspected. If a plugged hole exists they should be recovered.
5.6.2 Removal of Vegetation
Vegetation surroundings civil structures should be removed so that people can inspect the structures.
5.6.3 Allocation of Civil Engineer
No civil engineer has been allocated in Laxapana Complex. Therefore, no periodic site inspection has been conducted on the civil structures leaving electrical engineers to conduct flood control. It is difficult for electrical engineers to forecast the amount of inflow into the reservoir while taking account of rainfall data. This could cause a fault in flood control. Furthermore, nowadays people living in the downstream area are getting more aware of dam safety in terms of flood control. This aspect would lead to serious problems for dam owner i.e. CEB. Therefore, it is recommended that CEB should allocate a civil engineer to Laxapana Complex.
5.6.4 Periodic Inspection
It is reported that CEB has not conducted a periodic inspection on civil structures. Further there is no manual for operation and maintenance present. This should been conducted and established.
Final Report 5 - 27 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
5.7 Surging Analysis of the Old Laxapana Hydropower Plant
5.7.1 General
In order to understand water level fluctuation in the surge tank in the Old Laxapana Hydropower Plant and to discover the reasons of the explosive noise and turbulence as stated in chapter 5.2.5, a surging analysis has been carried out in the followings.
5.7.2 Methodology and Conditions
Surging calculations were performed through a computer program available at the J-POWER’s office in Japan. The program quotes the momentum and the continuity equations.
Table 5.11 and 5.12 show the conditions and the cases of the analysis respectively. Some of them are assumed values due to insufficient information on the plant.
Table 5.11 Conditions of Analysis
Item Condition Full supply water level: EL.866.85m Water level at Norton Bridge Pond Minimum operation water level: EL.860.75m Length of the headrace 2,556.7m Sectional area of the headrace 5.98m2 Head loss in the headrace 6.57m (where discharge is 15.1m3/s) Discharge for 5 units generation 13.4, 17.0, 14.64, 14.32, 15.1m3/s Surge tank type Simple type Horizontal sectional area of the 116.71m2 surge tank Top elevation of the surge tank EL. 874.77m Boundary elevation between the surge tank and the headrace EL. 855.19m (assumed value) Full rejection: Linear for 60 second Operational mode of the inlet valve Load increase from 2/5 to 5/5: Linear for 60 second (assumed value) Load increase from 2/5 to 5/5: Linear for 300 second
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Table 5.12 Case of Analysis
Water level at Norton Pond Case Operational Mode EL. (m) 1 866.85 (HWL) 5/5⇒0 (15.1m3/s⇒0) 2 866.85 (HWL) 5/5⇒0 (13.4m3/s⇒0) 3 866.85 (HWL) 5/5⇒0 (17.0m3/s⇒0) 4 866.85 (HWL) 5/5⇒0 (14.64m3/s⇒0) 5 866.85 (HWL) 5/5⇒0 (14.32m3/s⇒0) 6 860.75 (LWL) 5/5⇒0 (15.1m3/s⇒0) 7 vary* 5/5⇒0 (14.64m3/s⇒0) 2/5⇒5/5 (7.24m3/s⇒15.1m3/s) 8 860.75 (LWL) Linear for 60 second as closing time for valve 2/5⇒5/5 (7.26m3/s⇒14.64m3/s) 9 vary* Linear for 60 second as closing time for valve 2/5⇒5/5 (7.26m3/s⇒14.64m3/s) 10 860.75 (LWL) Linear for 300 second as closing time for valve 2/5⇒5/5 (7.26m3/s⇒14.64m3/s) 11 861.75 Linear for 300 second as closing time for valve
* In these cases, the minimum operation level i.e. EL. 860.75m was applied to the initial water level for calculation. However, the water level during the calculation in these cases became lower than the boundary elevation between the headrace and the surge tank. This means that it is impossible to obtain a diagram of the water level fluctuation. Therefore, the water level as a computation condition was raised until the water level fluctuation at the surge tank was successfully obtained.
5.7.3 Results
The table 5.13 shows the results of the analysis. The figures 5.5 to 5.8 show the fluctuation diagram in the surge tank.
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Table 5.13 Results of the Analysis
Water level at Maximum Minimum Case Norton Pond Operational Mode Water Level Water Level EL. (m) EL. (m) EL. (m) 1 866.85 (HWL) 5/5⇒0 (15.1m3/s⇒0) 872.253 - 2 866.85 (HWL) 5/5⇒0 (13.4m3/s⇒0) 871.943 - 3 866.85 (HWL) 5/5⇒0 (17.0m3/s⇒0) 872.533 - 4 866.85 (HWL) 5/5⇒0 (14.64m3/s⇒0) 872.174 - 5 866.85 (HWL) 5/5⇒0 (14.32m3/s⇒0) 872.118 - Lower than 6 860.75 (LWL) 5/5⇒0 (15.1m3/s⇒0) - 855.19 vary* 7 (861.75 m is an 5/5⇒0 (14.64m3/s⇒0) - 855.577 elevation to obtain a fluctuation diagram.) 2/5⇒5/5 (7.24m3/s⇒15.1m3/s) Lower than 8 860.75 (LWL) Linear for 60 second as closing - 855.19 time for valve vary* 2/5⇒5/5 (7.26m3/s⇒14.64m3/s) 9 (862.75 m is a Linear for 60 second as closing - 855.611 elevation to obtain a time for valve fluctuation diagram.) 2/5⇒5/5 (7.26m3/s⇒14.64m3/s) Lower than 10 860.75 (LWL) Linear for 300 second as closing - 855.19 time for valve 2/5⇒5/5 (7.26m3/s⇒14.64m3/s) 11 861.75 (LWL) Linear for 300 second as closing - 855.254 time for valve
Final Report 5 - 30 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Water Level (EL.m) Old Lax UP WL866.85 Q17.0 FRjct 041221 Discharge (m3/s)
874.000 20
872.000 18
870.000 16
868.000 14 Water level fluctuation 866.000 12 Tankﾀﾝｸ1 Level 864.000 10 Discharge
水位 流量
862.000 8
860.000 6
858.000 4
856.000 Discharge 2
854.000 0 0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0 時刻歴Time Figure 5.5 Water Level Fluctuation in Surge Tank (Case 3)
Old Lax UP WL860.75 Q7.24-15.1 LInc 041221
874.000 20
872.000 18
870.000 16
868.000 14
866.000 12
Tankﾀﾝｸ1 Level 864.000 10 Discharge
水位 流量
862.000 8
860.000 6
858.000 4
856.000 2
854.000 0 0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0 時刻歴Time Figure 5.6 Water Level Fluctuation in Surge Tank (Case 8)
Final Report 5 - 31 The Follow-up Study on the Rehabilitation of Hydropower Stations in the Kelani River Basin for The Study of Hydropower Optimization in Sri Lanka
Old Lax UP WL862.75 Q7.26-14.64 LInc 041221 Water Level (EL.m) Discharge (m3/s) 874.000 20 872.000 18
870.000 Discharge 16
868.000 14
866.000 12 Tankﾀﾝｸ1 Level 864.000 10 Discharge 水位 流量 862.000 8
860.000 6
858.000 4 Water level fluctuation 856.000 2
854.000 0 0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0 時刻歴Time
Figure 5.7 Water Level Fluctuation in Surge Tank（Case 9）
Old Lax DN WL860.75 Q7.26-14.64 LInc V300s 041221
874.000 20
872.000 18
870.000 16
868.000 14
866.000 12 Tankﾀﾝｸ1 Level 864.000 10 Discharge
水位 流量
862.000 8
860.000 6
858.000 4
856.000 2
854.000 0 0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0 時刻歴Time
Figure 5.8 Water Level Fluctuation in Surge Tank (Case 10)
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5.7.2 Conclusions
Under the above mentioned conditions shown in the chapter 5.7.2, the following is concluded:
• As for cases 1 to 5, the highest water level of the water level fluctuation in the surge tank will not exceed the top level of the surge tank (EL.874.77m) even if load rejection at the 5 units occurs simultaneously.
• When the plant is operated with the maximum discharge at EL.860.75m minimum operation level, air will enter the penstock due to the head loss of the headrace, which is 6.57m.
• As for cases 8 and 10, when the load increases from 2/5 to full during the minimum operation level (EL. 860.75m) of the Norton Bridge pond, the water level of the surge tank will reach to EL. 855.19m, which is the boundary elevation between the headrace and the surge tank shaft. During this time air would enter the penstock.
• In order to prevent air from entering the penstock, it is necessary to restrict the level of operation at the Norton pond to a lower operation level. For example, if the load increase is prohibited; the number of units operated could be few and so on. However, it is necessary to carry out further studies in order to provide the restrictions in details.
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