Public Disclosure Authorized Small Hydro Resource Mapping in Tanzania PHASE 1 REPORT April 2015 Public Disclosure Authorized Public Disclosure Authorized Public Disclosure Authorized
This report was prepared by SHER Ingénieurs-Conseils s.a. in association with Mhylab, under contract to The World Bank.
It is one of several outputs from the small hydro Renewable Energy Resource Mapping and Geospatial Planning Tanzania ]. This activity is funded and supported by the Energy Sector Management Assistance Program (ESMAP), a multi-donor trust fund administered by The World Bank, under a global initiative on Renewable Energy Resource Mapping. Further details on the initiative can be obtained from the ESMAP website.
This document is an interim output from the above-mentioned project. Users are strongly advised to exercise caution when utilizing the information and data contained, as this has not been subject to full peer review. The final, validated, peer reviewed output from this project will be a Tanzania Small Hydro Atlas, which will be published once the project is completed.
Copyright © 2015 International Bank for Reconstruction and Development / THE WORLD BANK Washington DC 20433 Telephone: +1-202-473-1000 Internet: www.worldbank.org
This work is a product of the consultants listed, and not of World Bank staff. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of The World Bank, its Board of Executive Directors, or the governments they represent.
The World Bank does not guarantee the accuracy of the data included in this work and accept no responsibility for any consequence of their use. The boundaries, colors, denominations, and other information shown on any map in this work do not imply any judgment on the part of The World Bank concerning the legal status of any territory or the endorsement or acceptance of such boundaries.
The material in this work is subject to copyright. Because The World Bank encourages dissemination of its knowledge, this work may be reproduced, in whole or in part, for non-commercial purposes as long as full attribution to this work is given. Any queries on rights and licenses, including subsidiary rights, should be addressed to World Bank Publications, The World Bank Group, 1818 H Street NW, Washington, DC 20433, USA; fax: +1-202-522-2625; e-mail: [email protected]. Furthermore, the ESMAP Program Manager would appreciate receiving a copy of the publication that uses this publication for its source sent in care of the address above, or to [email protected]. Small Hydro Tanzania REA / The World Bank Contract n°7169139
SHER Ingénieurs-conseils s.a. Rue J. Matagne, 15 5020 Namur – Belgium Phone : +32 81 32 79 80 Fax : +32 81 32 79 89 www.sher.be
Project Manager: Julien LEFEVERE Référence SHER : TNZ01 Phone : +32 (0) 81 327 982 Fax : +32 (0) 81 327 989 E-mail : [email protected]
Rev.n° Date Content Drafted Verified 0 02/2015 Small Hydro Mapping report - Interim Pierre SMITS Quentin GOOR 1 04/2015 Small Hydro Mapping report - Final Pierre SMITS Quentin GOOR
SHER INGÉNIEURS-CONSEILS S.A.
IS ISO 9001 CERTIFIED
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Abbreviations and Acronyms AfDB African Development Bank ASTER GDEM Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model CIF Climate Investment Funds CSOs Civil Society Organisations DfID Department for International Development EAPP East African Power Pool ESMAP Energy Sector Management Assistance Programme EUEI European Union Energy Initiative EWURA Energy and Water Utilities Regulatory Authority FAO Food and agricultural organization FGDs Focused Group Discussions GoT Government of Tanzania GRDC Global Runoff Data Centre GTZ Deutsche Gesellschaft für Technische Zusammenarbeit GW Gigawatt GWh Gigawatt hour ICEIDA Icelandic International Development Agency IDA/GEF International Development Agency / Global Environment Fund IFC International Finance Corporation IPP Independent Power Producers JICA Japan International cooperation Agency Kfw/BGR Kreditanstalt für Wiederaufbau kW Kilowatt kWh Kilowatt hour MDBs Multi-lateral Development Banks MDGs Millennium Development Goals MEM Ministry of Energy and Minerals MNRT Ministry of Natural Resources and Tourism MW Megawatt MW Mega Watt MWh Mégawatt hour PPP Public-Private Partnership PS Permanent Secretary REA Rural Energy Agency REF Rural Energy Fund SPPA Small Power Purchase Agreements SREP Scaling Up Renewable Energy Program SRTM Shuttle Radar Topography Mission SSA Sub-Saharan Africa TANESCO Tanzania Electric Supply Company TEDAP Tanzania Energy Development and Access Project ToRs Terms of Reference UNEP United Nations Environment Programme WB The World Bank WBO Water Basin Office ZECO Zanzibar Electricity Company Limited
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Table of Content
1 INTRODUCTION...... 12
1.1 BACKGROUND OF THE PROJECT ESMAP - FWC ...... 12 1.2 OBJECTIVE OF THE STUDY ...... 12 1.3 OBJECTIVE OF THE REPORT - SMALL HYDRO MAPPING ...... 12 1.4 GENERAL PROGRESS AND CHALLENGES ...... 13 2 TANZANIAN ELECTRICAL CONTEXT ...... 14
2.1 INSTITUTIONAL FRAMEWORK ...... 14 2.1.1 Actors ...... 14 2.1.2 Specifics of the Tanzania Institutional and Legal Framework ...... 18 2.1.3 Electric Sector Reform Strategy and Roadmap ...... 19 2.2 ACCESS TO ELECTRICITY AND ELECTRICAL SITUATION ...... 21 2.2.1 Electricity Demand ...... 21 2.2.2 Access Rate (%) and Demand Forecast...... 22 2.3 POWER GENERATION - CURRENT AND PROJECTED SITUATION ...... 22 2.4 FINANCIAL SITUATION AND FINANCING REQUIREMENTS ...... 23 2.5 RENEWABLE AND RURAL ENERGY ...... 24 2.6 OTHER RENEWABLE ENERGY SOURCES ...... 24 3 SCALING UP THE DEVELOPMENT OF SMALL HYDROPOWER IN TANZANIA ...... 28
3.1 CHALLENGES FOR DEVELOPING THE SMALL HYDRO IN TANZANIA ...... 28 3.2 STRENGTHS AND WEAKNESSES OF SMALL HYDROPOWER DEVELOPMENT ...... 29 3.3 PRIORITY DEVELOPMENT ZONES ...... 32 3.4 SMALL HYDROPOWER DEVELOPMENT: AN OPPORTUNITY FOR TANZANIA ...... 34 3.5 PROGRAMS SUPPORTING THE SMALL HYDRO DEVELOPMENT ...... 37 3.5.1 Tanzania Energy Development and Access Expansion project (TEDAP) ...... 37 3.5.2 Scaling-up Renewable Energy Program (SREP) ...... 37 3.5.3 Integrated Rural Electrification Planning (IREP) ...... 38 3.5.4 Mini-grids based on small hydropower sources to augment rural electrification in Tanzania - UNIDO ..... 38 3.5.5 ESME - Supporting Energy SMEs in sub-Saharan Africa - GVEP ...... 39 3.5.6 Rural Electrification Master Plan and Investment Prospectus - NORAD ...... 39 3.5.7 Possible future funding for rural electrification and small hydropower ...... 39 3.6 LESSONS LEARNT FROM PROJECTS SIMILAR TO SMALL HYDROPOWER ...... 40 4 ACTIVITIES UNDERTAKEN DURING THE FIRST PHASE ...... 43
4.1 MOBILIZATION ...... 43 4.2 ORGANIZATIONS VISITED ...... 43 4.3 BIBLIOGRAPHY AND DATA COLLECTION ...... 44 5 SPATIAL DATABASE ...... 50
5.1 BACKGROUND INFORMATION ...... 50 5.2 EXISTING POWER SYSTEM ...... 51 5.2.1 Current status of the power system ...... 51 5.2.2 Thermal power system ...... 51 5.2.1 Hydropower system ...... 52 5.2.2 Transmission and distribution networks ...... 53
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5.3 POTENTIAL HYDROPOWER SITES ...... 55 5.3.1 Studies related to hydropower in Tanzania ...... 55 5.3.2 Data collection challenges ...... 57 5.3.3 Constitution of the previously studied sites database ...... 57 5.4 SPATIAL ANALYSIS : SITEFINDER PROCESSING ...... 58 5.4.1 Objective and method ...... 58 5.4.2 Results ...... 59 5.5 FINAL SPATIAL DATABASE PRODUCTION ...... 59 6 COUNTRY-WIDE RESOURCE MAPS FOR SMALL HYDRO ...... 61
6.1 ADMINISTRATIVE BOUNDARIES ...... 61 6.2 PHYSICAL CONTEXT ...... 61 6.2.1 Satellite view ...... 61 6.2.2 Topography ...... 61 6.2.3 Slopes ...... 62 6.2.4 River system ...... 62 6.2.5 Average annual rainfall (30 arc-seconds (~1 km)) ...... 63 6.2.6 Land cover ...... 63 6.2.7 Protected areas ...... 63 6.3 SOCIO-ECONOMIC CONTEXT ...... 64 6.3.1 Population ...... 64 6.3.2 Mines and industries ...... 64 6.4 INFRASTRUCTURE ...... 65 6.4.1 Transportation network ...... 65 6.4.2 Power system ...... 65 7 SELECTION PROCESS FOR THE 70+ PROMISING SITES ...... 66
7.1 STUDY CRITERIA FOR THE SELECTION PROCESS FOR 70+ PROMISING SITES ...... 68 7.1.1 Generation capacity criteria ...... 68 7.1.2 Environmental criteria ...... 68 7.1.3 Uncertainties concerning topographical criteria ...... 68 7.1.4 36 sites studied at an advanced stage ...... 69 7.1.5 Economical criteria ...... 69 7.1.6 Results of the 70+ promising sites selection ...... 71 7.2 ORGANISATION OF VISITS FOR THE 70+ PROMISING SITES ...... 80 7.3 EXISTING SITES VISITED ...... 81 8 HYDROLOGICAL STUDY FOR THE 70+ PROMISING SITES ...... 83
8.1 OBJECTIVES AND LIMITATIONS OF THE HYDROLOGICAL STUDY ...... 83 8.2 HYDRO-METEOROLOGICAL DATABASE ...... 83 8.2.1 Data sources ...... 83 8.2.2 Database consolidation ...... 84 8.3 FLOW DURATION CURVES MODELING ...... 97 8.3.1 Introduction ...... 97 8.3.2 Model selection and parameterization ...... 97 8.3.3 Results ...... 102 9 ECONOMIC EVALUATION OF THE 70+ PROMISING SITES ...... 107
9.1 FACILITIES COST CALCULATION ...... 107
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9.2 ELECTRICITY PRODUCTION COST OF POTENTIAL SITES ...... 107 9.3 LCOE - LEVELIZED COST OF ENERGY ...... 108 10 SELECTION OF THE TOP 20 PRIORITIZED SMALL HYDRO SITES ...... 109
10.1 PRIORITIZATION PROCESS ...... 110 10.2 SELECTION RESULT OF THE TOP 20 PRIORITIZED SMALL HYDRO SITES...... 112 11 RECOMMENDATIONS FOR THE HYDROLOGICAL CAMPAIGN ...... 116
11.1 OBJECTIVES AND EXPECTED RESULTS ...... 116 11.2 METHODOLOGY ...... 116 11.2.1 Introduction ...... 116 11.2.2 Water level measurement ...... 116 11.2.3 Data recording and transfer ...... 117 11.2.4 Establishment of flow rating curves ...... 117 11.2.5 Positioning measuring instruments ...... 117 11.3 SELECTION OF SITES TO EQUIP WITH GAUGING EQUIPMENTS ...... 118 11.4 RECOMMENDATIONS FOR TECHNOLOGY TRANSFER ...... 121 12 IMPLEMENTATION PLAN OF THE PHASE 2 /3 - DATA COLLECTION AND VALIDATION / SMALL HYDRO ATLAS 123
12.1 RECOMMENDATIONS FOR PHASE 2 ...... 123 12.1.1 Hydrological measurements campaign...... 123 12.1.2 On-site training for the collection and processing of hydrological data ...... 125 12.1.3 Extra preliminary investigations in topography ...... 126 12.1.4 Extra preliminary investigations in geology and geotechnics ...... 126 12.1.5 Description and assessment of social and environmental risks ...... 127 12.2 PRODUCTION OF VALIDATED SMALL HYDRO ATLAS ...... 127 12.3 PRE-FEASIBILITY STUDIES ON THE 4 THE BEST SITES ...... 127 12.4 WORK SCHEDULE PHASE II AND PHASE III...... 129 13 TRAINING AND CAPACITY BUILDING ...... 130
13.1 DATABASE PRESENTATION FOR MANAGERS ...... 130 13.2 CONTENT ...... 130 13.3 TRAINING SESSION FOR ENGINEERS AND EXECUTIVES ...... 131 13.4 DATES AND DURATION ...... 131 13.5 PLACE AND PRACTICAL INFORMATION ...... 131 13.6 REQUIRED LEVEL OF TRAINEES ...... 131 13.7 REQUIRED HARDWARE OF TRAINEES ...... 131 13.8 SOFTWARE'S ...... 131 14 WORKING SESSION IN DAR-ES-SALAM ...... 133 15 POLICY RECOMMENDATIONS ...... 136 16 CONCLUSIONS ...... 138 17 AFTERWORD ...... 140 18 ANNEXES...... 141
18.1 ANNEXE 1 : BIBLIOGRAPHY ...... 141 18.2 ANNEX 2 : SITEFINDER : A TOOL TO DETECT SMALL HYDROPOWER POTENTIAL SITES ...... 145 18.2.1 Input data: Rainfall ...... 146 18.2.2 Topographic Data: Digital Elevation Model ...... 146
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18.2.3 Program Simplification ...... 150 18.2.4 Work flow ...... 150 18.3 ANNEX 3 : METHODOLOGY USED FOR ECONOMICAL EVALUATION ...... 152 18.3.1 Objective ...... 152 18.3.2 Global methodology ...... 153 18.3.3 Type of schemes designed...... 153 18.3.4 Hydrology ...... 153 18.3.5 Design of Works ...... 153 18.3.6 Costs estimate ...... 158 18.3.7 Electrical production ...... 158 18.3.8 LCOE estimation ...... 162 18.4 ANNEX 4 : PARTICIPANTS TO THE KICK-OFF MEETING (NOVEMBER 7, 2013) ...... 163 18.5 ANNEX 5 : PARTICIPANTS TO PRESENTATION OF PROGRESS REPORT (NOVEMBER 20, 2014) ...... 164 18.6 ANNEX 6 : PARTICIPANTS TO THE WORKING SESSION ON SMALL SCALE HYDRO RESOURCE MAPPING (MARCH 17, 2015) ...... 165 18.7 ANNEX 7 : PARTICIPANTS TO THE TRAINING SESSION ON SMALL SCALE HYDRO RESOURCE MAPPING (MARCH 18, 2015) ...... 166 18.8 ANNEX 8 : MAPS ...... 167
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Figures Figure 1 Project Location - SAGCOT and the Priority Clusters ...... 33 Figure 2. Existing power system in Tanzania...... 54 Figure 3: Inputs for SiteFinder. Left: Mean annual rainfall map, Right: DEM ...... 58 Figure 4 Interesting river stretches found by SiteFinder (SF022 and SF178) nearby Mahale Mountain National Park ...... 59 Figure 5. Indicative print screen of the current spatial database in Quantum GIS ...... 60 Figure 6 Prioritization in the study process ...... 67 Figure 7 Selection criteria ...... 68 Figure 8. Distribution of gross head amongst the 70+ promising sites...... 73 Figure 9. Distribution of the installed capacity amongst the 70+ promising sites...... 73 Figure 10. Distribution of the firm energy amongst the 70+ promising sites...... 74 Figure 11. Location map of the 70+ promising sites ...... 75 Figure 12. Dataset selection process: flow chart ...... 85 Figure 13. Spatial distribution of the hydrological and rainfall stations in Tanzania ...... 86 Figure 14. Hydrological network calculated from the DEM ...... 88 Figure 15 Location of the internal drainage basins of Tanzania ...... 89 Figure 16 Lake Rukwa and Lake Eyasi ...... 90 Figure 17 Lake Jipe, unknown lake and Bahi Swamp ...... 90 Figure 18 Lake Ambussel, a sink without lake on North-West of Ngorongoro Crater Area, and another south of Mbeya ...... 90 Figure 19 Lake Manyara and lake Burungi (2 on the same picture), lake Natron, and Lake Madagi in Ngorongoro Crater ...... 90 Figure 20. Determination of the country's hydrographic network : Lake Balangida and neighborghing lakes (3), south of Ngorongoro ...... 91 Figure 21. Calculated watersheds associated with the flow gauging stations ...... 92 Figure 22. Period of activity of the hydrological stations ...... 93 Figure 23. Number of "exploitable" years in relation with the streamflow time series length ...... 94 Figure 24. Period of activity of the rainfall stations with daily data ...... 96 Figure 25. Period of activity of the rainfall stations with monthly data...... 97 Figure 26. Examples of flow duration curves modeled by the Weibull and lognormal laws...... 98 Figure 27. Impact of the shape factor of the Weibull law ...... 99 Figure 28. Impact of the scale factor on the Weibull law ...... 99 Figure 29. Weibull law: scale factor versus mean flow ...... 100 Figure 30. Relationship between the average annual rainfall and the average flow...... 101 Figure 31. Average annual rainfall (spatial extrapolation) ...... 103 Figure 32. Ungauged sites classification ...... 104 Figure 33 Selection process of the 20 prioritized sites ...... 111 Figure 34 7 sites that will directly benefit from the proposed new gauging stations ...... 122 Figure 35 Responsibilities and interactions in the implementation of a hydrological network ...... 124 Figure 36. Example of computation realized by SiteFinder, showing the river elevation/discharge profile 146 Figure 37 Mean Annual Rainfall ...... 146 Figure 38: Resolution of ASTER (left) and SRTM data (right), on an area in Mbeya region...... 147 Figure 39 Local errors of ASTER DEM ...... 148
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Figure 40 ASTER DEM and SRTM DEM comparison ...... 148 Figure 41 Example of subtraction between ASTER and SRTM ...... 149 Figure 42 Subtraction on tiles S06E030 and S11E037 ...... 149 Figure 43 : Turbines operating range (Layman. 2005) ...... 157
Tables Table 1 Current and future generation ...... 23 Table 2 Key Financial Indicators of TANESCO (million USD) ...... 23 Table 3 Least cost supply option for 7 development zones ...... 32 Table 4 Comparative advantages and complementarities of Small Hydro towards other sources of energy 35 Table 5 Portfolio of medium and large hydro projects - Ministry of Energy and Minerals...... 36 Table 6 GVEP - 6 SHPP feasibility studies ...... 39 Table 7 Collected spatial information ...... 51 Table 8 Existing thermal power plants: key characteristics (source: Ministry of Energy and Mineral, 2013) 52 Table 9 Key characteristics of the major existing hydropower plants (>1MW) ...... 53 Table 10 Protected areas in Tanzania...... 64 Table 11 EWURA standardized small power projects tariffs for years 2011 and 2012 ...... 70 Table 12 Regional breakdown of the installed capacity and energy produced by the 70+ potential sites .... 71 Table 13 Water basin breakdown of the installed capacity and energy produced by the 70+ potential sites ...... 72 Table 14. Key information related to the 70+ promising hydropower sites ...... 76 Table 15 Data of existing sites visited ...... 82 Table 16 Collected data and their key characteristics ...... 84 Table 17. Breakdown of the hydrological and rainfall stations within the nine water basins...... 87 Table 18 Internal drainage basins and associated lakes of Tanzania ...... 89 Table 19 Estimated key parameters of the flow duration curve at the ungauged sites ...... 106 Table 20 Activities for the implementation of a gauging stations network ...... 125 Table 21 Basic assumptions comparison ...... 152 Table 22 : LCOE calculated by SREP ...... 152
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1 Introduction
1.1 BACKGROUND OF THE PROJECT ESMAP - FWC
The Energy Sector Management Assistance Program (ESMAP), a global knowledge and technical assistance program administered by the World Bank and supported by 11 bilateral donors, has launched, in January 2013, an initiative that will support country-driven efforts to improve RE resource awareness, put in place appropriate policy frameworks for RE development, and provide ‘open access’ to resource and geospatial mapping data. It will also support the IRENA Solar and Wind Atlas by improving the data availability and quality that can be accessed through the atlas on a modular basis.
This "Renewable Energy Mapping: Small Hydro Tanzania" study, is part of a technical assistance project, ESMAP funded, being implemented by Africa Energy Practice 1 (AFTG1) of the World Bank in Tanzania (the ‘Client’) which aims at supporting resource mapping and geospatial planning for small hydro. It is being undertaken in close coordination with the Rural Energy Agency (REA) of Tanzania, the World Bank’s primary Client country counterpart for this study.
The "Provision of Small Hydropower Resource Data and Mapping Services" IDA 8004801 Framework contract was signed 29th May 2013, while the specific contract " Renewable Energy Mapping: Small Hydro Tanzania", n. 7169139, is dated 4th November 2013.
1.2 OBJECTIVE OF THE STUDY
The objectives of the study are twofold:
To improve the quality and availability of information on Tanzania’s small hydropower resources. The project will provide the GoT (Client) and commercial developers with ground-validated maps (at least 70+ sites up to 10 MW) that show the varying levels of hydro potential throughout the country, and highlight several sites most suited for small hydropower projects.
To contribute to a detailed comprehensive assessment and to a geospatial planning framework of small-hydro resources in Tanzania; (ii) to verify the potential for the most promising sites and prioritized sites (~ 20 prioritized sites) to facilitate new small hydropower projects and ideally to guide private investments into the sector; and (iii) to increase the awareness and knowledge of the Client on RE potential.
1.3 OBJECTIVE OF THE REPORT - SMALL HYDRO MAPPING
The Small Hydro Mapping report presents the preliminary prioritization and recommendations for data gap mitigation (hydrology, geology, socio-environment, topography). The report includes also maps created from GIS layers, a training and capacity building program and a
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revised Technical, Financial Proposals for phase 2 and 3 and an Implementation Plan for ground-based hydrological monitoring and site investigations for Phase 2.
1.4 GENERAL PROGRESS AND CHALLENGES
Our approach considers that the knowledge of SHPP potential in Tanzania will be improved by the mutual benefit of a twofold source of information: bibliography (existing studies, lists of georeferenced sites, site locations, etc.) and an extensive site search model, namely SiteFinder, based on a digital elevation model (DEM) and on a hydrological model.
In order to match the objectives of the study, the consultant has adopted the following approach :
General Deep and understanding of comprehensive GIS analysis Sites selection Computation and the context of data and vs criteria definition analysis of data Small hydro document and collection and documents Review of maps development in and documents Sites selection Tanzania (baseline)
The different study steps are described in the following chapters.
Following the inception phase (step 1), based on a REA request, it was decided to add 20 potential sites to the list of 50+ promising sites to be visited during the field campaign. The World Bank expands also the study to four pre-feasibilities. The addendum was signed September 16, 2014 and the 20 additional field visits were undertaken between October 2014 and January 2015. The four pre-feasibilities will be undertaken during the phase 2.
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2 Tanzanian Electrical context
2.1 INSTITUTIONAL FRAMEWORK
2.1.1 Actors The main Government stakeholders in the Tanzanian Electric Sector are the following: The Ministry responsible for “electricity matters” (as it is designated in the Electricity Act, 2008), the Energy and Water Utilities Regulatory Authority established under EWURA Act, Chapter 414, the Rural Energy Agency established under Part IV of the Rural Energy Act, 2005, and the utility TANESCO. Other Ministries also have a role in the energy sector activities such as the Ministry of Environment.
Ministry in charge of Energy
According to the Electricity Act, 2008, the Minister of Energy is responsible for (i)“the development and review of the Government policies in the electricity supply industry;” (ii) the elaboration of “policies, plans and strategies for development of the electricity subsector”, (iii) the reorganization and restructuring of the electricity supply industry with a view to attracting private sector and other participation ; (iv)through the Rural Energy Agency (as created by this Act), the preparation of the Rural Electrification Plan and Strategy and the promotion of rural electrification; (v) the establishment of import and export of electricity.
Regulation
The Energy and Water Utilities Regulatory Authority (commonly designated as EWURA), as created by the Electricity Act, 2008: (i) awards licences to entities undertaking a licensed activity; (ii) approves and enforces tariffs and fees charged by licensees; (iii) approves licensees' terms and conditions of electricity supply; and (iv) approves initiation of the procurement of new electricity supply installations.
Under the 2008 Act, the following activities require a licence as stated in section 8 (1) of the Electricity Act No. 10 of 2008 which shall be issued by EWURA: a) Generation; b) Transmission; c) Distribution; d) Supply; e) System operation; f) Cross border trade in electricity; g) Physical and financial electricity trade; and h) Electricity installations
EWURA is charged to (i) protect customer's interests through the promotion of competition; (ii) promote access to, and affordability of, electricity services particularly in rural areas; (iii) promote least-cost investment and the security of supply for the benefit of customers;
The principles of tariff regulation are set out in the Electricity Act, notably as follows (i) tariffs should reflect the total cost of efficient business operations, without subsidies or grant; (ii) tariffs should be sufficient for the licensees to have a fair return on their investments; and (iii) tariffs should contain incentives to a more effective electricity consumption and should encourage adequate supply to satisfy demand. The approved tariffs may include automatic adjustments for changes in costs of fuel, power purchases and fluctuations in exchange rates.
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It is worth noting that EWURA in the exercise of its functions has to consult the relevant Ministries on matters of (i) security; (ii) compulsory acquisition of land;(iii) preservation of the environment;(iv) cross-border trade in electricity; and (v) development of other sources of energy in the electricity supply.
Rural Electrification
The Rural Energy Act, adopted in June 2005, established the Rural Energy Agency (REA), the Rural Energy Fund and the Rural Energy Board. REA was in fact created in October 2007, with the objective of “promoting rural socio-economic development by facilitating extended access to modern energy services” in rural areas of Mainland Tanzania” (thus excluding thus the island of Zanzibar). REA is governed by the Rural Energy Board, and its activities are financed by the Rural Energy Fund.
The principles of Rural Electrification, as set out in the Act, are that:
“(i) sustainable development shall be achieved when modem energy services in rural areas are promote d, facilitated and supported through private and community initiative and involvement;
(ii) the role of Government in rural energy service provision is that of a facilitator of activities and investments made by private and community entities;
(iii) the fulfilment of Government's role shall be best managed through an institution that is independent.”
Rural Electrification Fund (REF) has the mission to provide grants to qualified rural electrification project developers. REF is abounded by the Government annual budgetary allocation, international development partners and levies (up to five per cent on commercial generation of electricity to the national grid and on the generation of electricity in specified isolated systems, including systems for private consumption).
The resources of the Fund can be used for:
(i) grants to qualified developers, for example to co-finance (a) training and other forms of capacity building; (b) the provision of technical assistance related to the planning and preparation of a project prior to an application for a grant, including pre-investment studies for projects; (c) the capital costs of a project implemented; and (d) investments in innovative pilot and demonstration projects and applications for renewable energy when development partners make funds available for that purpose.
(ii) payment or discharge of the expenses or obligations incurred in connection with the performance of the functions of the Agency and the Board; and
(iii) payment of any remuneration or allowances to the members of the Board and employees of the Agency.
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The Fund may not make grants towards the operating or debt service costs of any project or developer.
A Trust Agent is selected by REF after a public tender to manage the disbursement of grants. The Trust Agent is a commercial bank (currently Tanzania Investment Bank – TIB), which is responsible for the administration of grant payments, including financial disbursement, verification and monitoring activities from the contract signing to commissioning.
Until now, notwithstanding its role, functions and financial resources through REF and various donors programmes, it has to be noted that the bulk activity of REA has been to manage turn- key rural electrification programmes that are built by private contractors, then transferred to TANESCO and connected to its grid.
The Public Utility1
TANZANIA ELECTRIC SUPPLY COMPANY LIMITED (TANESCO Ltd) is a company limited fully owned by the Government of Tanzania under the Ministry of Energy and Minerals and hence was duly registered under the Companies Act Cap 12 [R. E. 2002] as amended, under the Registrar of Companies under the Business Registration and Licensing Authority (BRELA). The New Electricity Act No. 10 of 2008 (see above) as amended which repeals the Electricity Act Cap 131[R. E. 2002] is the law that facilitates and regulates generation, transmission, distribution, supply and use of electric energy and hence is the main act that governs TANESCO Ltd works as being the current sole licensee.
TANESCO Ltd, the historic monopoly company, currently carries out most of the distribution, transmission and generation activities within the Country, with the exception of some small generation and distribution companies delivering small quantity of electricity in rural areas2.
Environmental issues, licences and permits
Most SPPs will progress through the following steps;
Project identification;
Securing rights to the resource;
Acquiring necessary permits and licenses;
Financing;
1 Extracted mostly from Tanesco’s Web Site (www.tanesco.co.tz ) 2 To our knowledge, as confirmed by REA last published Annual Report 2010-2011, there are at least 4 rural electrification installations based on small hydropower plants (two connected to the grid and two supplying isolated grids) : o Yovi (faith based organisation) o Mwenga (TMC) o Lumama (ACRA) o Ikondo – Njombe project
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Construction;
Testing and Commissioning; and
Operation and reporting,
Consents (permits, licenses, and clearances) required by various authorities for a grid- connected SPP are briefly presented below. While many of these steps may be completed contemporaneously, some steps require prior permissions.
These steps have been developed in the Guidelines for Developers of Small Power Projects in Tanzania from EWURA (2009).
The right to renewable energy resources that can be used to make electricity is sometimes contested. To avoid competing claims on the same resource, it is important that the SPP developer be able to demonstrate that he is the legal holder of rights to sufficient resources to make the project viable. For a hydropower project, required documents include water rights permission issued by the appropriate River/Lake Basin Water Office. Contact information depends on which basin the project is in. The water basins include: Pangani Basin, Rufiji Basin, Lake Victoria, Wami-Ruvu, Lake Nyasa, Lake Rukwa, Internal Drainage Basin to Lake Eyasi, Manyara and Bubu Depression, Lake Tanganyika, Ruvuma and Southern Coast. The Division of Water Resources within the Ministry of Water and Irrigation (MOWI) coordinates activities of the Water Basins.
In addition to permission from the River/Lake Basin Water Office, the project developer must also obtain written consent from the respective village government where the project will be executed.
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2.1.2 Specifics of the Tanzania Institutional and Legal Framework During the last 10 years, various important reforms were implemented in the electricity sector: the new Electricity Act in 2008, creating the Energy and Water Utilities Regulatory Authority (EWURA), the Rural Energy Agency (REA) and the related Rural Energy Fund (REF). In 2010, the National PPP Law was adopted in 2010.
Relating to rural electrification and access to electricity, a comprehensive regulatory framework was developed and adopted by EWURA which included standardized power purchase agreements (SPPA) and tariffs (SPPT) for small power projects (SPPs either connected to the main grid or operating on isolated grids), simplified regulatory rules for small power projects and comprehensive guidelines for the project developers.
Now the regulatory framework, in theory, reaches international standards but still suffers from insufficient application, which might alter negatively the perceived level of risks for private investors considering investments in the Tanzanian electricity sector.
The principles of the reform set out in the Act, are suitable for the introduction of a competitive market, a Third Party Access (T.P.A.) regime and the relinquishment of any previous “Single Buyer” regime. For example, the Act mandates the Minister to define the “eligible customers” who cannot exist in the present ‘single buyer regime’.
The 2008 Act can be considered as the basis of a reform towards the liberalisation of the market. For example, it is written that the Minister has to define “the part of the electricity market that shall be subject to competition” but the words “electricity market” nor “electricity sector” are not used, which makes the concept a bit vague. Moreover, it is written that the Minister will have to define “the form of competition that shall be introduced in each relevant part of the electricity market”.
Some statements are even more disturbing, such as paragraph 41.6 stating, “Notwithstanding the preceding provisions of this section, the Tanzania Electric Supply Company shall have a right to first refusal to the supply of electrical energy to all intensive electrical energy consumers”. This means that, in practice, the future eligible consumers will not be free to contract with any supplier of their choice. This can be very detrimental for investors and IPPs.
Some other key points should also be underlined:
To date, the legal framework for a fair competition and for attracting the private sector still is not in place, although some principles are already encrusted in the Act: no unbundling, no eligible consumers, Single Buyer system still in place, no Independent System Operator, TANESCO right of first refusal for supplying intensive consumers, etc.
The legal framework does not seem to offer the sufficient security and stability that would be perceived as incentives for a more significant commitment of the private sector: For example, in Chapter 41.3:“The Minister may, in consultation with the Authority, the Fair Competition Commission, consumers and players in the electricity
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supply industry, amend the policy at any time.” Or in Chapter 10.2:“The Authority may change terms and conditions of any licence issued under this Act, provided that (a) the licensee has been informed of the change or (b) the modification is in the public interest, where the benefits to the public significantly exceed any disadvantages to the licensee.” But, there is no mention whatsoever of any compensation to the licensee for loss of revenues, etc.
Considering the Rural Electrification, part. VIII of the Electricity Act practically prevents any private investor in entering the distribution activity as they will not be allowed to supply any “intensive energy consumer”. It looks as if the private sector had to be limited to the non- profitable consumers. New initiatives are now taken by EWURA, to develop a regulatory framework for distribution licensees in rural areas. These licensees should be granted the right to supply “intensive energy consumer”.
2.1.3 Electric Sector Reform Strategy and Roadmap In June 2014, considering the supply and financial crisis known by the country in recent years, the Government adopted the long awaited Report “Electricity Supply Industry Reform Strategy and Roadmap 2014 – 2025”, defining how and according to which calendar the electric sector will be reformed until complete unbundling of the utility, and liberalization of the electricity trade.
The reform initiatives and key actions cover the period from 2014 to 2025, with the objective to meet the current and future demand for electricity; reduce public expenditure on ESI for operational activities; attract private capital; and increase electricity connection and access levels. It has to be noted that it is fully coherent with “Big Results Now (BRN)” as described below. It should increase transparency and competition and lead to abolition of subsidies in the electricity sub-sector.
At present, Tanzania electric sector operates on the single buyer model. The reforms envision moving gradually from the single buyer model to retail competition market.
During the reform process, REA shall continue to play an instrumental role in promoting access to modern energy services.
The strategy proposes a four stage process that will result in a fully competitive electricity market structure by 2025:
Immediate Term (July 2014 – June 2015)
Short Term (July 2015 – June 2018)
Medium Term (July 2018 – June 2021)
Long Term (July 2021 – June 2025)
During the process, an Independent System Operator (ISO) shall be established in line with Section 20(1) of the Electricity Act, 2008 and will coordinate power supply system, dispatch
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power to transmission facilities and monitor cross-border electricity trading. The operator will operate the power system based on the Grid Codes developed by the Regulator. An Independent Market Operator (IMO) as well, in accordance with Section 20(2) of the Electricity Act, 2008 shall be established and regulated. The IMO shall administer operations of the wholesale electricity market trading.
a) Immediate term (July 2014- June 2015)
Amongst others, tasks to be undertaken during that phase include:
Review the Electricity Act, 2008 particularly Section 41(6) of, to allow private generators to supply power directly to bulk off takers;
Developing technology based Standard Power Purchase Agreement (PPA) model;
TANESCO will remain vertically integrated with ring fenced business units.
b) Short Term (July 2015 – June 2018)
The short term will involve the following tasks:
Unbundling of generation segment from transmission and distribution segments by December 2017;
Designating an Independent Market Operator (IMO) to manage wholesale and retail electricity trading.
The existing TANESCO will continue to be responsible for transmission and distribution until June 2021 when distribution is unbundled. Based on tariff and wheeling charges approved by the regulator, bulk off takers would be able to buy power directly from generators by paying wheeling charges to the transmission company. However, monopoly characteristics will still exist in the transmission and distribution.
Wholesale prices of electricity are fixed by respective Power Purchase Agreement (PPA) signed by buyer and respective private generation companies. IPPs, SPPs and PPPs will be procured competitively.
c) Medium Term (July 2018 – June 2021)
After following tasks, amongst others:
Unbundling of distribution from transmission segment;
Setting up a mechanism and rules for the operation of a retail market for electricity by the Regulator;
the market structure envisaged in the medium term comprises a competitive power generation segment.
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At the end of the period, the electric sector is vertically unbundled into three segments: generation, transmission and distribution. A wholesale market exists and generation companies are competing for bulk supply of electricity. A monopoly regulated transmission company undertakes the transmission role. The distribution and retailing of electricity to the final consumer is done by a Government owned Distribution Company.
d) Long Term (July 2021 – June 2025)
In the long term, commercially viable zonal offices will be established as independent distribution companies; the task thus will be to unbundle gradually distribution segment gradually into several Zonal distribution companies.
The electric sector is vertically unbundled into four segments: generation, transmission, distribution and retailing. The generation segment is comprised of a number of companies competing for wholesale supply of electricity to retailers. The Transmission Company undertakes the transmission role. The independent system operator (ISO) and independent market operator (IMO) undertake system and market operation. Distribution is horizontally unbundled.
Transmission will be fully owned by the Government, with Third Party Access: Transmission infrastructure will be guaranteed by relevant rules issued by the Regulator.
The price of electricity is determined by market forces with many buyers and sellers. Wholesale prices of electricity will be fixed in bilateral PPA between generators and distribution companies and/or retail companies. The retail market will also be competitive with prices determined by market forces. The Regulator will only set the tariff for transmission and distribution companies.
Customers will be free to choose electricity supply from a large number of retailers operating in the region.
2.2 ACCESS TO ELECTRICITY AND ELECTRICAL SITUATION
2.2.1 Electricity Demand For many years, the Tanzanian Electric system has not been able to satisfy the growing demand for electricity. Load shedding and power outages have become almost normality. The consequence is that naturally demand is supply driven, and thus it is very difficult to estimate what it could be if supply were sufficient. Government estimates are that demand for electricity is on average growing between 10 % and 15 % per annum.
The peak demand3 reached 828.99MW in 2011, for on grid customers. The total energy generated in 2011 within TANESCO power system was 3,704GWh while imports from IPPs and neighbouring countries were 1,621MWh. The total energy distributed in the country was
3 Power System Master Plan (PSMP) Update 2012, Ministry of Energy and Minerals, May 2013
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approximately 4,076GWh, implying total system loss of 23.5 % or 1,249GWh. The assumption is that approximately 2.1 % of electricity generated in 2010 represents the level of suppressed demand.
2.2.2 Access Rate (%) and Demand Forecast The official access rate by 2011 was 14.5%4 and 18.6% by 2012, wherein 11.8% were urban customers, 4.0% rural customers connected to TANESCO and 2.6% were customers supplied by distributed energy solutions (PV panels, solar lanterns, biogas lighting, and private energy systems). As of March 2014, 24 % of the Tanzanian population (7 % only in rural areas) was connected with electricity supply5. To achieve the desired socio-economic transformation, the Government of Tanzania aims to increase connection levels to 30 % by 2015, 50 % by 2025 and more than 75 % by 20336.
The new capacity to be installed to reach those ambitious (but legitimate) targets is estimated below.
In April 2013, the Government unveiled the report of the NKRA Energy Lab Initiative titled Big Results Now, in line with the Tanzania Development Vision 2025 . According to that Report, growth at 9% p.a growth, the unconstrained demand would almost double in the next 3 years.
2012 2015 2025 2035
Demand (GWh) 6 085 11 246 27 139 47 724
2.3 POWER GENERATION - CURRENT AND PROJECTED SITUATION
As of May 2014, Tanzania’s total installed generation capacity7 was 1,583 MW composed of hydro 561 MW (35 %), natural gas power plants of 527 MW (34 %) and liquid fuel power plants of 495 MW (31 %). TANESCO also imports power Uganda (10 MW), Zambia (5 MW) and Kenya (1MW). Due to traditional dependence on hydropower, the droughts that occurred in 2010 resulted in power supply shortages in the country. To bridge the electricity supply gap in the country, in 2011, TANESCO contracted Emergency Power Producers (EPP) at a relatively high cost.
To improve the growing demand and the security of supply, the GoT intends to diversify the sources of electricity generation to include natural gas, coal, hydro, uranium and renewable energies. It also counts on exchanges with the Eastern Africa Power Pool (EAPP), East Africa
4 MEM Medium Term Strategic Plan 5 Electricity Supply Industry Reform Strategy and Roadmap 2014 – 2025, Ministry of Energy and Minerals, June 30, 2014 6 This figure is mostly the same as the one which appears in the PSMP Update of 2012. 7 Electricity Supply Industry Reform Strategy and Roadmap 2014 – 2025
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Community Power Pool (EACPP) as well as the Southern Africa Power Pool (SAPP). The resulting generation is shown in the Table below.
Current Capacity Additional Capacity Capacity In MW [MW] (2015 - 25) [MW] by 2025 [MW] Hydro 561 1529 2090 Natural Gas 527 3968 4469 HFO/GO/Diesel 495 - 438 Coal - 2900 2900 Wind - 200 200 Solar - 100 100 Geothermal - 200 200 Interconnector - 400 400 TOTAL 1583 9297 10798 Table 1 Current and future generation
2.4 FINANCIAL SITUATION AND FINANCING REQUIREMENTS
TANESCO’s financial situation is rather precarious worrying for quite la long period already. It is one of the reasons for the urgent reform and restructuring plan recently put in place by the Government (under pressure from the international financial community).Table below show some financial indicators: over the nine-year period (2003 – 2011), there was only a single year where TANESCO had made a profit before tax. Even worse, there was only a single year where the operation had not been a loss-making exercise.
2003 2004 2005 2006 2007 2008 2009 2010 2011
Electricity Sales 159 173 196 185 234 310 313 324 344
Power purchase cost 68 114 156 187 195 162 141 147 228
Total cost of sales 183 244 250 290 308 307 326 342 485
Operating profit (loss) (63) (33) (22) (125) (51) 2 (2) (0) (22)
Profit (loss) before tax (214) (104) 43 (125) (54) (18) (36) (31) (48) Average tariff 6.83 7.02 7.47 6.69 7.35 9.18 9.00 7.76 10.49 (US cent/kWh) Table 2 Key Financial Indicators of TANESCO (million USD)
Sources : 2003 – 2009: Power Sector Reform and Regulation in Africa, p.30 2010 – 2011: Audited Financial Statements 2011, p.23 and p.51. Exchange rate: 2010 – 1440 TSH/USD, 2011 – 1585 TSH/USD (consultant’s estimates). Average tariff (= average price paid) calculated from statistics obtained from TANESCO.
In 2011, TANESCO’s financial situation has suffered from the very high costs of its emergency generation program (rental of generators to private operators), caused by a severe shortage of hydropower generation.
According to figures given in the World Bank Program Document on the First Power and Gas Sector Development Policy Operation, dated January 26, 2013, and data from Tanesco
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Corporate Business Plan of 2013, the Government projections forecast a accumulated deficit of TANESCO, without government subsidies, to be at around US$1 billion between 2012 and 2014, depending on the scenarios relating to hydrology and the investment plans (at constant tariff). The Government had committed to closing the residual financial deficit in the sector through budget subsidies during the transition period. The authorities have engaged to do so within the limit of the macroeconomic and fiscal framework agreed upon with the IMF.
On another hand, the scope of investment required to implement plans and meet Government policy objectives as explained above, is significant. The Power System Master Plan (Update 2013) identifies short term financing requirements (2012 to 2017) as USD 11.4 billion, or about USD 1.9 billion per year of which 73.5 % would be needed for generation. The generation additions to reach 7900 MW peak in 2035 (around 46000 GWh) may require total capital investment costs of 17.5 billion USD (without inflation and IDC) until 2035.
2.5 RENEWABLE AND RURAL ENERGY
The table, inserted in paragraph 2.3 above, as extracted from the “Electricity Supply Industry Reform Strategy and Roadmap 2014 – 2025”, shows that on an additional capacity projected to be 9300 MW between 2015 and 2025, the new and renewable energies (excluding hydro) counts only for 500 MW, or about 5,4 %. This table does not specify what is the portion of the small hydro in the foreseen 1500 MW of new hydro capacity.
The Reform Strategy Study has been thought as a national strategy for the Tanzanian Electric Sector as a whole, not distinguishing urban and rural energies. The investments needed to reach the access objectives, notably in rural areas, are not specified. But the document indicates clearly the willingness to create in the short term 7 “zonal distribution business units”, which of course shall include rural areas not very well served until now.
This strategic Document sates explicitly that: “During the reform process, REA shall continue to play an instrumental role in promoting access to modern energy services. In this context, rural electrification activities will continue to be funded by the GoT and Development Partners through the Rural Energy Fund. To increase connection and access levels, REA will facilitate support installation and maintenance of rural distribution systems.”
2.6 OTHER RENEWABLE ENERGY SOURCES
The following data are largely issued from the SREP-Investment Plan for Tanzania (2013).
Geothermal Energy
Tanzania has significant geothermal potential that is not yet fully quantified. Estimations using analogue methods indicate a potential exceeding 650 MW, with most prospects located in the East African Rift System. Most geothermal prospects have been identified by their on-surface manifestation, mainly hot springs. Surface assessments started in 1976 and, to date, more than 50 sites have been identified. These are grouped into three main prospect zones:
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northeastern (Kilimanjaro, Arusha and Mara regions), southwestern (Rukwa and Mbeya regions), and eastern coastal belt, which is associated with rifting and magmatic intrusions (Rufiji Basin). Only the southwestern zone has undergone detailed surface exploration studies. In 2006 and 2010, the MEM, in collaboration with the Geological Survey of Tanzania (GST), the German Federal Institute for Geosciences and Natural Resources (BGR), and TANESCO, carried out surface exploration and conducted detailed studies in the Ngozi-Songwe prospect in the Mbeya region.
Wind
Several areas of Tanzania are known to have promising wind resources. In areas where assessments have been conducted to date, only Kititimo (Singida) and Makambako (Iringa) have been identified as having adequate wind speeds for grid-scale electricity generation. At Kititimo, wind speeds average 9.9 miles per second and 8.9 miles per second at Makambako, at a height of 30 m. The MEM, in collaboration with TANESCO, is conducting wind resource assessments in Mkumbara (Tanga), Karatu (Manyara), Gomvu (Dar es Salaam), Litembe (Mtwara), Makambako (Iringa), Mgagao (Kilimanjaro), and Kititimo (Singida). The REA is supporting wind measurements at Mafia Island (Coast region). MEM and TANESCO will be conducting wind resource assessments in Usevya (Mpanda). To date, four companies have expressed interest in investing in wind energy, namely Geo-Wind Tanzania, Ltd. and Wind East Africa in Singida and Sino Tan Renewable Energy, Ltd. and Wind Energy Tanzania, Ltd. at Makambako in Iringa. These companies are considering investments in wind farms in the 50– 100 MW range.
Solar
Tanzania has high levels of solar energy, ranging between 2,800 and 3,500 hours of sunshine per year, and a global radiation of 4–7 kWh per m2 per day. Solar resources are especially good in the central region of the country. Thus, solar energy as a viable alternative to conventional energy sources is a natural fit for Tanzania if efficiently harnessed and utilised. Both solar PV and solar thermal technologies are under development in the country.
Off-Grid Solar Photovoltaics
To date, about 6 MWp (megawatt peak) of solar PV electricity has been installed countrywide for various applications in schools, hospitals, health centres, police posts, small telecommunications enterprises, and households, as well as for street lighting. More than half of this capacity is utilised by households in periurban and rural areas. The government is implementing awareness-raising and demonstration campaigns on the use of solar systems for domestic and industrial use, as well as supporting direct installation in institutions. To make solar PV more attractive, the government has removed the value added tax (VAT) and import tax for main solar components (panels, batteries, inverters, and regulators), which has allowed endusers to get PV systems at a more affordable price.
Grid-Connected Solar Photovoltaics
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In central Tanzania, a MWp of solar PV generates about 1,800 MWh per year (net of losses), and will require about 1 hectare of land. Theoretically, the total estimated 2025 electricity demand of 27,000 GWh could be met by solar PV fields of about 15,000 hectares or about 0.02 percent of Tanzania’s land mass. That is, the theoretical potential of solar is unlimited. However, for purposes of system stability, solar is usually restricted to less than 20–30 percent of daytime peak demand. On the basis of a 20 percent constraint, the potential for grid-tied solar in 2025 could be about 800 MW. Given that large-scale, grid-tied solar PV installations are being undertaken in some countries for under US$ 1,750 per kWp, its prospects in Tanzania should be excellent. The Power System Master Plan (PSMP) envisages 120 MWp of solar in the power expansion plan by 2016. Several private firms have expressed interest in investing in 50–100 MWp of solar PV. NextGen Solawazi has signed a SPPA with TANESCO to supply electricity from 2 MWp of PV to an isolated grid. TANESCO has also signed a Letter of Intent (LOI) for a 1 MWp isolated grid-tied PV project. There is also a potential value in using solar and hydro in combination by adding capacity value to a power source considered intermittent.
Solar Thermal
Solar thermal energy has been used for generations in Tanzania for drying crops, wood, and salt. Currently, solar dryers are used in the agricultural sector to dry cereals and other farm products, including coffee, pyrethrum, and mangos. The Sokoine University of Agriculture, University of Dar es Salaam and TaTEDO have been at the forefront of promoting solar dryers. These institutions are also promoting solar thermal for cooking in parallel with solar drying. Solar water heating systems in Tanzania are used mainly by households and various types of institutions (e.g., hotels, hospitals, health centres, and dispensaries). Despite the potential of solar thermal and the demand for low-temperature water for both domestic and commercial applications, the uptake level is low. Lack of awareness, inability to mobilise financing, relatively lower priority given to such investments are some of reasons attributed to the little use of solar hot water heating.
Biomas
Biomass is Tanzania’s single largest energy source. According to REA estimates, agricultural, livestock, and forestry residues amount to about 15 million tons per year (MTPY). A portion of that amount may be available for use in power generation. This includes sugar bagasse (1.5 million MTPY), sisal (0.2 MTPY), coffee husk (0.1 MTPY), rice husk (0.2 MTPY), municipal solid waste (4.7 MTPY), and forest residue (1.1 MTPY), with the balance from other crop waste and livestock. Further supplies can be obtained through sustainably harvested fuelwood from fast- growing tree plantations. For example, a 50 MW biomass power plant could obtain all its fuelwood needs from a 10,000 hectare plantation.
Heat Applications
Much of the biomass is used for heat applications. These include cooking in the residential sector and process heating for agriculture and industry.
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Power Production
Tanzanian industry using wood or agricultural feedstock (e.g., sugar, tannin, and sisal) has been generating its own power from waste biomass materials. It is estimated that about 58 MW of such generation is taking place.
Under the SPPA programme, two biomass power projects are supplying power to TANESCO: TPC, a major sugar producer with an SPPA for 9 MW of power, and TANWATT, a tannin producer with an SPPA for 1.5 MW. In June 2013, a third SPPA for 1 MW, the Ngombeni project, is expected to be commissioned to supply power to TANESCO’s isolated grid on Mafia Island. TANESCO has signed SPPAs for three additional biomass projects with a total capacity of 9.6 MW.
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3 Scaling up the development of small hydropower in Tanzania
3.1 CHALLENGES FOR DEVELOPING THE SMALL HYDRO IN TANZANIA
Tanzania is emerging as one of the few Sub-Saharan Africa (SSA) countries with a viable mini-grid program where mini-grids are operated by private companies that could be scaled up. TANESCO has signed Small Power Purchase Agreements (SPPA) with 11 developers for 46.1 MW. Three are already selling power to TANESCO. It has also signed 7 Letters of Intent, a precursor to signing the SPPA, with 30.9 MW of projects.
Availability of renewable energy resources, increasing electricity demand, the supportive Government vision and the readiness among private sector players create viable opportunities for expanding renewable-based on grid or off-grid electrification solutions. There was consensus that Tanzania should support development of renewable energy technologies for rural electrification.
Types of connection existing in Tanzania:
Main grid (Tanesco);
Mini-grid (Tanesco);
Stand-alone off-grid system powered by a unique source of production (Tanesco /Private).
These three types have the following characteristics:
Interconnected main grid (Tanesco)
Small hydro projects given their size and their relatively high costs of production (and with a marginal production on the network) are generally difficult to justify economically in a least cost expansion plan. This justification is mainly done by comparison with an equivalent thermal plant running on heavy fuel oil (HFO); this involves making the largest possible unity (close to 10 MW in the case of this study) to be competitive and if possible close to the HV network to minimize connection costs.
Production shortfalls during low flow periods, particularly for run-of-the river plants are relatively not disadvantageous given the limited impact that can be easily compensated by thermal power plants.
These projects must meet the standards set by Tanesco to be connected to the main grid. Projects that have a possible regulation (downstream of a reservoir dam) have the advantage of giving a little more base or peak power on the network.
The new hydroelectric options considered in the PSMP (Power System Master Plan - 2012 Update, May 2013) don't include any Small hydropower plants.
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Mini-grid (Tanesco/Private)
Hydropower projects of intermediate size can easier supply mini-grid operated by Tanesco or a private distribution and production company that often have other expensive means of production (diesel), intermittent (solar and wind) or from local biomass. Deficits during periods of low flow require more from the thermal power plants to address the production shortages in the dry season.
For each of the mini-grids, a local development plan has to be done by the Ministry of Energy and Mines/EWURA and all operators based on concurrent means (mini hydro, solar, etc.).
The intermittency of renewable energy, particularly solar, can present problems of grid operation and of management optimisation in hydro and thermal power plants.
The distance of small hydro from load centres can occasionally double the cost of construction which may suspend the development of the project for financial reasons.
Stand-alone off-grid system powered by a unique source of production
These grids need to be powered by small plant (less than 1MW) and located near the load centres. They are planned with the Government in various bilateral programs of rural or decentralised electrification.
These hydropower projects can only be economically justified by comparison with small power generators running on diesel.
To meet the daily demand, the design flow of these small run-of-the-river plants should be as close as possible to the low flow in order to consistently produce and dispose, if technically feasible, with a sufficient modulation capacity to supply the (daily) peaks.
3.2 STRENGTHS AND WEAKNESSES OF SMALL HYDROPOWER DEVELOPMENT
The table below summarizes the strengths and weaknesses of the development of small hydropower in Tanzania as well as recommendations for its development
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Connection Strengths of small hydropower (1-10MW) Weaknesses of small hydropower (1-10MW) Recommendations typology - Opportunity for projects located at a short distance from the existing HV grid: Easy Evacuation of energy, to strengthen the main Grid. - Positive impact on GHG emissions: Participation in reducing greenhouse gas emissions to achieve the long- term country objectives. - Potentially eligible for CDM credits: Improved profitability of projects if they have access to CDM credits from the World Bank. - Low investment costs and reduced barriers to funding: - Large hydro is generally preferred in national master plans: large hydro projects are regularly favored in Small hydro projects that have competitive production national master plans over smaller projects. In Tanzania, - Promote short-term development projects with a costs with larger projects require a much lower however, even projects of 5-10 MW can make a capacity up to 10MW : particularly projects closest to the investment cost. Therefore, the conditions of access to significant contribution to the country’s energy mix grid and the existing access which have low production financing for these smaller facilities are easier. (Thermal and Hydro) without the rental units (IPP's). costs and reasonable hydrological and socio- - Shorter development cycle: Duration of development environmental risks issues related to their development.
Main Grid and construction (including research for funding) is shorter than for large hydro. Therefore, the projects - Potential saturation of the grid: smaller projects are (Tanesco) - Creation of a Master Plan: Such a plan would enable a smaller than 10MW can enhance production in the less able to afford HV network enhancements once the should be able to study and comparison to be made shorter-term. grid is saturated. between various planning scenarios, taking into account
- Competitive cost of production compared to thermal: the economic relevance benefits of the gradual - Base power: small hydro projects usually have only Opportunity to substitute thermal energy production at a introduction of more small hydro projects versus a single limited storage capacity (tank) to allow for peak lesser cost. large project. - Energy independence: substitution of some thermal production. energy by small hydro reduces the need to import petroleum products, which are expensive and vulnerable to international market price fluctuations. - - Reduced environmental and social impacts compared to large hydro projects. - Flexibility In maintenance: The impact of maintenance will overall have a lesser impact to national electricity output compared with for large hydropower projects. In addition, proper planning of this maintenance allows for greater flexibility.
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Connection Strengths of small hydropower (1-10MW) Weaknesses of small hydropower (1-10MW) Recommendations typology - Put in place productive investment planning necessary - Adequacy of the supply and demand: The size of small for the development of small remote centres which takes hydropower projects is generally better suited to local - Complex Planning: Complexity of planning networks of account of the different possible sources of production demand. developments in the medium-term, given a significant (Wind, solar, biomass, thermal) number of potential sites and development - Prioritize small hydropower projects close to remote -- Energy supply to remote centres that would not opportunities, but no prior indications of which types or centres and at competitive cost compared to thermal Mini-grids benefit the development of the energy produced by large configurations of generation are to be used. units. hydropower and thermal projects since transmission and (Jirama/Private) - Provide, where possible, phasing of the development distribution lines would not be developed as far as these - Network management complexity in the case of too of small hydropower projects according to demand (eg in remote networks and centres. high penetration of intermittent renewable energy: he t the number of penstocks and turbines). small hydropower by itself, without regulating reservoir, - Invest in the development and rehabilitation of roads - Ability to obtain financial aids (Concessionary finance, cannot adequately manage intermittent production of and rural tracks that would reduce the investment costs subsidies at low interest rates) given the capital-intensive other RE sources such as solar and wind power. for the development of small hydro projects and thereby nature of hydroelectric projects. strengthen their competitiveness against large hydro.
- Ability to reduce development costs: Possible - Promote the development of projects in areas that Simplifying of the design to minimize production costs to receive well distributed rainfall over the year. the maximum. - Adequacy of the supply and the demand: Size of small - Plan for ultimate grid integration of projects: - Unsuitable in areas with significant periods of low hydropower projects generally better suited to local Stand-alone off-grid flows: Difficulty in justifying mini hydropower projects When possible, in the development of projects plan to demand. system where low flows are severe, which is the case especially allow future connection to the network, so that these - Power supply to remote centres that would not benefit in areas of lower and / or poorly distributed rainfall. projects are not abandoned after connection to the main (supplied by a single from the development of the energy produced by large grid occurs. production source) hydro projects as transmission lines and distribution - Complex planning: Complexity of undertaking the would not be developed as far as these remote networks relevant studies across the entire country - Investing in the development and rehabilitation of and centers roads and rural tracks that would reduce the investment - Availability of financial aid (grants, subsidies at low costs for the development of small hydro projects and interest rates) given the capital-intensive nature of thereby strengthen their competitiveness against large hydropower projects. hydro.
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3.3 PRIORITY DEVELOPMENT ZONES
Several initiatives are on-going in Tanzania aiming at supporting the rural development and pointing out priority development zones for which examples are :
Tanzania Rural Electrification Study;
Southern Agricultural Growth Corridor of Tanzania (SAGCOT);
National Electrification Programme Prospectus.
These programmes/studies are described below :
LEAST-COST SUPPLY OPTION IN SEVEN DEVELOPMENT ZONES DESCRIBE IN THE TANZANIA RURAL ELECTRIFICATION STUDY - MASTER PLAN AND PROGRAMME REPORT, 2005
Although this interesting study is quite outdated, many aspects, postulates and conclusions are still valid. A financial and economic assessment of supply option is included in the study. The following 4 electricity supply options were considered: (1) Connection to the national grid, (2) Connection to decentralised supply grids with additional thermal power supply for the area, (3) Local thermal power generation, (4) Decentralised supply from new hydropower plants. For each of the four supply options, as far as applicable, supply costs and the respective levelized costs (present value (PV) of costs divided by the PV of energy, 20 years planning period, 12% discount rate) were calculated down to the customer level: By comparing the costs of the supply options, the least-cost alternative was identified. The key findings of the financial and economic assessment are summarised in the following table:
Demand Load Least cost supply Priority development zones Villages 2004 2020 2004 2020 option kWh kWh kW kW Arusha 3 995,000 3,029,000 500 1,500 National Grid Lindi-Mtwara 33 6,941,000 14,791,000 3,500 7,500 Local Thermal Mwanza-Shinyanga 6 9,360,000 13,079,000 2,750 4,000 National Grid Rukwa 25 5,135,000 14,256,000 2,500 7,250 Hydro-power Kigoma 9 4,850,000 12,394,000 2,000 5,750 Hydro-power Iringa 6 1,793,000 3,209,000 750 1,500 National Grid Ruvuma 22 6,145,000 13,599,000 2,250 5,250 Hydro-power Table 3 Least cost supply option for 7 development zones
As can be seen, 3 interesting zones have been identified where a hydropower development can be undertaken: Rukwa, Kigoma and Ruvuma. We underline that the mini-grid Lindi- Mtwara is considered in another document (Power system Master Pan) to be supplied by the 400 MW gas project in 2016, but without interconnection with the main grid this generation will be much greater than the local demand and a supplement of load coming from hydropower plants would be a tremendous opportunity for the upcoming years.
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SOUTHERN AGRICULTURAL GROWTH CORRIDOR OF TANZANIA (SAGCOT)
SAGCOT investments will focus on six areas with high potential for quick agricultural development ("clusters"). Over the next 20 years the initiative aims at bringing 350,000 ha of land into commercial production, increasing annual farming revenues by US$1.2 billion, and lifting some 450,000 farming households out of poverty. Moreover, the SAGCOT Centre will also initiate the preparation of a prioritized public infrastructure investment plan; focusing on integrated road network and power supply development. Two clusters, highlighted in yellow on the Figure 1, are of particular interest: Sumbawanga and Ludewa, as they are located in off grid areas. We can expect that a mutual reinforcement coming both from an improvement of modern agriculture and agro-industry combined with additional power supply could benefit these areas.
Figure 1 Project Location - SAGCOT and the Priority Clusters
NATIONAL ELECTRIFICATION PROGRAMME PROSPECTUS
A twofold approach has been carried out : the one forecasting the development of the urban demand and the second developing least cost approaches for rural areas for the following three markets segments : 1/ the on-grid electrification options; 2/ the off-grid supply options and 3/ the disseminated energy services options for scattered populations in remote areas.
For the needs of the rural electrification process, the study develops the concept of "development pole" as a result of a villages selection based on an indicator (IDP : Indicator for Potential Development) that takes into account 3 main parameters: education, health and local development.
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The report has outlined 13 off-grid hydro-projects to supply 19 development centers. It is noted that all these 13 sites have been included in our database and therefore are part of our selection process.
3.4 SMALL HYDROPOWER DEVELOPMENT: AN OPPORTUNITY FOR TANZANIA
Seeing the strengths and weaknesses presented above, the projects range considered by the study (1-10 MW) offers great opportunities to support energy development in Tanzania.
Small hydropower, compared to other energy productions, has the following comparative advantages and complementarities:
Small hydro Comparative Other sources of energy Complementarity (1~10MW) advantage
Small hydropower is very interesting as an alternative to thermal energy especially compared with the diesel generator (diesel) especially if they are far from the supply centres (transport cost).
Considering that small hydropower need small fuel imports, it has a direct beneficial effect on the balance of payments of Tanzania.
Thermal Given a cost per MWh estimated between 146 US$ / MWh for Marginal cost production on the main grid for the actual mix hydro+thermal (2013-2020)8 and 590 US$/MWh9 for isolated diesel generator, many small hydropower projects are in direct competition with them.
However, there is a great complementarity between small hydro and thermal power plants that can compensate for the low flow periods or be used to supplement the daily peak.
Large hydropower projects usually have a lower cost of production, however small projects are often:
quickly implemented
their funding is more easily mobilised
the marginal contribution of a small project is often better suited to the increasing demand Large run-of-the their lower socio-environmental impact - hydropower river Also note that the downtime (inspection, maintenance, failures) of a large project has a severe impact on the whole energy production whereas the small project will have a limited impact.
Given that large projects usually have a low production cost, any new major project will question the relevance of smaller projects, especially those operated by private companies. These projects are therefore rather in competition than complementing
8 Ministry of Energy and Minerals, Power System Master Plan 2012 - Update (may 2013) 9 SREP - Investment plan for Tanzania (2013)
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Small hydro Comparative Other sources of energy Complementarity (1~10MW) advantage each other.
This type of project can be expensive in terms of cost per kWh if it is analysed as an individual project. It has to be planned in the context of a project offer requiring daily or seasonal peak capacity, or a mixture of the two. reservoir Small hydro can directly benefit from the existence of a - hydropower project with reservoir that would overcome the low flow periods and the peak cumulative capacity. This type of development must be coherent with the increasing demand in Tanzania.
Where the small hydropower is possible, it is in general economically competitive compared to the windpower (from US$ 96 to 130/MWh)10. It has the advantage of being stable and predictible. Wind energy has to be more highly compensated by other sources of non-intermittent energy which results in additional development costs. Wind However, in the West centre and North Centre of the country, the wind power does not compete with the small hydro where it is difficult to implement, not recommended or impossible. A certain complementarity could exist in the future with the development of small networks combining hydro-wind-thermal or medium capacity pumped-storage projects associated with wind farms.
When possible small hydro is economically competitive compared to solar (460 US $ / MWh) and has the advantage of being more consistent than solar. The solar power must be compensated by other non intermittent sources of energy. The solar power must be compensated by other non intermittent sources of energy, which results in additional developement costs. Solar However, in the west, a part of the central area and in the south of the country, the solar power does not compete with the small hydro where it is difficult to implement, not recommended or impossible. A certain complementarity could exist in the future with the development of small networks combining hydro-solar-thermal or medium capacity pumped-storage projects associated with solar parks.
Some Biomass projects could potentially be competitive. The examples of Sao Hill and Mufindi show generation costs at 73 and 76 US$/MWh. Biomass A certain complementarity could exist in the future with the development of small networks combining hydro-Biomass (and possibly thermal). Table 4 Comparative advantages and complementarities of Small Hydro towards other sources of energy
10 SREP - Investment plan for Tanzania (2013) and Ministry of Energy and Minerals, Power System Master Plan 2012 - Update (May 2013)
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We see that the development of small hydro fits perfectly into the development of a mixed energy in Tanzania.
On the competitiveness of small hydropower on the interconnected main grid of Tanzania, several new hydropower sites of 34 to 600 MW had been considered via previous studies:
Unit Cost for Installed Average Portfolio of medium and large average capacity energy hydro projects11 Energy [MW] [$/kWh] [US$/MWh] Songwe Bipugu 34 $ 0,08 $ 77,20 Malagarasi 45 $ 0,11 $ 106,50 Kakono 53 $ 0,03 $ 31,70 Rusumo 80 $ 0,09 $ 91,90 Masigira 118 $ 0,04 $ 44,90 Upper Kihansi 120 $ 0,13 $ 133,70 Mpanga 144 $ 0,04 $ 36,30 Taveta 3 145 $ 0,04 $ 37,00 Songwe Manolo 149 $ 0,05 $ 50,20 Songwe Sofre 157 $ 0,05 $ 45,70 Stieglers 1 300 $ 0,04 $ 41,00 Stieglers 3 300 $ 0,03 $ 27,30 Ikondo 1 340 $ 0,05 $ 47,80 Ruhudji 358 $ 0,08 $ 79,10 Rumakali 520 $ 0,06 $ 55,90 Stieglers 2 600 $ 0,03 $ 34,40 Unit Cost for average Energy (all projects) $ 58,79 Unit Cost for average Energy (without Songwe and Stiegler’s Gorge) $ 68,86 Table 5 Portfolio of medium and large hydro projects - Ministry of Energy and Minerals
Two hydro options will require removal on significant obstacles before becoming firm candidates for implementation:
Songwe project is a multipurpose project located on the border between Tanzania and Malawi, its development will involve trade-offs between two countries and various competing uses of the water resource. It is necessary to initiate joint discussions on the best way to develop the project.
The Stiegler’s Gorge option is located within the Selous Game Reserve; its development is constrained by the Algiers Conventions which defines the developments possibilities within national parks and game reserves. It is therefore important to redefine the game reserve borders.
Very few of these identified medium and large hydro options have recent (pre-)feasibility study reports. There is an urgent need to verify and update these studies, considering the increasing sediment transport, the socio-environmental constraints and the other competitive use of water.
11 Ministry of Energy and Minerals, Power System Master Plan 2012 - Update (May 2013)
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Thermal generation alternatives for Tanzania vary between 38 to 56 US$/MWh, including Coal and Gaz. But investigations of the gas and coal reserves need to be pursued to ensure that as much of the gas and coal reserves as possible are proven.
The small hydro projects that would be connected to the main grid should be economically competitive with the best projects.
3.5 PROGRAMS SUPPORTING THE SMALL HYDRO DEVELOPMENT
3.5.1 Tanzania Energy Development and Access Expansion project (TEDAP)
TEDAP provides support to the Rural Energy Agency (REA) for the development of small renewable energy projects and off-grid electrification. With the assistance of the TEDAP project, the Government established a comprehensive support package for small renewable energy projects (up to 10MW). This project allows/facilitates selling power to Tanesco grid(s) or directly to communities. The package consists of :
a simplified regulatory framework, including standardized power purchase agreements and tariffs;
grants for connections from REA (US$ 500 / connection) ;
credit line channelled through Tanzanian commercial Bank (~US$ 23 millions) and ;
technical assistance and pre-investment support provided by REA.
As a result of this support, the SPPA7 framework and Letter of Intents have been signed for about 77 MW of renewable energy (mostly small hydro and biomass).
3.5.2 Scaling-up Renewable Energy Program (SREP) The Scaling-up Renewable Energy Program (SREP) is part of the Climate Investment Funds and aims at demonstrating the economic, social, and environmental viability of a low-carbon development pathway by creating new economic opportunities and increasing energy access through the production and use of renewable energy.
SREP and other co-financing will support, through the Renewable Energy for Off Grid Electrification Project, the provision of transaction advisory services, investments in mini-grid, micro-grid and stand-alone renewable energy-based rural electrification, risk mitigation to cover delayed payments by power purchasers, and knowledge management and capacity building. Total estimated cost is US$ 160 million, of which US$ 25 million is sought from SREP with about $ 50 million to be sought from the World Bank Group. Private sector, other development partners and commercial banks provide the balance. The project is expected to result in investments of about 47 MW of renewable energy plants, to benefit over 100,000 households and rural enterprises directly with electricity connection, and over 300,000 indirectly through the development of investment pipeline.
The SREP RERE project is expected to finance:
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setting up of a transaction advisory facility;
expansion of the credit line for small renewable energy projects;
performance grants for mini-grid connections, and sustainable solar market packages for stand-alone systems;
establishment of a risk mitigation mechanism; and
capacity building, knowledge management and project management.
3.5.3 Integrated Rural Electrification Planning (IREP) The program “Integrated Rural Electrification Planning” (IREP) is primarily financed by the European Commission in partnership with REA. IREP ended in June/July 2013 and produced rural electrification investment plans in six pilot regions, namely Morogoro, Lindi, Pwani/Coast, Tanga, Iringa and Dodoma as well as providing Capacity-Building activities. The rural electrification investment plans include spatial analysis (classification of villages to be electrified based on socio-economic criteria), produced load forecasts and describe network options (grid extension, off grid systems, production connected to the grid). The project included biomass, small-hydro, geothermal, PV/Diesel hybrids. However, the project does not collect long-term ground-based (stream gauge) data.
3.5.4 Mini-grids based on small hydropower sources to augment rural electrification in Tanzania - UNIDO This project will develop micro / mini hydropower based mini-grids in Tanzania to supplement the country’s effort to increase access to rural electrification. Micro / mini hydro power will substitute the GHG intensive diesel generators in areas where there is no electricity.
This project therefore aims at addressing most of these barriers by establishing a platform for the development of small scale hydro power in the country. The activities include:
detailed feasibility studies for the demonstration sites;
building of capacity for the stakeholders in developing micro / mini hydropower based mini-grids;
developing viable business model for micro / mini hydropower based mini-grid
demonstration of micro / mini hydropower plants for a cumulative capacity of at least 3.2 MW.
The project is expected to strengthen the policy, regulatory and institutional framework supporting the micro / mini hydropower based mini-grid systems in Tanzania.
The project is expected to build necessary human and institutional capacities at all levels in order to achieve the scientific, engineering and technical skills and also the infrastructure necessary for the design, development, fabrication, installation and maintenance of micro / mini hydropower plants.
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The proposed micro / mini hydropower based mini-grids to be setup under the project are expected to bring global benefits by reducing around 335,658 t CO2e directly and around 2,685,185 t CO2e indirectly, which otherwise would have resulted from the use of diesel generators, as it is the most common electricity source in Tanzania.
3.5.5 ESME - Supporting Energy SMEs in sub-Saharan Africa - GVEP The Supporting Energy SMEs Project is a $30 million programme funded by the Russian government, managed through the World Bank, and covering Kenya, Rwanda, Tanzania and Senegal. The activities include: assisting developers of mini-grids and small hydro systems to finance and deliver their projects, supporting the development of the solar PV market, and providing capacity building and technical assistance to government agencies.
GVEP has undertaken 6 SHPP feasibility studies in 2013 including :
• Establish technical and economic feasibility of 6 mini hydro projects;
• Assess the cost of implementing each of the 6 projects;
• Prepare detailed design of the projects;
• Prepare an implementation schedule.
Item Project Location Easting Northing 1 Luswisi Ileje district, Mbeya Region 553.94E 771.29N 2 Ihalula Njombe district, Njombe Region 776.00E 987.04N 3 Macheke Ludewa district, Njombe Region 492.32E 695.75N 4 Lingatunda Madaba district, Songea Region 697.21E 758.67N 5 Mwoga Kasulu district, Kigoma region 494.41E 818.73N 6 Darakuta Babati district, Arusha Region 767.93E 550.72N Table 6 GVEP - 6 SHPP feasibility studies
3.5.6 Rural Electrification Master Plan and Investment Prospectus - NORAD The Rural Electrification Master Plan and Investment Prospectus is the overall guiding framework which is currently being prepared nation-wide by REA and financed by NORAD.
The Prospectus exercise aims at identifying a least cost rural electrification strategy that together with the continued electrification development in urban areas will contribute to attain the national objective for electrification ratio: 30% by 2015 and 50% by 2020.
Therefore a twofold approach has been carries out, the one forecasting the development of the urban demand and the second developing least cost approaches for rural areas for the following three markets segments, the on-grid electrification options, the off-grid supply options and the disseminated energy services options for scattered populations in remote areas.
3.5.7 Possible future funding for rural electrification and small hydropower Regarding expected future donor contributions:
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NORAD will finance 122MUS$ during the period 2013-2016;
SIDA will finance the 220-kV Southern Highland Transmission Project and will continue in at least 2013 to provide funds for the REF;
KfW is said to have committed to the financing of an electrification project in the Northwest;
The Chinese Government is expected to support RE directly or indirectly;
The World Bank and the African Development Bank are expected to continue financing RE projects.
3.6 LESSONS LEARNT FROM PROJECTS SIMILAR TO SMALL HYDROPOWER
We can generally take a few lessons from small hydropower project development, including:
The small hydropower project development (1-10MW) requires engineering services, which the local and international markets understand, to avoid equipment, material and service prices rocketing.
We need to avoid selecting an electromechanical equipment manufacturer at the beginning of the project. This results, systematically, in underperformance of capacity and production, and generally an inadequacy faced with the client needs (automation, flexibility, security, etc.). Specification is advised during the study process, all features if the turbines related to local conditions of load, hydrology, engineering, consumption patterns to accurately establish the specification in detail.
The key solutions in hydropower and especially in small hydro should be prohibited. Resorting to multidisciplinary independent engineering services is strongly advised for all services: identification, feasibility study, detailed studies, writing tender documents, tender assessment, supervise electromechanical equipment manufacturing (from the factory) and works, commissioning the electromechanical equipment both at the factory and at the site, supervision of implementation of operations and maintenance.
To avoid construction and delivery delays, construction planning requires good knowledge of the project environment and organisation and supplier mobilisation opportunities.
During the study phase, the small hydro projects are faced with long-term difficulties in the estimation of material and labour quantities to be mobilised especially for access roads, the dam and the waterway works. This is mainly linked with the simplification of geotechnical studies in these small projects. It is in fact hardly justifiable to provide major budgets for geotechnics during the study stage. Henceforth, these aspects are often put back during construction when finance is
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mobilised but with the risk that some posts explode (excavation, extra construction material, etc.).
Even a small hydropower project needs to be subject to a IWRM process (Integrated Water Resource Management). In fact, the water comes from a more- or-less important river stretch. Along the stretch it is therefore unavailable for the fauna, flora and human activities. Water quantity also depends on anthropogenic activities and on the environment of the watershed. We can also talk about cascade schemes where the upstream works (irrigation, hydropower, drinking water) influence downstream works, which must be included and considered in their development.
It is usually necessary to be careful and critical, in the establishment of the flow duration curve and the flood flow calculation, compared to existing hydrological data. In fact, the hydrological data availability and quality is often missing although it is essential for the technical and economic parameters of the hydro project development. More specifically, it is advised to systematically and critically review the raw measured data as well as the flow rating curve(s) and to establish connections between the observed rain and/or validated gauging measures for similar watersheds. The installation and monitoring of gauging stations concerning the site is generally strongly recommended.
It is only thanks to readings over long periods (more than 20 years of continual daily measures) that the hydrology is significant and informative on the hydrological regime of the river including its extreme values such as floods and droughts that affect the sizing of the facilities. Moreover, the identification of trends and hydrological cycles can only be performed over these long times, particularly when it concerns climate change.
Given the general deterioration tends of watersheds in tropical countries (deforestation, agricultural activities, development of mining activities over rivers, etc.), adapted measures must be taken to manage or prevent sediment transport. The cost of infrastructures to remove sediments and production deficiencies linked to Desilting basin must be taken into account in the economic and financial calculations. In the current context of soil deterioration in some parts of Tanzania, hydropower projects must absolutely take into account sediment transport in future studies. The transported quantities should be shown with a curve of classified sediment load and by grain size curves associated with a representative series of flows. Regarding storage reservoirs, the sizing (capacity, height, dead storage height, outlet gate, etc.) and the life expectancy of works must take into account the filling of storage reservoirs by sediment. Moreover, it seems necessary that national protection and conservation programmes for watersheds be developed while educating the people on impacts of current activities on soil deterioration (diminishing fertility of agricultural land, increasing risk of landslides, increase of sediment load in rivers, etc.).
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The training of operational staff of small hydropower plants should start at the end of works and during the commissioning of works and equipment. This will allow the employees to familiarise themselves with engineering, manipulation and awareness and with electromechanical equipment. The training benefits from the presence and experience of the organisation and the providers. For people who get to know each-other, the contacts and future technical interventions (operation phase) are generally more harmonious.
The small hydro sites are often not adapted for local companies. On the other hand, opportunities to acquire new skills exist via the larger companies outsourcing contracts and their ability to take over the sites. These local companies could then use the acquired skills in the smaller projects (pico et micro hydropower plants).
The planning of small hydro sites can take the country to demand compliance with national standards if the latter exist, or accepted international standards (Eurocodes, ASTM, IEEE, IEC, ISO, FIDIC, etc.). The multiplicity of standards is normally a factor which slows down proper development of projects and limits interest of capable companies for the country or funding agencies who are investing. Standardisation also enables the Ministry and its associated organisations to master the adopted standards. The engineering company or provider is therefore not advised to impose its own standards.
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4 Activities undertaken during the first Phase
4.1 MOBILIZATION
A fact finding mission has been quickly organized in Dar-Es-Salam and focused on collecting all the required information and data and meeting all the key actors in the sector in Dar-Es-Salam in order to draft, as much as possible, a list of potential and existing sites from previous studies. Special attention was paid to obtaining hydrological and topographical data and geographical information.
The experts from SHER mobilized during the fact finding mission were:
Pierre SMITS, team leader, from November 5, 2013 to November 14, 2013
Emmanuel Gabriel MICHAEL, Small hydropower expert, Tanzania-based expert
Thomas DUBOIS, Civil Engineer, from November 11, 2013 to November 14, 2013
A second mission is foreseen for Mr Thomas Dubois on week 49 (2nd to 6th December 2013) to finalize the preliminary collection phase.
A special report "Fact finding mission" was written at the end of the first mission.
Following the inception phase (step 1), the desk-based study last from December 2013 to February 2014. The site visits took place between March 2014 and late May 2014, a period of 3 months for the first set of 50+ sites and between October 2014 and January 2015 for the second set of 20 sites. A total of 75 potential sites and 11 existing sites or in construction were visited.
4.2 ORGANIZATIONS VISITED
During their presence in Dar-Es-Salaam, the experts’ team was able to collect further information. The team tried to visit all the organizations that could possibly provide important information linked to the project. The visited organizations were:
Rural Energy Agency (REA),
TANESCO,
Tanzania Meteorological Agency,
Ministry of Lands, Housing and Human Settlements Development, Survey and mapping department,
The World Bank,
The European Union,
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Ministry of Water
SWECO,
InfoBridge,
eMJee Development Consult,
4.3 BIBLIOGRAPHY AND DATA COLLECTION
During the inception phase, SHER found in its own databases or through third parties the following GIS layers (Raster and vector):
Subject Source Administrative boundaries
SHER Database
Roads, trails and Rails
SHER Database
Rivers and lakes
SHER Database USGS HydroSHEDS Generated with the SRTM using Archydro (ArcGIS extention)
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Subject Source Existing Hydropower plants and on-going construction Hydropower plants
REA, TANESCO, MEM, Diocese
Mean annual rainfall
Tanzania land resource for coffee map Mean Annual Rainfall Map (ODI, "Rethinking natural resource degradation in semi-arid sub-saharan Africa: the case of semi-arid Tanzania"
Population information on village level
National Bureau of Statistics Ministry of Finance, REA
Grid connected information at village level
TANESCO, REA
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Subject Source Geological maps
USDM, Musée Royal de Tervuren National map 1:2,000,000 Quarter degree Sheets 1:250,000
Seismic information
Musée Royal de Tervuren
Land cover
FAO
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Subject Source Erosion map
Land office
Grid (existing, projected) HV/MV, incl. isolated grids, incl. voltage level
REA, TANESCO, IED report
National parks and game reserves
Tourist Board; Tanzania Conservation Resource Centre; Survey and mapping department World Database on Protected Areas
The complete digitized 1:250'000 topo maps coverage (64 Maps)
MoL, Survey and mapping department
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Subject Source The complete digitized 1:50'000 topo maps coverage (1,333 Maps, 200 Mo each)
MoL, Survey and mapping department
Digital elevation model
DEM SRTM : whole coverage DEM ASTER : whole coverage
Industries
Industries and agro-industries data and location where collected through Ministry of Industry and Trade
Mines
Industries and agro-industries data and location where collected through Ministry of Energy and Minerals
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Subject Source Existing Tanesco thermal plants
Digitized from IED reports
REA provide us with the following vector layers, coming from IREP:
Existing and planned low voltage grids
Tanzanian villages with population information (unfortunately not updated with the 2012 census)
Some considered small hydropower potential sites
Some existing hydropower plants
The information provided by REA was of particular importance for the project. TANESCO provides a grid layer map but schematic and unfortunately, no TANESCO useful layers about the grid or potential sites were available on time which conducts to extra identification work.
All the raster and vector layers were converted, as necessary, in the GCS_WGS_1984 Geographic Coordinate System with D_WGS_1984 as datum, prime meridian as Greenwich and Degree as angular unit.
The collected documents are presented in Annexe 1 : Bibliography.
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5 Spatial database
Spatial information related to the hydropower sector in Tanzania is consolidated into a geographical information system (GIS) and its key features are presented in the sections below.
5.1 BACKGROUND INFORMATION
Spatial information and data can be of two types:
Raster data: information is represented by a grid of uniform cells to which a value (attribute) is attributed. Each cell covers a geographical area considered as being homogeneous (attribute value).
Vector data: those data are described as point, lines or polygons to which attributes are assigned.
Spatial data collected during Stage 1 of this study, their key features and their sources are summarized in the table below (Table 7 Collected spatial information):
Thematic Format Key features Sources Country / Regions / Districts / FAO Global Country Boundaries, 2012 Administrative boundaries Vector Divisions REA, 2014 Major cities Vector 32 cities Open Street Map, 2014 1:250,000 (64 tiles) Ministry of Land, Survey and Mapping Raster Full country coverage Department Topographical maps 1:50,000 (1,333 tiles) Ministry of Land, Survey and Mapping Raster Full country coverage Department SRTM v4.1 NASA, 2014 Raster Spatial resolution ~ 90m http://www2.jpl.nasa.gov/srtm/ Digital Elevation Model ASTER GDEM v2 Raster Spatial resolution ~ 30m http://www.jspacesystems.or.jp/en_/ (experimental) Land cover Vector
Tourist Board ; Tanzania Conservation Protected areas, National Resource Centre ; Ministry of Land ; Protected areas Vector Parks and Game reserves World Database on Protected Areas ; Protected Planet, 2014 IPCC default soil classes ISRIC-WISE Soil map Raster derived from the Harmonized http://www.isric.org World Soil Data Base (v1.1) Ministry of Energy and Minerals ; World Mining activities Vector - Bank AICD database ; SHER Satellite image Raster Image Landsat 2013 Google Earth Census data at village and National Bureau of Statistics ; Ministry of Population Shapefile region levels Finance, REA FAO, 2000 Lakes Vector Inland water bodies in Africa http://www.fao.org/geonetwork River "flow accumulation" FAO, 2006 River network Vector network from the HYDRO1k http://www.fao.org/geonetwork for Africa Flow gauging stations Vector Location of the YYY gauging Rainfall Raster Monthly average rainfall grid WorldClim, v1.4
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Thematic Format Key features Sources Spatial resolution ~ 1km http://www.worldclim.org/ National, regional and other Road network Vector World Bank AICD database roads of Tanzania Rail network Vector Main rail network World Bank AICD database Ports Vector Major ports World Bank AICD database Airports Vector Major airports World Bank AICD database Power grid Vector Existing power grid IED, 2013 ; REA Planned expansion of the Power grid Vector World Bank AICD database transmission network 34 thermal power plants IED, 2013 ; Power System Master Plan, Existing thermal power plants Vector amongst which 10 connected 2013 to the National Power Grid REA, TANESCO, Ministry of Energy, Existing hydropower plants Vector 46 hydropower plants Diocese, Power System Master Plan, 2013 Table 7 Collected spatial information
5.2 EXISTING POWER SYSTEM
5.2.1 Current status of the power system In May 2014, Tanzania’s total installed generation capacity12 was 1,583MW distributed as follow: 561MW (35 %) from hydropower, 527MW (34%) from natural gas of and 495MW (31%) from liquid fuel. TANESCO also imports power from Uganda (10 MW), Zambia (5MW) and Kenya (1MW). Due to traditional dependence on hydropower, the droughts that occurred in 2010 resulted in power supply shortages in the country. To bridge the electricity supply gap in the country, in 2011, TANESCO contracted Emergency Power Producers (EPP) at a relatively high cost.
5.2.2 Thermal power system Tanzania has a thermal installed capacity of 908.7MW (2013) distributed as follow: 574MW gas-fired (63.2%), 208MW HFO-fired (22.9%), 100MW GO-fired (11%), 19.7 biomass-fired (2.2%) and 7MW IDO-fired (0.7%)13. The spatial distribution of the major plants is presented in Figure 2 and shows that most of the thermal power is installed around Dar Es Salaam with a total of 757MW representing 83.3% of the total thermal installed capacity of the country. The key characteristics of the existing thermal power plants are presented in Erreur ! Source du renvoi introuvable..
Installed capacity Avalable Energy Year Power Plant Name Fuel type (MW) (GWh) installed
IPP Units
Songas 1 Gas 42 251 2004
Songas 2 Gas 120 721 2005
12 Electricity Supply Industry Reform Strategy and Roadmap 2014-2025. 13 Ministry of Energy and Minerals, Power System Master Plan, 2013.
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Installed capacity Avalable Energy Year Power Plant Name Fuel type (MW) (GWh) installed
Songas 3 Gas 40 242 2006
Tegeta IPTL HFO 103 595 2002
TPC Biomass 17 70 2011
TANWAT Biomass 2.7 10 2010
Sub total 324.7 1889
TANESCO
Ubungo 1 Gas 102 655 2007
Tegeta GT Gas 45 282 2009
Ubungo 2 Gas 105 655 2012
Zuzu D IDO 7 31 2014
Sub total 259 1623
RENTAL UNITS (IPP's)
Symbion Gas/Jet 120 746 2011
Aggreko (Ubungo) GO 50 674 2011
Aggreko (Tegeta) GO 50
Symbion Dodoma HFO 55 371 2012
Symbion Arusha HFO 50 337 2012
Sub total 325 2128
TOTAL 908.7 5640 Table 8 Existing thermal power plants: key characteristics (source: Ministry of Energy and Mineral, 2013)
5.2.1 Hydropower system According to TANESCO, Tanzania has seven major hydropower plants (with an installed capacity greater than 1MW) connected to the national power grid, totalizing 565MW. The largest facility is Kitadu and features an installed capacity of 204MW followed by Kihansi (180MW), Mtera (80MW) and New Pangani Falls (68MW). These hydropower stations are located in the areas characterized by steep slopes and abundant rainfall i.e. along the two branches of the East Africa Rift. The key characteristics of these hydropower plants are presented in Table 9 and their location is illustrated in Figure 2.
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Max Rated Average Power Active Installed Firm gross turbine energy Installation plant Type* storage Capacity energy head discharge genration year name (Mm³) (MW) (GWh/y) (m) (m³/s) (GWh/y) Mtera R 3,187.0 101.0 97.5 80 429 195 1988
Kidatu R 127.0 175.0 132.0 204 1111 601 1975
Hale RoR 0 70.0 45.0 21 93 55 1967 Lower 1.0 852.75 23.76 180 694 492 2000 Kihansi New Pangani 0.81 169.7 45.0 68 341 201 1995 Falls Nyumba Ya R 871.4 25.2 42.5 8 36 20 1968 Mungu Mwenga RoR 0 62 8 4 28.51 0 2012
TOTAL 4,187.21 - - 565 2,820.5 1,564 - *R = Reservoir ; RoR = Run-of-River
Table 9 Key characteristics of the major existing hydropower plants (>1MW)
5.2.2 Transmission and distribution networks The transmission and distribution network of Tanzania are owned and operated by TANESCO. The transmission power network consists of 2,732km of 220 kV lines, 1,538km of 132 kV lines and 546km of 66kV lines. On the top of that, transboundary transmission lines exist between Tanzania and Uganda (132kV) and between Tanzania and Zambia (66kV and 33kV) to import power to Tanzania. Beside the national grid exists a series of isolated centers.
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Figure 2. Existing power system in Tanzania.
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5.3 POTENTIAL HYDROPOWER SITES
5.3.1 Studies related to hydropower in Tanzania
5.3.1.1 Studies provided by REA
The following documents and studies have been provided by REA:
Code Date Name of Document Author B-27 2007 Reconnaissance Study for Mini hydropower Potential Sites in Mbeya Region Tanesco B-28 2006 Reconnaissance Study for Mini hydropower Potential Sites Rukwa Region Tanesco B-29 2009 List of selected Projects for feasibility study - B-30 2006 Reconnaissance Study Mini Hydropower Potential in Kagera Region Tanesco B-31 2007 Reconnaissance Study for Minihydropower Potential Sites Iringa Region Phase II Tanesco B-32 2009 Reconnaissance Study for Minihydropower Potential Sites Iringa Region Phase III Tanesco B-33 2010 Pre-feasibility study of upper Ijangala small hydropower plant - mini hydropower Idaraya Udiakonia project of Tandala Diaconical centre B-34 2010 The report on pre-feasibility study of small hydropower potential schemes in Dar Es Salaam Morogoro, Iringa, Ruvuma and Mbeya regions - Tanzania Institute of Technology (DIT) B-35 2009 Rural Electrification Plan Suma SHP, Tanzania IED B-36 2012 Draft final report part two : Nkole SHPP (Kwabululu) ENCO (Michele Reolon) B-37 2012 Final Report Part One : Zigi SHPP ENCO (Michele Reolon) B-38 2005 Mini-Hydropower Potential Sites In Tanzania Tanesco B-39 2009 List of Minihydropower Potential Sites In Tanzania - B-63 2011 IREP IED
5.3.1.2 Studies provided by TANESCO The following documents were provided by TANESCO:
Code Date Name of Document Author B-68 2005 Small Hydropower potentials in Tanzania Tanesco B-69 2010 List of Minihydro potential sites in Tanzania Update Tanesco
5.3.1.3 Studies found by SHER and its local consultant All the remaining documents have been provided by SHER and its local partners. The following studies especially were useful for the study:
Code Date Name of Document Author B-01 2013 Africa's Renewable Future - The Path to Sustainable Growth Irena B-02 2012 Implementation Strategy For A Global Solar And Wind Atlas Irena B-03 2013 Biomass Potential In Africa DBFZ - Irena B-04 - Tanzania - Power Sector Situation - B-05 - Tanzania - Institutional Frawework - B-06 - Rural Energy Agency and Innovation in Delivery of Modern Energy Services to Rural Rural Energy Agency Areas B-07 2013 Call for Review and commentary on the draft Investment plan for scaling-up Ministry of Energy and renewable energy program in Tanzania Minerals B-08 2013 Scaling-up Renewable Scaling-up Renewable Energy Programme (SREP) - Investment Plan for Tanzania Energy Programme (SREP) B-09 2013 Power System Master Plan 2012 Update Ministry of Energy and
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Code Date Name of Document Author Minerals B-10 2007 Department Research Challenges in Small Hydropower Development in Tanzania: Rural Electrification and Development, Perspective TANESCO B-11 2012 Energies - Universities Visions, Scenarios and Action Plans Towards Next Generation Tanzania Power System (Korea and Tanzania) B-12 2009 Tanzania`s Small-Hydro Energy Market - Target Market Analysis GTZ B-13 2005 The united Republic of Rural Energy Act, 2005 Tanzania B-14 2013 Joint Mission Aide Mémoire SREP B-15 2005 The united Republic of Rural Energy Act, 2005 Tanzania B-16 2011 Financing Windows For Rural/Renewable Energy Development In Tanzania (Matching Rural Energy Agency Grants, Performance Grants, Technical Assistance, Credit Line and Renewable Energy Programme of Activities) B-17 2010? Annual report 2009-2010 Rural Energy Agency B-18 2011? REA Annual Report 2010-2011 Rural Energy Agency B-19 2012 Ministry of Energy and Power System Master Plan 2012 Update - Interim executive Summary Report Minerals B-20 2010 The united Republic of The public Private Partnership Act, 2010 - Bill Supllement Tanzania B-21 2013 Project Appraisal Document On A Proposed Credit In The Amount Of Dr 14 Million World Bank (Us$21.46 Million Equivalent) To The United Republic Of Tanzania For The Energy Sector Capacity Building Project B-22 2010 Ministry of Finance and National Strategy For Growth And Reduction Of Poverty II Nsgrp II Economic Affairs B-23 2013 NKRA Energy - Energy Energy Lab Report on Priority Projects Under Big Results Now Initiative Lab B-24 2008 The united Republic of Electricity Act 2008 Tanzania B-25 - List of GVEP supported hydro sites GVEP B-40 2000 Pre-invesment report on mini hydropower development - case study on the Mtambo SECSD (P) LTD. River - Rukwa Region B-41 2000 Pre-invesment report on mini hydropower development - case study on the Muhuwesi SECSD (P) LTD. River - Ruvuma Region B-42 2009 Norwegian support to implementation of small hydropower projects in tanzania - Norplan assessment and prioritization study B-43 2011 Pre-Feasibility Assessment for Potential Mini-hydropower Demonstration sites under Emmanuel Michael GEF4 Project in Tanzania B-44 2011 Technical Assessment for Potential Community-based Micro-hydropower potential in CAMCO Muheza, Korogwe & Lushoto Districts B-45 2005 Feasibility Study of the Rural Electrification (Area Supply) Subproject SP-4.1 DECON – SWECO – Sumbawanga-Nkasi Inter-Consult B-46 2005 DECON – SWECO – Annex 1.15 - Feasibility Report on SP-7.2 – Sunda Falls Hydropower Subproject Inter-Consult B-47 2005 DECON – SWECO – Tanzania Rural Electrification Study-MASTER PLAN Inter-Consult B-48 2013 Feasibility Study of Six Mini-Hydropower Projects (MHP) in Tanzania -Inception Report Intec - Entec - Skat B-49 2007 Potential hydropower sites in the Pare Mountains TATEDO B-50 2010 The report on pre-feasibility study of small hydropower potential schemes in Ruvuma Dar Es Salaam Institute and Iringa regions-Tanzania of Technology (DIT) B-51 2012 Renewable Energy Projects available for Investment in Tanzania REA B-52 2005 Potential hydropower sites in the Usambara Mountains TATEDO B-53 2012 Tanesco A list of minihydropower potential sites in Tanzania B-54 2002 Small and mini-hydropower potential sites in Tanzania Year 2002 Tanesco B-55 2011 Kitewaka Pre-feasibility study - B-56 2013 REA Project pipeline list Feb 2012 Rural Energy Agency B-57 2013 Existing Studies Hydro Inventory -
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Code Date Name of Document Author B-58 1999 Kigoma region pre-investment report on mini hydropower development case study on SECSD (P) Ltd. the Malagarasi river B-59 2000 Ruvuma region pre-investment report on mini hydropower development case study SECSD (P) Ltd. on the Muhuwesi river B-60 2000 Kilimanjaro region pre-investment report on mini hydropower development case SECSD (P) Ltd. study on the Kikuletwa river B-61 2002 Eng. Dr. Henry K. Ntale Reconnaissance mission: development of the Pangani and Kiwira hydropower schemes Vala Associates Limited B-62 2010 Mkonge Energy Hydropower Prefeasibility Projects Potential Along Kiwira River in Tanzania to be Systems Company Executed by Mkonge Energy Systems Company Limited (MeS) Limited (MeS) B-64 - Summary of identified small and medium hydropower potentials in tanzania and their Tanesco level of study B-65 2004 Feasibility Study for Electrification of Muze Village TANESCO B-66 2002 Ninham Shand Limkerenge hydro feasibility study Consulting Services B-67 2004 A proposal for a rural transformation project in Wino and Mahanje wards, Songea Stone Power AB, Rural District, Tanzania Sweden
Those studies constitute the baseline of the studied sites database.
5.3.2 Data collection challenges Given the several institutions involved directly or indirectly in the hydropower sector, data collection was particularly complex. The main institutions are obviously REA and TANESCO. But contacts were made with the Tanzanian Meteorological Agency, Water Basin Offices, Survey and Mapping, Donors, NGO, Private owners, all requiring huge efforts for data access and/or authorization.
5.3.3 Constitution of the previously studied sites database Once all the previous works and studies were received, a GIS database was built up. It was implemented in 3 steps:
Step 1 : Data gathering in a spreadsheet : all the previous works on the subject were first carefully studied and analyzed, and all the useful data gathered in a spreadsheet (geographical coordinates, head, potential capacity, administrative information, local demand, name, etc.). The sites where classified for M-001 to M-375. Power ranges from few kW up to 50 MW.
Step 2 : GIS import in a shape file : the data were imported in a GIS shape file using their coordinates, allowing us to locate the sites on the Tanzanian map. Geographic coordinates of all sites were converted into WGS 1984, the Geographic Coordinate requested System.
Step 3 : Discarding unnecessary sites : Once all the sites were reported on the GIS file, a first clean up was made. The selection criteria are detailed below.
The following sites have been discarded:
Sites with no coordinates: 22 sites
Sites with wrong coordinates or out of national territory: 23 sites
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Multi-referenced sites, i.e. site studied in several works. In such a case, the most recent study was taken into account (or the most detailed one in the case the most recent work is just a list): 49 sites enter in this category.
281 potential sites identified and located from the bibliography
5.4 SPATIAL ANALYSIS : SITEFINDER PROCESSING
5.4.1 Objective and method Site Finder is a Python program developed by SHER whose objective is to detect small hydropower potential sites. The software needs a DEM (Digital Elevation Model: a numeric topography model) and the mean annual rainfall map.
Figure 3: Inputs for SiteFinder. Left: Mean annual rainfall map, Right: DEM
The program simulates runoff in the area and deducts river flows. That, combined with the topography layer, allows the program to compute the specific potential (i.e. power potential per unit length) on the whole river path. The process output is a GIS layer highlighting the high potential of the rivers of the covered area. It allows the operator to analyze the results in a convenient way by enabling a cross-check with other GIS data such as topography map, satellite images, etc.
Below is an example on two rivers in Tanzania nearby Mahale Mountain National Park.
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Figure 4 Interesting river stretches found by SiteFinder (SF022 and SF178) nearby Mahale Mountain National Park
A detailed analysis of the SiteFinder process applied in Tanzania is described in Annex 18.2.
5.4.2 Results 351 sites were detected by SiteFinder. From those:
44 sites are located in the middle of protected areas and have therefore been discarded;
6 sites are existing hydropower stations;
36 sites have already been studied and are therefore not repeated in the database;
91 sites have been discarded after the visual 1:50,000 topo-map check.
174 sites, detected by SiteFinder, were finally selected as potential sites
5.5 FINAL SPATIAL DATABASE PRODUCTION
Spatial information related to the hydropower sector in Tanzania is consolidated into a geographical information system (GIS) with the GCS_WGS_1984 coordinates reference system (Datum: D_WGS_1984 ; Prime Meridian: Greenwich ; Angular Unit: Degree).
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The proposed GIS has been designed to meet the compatibility and standards defined in the terms of references in order to make those data easily published on the World Bank GIS platform. Moreover, the Consultant uses the open source GIS software QuantumGIS for the spatial data processing and publication which facilitates its distribution and transfer to the local counterparts during the upcoming training session.
The spatial database will be delivered with international standard format (ESRI shapefiles and geoTIFF images). A Quantum GIS14 project will be set up in order to summarize all the spatial information into a standalone GIS where the symbology will correspond to the maps presented in the HydroAtlas. For illustration purposes, Figure 5 below shows what the GIS database will look like.
Also, a Microsoft Excel file summarizing all the information related to the spatial layers attributes will be delivered. This file will contain all the metadata related to these layers and attributes.
Figure 5. Indicative print screen of the current spatial database in Quantum GIS
Finally, KMZ files (Keyhole Markup Language) presenting the key information will be delivered. That format allows the user to open the files with Google Earth15 and it therefore facilitates the use and distribution of the information amongst less specialized persons.
14 Quantum GIS is a powerfull and open source GIS software. (www.qgis.org). 15 https://www.google.com/earth/
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6 Country-wide resource maps for Small Hydro
Maps presented in 'Annex 8 : Maps' illustrate the following main spatial elements and constitute the backbone of the Small Hydro Altas of Tanzania that will be produced in Phase 3, in the format of a stand-alone report, slide pack, and relevant GIS layers :
Administrative boundaries
Physical context
Socio-economic context
Infrastructure
6.1 ADMINISTRATIVE BOUNDARIES
Tanzania is bordered by Kenya and Uganda to the North; Rwanda, Burundi and the Democratic Republic of Congo to the West; Zambia, Malawi and Mozambique to the South and the Indian Ocean to the East.
Tanzania is divided into 30 regions, 136 districts and 2800 divisions.
6.2 PHYSICAL CONTEXT
6.2.1 Satellite view Landstat image presented in Annex 8 : Maps illustrates the spectral information from the Earth’s surface within the Tanzanian border collected during the wet season (October 4, 2013). Drier areas are clearly identified by brown areas patterns mainly in the extreme Northeastern and central parts of the country. The image also shows that the Northeastern region around the Mount Kilimanjaro is densely forested. Lakes are clearly visible amongst which Lake Nyasa, Lake Victoria (Africa's largest lake), and Lake Tanganyika (Africa's deepest lake) which border the country. Inland lakes which constitute endorheic basins are also visible.
Landsat imagery is used to contribute to resources assessment and to monitor the environmental changes such deforestation, land use change, population growth, etc through the analysis of time series of images.
6.2.2 Topography Topographic data of Tanzania are represented by the Digital Elevation Model (DEM) of illustrated in Annex 8 : Maps. Those data were generated from the NASA’s Shuttle Radar Topography Mission and features a spatial resolution of 3 arc-second (around 93m at the equator).
Tanzania’s topography is characterized by the presence of two branches of the East Africa Rift: the Western Rift Valley which includes amongst others Lake Tanganyika, and the Eastern Rift
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Valley which includes the Mount Kilimanjaro, Africa’s highest peak. Altitude in Tanzania varies from zero on the Indian Ocean coast up to 5,895m at the top of the Mount Kilimanjaro.
Tanzania’s topography features a series of internal drainage basins (endorheic basins) which outlets are the series of endorheic lakes in the Northern part of the country, along the Eastern Rift Valley. Central Tanzania is a large plateau.
The SRTM dataset is particularly relevant for slopes analysis which leads to the analysis of flow directions and accumulation zones, and eventually for watersheds delineation.
6.2.3 Slopes Slopes are calculated from the digital elevation model described in the previous section. The two branches of the East Africa Rift are clearly visible with slopes above 15%. The map also illustrates the presence of large area where slopes are below 5% with a flat topography where hydropower potential is less attractive.
6.2.4 River system Tanzania is divided into nine major basins as illustrated in Annex 8 : Maps:
1) The Wami and Ruvu rivers discharge into the Indian Ocean, north of Dar Es Salaam and form the Wami/Ruvu and associated coast River Basin.
2) The Internal Drainage Basin contains most of the endorheic basins the in the Northern part of the country, along the Eastern Rift Valley.
3) Lake Victoria Basin drains all the rivers that discharge into the Lake Victoria. As a consequence, these rivers are part of the Nile river basin (White Nile sub-basin) ending in the Mediterranean Sea.
4) Lake Tanganyika Basin drains all the rivers that discharge into Lake Tanganyika. This system is part of the Congo River basin which eventually pours into the Atlantic Ocean.
5) Lake Rukwa Basin is an endorheic basin which drains into the inland Lake Rukwa.
6) The Rufiji Basin is the largest river basin of Tanzania and it discharges into the Indian Ocean.
7) The Ruvuma and Southern Rivers Basin is shared with Mozambique and all its constituting rivers discharge into the Indian Ocean.
8) Lake Nyasa Basin drains all the rivers that discharge into Lake Nyasa.
9) The Pangani Basin originates in the mountains of the Arusha region and discharges into the Indian Ocean.
It is worth noting that Tanzania is the only African country whose river system discharge into the three seas/oceans bordering the continent (Mediterranean Sea, Indian Ocean and Atlantic Ocean).
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The watersheds illustrated in Annex 8 : Maps were delineated based on the Digital Elevation Model detailed in section 5.4.
6.2.5 Average annual rainfall (30 arc-seconds (~1 km)) Rainfall data from the climatic database WORLDCLIM16 (version 1.4) have been compiled in our database. These data are available for the whole country on a monthly time scale and a spatial resolution of around 1km.
As illustrated, interannual average rainfall in Tanzania varies considerably depending on the region: the driest areas are located in the extreme North-East along the Kenyan border and the central region South of Dodoma with less than 500mm of rain per year, on average.
6.2.6 Land cover The land cover map of Tanzania is based on 10 years of collection of MODIS imagery, from 2001 to 2010 featuring a spatial resolution of 0.5 km. Most of the country is covered by savanna and grasslands in the central plateau while the two branches of the East Africa Rift are mainly covered by woody savannas.
6.2.7 Protected areas Protected areas are taken from the 2014 United Nations List of Protected Areas, consisting of a compilation of all designated protected areas in the world. According to the database, around 460,129 km² are designated as protected area, which represents 48.5% of the total country area. The database differentiates the protected areas of international and national interest as follow:
Protected areas
International interest Number of sites Area (km²)
Ramsar sites, wetlands of international importance 4 48,684.24
UNESCO-MAB Biosphere Reserves 3 52,281.00
World Heritage Site 4 68,410.93
National interest
Collaborative Fishery Management Area 1 1,914.00
Conservation Area 4 8,786.50
Forest Reserve 496 92,131.57
Forest Reserve and Game Controlled Area 1 1,021.46
Forest Reserve and Game Reserve 2 0
16 http://www.worldclim.org/
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Protected areas
Game Controlled Area 5 4,065.00
Game Reserve 26 92,685.61
Locally Managed Marine Area 1 3.00
Marine Park 2 1,472.00
Marine Reserve 2 28.60
Marine Sanctuary and Forest Reserve 1 1.00
National Park 16 57,105.00
Nature Reserve 6 2,026.28
State Forest Reserve 1 25.25
Village Forest 1 0
Village Forest Reserve 35 1,421.03
Wildlife Management Area 15 28,067.00 Table 10 Protected areas in Tanzania
6.3 SOCIO-ECONOMIC CONTEXT
6.3.1 Population Annex TT presents the population density per district (inhabitant per km²), based on the 2012 census. With a total population of 44,928,923 inhabitants (Census 2012), the density is higher than 1000 inhabitants per square kilometer around the major cities in the following districts: Morogoro Urban, Tunduma, Ilema, Mbeya Urban, Bukoka Urban, Arusha Urban, Maghaibi, Temeke, Nyamagana, Musoma Urban, Kigoma-Ujiji, Moshi Urban, Ilala, Kinondoni, Mjini, Kusini and Chake Chake. On the contrary, there are vast low populated areas corresponding notably to the protected areas.
6.3.2 Mines and industries Mines and industries are key elements that influence power demand. Industries are located around most of the major cities. On the other hand, mines are mostly located in the North of the country. According to the Tanzania Chamber of Minerals and Energy, the following list of minerals have been identified in Tanzania: gold, iron ore, nickel, copper, cobalt, silver, diamond, tanzanite, ruby, garnet, limestone, soda ash, gypsum, salt, phosphate, coal, uranium, gravel, sand and dimension stones.
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6.4 INFRASTRUCTURE
6.4.1 Transportation network According to the Road Act (2007), there are 86,472 km of classified road in Tanzania. The National Road Network consists of 12,786 km of trunk roads (out of which 5,130 km are paved) and 21,105 km of regional roads (amongst which 840 km are paved).
In terms of port, Dar Es Salaam is (with Mombasa in Kenya) one the key player in the in the container sector on the East coast of Africa. The port is connected by rail and road to the main cities across the country.
6.4.2 Power system
6.4.2.1 Transmission and distribution networks The transmission and distribution network of Tanzania are owned and operated by TANESCO.
Overall, the transmission power network consists of 2,732km of 220 kV lines, 1,538km of 132 kV lines and 546km of 66kV lines. On the top of that, transboundary transmission lines exist between Tanzania and Uganda (132kV) and between Tanzania and Zambia (66kV and 33kV) to import power to Tanzania.
Beside the national grid exists a series of isolated centers.
6.4.2.2 Existing thermal power plants Tanzania has a thermal installed capacity of 908.7MW (2013) distributed as follow: 574MW gas-fired (63.2%), 208MW HFO-fired (22.9%), 100MW GO-fired (11%), 19.7 biomass-fired (2.2%) and 7MW IDO-fired (0.7%). The spatial distribution of the major plants is presented in Annex 8 : Maps and shows that most of the thermal power is installed around Dar Es Salaam with a total of 757MW representing 83.3% of the total thermal installed capacity of the country.
6.4.2.3 Existing hydropower plants According to TANESCO, Tanzania has seven major hydropower plants (with an installed capacity greater than 1MW) connected to the national power grid, totalizing 565MW. The largest facility is Kitadu and features an installed capacity of 204MW followed by Kihansi (180MW), Mtera (80MW) and New Pangani Falls (68MW). These hydropower stations are located in the areas characterized by steep slopes and abundant rainfall i.e. along the two branches of the East Africa Rift.
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7 Selection process for the 70+ promising sites
The diagram on the next page shows schematically the study process for the setting up of the database, the selection of 70+ promising SHPP sites and the prioritization of 20 prioritized SHPP sites. It appears that the progress of the study, based on pre-determined criteria, reduce the number of sites and, in parallel, information and knowledge on potential sites increase.
Note also that the selection process is a dynamic and iterative process that goes tapering based on the increase of knowledge on the sites.
As a result of the desk-based work, we have identified :
281 potential sites from the bibliography;
174 potential sites from SiteFinder;
A total of 455 potential sites: which constitute the backbone of the Small Hydro sector development
These potential sites are stored in a single database, both in Excel and Shapefile format.
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Figure 6 Prioritization in the study process
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7.1 STUDY CRITERIA FOR THE SELECTION PROCESS FOR 70+ PROMISING SITES
Substantive work was carried out to establish a portfolio of hydropower projects that meet the objective of the study. Considering the information available in the database of 455 sites, the following criteria were selected:
Sites already studied at an advanced stage Environmental were discarded Sites with criteria : uncertainties concerning out of protected topography were areas discarded
Economical criteria Generation 70+ The sites with a capacity between promising economical 300 kW and 10 MW sites advantage were prefered
Figure 7 Selection criteria
7.1.1 Generation capacity criteria The terms of reference of this study indicate that ‘small hydro’ shall be defined as having a generation capacity of between 1 to 10 MW. Nevertheless, REA expressed its wish to include potential sites under 1 MW in the selected potential sites list for which a site visit is foreseen.
It has consequently been decided to set a minimum of 300 kW under which sites are not included in the selection, which corresponds to a minimal size in terms of investment and technical barrier for electro-mechanical equipment under which a private developer will face problems to recover its investment and/or find quality equipment for a reasonable price (transport cost amongst price of equipment). The database includes 122 sites with a potential lower than 300 kW.
7.1.2 Environmental criteria Tanzania has a tremendous natural and environmental potential. All the potential sites located in protected areas were discarded (National Parks, Nature Reserves, Forest Reserves, Game Reserves, Wildlife Management Areas, Village Forest Reserves World Heritage Sites) to avoid any future environmental barriers in the development of the potential sites.
7.1.3 Uncertainties concerning topographical criteria 37 sites, with potential above 300 kW and under 10 MW, were discarded after the visual 1:50,000 topo-map check. The main findings are lack (or absence) of head or watershed much smaller than expected or described in the previous studies and/or lists of sites.
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7.1.4 36 sites studied at an advanced stage An advance study stage is considered here as a study giving at least a basic layout for the site, referenced by drawings or a sketch on a map, with accurate head and hydrological information, and visited on the field.
Because we already possess all the sub-mentioned information, a single site visit would not be of any use. Those sites are thus not considered for phase 1 - step 2 (single site visit). They will however be considered again for phase 2: hydrological monitoring, since some of them are considered as very interesting but suffer from lack of consistent hydrological data.
The concerned studies and sites are:
SECSD (Malagarasi (Kigoma), Muhuwesi (Ruvuma-Tunduru), Kikuletwa (Kilimanjaro)
Norconsult:
. Pinyinyi (see Tanzania Rural Electrification Study, Hydropower Sub-Project 1.5 Lower Pinyinyi Hydropower Plant, Sweco, 2005a),
. Nzowve (see Tanzania Rural Electrification Study, Hydropower Sub-Project 4.2 Nzowve Hydropower Plant, Sweco, 2005c),
. Mtambo (see the unfounded Pre-investment report on mini hydropower development. Case study on the Mtambo River, SECSD, 2000).,
. Kwitanda (see Pre-investment report on mini hydropower development. Case study onthe Muhuwesi River, SECSD, 1999. Tanzania Rural Electrification Study, Hydropower Sub-Project 7.2 Sunda Falls Hydropower Plant.)
Sweco ( Nzovwe - Malagarasi - Lower Pininyi - Upper Pininyi - Nakatuta - Sunda Falls)
Intec Entec Skat (Darakuta - Ihalula - Lingatunda - Luswisi - Mlangali - Mwoga)
Enco (Zigi - Nkole)
IED (only those that were visited on site)
SNC Lavalin (Rusumo Falls)
36 sites have been previously studied at an advanced stage and are therefore discarded from the list of promising sites. In a near future, it would be interesting, for the GoT to undertake a study to
7.1.5 Economical criteria Two different tariffs are applied depending if the electricity is sold to the Main Grid or to a minigrid-grid where there is a possible substitution of costly thermal energy. The standardized small power projects tariffs for years 2011 and 2012 are:
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2011 Tariff 2012 Tariff Description Increase TZS/kWh US$/kWh17 TZS/kWh US$/kWh18
Main grid connection tariff
Standarized SPP Tariff 121.13 0.08 152.54 0.10 26 % Dry season Seasonally 145.36 0.09 183.05 0.12 26 % (August to November) adjusted SPPT Wet season Payable in 109.02 0.07 137.29 0.09 26 % (December to July) Mini grid connection tariff
Standarized SPP Tariff 380.22 0.24 480.50 0.31 27 % Table 11 EWURA standardized small power projects tariffs for years 2011 and 2012
The tariff is approximately 3 times better for the mini-grid/micro-grid connection. As private investment and worthwhile investment are promoted throughout this study, sites selection is then focused on mini grid developments, which are better remunerated.
As outlined in the SREP-Investment Plan for Tanzania, 20 townships in other regions served by TANESCO depend on isolated diesel (18) and natural gas (2) generators and imports. In addition, there is an estimated 300 MW of private diesel generation not connected to the TANESCO grid whose fuel cost is expected to exceed 0.35 US$/kWh, to be compared to the leveled electricity cost for small hydropower at 0.23 US$/kWh19.
Moreover, new TANESCO tariffs have been approved for 2014 and 2015 with increases of:
Existing tariff Approved tariff Increase Customers Category Component Unit 2013 2014 2015 2013-2014 Service Charge [TZS/month] - - - - Low usage tariff for Energy charge (0-75 kWh) [TZS/kWh] 60 100 100 67% Domestic customers Above 75 kWh [TZS/kWh] 273 350 350 28% Service Charge [TZS/month] 3841 5520 5520 44% General usage tariff Energy charge [TZS/kWh] 221 306 306 38% Customers with average Service Charge [TZS/month] 14233 14233 14233 0% consumption above 7,500 kWh per year Energy charge [TZS/kWh] 132 205 205 55% Service Charge [TZS/month] 14233 16769 16769 18% Connected to MV Energy charge [TZS/kWh] 118 163 163 38% Service Charge [TZS/month] 14233 - - -100% Connected to HV Energy charge [TZS/kWh] 106 159 159 50%
It has been therefore decided to prefer the sites located close to a Minigrid or in a pure off- grid location to supply an isolated load centre. The sites located outside a buffer of 15 km of the planned MV grid were discarded. Some exceptions exist when their potential is interesting only to supply a large demand or when located just beyond the 15 km.
17 Average exchange rate for 2011 : 1US$ = 1562 TZS (source : OANDA) 18 Average exchange rate for 2012: 1US$ = 1561 TZS (source : OANDA) 19 Source : SREP - Investment plan for Tanzania
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7.1.6 Results of the 70+ promising sites selection As shown in the table below, the portfolio of the 75 promising small hydropower sites features a total firm power capacity of 41.4MW with a secured (95% of the time) expected annual energy generation of 365.3GWh (firm energy). The total installed capacity of the 75 sites sums up to 394.8MW should the sites be equipped with a design flow corresponding to the long- term annual average (Q50%). With the latter scenario the expected annual generation would reach up to 2358.2 GWh. The breakdown per region and per water basin of the number of sites, firm power and energy and installed capacity are presented in the tables below.
Firm Energy Number Firm power Power @Q Region 50% energy @Q of sites (MW) (MW) 50% (GWh/y) (GWh/y) Arusha 1 1.2 15.6 10.1 99.2 Dar Es Salaam 0 - - - - Dodoma 5 2.2 46.5 20.5 226.1 Geita 0 - - - - Iringa 8 4.3 34.7 37.5 275.9 Kagera 5 0.1 2.6 1.3 7.1 Kaskazini- 0 - - - - Pemba Kaskazini- 0 - - - - Uguja Katavi 1 0.0 0.8 0.0 4.4 Kigoma 4 11.4 27.6 99.8 205.8 Kilimanjaro 0 - - - - Kusini- 0 - - - - Pemba Lindi 3 2.6 4.3 22.5 36.0 Manyara 0 - - - - Mara 2 2.0 27.0 17.5 171.9 Mbeya 2 1.2 38.1 10.6 286.8 Morogoro 0 - - - - Mtwara 1 0.0 3.5 0.4 20.8 Mwanza 0 - - - - Njombe 4 7.9 41.8 69.5 285.7 Pwani 1 0.8 11.2 7.3 87.1 Rukwa 16 1.5 73.7 12.9 282.8 Ruvuma 16 4.2 25.4 36.5 170.9 Shinyanga 0 - - - - Simiyu 0 - - - - Singida 4 1.6 40.2 14.6 166.8
Tabora Tanga 2 0.5 2.1 4.3 30.9 Zanzibar South 0 - - - - and Central Zanzibar West 0 - - - - Grand Total 75 41.4 394.8 365.3 2358.2 Table 12 Regional breakdown of the installed capacity and energy produced by the 70+ potential sites
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Firm Energy Number Firm power Power @Q Water basin 50% energy @Q of sites (MW) (MW) 50% (GWh/y) (GWh/y) Kagera and Lake Victoria 7 2.1 29.6 18.8 178.9 Lake Nyasa 16 11.9 63.9 103.8 436.1 Lake Rukwa 13 2.2 98.2 19.0 486.3 Malagarasi and Lake 10 11.9 41.9 104.3 293.5 Tanganyika Northern Lakes 8 4.5 99.2 42.2 468.0 Pangani and Northern 2 0.5 2.1 4.3 30.9 Indian Ocean Coast Rufiji 10 4.6 37.8 40.6 300.0 Ruvuma and Southern 8 2.9 11.1 25.1 77.3 Indian Ocean Coast Wami, Ruvu and Central 1 0.8 11.2 7.3 87.1 Indian Ocean Coast Grand Total 75 41.4 394.8 365.3 2358.2 Table 13 Water basin breakdown of the installed capacity and energy produced by the 70+ potential sites
Not surprisingly, it appears that 42% of the sites are located in the Rukwa and Ruvuma regions (both regions having 16 promising hydropower sites), characterized by steep slopes and interesting rainfall throughout the year. Ten (10) regions does not feature any potential hydropower sites responding to the scope of this study due to their less attractive hydropower potential due to the combination of the following parameters: unfavorable topography (lack of head), low flow season characterized long zero flow periods, extreme solid transport in the river (sedimentation issues), inadequate power supply/demand balance, high production costs.
In terms of water basins, the Northern Lakes basins counts 8 sites featuring a total installed capacity of 99.2MW, followed by the Lake Rukwa basin and Lake Rukwa basin featuring 98.2MW and 63.9MW respectively.
The 75 potential hydropower sites cover a wide range of scheme types with gross head varying from a few meters up to 800m for the SF-206 site located on the Chulu River in the Rukwa region. The statistical distribution of gross head amongst the 75 sites is illustrated in Figure 8. It shows that 19% of the sites have a gross head greater than 200m, 43% greater than 100m and 36% lower than 50m.
Figure 10 shows that 23% of the sites (17 sites) features an installed capacity greater than 10MW with a maximum of 26MW for the site SF-029 on the Ruhuhu River. 29% of the sites (22 sites) have an installed capacity above 5MW and 35% (26 sites) have an installed capacity below 1MW.
In terms of firm energy generation, 23% of the sites (17 sites) have an expected firm annual generation above 5GWh, as illustrated in Figure 10.
The location of the 75 promising potential hydropower sites is presented in Figure 11.
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Figure 8. Distribution of gross head amongst the 70+ promising sites.
Figure 9. Distribution of the installed capacity amongst the 70+ promising sites.
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Figure 10. Distribution of the firm energy amongst the 70+ promising sites.
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Figure 11. Location map of the 70+ promising sites SHER s.a. in association with Mhylab Small Hydro mapping report - April 2015 Page 75 of 181 Small Hydro Tanzania REA / The World Bank Contract n°7169139 - Selection process for the 70+ promising sites -
Table 14. Key information related to the 70+ promising hydropower sites
COORDINATES GROSS FIRM @ Q50% SITE REGION WATERSHED CHARACTERISTICS LAT LON HEAD POWER ENERGY POWER ENERGY CODE NAME (DD) (DD) MAJOR WATER BASIN RIVER AREA (km²) (m) (kW) (GWh/y) (kW) (GWh/y) M-070 Momba II 32.376 -8.792 Mbeya Lake Rukwa Momba 4978 355 441 3.9 21700 161.8 M-110 Kitewaka 34.837 -10.352 Njombe Lake Nyasa Kitewaka 2461 54 3958 34.7 14960 106.0 M-113 Kyamato 31.809 -1.222 Kagera Kagera and Lake Victoria Kyamato 11 50 4 0.0 30 0.2 M-118 Achesherero 31.159 -1.663 Kagera Kagera and Lake Victoria Achesherero 55 90 27 0.2 200 1.3 M-119 Lubare 31.167 -1.739 Kagera Kagera and Lake Victoria Lubare 18 125 12 0.1 20 0.2 M-121A Kitogota I 31.601 -1.693 Kagera Kagera and Lake Victoria Kitogota 104 100 74 0.7 2180 4.3 M-121B Kitogota Falls 31.621 -1.671 Kagera Kagera and Lake Victoria Kitogota 118 25 23 0.2 160 1.1 M-127 Ruhuhu 34.805 -10.448 Ruvuma Lake Nyasa Ruhuhu 14582 15 1905 16.7 13120 87.7 Ruvuma and Southern M-221 Mambi 39.573 -10.409 Lindi Mambi 1481 152 2348 20.6 3560 30.4 Indian Ocean Coast M-267A Ngongi I 34.932 -11.191 Ruvuma Lake Nyasa Ngongi 52 110 55 0.5 310 2.1 M-267B Ngongi II 34.919 -11.217 Ruvuma Lake Nyasa Ngongi 84 290 232 2.0 1310 8.9 M-268A Luwika I 34.820 -11.095 Ruvuma Lake Nyasa Luwika/lualala 72 75 50 0.4 290 2.0 M-268B Luwika II 34.809 -11.104 Ruvuma Lake Nyasa Luwika/lualala 78 750 535 4.7 3030 20.6 M-277 Luika 34.553 -10.066 Njombe Lake Nyasa Luika 63 58 54 0.5 200 1.4 M-288 Kelolilo 34.708 -10.102 Njombe Lake Nyasa Kelolilo 104 69 109 1.0 400 2.9 M-295 Myombezi 35.383 -9.806 Ruvuma Lake Nyasa Myombezi 36 111 73 0.6 100 0.9 M-297 Lipumba 35.012 -10.825 Ruvuma Lake Nyasa Mngaka 350 4 13 0.1 70 0.5 Litembo M-298B 34.830 -10.975 Ruvuma Lake Nyasa Ndumbi 34 25 8 0.1 50 0.1 Extension M-299 Luaita 34.979 -10.963 Ruvuma Lake Nyasa Luaita 54 70 35 0.3 200 1.4 Ruvuma and Southern M-301 Lukarasi shp 35.097 -10.782 Ruvuma Mkurusi 30 27 7 0.1 40 0.3 Indian Ocean Coast M-355A Mgaka I 35.031 -10.712 Ruvuma Lake Nyasa Mgaka 520 30 299 2.6 1300 9.1 M-355B Mgaka II 35.019 -10.652 Ruvuma Lake Nyasa Mgaka 651 35 436 3.8 1900 13.3 Malagarasi and Lake N-002 Kawa 31.211 -8.489 Rukwa Kawa 170 260 48 0.4 130 1.1 Tanganyika
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COORDINATES GROSS FIRM @ Q50% SITE REGION WATERSHED CHARACTERISTICS LAT LON HEAD POWER ENERGY POWER ENERGY CODE NAME (DD) (DD) MAJOR WATER BASIN RIVER AREA (km²) (m) (kW) (GWh/y) (kW) (GWh/y) Ruvuma and Southern N-010 Kitandazi II 35.079 -11.019 Ruvuma Mbinga 180 35 58 0.5 330 2.3 Indian Ocean Coast Ruvuma and Southern N-011 Kingilikiti 34.971 -11.179 Ruvuma Lumeme 115 28 30 0.3 170 1.2 Indian Ocean Coast SF-017 Momba I 31.954 -8.759 Rukwa Lake Rukwa Momba 2683 64 182 1.6 5860 35.7 Malagarasi and Lake SF-018 Kalambo Falls 31.240 -8.596 Rukwa Kalambo 3193 200 315 2.8 10360 63.1 Tanganyika Malagarasi and Lake SF-019 Lwazi 31.073 -8.278 Rukwa Lwazi 505 120 65 0.6 2100 12.8 Tanganyika SF-020 Mfizi II 31.110 -7.187 Rukwa Lake Rukwa Mfizi 2505 150 21 0.2 3040 17.6 Malagarasi and Lake SF-022 Luegere 30.029 -5.895 Kigoma Luegere 1320 159 9037 79.2 19010 145.4 Tanganyika SF-029 Lupapilo 34.759 -10.489 Njombe Lake Nyasa Ruhuhu 14618 30 3810 33.4 26230 175.5 Pangani and Northern SF-041 Kivumilo 38.869 -4.512 Tanga Umba 5490 9 289 2.5 1640 13.3 Indian Ocean Coast SF-052A Mara I 34.659 -1.560 Mara Kagera and Lake Victoria Mara 10076 25 712 6.2 9630 61.4 SF-052B Mara II 34.642 -1.588 Mara Kagera and Lake Victoria Mara 10076 45 1283 11.2 17340 110.5 SF-056 Manique 35.819 -2.535 Arusha Northern Lakes Manique 1289 350 1153 10.1 15570 99.2 SF-067 Mponde II 35.230 -5.535 Dodoma Northern Lakes Mponde 1913 95 301 2.6 4060 31.6 SF-068 Luwila 35.023 -5.616 Singida Northern Lakes Luwila 2176 120 328 3.5 21750 34.7 SF-069 Maparengi 35.038 -5.743 Singida Northern Lakes Maparengi 3111 150 781 6.8 10560 82.1 SF-080A Sasimo I 36.505 -7.218 Dodoma Rufiji Sasimo 514 60 123 1.1 1070 8.5 SF-080B Sasimo II 36.508 -7.230 Dodoma Rufiji Sasimo 514 110 225 2.0 1970 15.6 SF-082 Lukosi 36.192 -7.728 Iringa Rufiji Lukosi 1521 176 1976 17.3 11210 91.1 SF-083 Mlowa 36.172 -7.665 Iringa Rufiji Mlowa 694 117 477 4.2 2710 22.0 SF-091 Bubu II 35.490 -5.387 Dodoma Northern Lakes Bubu 7601 90 1290 11.3 17430 135.5 SF-092 Bubu I 35.497 -5.372 Dodoma Northern Lakes Bubu 7566 35 214 3.6 21970 35.0 SF-107 Ndembela I 34.980 -8.232 Iringa Rufiji Ndembela 1641 100 609 5.3 6740 52.8 SF-108 Ndembela II 34.913 -8.245 Iringa Rufiji Ndembela 1794 105 698 6.1 7720 60.5 SF-109 Lyandembela I 35.108 -8.292 Iringa Rufiji Lyandembela 1375 33 169 1.5 1860 14.6
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COORDINATES GROSS FIRM @ Q50% SITE REGION WATERSHED CHARACTERISTICS LAT LON HEAD POWER ENERGY POWER ENERGY CODE NAME (DD) (DD) MAJOR WATER BASIN RIVER AREA (km²) (m) (kW) (GWh/y) (kW) (GWh/y) Ruvuma and Southern SF-123 Mchakama 39.265 -9.106 Lindi Mavuji 3002 5 118 1.0 190 1.6 Indian Ocean Coast Wami, Ruvu and Central SF-143 Wami 38.377 -6.241 Pwani Wami 39982 8 829 7.3 11210 87.1 Indian Ocean Coast Pangani and Northern SF-145 Mkalamo 38.642 -5.790 Tanga Msangazi 3827 20 204 1.8 420 17.6 Indian Ocean Coast SF-153 Ndurumo 34.633 -4.383 Singida Northern Lakes Ndurumo 2524 85 449 3.9 6080 47.2 Malagarasi and Lake SF-172 Ruchugi 30.421 -5.022 Kigoma Ruchugi 2816 13 295 2.6 1680 11.4 Tanganyika Malagarasi and Lake SF-178 Mgambazi 29.994 -5.828 Kigoma Mgambazi 618 90 1363 11.9 2870 21.9 Tanganyika Malagarasi and Lake SF-187 Muyovozi 30.993 -3.196 Kigoma Muyovozi 2484 40 702 6.2 3990 27.1 Tanganyika SF-189 Lupa 33.214 -8.655 Mbeya Lake Rukwa Lupa 5886 82 764 6.7 16360 125.0 SF-206 Chulu 31.449 -7.596 Rukwa Lake Rukwa Chulu 91 800 84 0.7 2240 13.8 SF-207 Kilida 31.348 -7.447 Rukwa Lake Rukwa Kilida 98 500 61 0.5 1530 9.4 SF-208 Mfizi I 31.075 -7.235 Rukwa Lake Rukwa Mfizi 2382 40 5 0.0 770 4.5 SF-211 Lwiche 31.576 -7.765 Rukwa Lake Rukwa Lwiche 832 519 241 2.2 24240 44.8 SF-212 Muze 31.515 -7.723 Rukwa Lake Rukwa Muze 305 420 158 1.4 4060 25.0 SF-213 Nyembe 32.014 -8.326 Rukwa Lake Rukwa Nyembe 178 684 114 1.0 14760 27.2 Malagarasi and Lake SF-214A Kalambo I 31.430 -8.291 Rukwa Kalambo 1305 20 26 0.2 840 5.1 Tanganyika Malagarasi and Lake SF-214B Kalambo II 31.423 -8.298 Rukwa Kalambo 1318 20 26 0.2 850 5.2 Tanganyika SF-217 Samvya 31.820 -8.434 Rukwa Lake Rukwa Samvya 565 85 49 0.4 1570 9.6 SF-219 Kianda 32.136 -8.526 Rukwa Lake Rukwa Kianda 60 700 39 0.3 1270 7.7 Ruvuma and Southern SF-266 Muhuwezi 36.945 -10.702 Ruvuma Muhuwezi 630 105 149 1.3 2680 16.8 Indian Ocean Coast Ruvuma and Southern SF-271 Mihima 39.157 -10.278 Lindi Mihima/namangale 129 104 104 0.9 590 4.0 Indian Ocean Coast Ruvuma and Southern SF-277 Mbagala 38.715 -11.049 Mtwara Mbagala 3323 40 46 0.4 3530 20.8 Indian Ocean Coast SF-278 Mfizi III 31.124 -7.154 Katavi Lake Rukwa Mfizi 3108 30 5 0.0 760 4.4 SHER s.a. in association with Mhylab Small Hydro mapping report - April 2015 Page 78 of 181 Small Hydro Tanzania REA / The World Bank Contract n°7169139 - Selection process for the 70+ promising sites -
COORDINATES GROSS FIRM @ Q50% SITE REGION WATERSHED CHARACTERISTICS LAT LON HEAD POWER ENERGY POWER ENERGY CODE NAME (DD) (DD) MAJOR WATER BASIN RIVER AREA (km²) (m) (kW) (GWh/y) (kW) (GWh/y) SF-289 Lyandembela II 35.163 -8.265 Iringa Rufiji Lyandembela 1214 33 149 1.3 1650 12.9 SF-294 Kigogo 35.243 -8.682 Iringa Rufiji Kigogo 56 562 141 1.2 1930 15.0 SF-296 Vambanungwi 35.054 -8.763 Iringa Rufiji Vambanungwi 160 110 66 0.6 890 6.9 SF-305 Mponde I 35.137 -5.404 Singida Northern Lakes Mponde 1547 16 15 0.3 1780 2.8 Malagarasi and Lake SF-343 Samba 30.836 -7.457 Rukwa Samba 336 92 24 0.2 60 0.5 Tanganyika SF-UN Mbawa 34.757 -11.025 Ruvuma Lake Nyasa Mbawa 90 350 281 2.5 450 3.9
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7.2 ORGANISATION OF VISITS FOR THE 70+ PROMISING SITES
Following the selection process, with a better appreciation of the site field visits allowed to meet the diverse data needed to assess the hydropower potential of the different sites and to determine their preliminary cost.
Visits took place between March 2014 and late May 2014, a period of 3 months for the first set of 50+ sites and between October 2014 and January 2015 for the second set of 20 sites visit.
The data for each site can be classified into primary data (measured on site) and secondary data (derived from the primary data).
Six (6) categories of data can be defined:
The Administrative data, allowing to validate the site name (or void if any);
The Point data, obtained using a GPS / altimeter, set by their three-dimensional coordinates (longitude, latitude, altitude);
The Vector data deduced from point data type and enabling the obtaining of different linear structures;
The Measured data performed on site using a decametre for length measurements, a turbidity meter for turbidity measurements, or a flow meter for flow measurements;
The Appreciation data to textually describe particular elements at that site;
Photos, giving a better perception of the site visited player. The photos are georeferenced and oriented.
The table below summarizes the different data collected by type. The material means used to collect these data and the class to which these data are also specified.
Class Data type Collected data Material or tool 1aire 2aire Administrative River name Questioning the locals Name of the nearest village to the site Questioning the locals Point along the river GPS / altimeter at the intake site GPS / altimeter at the surge chamber site GPS / altimeter At the power house site GPS / altimeter At any point remark identified on the site (head, GPS / altimeter tributary, bridge, ford ...) . Vector The trace made during the site visit GPS / altimeter Channel or tunnel Programme GIS Penstock Programme GIS The power line to create Programme GIS Access road to create Programme GIS The section of road to be rehabilitated to allow GPS / altimeter
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Class Data type Collected data Material or tool 1aire 2aire access to the site Measurement Width of the floodplain of the river Measuring tape Estimated width of the dam Measuring tape Estimated height of the dam Topographic map Turbidity Turbidity measurement Flow Flow measurement Slope of the sides of the valley Topographic map Original waterfall GPS / altimeter Appreciation General description of the planned scheme Observation Shape of the valley Observation Type of the envisaged dam Observation Type of the envisaged development Observation Type of the envisaged connection Observation Network to which the project will be connected Programme GIS General geology of the site Observation Availability of raw materials near the site Observation Sediment transport Observation Potential impact of development Observation and discussion with the locals Accessibility to the site Observation Existing infrastructures Observation and discussion with the locals Future infrastructures Observation and discussion with the locals Photos
7.3 EXISTING SITES VISITED
In addition to the potential sites visit, the team of experts have also visited 11 existing sites. The information about these sites has been synthesized in a "Site visit report - existing sites".
E Code Name River Region Type Connexion H [m] Q [m³/s] P [kW] BV [km²] [GWh/y) Luhira and Connected to E-001 Peramiho - Likingo Ruvuma Run of the river 43,3 2,6 940 6,4 422,22 Mkingazi a mini-grid E-002 Lupilo Ruvuma Ruvuma Daily reservoir Off-grid 8 11,4 620 1,31 1662,6
E-003 Kitai Likoyu Ruvuma Run of the river Off-grid 9,5 0,1 8 0,07 60,47 Connected to E-004 Kitandazi I Mbinga Ruvuma Run of the river 36 1,1 330 2,28 176,24 a mini-grid E-005 Maguu Unknown Ruvuma Daily reservoir Off-grid 7,5 0,072 4 0,01 9,99
M-266 Lumeme Lumeme Ruvuma Run of the river Off-grid 26 0,2 40 0,35 105,62
M-298A Litembo Existing Ndumbi Ruvuma Run of the river Off-grid 12 0,062 6 0,05 33,82 Connected to M-348 Ndanda Ndanda Mtwara Daily reservoir 170 0,2 310 0,5 12,84 the main grid
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E Code Name River Region Type Connexion H [m] Q [m³/s] P [kW] BV [km²] [GWh/y) N-001 Lundomato Mission Mhusi Ruvuma Run of the river Off-grid 10 0,016 1 0,01 18,81
N-003 Kindimba Existing Mangaka Ruvuma Run of the river Off-grid 25 0,039 8 0,07 21,4
SF-030 Masigira Ruhuhu Iringa Run of the river Off-grid 30 15,8 3.920 33,57 1997,03 Table 15 Data of existing sites visited
Some proposals of improvement have been described in the report.
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8 Hydrological study for the 70+ promising sites
8.1 OBJECTIVES AND LIMITATIONS OF THE HYDROLOGICAL STUDY
The main objective of the hydrological study is to assess the key statistical characteristics of the hydrological time series at the selected potential hydropower sites locations.
These statistical characteristics have a major role for the estimation of the technical and economic parameters of the potential hydropower schemes as well as for their development planning and connection type.
For the vast majority of the potential hydropower sites of interest in the context of this study, only little reliable hydrological information exists at the sites location. Hence, we have developed and applied a specific methodology to estimate the key statistical characteristics of the hydrological time series at ungauged locations. This methodology relies on the information (flow gauging stations and rainfall gauges) available within the watersheds or located in watersheds that can be considered as similar from a hydrology point of view. This methodology, the available data and the key results are described in the following sections.
The spatial and temporal resolution of the information available for the rivers of interest in the context of this study and the related methodology applied constraints the accuracy of the results. Indeed, the estimated statistical characteristics of the hydrological time series at the sites of interests are indicative only and cannot be used for detailed design purposes without further hydrological measurements and analysis.
8.2 HYDRO-METEOROLOGICAL DATABASE
8.2.1 Data sources The data collection process has started with the information available at the Water Basins level. Tanzania is divided into nine water basins as follow: Wami/Ruvu, Internal Drainage Basin, Lake Victoria Basin, Lake Tanaganyika Basin, Lake Rukwa Basin, Rufiji Basin, Ruvuma & Southern Rivers, Lake Nyasa Basin and Pangani Basin.
Information has been collected from three of those nine water basins: (i) Pangani Water Basin, (ii) Rufiji Water Basin and (iii) Lake Nyasa Water Basin.
In addition to the data collected in the Water Basin Agencies, data from the Global Runoff Data Centre (GRDC) have been received. The GRDC is an international database (with data up to 200 years old) that fosters multinational and global long-term hydrological studies (www.bafg.de). The data archived by the GRDC come from official monitoring networks. As a consequence, for the Pangani, Rufiji and Lake Nyasa water basins, most of the data received from the GRDC were the same that those received from the water basins agencies. GRDC database also covers the six other water basins for which we have not received information from the national level focal point. Unfortunately, the data archived by the GRDC are often quite old.
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Regarding the rainfall data, the SIEREM (Système d’Information Environnementale sur les Ressources en Eau et leur Modélisation) website (www.hydrosciences.fr/sierem/) gives a good and comprehensive overview of the existing rainfall gauges for the whole country. The website gives an inventory of the existing rainfall gauges but not the measured data themselves. For Tanzania, the SIEREM indicates the existence of 2,156 rainfall gauges across the country.
Finally, we completed our data collection with information available in the literature amongst which regional studies like the Ruhudji Hydropower Project Design Hydrology Report.
The data collected during the inception phase, as well as its key characteristics are summarized in Table 16 below. These data were received in various formats such as Microsoft Excel files, Microsoft Access database, text files, etc.
Streamflow data Rainfall data Concerned Number of Number of Number of Number of Date area Timestep identified station Timestep identified station source stations with data stations with data
Pangani Pangani Daily 47 8 - 27 0 Water water basin Basin
Rufiji Rufiji Water Daily 19 19 Daily 11 11 Water Basin Basin
Lake Nyasa Lake Nyasa Water Daily 24 11 Daily 12 12 Water Basin Basin
GRDC Daily 97 89 - - - Tanzania
SIEREM - - - - - Tanzania
Tanzanie Kagera Daily 36 9 Daily 176 176 Kagera basin
Ruhudji Ruhudki Daily 4 4 Monthly 18 18 hydrology Basin
Table 16 Collected data and their key characteristics
8.2.2 Database consolidation
8.2.2.1 Data compilation There are obviously numbers of duplicates among the information coming from the various sources. There are also many stations without available data. And finally, there are a numbers of stations for which the accurate location (geographical coordinates) is unknown or unclear.
A considerable effort has been made to constitute a collection of unique and properly located hydrological and meteorological stations with their associated data. This work was carried out using the following steps (for both the hydrological and meteorological stations):
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1. Identification and deletion of the stations without data;
2. Identification and merging of the duplicated stations (and associated data) coming from the various sources of information;
3. Validation of the stations location:
o If the station has geographical coordinates, validation on maps and satellite imagery;
o If the station does not have any geographical coordinates, we tried to locate it by using the metadata associated with the station (name of the river, name of the city in the neighborhood of the station). This thorough effort was carried out using the topographical maps of Tanzania, the DEM and Google Earth imagery. If the location process was unsuccessful, the station was excluded from the database.
The aforementioned process is illustrated in the flow chart below (Figure 12).
Figure 12. Dataset selection process: flow chart
The compilation process resulted in two datasets:
The hydrological dataset with 664,470 daily streamflow data from 100 different flow gauging stations. This figure of 100 is lower than the 203 stations previously mentioned in the inception report because of the large number of duplicates and the number of stations without enough data to be considered.
The meteorological dataset with 965,598 daily rainfall measurements and 23,426 monthly rainfall data coming from 243 different stations.
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The table below (Table 17) shows the breakdown of rainfall and hydrological stations for which data are available within the nine water basins. Figure 13 illustrates the spatial distribution of the hydrological stations and rainfall gauges in Tanzania.
Figure 13. Spatial distribution of the hydrological and rainfall stations in Tanzania
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Hydrological station Meteorological station Area Number of stations Average Number of stations Average Water basin with data density with data density [km²] [-] [km²/station] [-] [km²/station] Internal Drainage Basin 146 289 4 36 572 15 9 753 Lake Nyasa Basin 27 654 14 1 975 25 1 106 Lake Rukwa Basin 77 707 9 8 634 1 77 707 Lake Tanganyika Basin 161 203 4 40 301 17 9 483 Lake Victoria Basin 119 968 9 13 330 144 833 Pangani Basin 54 748 12 4 562 0 / Rufiji Basin 179 745 29 6 198 32 5 617 Ruvuma & Southern Rivers 106 153 5 21 231 8 13 269 Wami/Ruvu and associated 67 138 14 4 796 1 67 138 Coast Rivers Total 940 605 100 9 406 243 3 871 Table 17. Breakdown of the hydrological and rainfall stations within the nine water basins.
To facilitate the processing of this large amount of data, the data were stored in a geodatabase (standard database with geographical capabilities).
The geodatabase not only stores the rainfall and flow measurements, but also the hydrological and rainfall stations, their characteristics, their location and other geographical information useful for hydrological analysis (river networks, natural catchments and catchments associated to the hydrological stations, etc). This approach provides the flexibility to query data with spatial criteria using any GIS software or other criteria in MS Access (or other database management packages).
8.2.2.2 Watersheds delineation Given the size of the country and the large number of hydrological stations and potential hydropower sites, the watersheds delineation process has been done using ArcHydro from the ESRI’s ArcGIS software. The process involves the following steps:
The Digital Elevation Model (DEM) is modified, where necessary, by interpolation in order to fill any areas that contain no value and to eliminate possible imperfections in the DEM (pour points);
Calculation of the flow direction for each cells of the DEM corresponding to the direction of the strongest gradient between adjacent cells;
Calculation of the flow accumulation grid (the value associated to each cell of the grid corresponds to the number of cells located upstream of this cell);
Stream definition based on the flow accumulation layer;
Watersheds delineation.
The results of this spatial analysis are GIS layers (shapefiles and rasters) with the hydrographic network and the corresponding catchments.
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The surface hydrological network determined by the aforementioned process is illustrated in the Figure 14 below.
Figure 14. Hydrological network calculated from the DEM
Tanzania’s topography features a series of internal drainage basins (endorheic basins) which outlets are the series of endorheic lakes in the Northern part of the country, along the Eastern Rift Valley. Internal drainage basins must be processed semi-manually because they are not properly managed by the watershed delineation algorithm and could otherwise lead to errors in the delineation of the other watersheds. The position of the internal drainage basins is shown in Figure 15 below.
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Figure 15 Location of the internal drainage basins of Tanzania
Number Name 1 Lake Jipe 2 Lake Ambussel 3 Lake Balangida 4 Lake Mikuya 5 Lake Mikuya 6 Lake near Endesh 7 Lake Balangida Lehu 8 Lake Natron 9 Sink with no lake 10 Lake Manyara 11 Lake Eyasi 12 Lake Burungi 13 Bahi Swamp 14 Lake Rukwa 15 Unknown 16 Lake Madagi (Ngorongoro Crater) 17 Masai Steppe Table 18 Internal drainage basins and associated lakes of Tanzania
The figures below present some of the lakes associated with an internal drainage basin. Blue and light colors show low elevation values while dark colors show higher elevation value. Hence lakes and depressions are represented by blue or light shapes.
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Figure 16 Lake Rukwa and Lake Eyasi
Figure 17 Lake Jipe, unknown lake and Bahi Swamp
Figure 18 Lake Ambussel, a sink without lake on North-West of Ngorongoro Crater Area, and another south of Mbeya
Figure 19 Lake Manyara and lake Burungi (2 on the same picture), lake Natron, and Lake Madagi in Ngorongoro Crater
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Figure 20. Determination of the country's hydrographic network : Lake Balangida and neighborghing lakes (3), south of Ngorongoro
The last step of the delineation process consists in a visual check of the calculated watershed using topographical maps.
The watersheds associated to the flow gauging stations are illustrated in Figure 21 below. The area covered by the verified, available and usable gauged catchments represents 37% (344,779 km²) of the total country area. Also, 28 of the 53 potential hydropower sites are located in a gauged catchment.
Finally, it should be noted that some of the hydrological stations have approximate locations (we did not receive their exact location). As a consequence, the delineation of their associated catchment is also approximate. An update will be required should we get the exact location of these hydrological stations.
It is important to note that the accuracy of the river network identification depends on the elevation contrasts and the DEM’s cells size. The delineation process will be less accurate in flat areas than in mountainous regions. Also, a DEM featuring large cells could artificially hide some steep-sided valleys.
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Figure 21. Calculated watersheds associated with the flow gauging stations
8.2.2.3 Data quality assessment Quality data are necessary to produce meaningful and reliable information on the hydrological regime (historical and future) of rivers at a specific location. Exploitable time series of hydrological data have the following important characteristics:
it covers a long period;
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it covers a recent period. This is very important for assessing the potential existence of trends, especially in a context of possible climate change;
it has a high degree of completeness (few missing data).
Figure 22 shows the lengths of the daily streamflow time series associated with the hydrological gauging stations. Just over 50% of the hydrological stations have at least 20 years of recorded data and only 23 stations have measured data for the years after 1990 and 13 until 2010.
The hydrological stations are characterized by various degree of completeness. Hence, we suggest keeping for each station the daily data for the years that have no more than 5% of missing data. Beyond this threshold, we can consider that the results of the statistical analysis will be influenced by the missing data. Figure 23 shows the number of “exploitable” years (years with less than 5 % of missing data) compared to the total length of the time series for each hydrological station.
Figure 22. Period of activity of the hydrological stations
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Figure 23. Number of "exploitable" years in relation with the streamflow time series length
Figure 24 shows the length of the available daily rainfall time series. The rainfall dataset has 186 rainfall stations for which daily rainfall are available. However, as it can be seen on this figure, most of the stations feature relatively old data: only 12 stations have recent measurements. Regarding the length of the time series, 56 % of the rainfall stations have at least 20 years of data.
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Figure 24. Period of activity of the rainfall stations with daily data
Figure 25 shows the length of the monthly rainfall time series. These time series are quite long and could be useful to characterize local rainfall regime. Unfortunately, these time series do not contain recent measurements.
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Figure 25. Period of activity of the rainfall stations with monthly data
8.3 FLOW DURATION CURVES MODELING
8.3.1 Introduction As mentioned previously, there is little information on the hydrological regime of the rivers at the location of the potential hydropower sites identified in the context of this study. Hence, we propose the following two-stage approach to estimate the key hydrological statistics at the sites of interest:
Stage 1: Models selection and parameterization at gauged sites;
Stage 2: Actual modeling by extrapolation at ungauged sites.
8.3.2 Model selection and parameterization
8.3.2.1 Statistical model selection The model selection and parameterization is carried out using the hydrological and rainfall datasets described in the previous sections. The objective of this first step is to fit a statistical model for the flow duration curves at the 90 gauged sites using the key features of their watersheds.
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Two statistical models widely used in hydrology are compared: Weibull and Lognormal laws, both characterized by two parameters. By fitting these two models to the observed data, it appeared that both models are relevant; however the Weibull law performed usually slightly better as illustrated in the Figure 26 below. As a consequence, the 2 parameters-Weibull law will be used to model the flow duration curves in the subsequent analysis.
Figure 26. Examples of flow duration curves modeled by the Weibull and lognormal laws.
The selected Weibull law is characterized by two parameters:
- The shape factor determines the shape of the curve. As illustrated in Figure 27, the Weibull law is flatter as the shape factor increases;
- The scale factor determines the area below the curve. As illustrated in Figure 28, the area below Weibull law is larger as the scale factor increases.
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Figure 27. Impact of the shape factor of the Weibull law
Figure 28. Impact of the scale factor on the Weibull law
8.3.2.2 Model parameterization The objective of the model parameterization is to build a relationship between the aforementioned two parameters of the selected Weibull law and the key features of the related gauged sites. These key features include the average annual rainfall, the watershed area, watershed average slope, altitude, etc). This analysis is carried out using the 90 flow gauged sites sample.
Scale factor (λ) analysis - For each gauged site, the scale factor of the Weibull law is equal to the average flow of that site, as illustrated in Figure 29.
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Figure 29. Weibull law: scale factor versus mean flow
The analysis revealed that the average flow of the river is the most correlated to the average annual volume of rainfall in the watershed. The advantage of the latter is that it takes into account the size of the watershed and other climatic characteristics of the watershed). The relationship obtained by statistical regression is as follow (based on the 90 gauged sites sample):
Scale factor = Qmean (m³/s) = 0.0065 x Average annual rainfall in the watershed (m³)
The relationship is illustrated in Figure 30 and shows a R² of 75%.
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Figure 30. Relationship between the average annual rainfall and the average flow.
Shape factor (γ) analysis - This parameter is more difficult to adjust because it implicitly includes considerations that affect the shape of the flow duration such as: presence of temporary runoff storage zones, physiographic characteristics of the watershed (distribution of slopes, shape of the river network), hydrogeology characteristics, etc. The variance-covariance analysis did not to identify satisfactory relationships between those variables and the value of the shape factor.
8.3.2.3 Extrapolation to ungauged sites Given the lack of good quality data and their non uniform spatial distribution across the country characterized by a variety of different hydro-climatic context, we consider hazardous to use the above statistical relationships for all the ungauged sites. Hence we classified the ungauged watersheds into three categories depending on their locations relative to the existing gauging stations. The three categories are as follow:
- Group 1: the ungauged site is located upstream or downstream an existing gauging station and their watersheds ratio is between 0.5 and 2. In this case, we consider that the hydrological conditions of the gauged site are representative for the ungauged site. Therefore, we assume the shape factor of the ungauged site remains identical to the one of the gauged site but the scale factor is adjusted based on the watersheds ratio. Hence we have:
. ungauged site = gauging station . ungauged site = gauging station * A ungauged site / A gauging station
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Where ungauged site and gauging station are the shape factors of the Weibull laws at the
ungauged and gauged sites respectively, A ungauged site and A gauging station are the area of the watersheds at the ungauged and gauged sites respectively.
We make the assumption that estimations of the flow duration curves of the ungauged sites within this category are relatively accurate (high confidence).
- Group 2: the ungauged site is located upstream or downstream an existing gauging station and their watersheds ratio is either below 0.5 or above 2. In this case, we consider that the hydrological conditions of the gauged site are representative for the ungauged site. Therefore, we assume the shape factor of the ungauged site remains identical to the one of the gauged site but the scale factor is calculated using the statistical relationship between the scale factor and the average annual volume of rainfall as explained in the previous section. Hence we have:
. ungauged site = gauging station . ungauged site = 0.0065 x Pungauged site x A ungauged site
Where ungauged site and gauging station are the shape factors of the Weibull laws at the
ungauged and gauged sites respectively, A ungauged site and Pungauged site are the area and the average annual precipitation in the ungauged watershed respectively.
We make the assumption that estimations of the flow duration curves of the ungauged sites within this category are less accurate than those from group 1 (medium confidence).
- Group 3: the ungauged site is located within an ungauged watershed and there is no gauged watershed in the immediate neighborhood. In this case, we assume that the scale factor is calculated using the statistical relationship between the scale factor and the average annual volume of rainfall as for group 2. The estimation of the shape factor remains a challenge as no statistical relationship with other variables was found, as previously explained. Hence, the shape factor of the ungauged sites was estimated based on similarities with other watersheds that could be considered as being similar i.e. with similar range of altitudes, slopes, climatic zones and sizes.
We make the assumption that estimations of the flow duration curves of the ungauged sites within this category are less accurate than those from group 2 (low confidence).
It is important to bear in mind that the proposed method is flexible: ungauged sites can be moved from one group to another if more gauging stations becomes available during the course of the study. Indeed, the initial inventory of the existing flow gauging stations is probably not exhaustive but is based on the information collected up to this stage of the study.
8.3.3 Results Figure 31 presents the average annual rainfall map of Tanzania. This map was produced by the spatial analysis of the rainfall dataset presented in the previous section. The purpose of this
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map is to allow the calculation of the average annual rainfall which is the key variable used for the estimation of the scale factor of the Weibull model for group 2 and 3.
Figure 31. Average annual rainfall (spatial extrapolation)
Each ungauged sites were classified in one of the aforementioned groups based on their location relative to an existing gauging station as illustrated in Figure 32 and distributed among those groups as follow:
Number of sites Groupe 1 18 Groupe 2 35 Groupe 3 43
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Figure 32. Ungauged sites classification
Finally, the flow duration curves of the ungauged sites were estimated using the methodologies specifics to each group. The key results are presented in Table 19.
Flow (m³/s) Scale Shape Site code Percentiles Factor Factor Q 50 / mean 2.5 30 Median 65 90 95 96 97 98 E-001a 0.52 1.50 0.51 1.28 0.59 0.41 0.30 0.12 0.07 0.06 0.05 0.04 E-001b 2.84 1.50 2.78 7.04 3.21 2.22 1.62 0.63 0.39 0.34 0.28 0.21 E-002 12.82 1.50 12.59 31.83 14.51 10.04 7.31 2.86 1.77 1.52 1.25 0.95 E-003 0.45 1.50 0.44 1.12 0.51 0.35 0.26 0.10 0.06 0.05 0.04 0.03 E-004 1.44 1.50 1.41 3.58 1.63 1.13 0.82 0.32 0.20 0.17 0.14 0.11 E-005 0.08 1.50 0.08 0.20 0.09 0.06 0.05 0.02 0.01 0.01 0.01 0.01 M-070 12.86 0.67 12.85 98.88 16.97 7.43 3.65 0.44 0.15 0.11 0.07 0.04 M-110 40.39 1.96 39.07 81.05 44.40 33.49 26.27 12.80 8.86 7.89 6.79 5.51 M-113 0.09 1.30 0.09 0.26 0.11 0.07 0.05 0.02 0.01 0.01 0.01 0.01 M-118 0.36 1.30 0.36 1.04 0.42 0.27 0.19 0.06 0.04 0.03 0.03 0.02 M-119 0.11 1.30 0.11 0.33 0.13 0.09 0.06 0.02 0.01 0.01 0.01 0.01 M-120 0.01 1.30 0.01 0.03 0.01 0.01 0.01 0.00 0.00 0.00 0.00 0.00 M-121A 0.90 1.35 0.89 2.47 1.03 0.69 0.48 0.17 0.10 0.08 0.07 0.05 M-121B 1.03 1.35 1.02 2.83 1.18 0.79 0.55 0.20 0.11 0.10 0.08 0.06 M-127 138.05 1.35 136.14 379.32 158.40 105.22 73.96 26.05 15.28 12.90 10.39 7.66 M-221 10.49 1.73 10.22 23.08 11.68 8.49 6.45 2.86 1.88 1.65 1.39 1.10 M-266 0.88 1.50 0.86 2.17 0.99 0.69 0.50 0.20 0.12 0.10 0.09 0.07
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Flow (m³/s) Scale Shape Site code Percentiles Factor Factor Q 50 / mean 2.5 30 Median 65 90 95 96 97 98 M-267a 0.44 1.50 0.43 1.10 0.50 0.35 0.25 0.10 0.06 0.05 0.04 0.03 M-267b 0.71 1.50 0.70 1.77 0.81 0.56 0.41 0.16 0.10 0.09 0.07 0.05 M-268a 0.60 1.50 0.59 1.48 0.68 0.47 0.34 0.13 0.08 0.07 0.06 0.04 M-268b 0.64 1.50 0.63 1.59 0.73 0.50 0.37 0.14 0.09 0.08 0.06 0.05 M-277 0.50 2.00 0.48 0.98 0.55 0.41 0.33 0.16 0.11 0.10 0.09 0.07 M-288 0.85 2.00 0.82 1.68 0.93 0.71 0.56 0.28 0.19 0.17 0.15 0.12 M-295 0.36 2.00 0.35 0.71 0.39 0.30 0.24 0.12 0.08 0.07 0.06 0.05 M-297 2.80 1.50 2.75 6.95 3.17 2.19 1.60 0.63 0.39 0.33 0.27 0.21 M-298 0.28 1.50 0.27 0.69 0.32 0.22 0.16 0.06 0.04 0.03 0.03 0.02 M-299 0.44 1.50 0.43 1.10 0.50 0.35 0.25 0.10 0.06 0.05 0.04 0.03 M-301 0.24 1.50 0.23 0.58 0.27 0.18 0.13 0.05 0.03 0.03 0.02 0.02 M-348 0.08 1.00 0.08 0.33 0.10 0.06 0.04 0.01 0.00 0.00 0.00 0.00 M-355A 6.47 1.77 6.29 13.98 7.18 5.26 4.02 1.81 1.21 1.06 0.90 0.71 M-355B 8.09 1.77 7.88 17.50 8.99 6.58 5.03 2.27 1.51 1.33 1.12 0.89 N-001 0.15 1.00 0.15 0.58 0.18 0.10 0.06 0.02 0.01 0.01 0.01 0.00 N-002 1.20 0.75 1.20 7.38 1.53 0.73 0.39 0.06 0.02 0.02 0.01 0.01 N-003 0.18 1.50 0.17 0.44 0.20 0.14 0.10 0.04 0.02 0.02 0.02 0.01 N-010 1.47 1.50 1.45 3.66 1.67 1.15 0.84 0.33 0.20 0.18 0.14 0.11 N-011 0.95 1.50 0.93 2.36 1.07 0.74 0.54 0.21 0.13 0.11 0.09 0.07 N-020 0.00 1.30 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SF-017 18.14 0.75 18.12 111.83 23.24 11.13 5.90 0.90 0.35 0.26 0.17 0.10 SF-018 10.26 0.75 10.25 63.95 13.16 6.27 3.31 0.50 0.19 0.14 0.10 0.06 SF-019 3.46 0.75 3.45 21.31 4.43 2.12 1.13 0.17 0.07 0.05 0.03 0.02 SF-020 4.99 0.52 4.99 68.53 7.12 2.47 0.99 0.07 0.02 0.01 0.01 0.00 SF-022 16.11 3.50 529.47 23.78 16.99 14.51 12.66 8.47 6.90 6.46 5.94 5.28 SF-024 29.33 3.50 27.30 43.30 30.92 26.41 23.05 15.42 12.55 11.76 10.82 9.62 SF-029 138.39 1.35 14.99 380.26 158.80 105.48 74.15 26.12 15.32 12.94 10.41 7.68 SF-030 46.89 2.07 45.21 90.75 51.29 39.26 31.19 15.77 11.13 9.97 8.65 7.09 SF-041 28.18 1.50 27.66 69.96 31.89 22.07 16.07 6.29 3.89 3.34 2.75 2.09 SF-052 67.27 1.00 66.96 263.17 80.99 46.63 28.98 7.09 3.45 2.75 2.05 1.36 SF-056 7.85 1.00 7.81 30.71 9.45 5.44 3.38 0.83 0.40 0.32 0.24 0.16 SF-067 7.48 1.00 7.45 29.28 9.01 5.19 3.22 0.79 0.38 0.31 0.23 0.15 SF-068 8.67 1.00 8.63 33.93 10.44 6.01 3.74 0.91 0.45 0.35 0.26 0.18 SF-069 12.33 1.00 12.27 48.23 14.84 8.55 5.31 1.30 0.63 0.50 0.38 0.25 SF-080 2.95 1.20 2.92 9.18 3.44 2.17 1.46 0.45 0.25 0.21 0.16 0.11 SF-082 9.86 1.50 9.68 24.48 11.16 7.72 5.62 2.20 1.36 1.17 0.96 0.73 SF-083 3.59 1.50 3.53 8.92 4.07 2.81 2.05 0.80 0.50 0.43 0.35 0.27 SF-091 33.85 1.00 33.69 132.41 40.75 23.46 14.58 3.57 1.74 1.38 1.03 0.68 SF-092 33.72 1.00 33.57 131.93 40.60 23.38 14.53 3.55 1.73 1.38 1.03 0.68 SF-107 11.44 1.08 11.36 40.29 13.58 8.16 5.26 1.43 0.74 0.60 0.46 0.31 SF-108 12.50 1.08 12.42 44.05 14.84 8.92 5.75 1.57 0.81 0.65 0.50 0.34 SF-109 9.59 1.08 9.52 33.76 11.38 6.83 4.41 1.20 0.62 0.50 0.38 0.26 SF-123 20.71 1.50 20.32 51.41 23.43 16.22 11.81 4.62 2.86 2.46 2.02 1.54 SF-143 243.46 1.00 242.32 952.40 293.11 168.75 104.88 25.65 12.49 9.94 7.42 4.92
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Flow (m³/s) Scale Shape Site code Percentiles Factor Factor Q 50 / mean 2.5 30 Median 65 90 95 96 97 98 SF-144 18.09 1.00 18.00 70.75 21.77 12.54 7.79 1.91 0.93 0.74 0.55 0.37 SF-145 24.02 1.00 23.91 93.96 28.92 16.65 10.35 2.53 1.23 0.98 0.73 0.49 SF-147 10.34 0.90 10.31 47.08 12.71 6.88 4.06 0.85 0.38 0.30 0.21 0.14 SF-153 12.51 1.00 12.45 48.92 15.06 8.67 5.39 1.32 0.64 0.51 0.38 0.25 SF-164 17.33 1.30 17.12 49.50 20.00 13.08 9.07 3.07 1.77 1.48 1.18 0.86 SF-172 19.98 1.50 19.61 49.61 22.61 15.65 11.40 4.46 2.76 2.37 1.95 1.48 SF-178 4.29 3.50 3.99 6.33 4.52 3.86 3.37 2.26 1.84 1.72 1.58 1.41 SF-185a 0.32 1.00 0.32 1.24 0.38 0.22 0.14 0.03 0.02 0.01 0.01 0.01 SF-185b 4.51 1.00 4.49 17.63 5.43 3.12 1.94 0.48 0.23 0.18 0.14 0.09 SF-185c 10.20 1.00 10.15 39.90 12.28 7.07 4.39 1.08 0.52 0.42 0.31 0.21 SF-187 15.37 1.50 15.09 38.17 17.40 12.04 8.77 3.43 2.12 1.82 1.50 1.14 SF-189 37.08 0.85 37.00 184.53 46.13 24.09 13.77 2.63 1.13 0.86 0.61 0.38 SF-189 37.08 0.85 37.00 184.53 46.13 24.09 13.77 2.63 1.13 0.86 0.61 0.38 SF-206 0.55 0.80 0.55 3.04 0.70 0.35 0.19 0.03 0.01 0.01 0.01 0.00 SF-207 0.60 0.80 0.60 3.29 0.75 0.38 0.21 0.04 0.02 0.01 0.01 0.01 SF-208 4.74 0.52 4.74 65.18 6.78 2.35 0.94 0.06 0.02 0.01 0.01 0.00 SF-211 2.26 0.82 2.26 12.06 2.84 1.44 0.81 0.14 0.06 0.05 0.03 0.02 SF-212 1.87 0.80 1.87 10.29 2.36 1.18 0.65 0.11 0.05 0.03 0.02 0.01 SF-213 1.09 0.75 1.09 6.70 1.39 0.67 0.35 0.05 0.02 0.02 0.01 0.01 SF-214A 8.31 0.75 8.30 51.22 10.64 5.10 2.70 0.41 0.16 0.12 0.08 0.05 SF-214B 8.40 0.75 8.39 51.75 10.75 5.15 2.73 0.42 0.16 0.12 0.08 0.05 SF-217 3.65 0.75 3.65 22.52 4.68 2.24 1.19 0.18 0.07 0.05 0.04 0.02 SF-219 0.37 0.75 0.37 2.26 0.47 0.23 0.12 0.02 0.01 0.01 0.00 0.00 SF-260 0.57 1.00 0.57 2.23 0.69 0.40 0.25 0.06 0.03 0.02 0.02 0.01 SF-266 4.66 0.90 4.65 21.24 5.73 3.10 1.83 0.38 0.17 0.13 0.10 0.06 SF-267 0.80 1.50 0.78 1.98 0.90 0.62 0.45 0.18 0.11 0.09 0.08 0.06 SF-271 0.88 1.50 0.87 2.19 1.00 0.69 0.50 0.20 0.12 0.11 0.09 0.07 SF-277 19.68 0.60 19.68 191.14 26.82 10.68 4.84 0.46 0.14 0.10 0.06 0.03 SF-278 6.19 0.52 6.19 85.02 8.84 3.06 1.23 0.08 0.02 0.01 0.01 0.00 SF-289 8.46 1.08 8.41 29.81 10.04 6.03 3.89 1.06 0.55 0.44 0.34 0.23 SF-294 0.61 1.00 0.61 2.39 0.74 0.42 0.26 0.06 0.03 0.03 0.02 0.01 SF-296 1.42 1.00 1.41 5.54 1.71 0.98 0.61 0.15 0.07 0.06 0.04 0.03 SF-305 6.13 1.00 6.10 23.97 7.38 4.25 2.64 0.65 0.31 0.25 0.19 0.12 SF-343 1.03 0.86 1.02 5.03 1.28 0.67 0.39 0.08 0.03 0.03 0.02 0.01 SF-UN 0.73 1.50 0.71 1.81 0.82 0.57 0.42 0.16 0.10 0.09 0.07 0.05 Table 19 Estimated key parameters of the flow duration curve at the ungauged sites
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9 Economic evaluation of the 70+ promising sites
To evaluate the 70+ promising sites, the consultant adapted his “EconEval” software to the Tanzanian context to be able to calculate expected production and project costs from characteristics of the planned facility, in its context and from a hydrological point of view. From the production and the cost, he deducts the LCOE (Levelized cost of energy) for each site, therefore enabling a harmonious comparison of the sites.
The aim of the EconEval program is the production of a complete database, including:
Basic information, collected on site (topographical coordinates of main works for example) or resulting from a preliminary calculation (mainly for hydrology),
Textual information about that nature of the site, the planned facility,
Information resulting from an economic calculation, such as the annual producible, the LCOE relative to different scenarios, etc.
This database enables the publication of standardised document describing the sites.
A complete description of EconEval is given in Annex 18.3.
9.1 FACILITIES COST CALCULATION
The main elements that are taken into consideration in the cost are summarised below:
Hydropower type (run-of-the-river / storage reservoir)
Design flood and flow duration curve
Works design (Dam – Spillway – Sand trap – Supply works (canal or headrace tunnel) – Forebay or Surge chamber - Penstock - Powerhouse)
Hydromechanical equipment (+ types of turbines)
Access roads
Electrical lines
The unit prices used for the estimation of costs had been determined using the costs of raw materials found in the subregion.
9.2 ELECTRICITY PRODUCTION COST OF POTENTIAL SITES
The electricity production calculation depends on the type of hydropower planned (run-of-the- river or storage reservoir) and on the choice of the design flow, itself depending on the connection type (off-grid or grid connected). The energy is estimated based on the flow duration curve available in the hydrological study explained in part 8. We define the
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corresponding capacity to each flow interval associated with the planned Hydropower type. For each specified capacity, we can deduct the energy created over each time interval. Depending on the design flow, different possibilities are possible. We consider the design flow
to be always above which is the minimum design flow for a run-of-the-river facility operating off-grid.
9.3 LCOE - LEVELIZED COST OF ENERGY
The levelized Cost of Energy (LCOE) is specified from investment costs (Capex – Capital Expenditure), operating costs (Opex – Operational Expenditure) and the expected production of energy.
The investment costs concern:
Study and work supervision costs (considered as 10% of the total investment cost),
Civil engineering and equipment investment costs (CE an EM),
Ressettlement and environmental impact costs (considered as 10% of the total investment cost),
Costs related to access and connection to the grid.
Annual operating costs are:
Cost for worn parts replacement: 0.25% of the Civil and equipment investments
operation costs (O&M): 10€ / kW installed
insurance costs: 0.1% of the CE and EM investments
The LCOE is then calculated based on expected production and costs from the following formula:
Where NPV is the Net Present Value which is obtained by: where n
is the discount rate given by default as 10%.
The updated energy cost can be calculated over any time interval. Here, it was obtained from the lifespan of the facility: 50 years. We consider the decommissioning costs will be 10% of the Civil and equipment investments.
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10 Selection of the top 20 prioritized small hydro sites
For the selection of the 20 prioritized sites, we then process per group located in the same geographical area that can be connected to an existing network (Main grid or Mini-grid powered with a thermal generator) or power a pure off-grid load centre. This is necessary since all the sites that are close to each other will be in direct competition to supply the same consumption centres.
The criteria used to make the selection of the 20 prioritized sites are presented in the list below:
1. Sites in groups within the same load centre or grid;
2. Estimate capacity between ~300 kW and 10 MW;
3. Exclusion of site located on river with zero flow during the dry season;
4. Competitive LCOE (Levelized Cost Of Energy)
5. No evidence of environmental stress including sediment transport.
We review the five criteria used :
Group of sites for the same load centre or grid
The projects are grouped by their ability to connect to the nearest load centre, either to the main grid or to a mini-grid or off-grid.
Predicted power between ~ 300 kW and ~10 MW
The terms of reference of this study indicate that ‘small hydro’ shall refer as having a generation capacity of between 1 to 10 MW. Nevertheless, REA expressed its wish to include potential sites under 1 MW in the selected potential sites for which a site visit is foreseen. It has consequently been decided to set a minimum of 300 kW under which sites will not be included in the selection, which corresponds to a minimal size in terms of investment and technical barrier for electro-mechanical equipment under which a private developer will face problems to recover its investment and/or find quality equipment for a reasonable price. Note however that some sites are located in areas where the uncertainty of hydrological data is still rather high, which can have a positive or negative influence on the final installed capacity or production.
Exclusion of site located on river with zero flow during the dry season
Field visits and interviews with locals have highlighted rivers that have zero flow during the dry season even if the hydrological model predicted a minimum flow. These sites are usually not appropriate for small hydro for multiple reasons : zero production several months of the years; production hard to predict; the maintenance team must be paid even if there is no production. This problem is particularly disadvantageous for Mini-Grid as the thermal capacity must be
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high enough to balance the lack of production and is even more critical for Off-grid situation where there won't be any power supply during the dry season.
Competitive LCOE (Levelized Cost Of Energy)
In accordance with the economic constraints (see chapter 3) and the competitiveness of the future sites, the consultant has set a maximum threshold for the LCOE at :
< 50 US$/MWh for main Grid connection;
< 100 US$/MWh for Mini-Grid connection;
< 200 US$/MWh for pure off-grid operation (no other source of power).
The LCOE has been calculated only at generator without access and connection costs (which makes a good project or not) which is comparable to the figures collected in the Power System Master Plan (Update 2013) and in the SREP-Investment Plan for Tanzania (2013).
No evidence of environmental constraint including sediment transport
Site visits have enabled us to identify readily identifiable criteria limiting the development of promising potential sites. These include the site’s location within protected area, the presence of landslide or an important sediment transport even in the dry season
10.1 PRIORITIZATION PROCESS
The following figure illustrates the prioritization process to select the 20 highest priority small hydropower sites.
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Figure 33 Selection process of the 20 prioritized sites
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10.2 SELECTION RESULT OF THE TOP 20 PRIORITIZED SMALL HYDRO SITES
H Q_eq P E LCOE Code Nom_site River Connection Group Flow constraint Environmental constraint Selection [m] [m³/s] [kW] [GWh/y) [USD/kWh] M-070 Momba II Momba Main grid Group H 355 7,4 21700 161,8 0,030 OK low M-110 Kitewaka Kitewaka Ludewa minigrid Group G 54 33,5 14960 106 0,043 OK sediment transport - M-113 Kyamato Kyamato Bukoba minigrid Group A 50 0,07 30 0,19 0,524 OK low - M-118 Achesherero Achesherero Bukoba minigrid Group A 90 0,3 200 1,34 0,166 OK low - M-119 Lubare Lubare Off-grid 125 0,02 20 0,17 1,168 OK low - M-121A Kitogota I Kitogota Bukoba minigrid Group A 100 2,7 2180 4,28 0,532 OK low M-121B Kitogota Falls Kitogota Bukoba minigrid Group A 25 0,8 160 1,08 0,096 OK low M-127 Ruhuhu Ruhuhu Mbinga minigrid Group J 15 105,2 13120 87,73 0,028 OK sediment transport - very low flow M-221 Mambi Mambi Off-grid 152 2,9 3560 30,39 0,043 during dry Upstream irrigation projects - season M-267A Ngongi I Ngongi Mbinga minigrid Group J 110 0,3 310 2,12 0,225 OK sediment transport - M-267B Ngongi II Ngongi Mbinga minigrid Group J 290 0,6 1310 8,91 0,111 OK sediment transport - Luwika/Lualal M-268A Luwika I Mbinga minigrid Group J 75 0,5 290 1,96 0,154 OK sediment transport - a Luwika/Lualal M-268B Luwika II Mbinga minigrid Group J 750 0,5 3030 20,58 0,146 OK sediment transport - a M-277 Luika Luika Ludewa minigrid Group G 58 0,4 200 1,4 0,184 OK low M-288 Kelolilo Kelolilo Ludewa minigrid Group G 69 0,7 400 2,85 0,141 OK low M-295 Myombezi Myombezi Off-grid 111 0,1 100 0,89 0,192 OK low M-297 Lipumba Mngaka Mbinga minigrid Group J 4 2,2 70 0,49 0,161 OK sediment transport - Litembo M-298B Ndumbi Off-grid 25 0,2 50 0,11 1,002 OK low - Extension M-299 Luaita Luaita Mbinga minigrid Group J 70 0,3 200 1,35 0,219 OK low very low flow M-301 Lukarasi shp Mkurusi Mbinga minigrid Group J 27 0,2 40 0,28 0,925 during dry sediment transport - season M-355A Mgaka I Mgaka Mbinga minigrid Group J 30 5,3 1300 9,09 0,097 OK sediment transport -
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H Q_eq P E LCOE Code Nom_site River Connection Group Flow constraint Environmental constraint Selection [m] [m³/s] [kW] [GWh/y) [USD/kWh] M-355B Mgaka II Mgaka Mbinga minigrid Group J 35 6,6 1900 13,28 0,077 OK sediment transport N-002 Kawa Kawa Off-grid 260 0,06 130 1,05 0,887 OK low - N-010 Kitandazi II Mbinga Mbinga minigrid Group J 35 1,2 330 2,26 0,148 OK low N-011 Kingilikiti Lumeme Mbinga minigrid Group J 28 0,7 170 1,16 0,156 OK low - Sumbawanga SF-017 Momba I Momba Group L 64 11,1 5860 35,69 0,111 OK low minigrid Sumbawanga SF-018 Kalambo Falls Kalambo Group L 200 6,3 10360 63,06 0,026 OK Tourism and transboundary site minigrid Sumbawanga SF-019 Lwazi Lwazi Group L 120 2,1 2100 12,78 0,042 OK low minigrid SF-020 Mfizi II Mfizi Mpanda minigrid Group K 150 2,5 3040 17,55 0,045 OK moderate sediment transport SF-022 Luegere LUEGERE Kigoma minigrid Group D 159 14,5 19010 145,35 0,028 OK low SF-029 Lupapilo Ruhuhu Mbinga minigrid Group J 30 105,5 26230 175,49 0,040 OK sediment transport - SF-041 Kivumilo UMBA Main grid Group H 9 22,1 1640 13,34 0,068 OK low sediment transport / Bordering SF-052A Mara I MARA Main grid Group H 25 46,6 9630 61,36 0,089 OK - of the Serengeti Park sediment transport / Bordering SF-052B Mara II MARA Main grid Group H 45 46,6 17340 110,52 0,061 OK - of the Serengeti Park zero flow during SF-056 Manique MANIQUE Loliondo Minigrid Group F 350 5,4 15570 99,23 0,067 sediment transport - dry season zero flow during SF-067 Mponde II MPONDE Main grid Group H 95 5,2 4060 31,55 0,070 sediment transport - dry season zero flow during SF-068 Luwila LUWILA Main grid Group H 120 24 21750 34,66 4,096 sediment transport - dry season zero flow during SF-069 Maparengi MAPARENGI Main grid Group H 150 8,5 10560 82,07 0,038 sediment transport - dry season very low flow SF-080A Sasimo I SASIMO Main grid Group H 60 2,2 1070 8,52 0,067 during dry low - season very low flow SF-080B Sasimo II SASIMO Main grid Group H 110 2,2 1970 15,59 0,045 during dry low - season SF-082 Lukosi Lukosi Main grid Group H 176 7,7 11210 91,1 0,031 OK low SF-083 Mlowa Mlowa Main grid Group H 117 2,8 2710 22 0,040 OK sediment transport - SF-091 Bubu II BUBU Main grid Group H 90 23,5 17430 135,47 0,039 zero flow during sediment transport -
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H Q_eq P E LCOE Code Nom_site River Connection Group Flow constraint Environmental constraint Selection [m] [m³/s] [kW] [GWh/y) [USD/kWh] dry season zero flow during SF-092 Bubu I BUBU Main grid Group H 35 93,5 21970 35,01 1,862 sediment transport - dry season SF-107 Ndembela I NDEMBELA Main grid Group H 100 8,2 6740 52,84 0,043 OK Low / On going project SF-108 Ndembela II NDEMBELA Main grid Group H 105 8,9 7720 60,52 0,047 OK Low / On going project SF-109 Lyandembela I Lyandembela Main grid Group H 33 6,8 1860 14,61 0,051 OK Low / On going project SF-123 Mchakama Mavuji Off-grid 5 4,6 190 1,63 0,273 OK sediment transport - High flow out of SF-143 Wami Wami Main grid Group H 8 168,8 11210 87,1 0,029 low exept for fishing range very low flow SF-145 Mkalamo MSANGAZI Off-grid 20 16,6 420 17,58 0,081 during dry sediment transport - season zero flow during SF-153 Ndurumo NDURUMO Main grid Group H 85 8,7 6080 47,22 0,055 sediment transport - dry season SF-172 Ruchugi Ruchugi Kasulu minigrid Group B 13 15,6 1680 11,4 0,319 OK sediment transport - SF-178 Mgambazi MGAMBAZI Kigoma Minigrid Group D 90 3,9 2870 21,93 0,037 OK low SF-187 Muyovozi Muyovozi Kibundo minigrid Group C 40 12 3990 27,11 0,051 OK low SF-189 Lupa Lupa Main grid Group H 82 24,1 16360 124,98 0,024 OK sediment transport Sumbawanga SF-206 Chulu Chulu Group L 800 0,3 2240 13,81 0,105 OK low minigrid Sumbawanga SF-207 Kilida Kilida Group L 500 0,4 1530 9,4 0,102 OK sediment transport - minigrid SF-208 Mfizi I Mfizi Mpanda minigrid Group K 40 2,3 770 4,47 0,074 OK sediment transport Sumbawanga SF-211 Lwiche Lwiche Group L 519 5,8 24240 44,78 0,310 OK sediment transport - minigrid Sumbawanga SF-212 Muze Muze Group L 420 1,2 4060 24,96 0,065 OK sediment transport minigrid Sumbawanga SF-213 Nyembe Nyembe Group L 684 2,7 14760 27,16 0,556 OK low - minigrid Sumbawanga SF-214A Kalambo I Kalambo Group L 20 5,1 840 5,14 0,056 OK low minigrid Sumbawanga SF-214B Kalambo II Kalambo Group L 20 5,2 850 5,19 0,073 OK low minigrid Sumbawanga SF-217 Samvya Samvya Group L 85 2,2 1570 9,58 0,074 OK low minigrid
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H Q_eq P E LCOE Code Nom_site River Connection Group Flow constraint Environmental constraint Selection [m] [m³/s] [kW] [GWh/y) [USD/kWh] Sumbawanga SF-219 Kianda Kianda Group L 700 0,2 1270 7,71 0,112 OK sediment transport - minigrid SF-266 Muhuwezi Muhuwezi Tunduru minigrid Group M 105 3,1 2680 16,81 0,094 OK moderate sediment transport very low flow Mihima SF-271 Mihima Masasi minigrid Group I 104 0,7 590 3,99 0,066 during dry low Namangale season SF-277 Mbagala Mbagala Masasi minigrid Group I 40 10,7 3530 20,8 0,077 OK moderate sediment transport SF-278 Mfizi III Mfizi Mpanda minigrid Group K 30 3,1 760 4,39 0,15 OK sediment transport SF-289 Lyandembela II Lyandembela Main grid Group H 33 6 1650 12,92 0,047 OK Low / On going project SF-294 Kigogo Kigogo Main grid Group H 562 0,4 1930 15,01 0,036 OK low Vambanungw SF-296 Vambanungwi Main grid Group H 110 1 890 6,89 0,045 OK sediment transport - i zero flow during SF-305 Mponde I MPONDE Main grid Group H 16 17 1780 2,83 3,851 sediment transport - dry season SF-343 Samba Samba Off-grid 92 0,075 60 0,47 1,255 OK low - SF-UN Mbawa Mbawa Off-grid 350 0,2 450 3,87 0,526 OK sediment transport -
* Key: : priority site : no-priority site - : site without interest
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11 Recommendations for the hydrological campaign
11.1 OBJECTIVES AND EXPECTED RESULTS
The objective of the hydrological measures campaign on the selected sites (amongst the 20 priority hydropower sites) is to reduce uncertainties on the currently available data. These new hydrological measures will improve the accuracy of the technical and economic parameters of the selected potential hydropower schemes.
The duration of the flow measure campaign will be about 18 months and will deliver (i) time series of flow data with a daily time step and (ii) flow rating curves (relationship between the measured water level in the river and the discharge) for the selected sites.
It is worth mentioning that it is only through records over long periods of time (more than 20 years of continuous measures) that the hydrology is meaningful and informative, especially for the understanding of extreme events such as floods and drought (particularly in a context of possible climate change). Given the duration of the planned campaign in the context of this study (about 18 months), this will give indicative information on the hydrology at the sites of interest, rather than a comprehensive description which could only be done with measures over a longer period of time. The extreme events such as floods and droughts could not be analysed in the context of this field measures campaign.
11.2 METHODOLOGY
11.2.1 Introduction Water level measurement is the most common technique to estimate the flow at a specific river location. The relationship between the river flow and the water level (flow rating curve) depends on the hydraulic conditions. Hence, it is important to choose an appropriate location to install the gauging station in order to have a unique relationship between the measured water level and the river flow i.e. one water level must correspond to only one river flow and vice versa. Open channel hydraulics theory calls these specific locations of rivers “control sections”.
11.2.2 Water level measurement Based on our experience in the set up and operation of river flow gauging systems, the following technologies were chosen as being appropriate to the context this study.
Radar system – In this case, the water level is measured with a radar wave transmitter / receiver system placed at a known height above the water level. The measured signal is then recorded.
Pressure probe – This technique involves the installation of a pressure sensor in a pipe in hydrostatic equilibrium with the water level in the river. The water level measure is done by transforming the measured hydrostatic pressure.
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11.2.3 Data recording and transfer Whatever the technique of water level measure, the recording and transmission of data are essential components that remain technologically and financially identical in the measuring system.
Data recording and transmission will be done using a datalogger equipped with a GSM / GPRS modem and will be placed near the measuring device (sensor). The data will be transmitted via the GSM network (if possible) to a computer where an operator will be able to process the measured data and validate it (or not). The main advantage is that measures are taken and therefore processed in a continuous manner, which enables rapid identification of potential problems and to consequently intervene to find an appropriate solution. If the sites cannot be equipped with this technology because of insufficient network coverage, other technologies will be considered on a case by case basis.
11.2.4 Establishment of flow rating curves The establishment of a flow rating curve at a specific site is done from flow measurements at different moments of the year, representing all the hydrological conditions met at the measured site (during both the dry and flood seasons). Flow measurement (gauging) is a field operation during which the river flow is calculated from the measure of water velocities at different water depth along the cross section of the river. Associated with a water level measurement, the gauging operation enables the determination of a common point between the water level and the river flow at that location (one unique point of the rating curve).
It is good practice to consider that ten (10) different points are necessary to establish a representative flow rating curve (for each selected sites). Beyond the duration of this study, the flow duration curve will need to be frequently checked by new gauging operations, given the dynamic character of a river (changing river bed conditions after a flood for example).
11.2.5 Positioning measuring instruments The location of a gauging station must be chosen very carefully. In fact, the quality of measures and records depends on the choice of the location.
It is essential to aim at establishing a unique relationship between measures of water levels and the river flow at that location, meaning that at one water level must correspond to only one river flow and vice-versa.
It is also important to consider the sustainability of the stations over time because it is only with records over long periods of time that the hydrology is significant and informative on the hydrological regime of the river especially for its extreme events such as floods and droughts (particularly in the context of possible global changes).
The exact location of the gauging stations will be determined during a fact finding mission with the specialised expert, who will determine, with the consultant, the best adapted location considering a trade-offs between different parameters such as representativeness of measures for the hydropower site of interest (the gauging station should not necessarily be located at
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the exact location of the potential hydropower site of interest), the security of the gauging equipment (vandalism risk), technical installation, operation and maintenance constraints.
11.3 SELECTION OF SITES TO EQUIP WITH GAUGING EQUIPMENTS
For budgetary reasons, it is not foreseeable to equip all 20 priority hydropower sites with water level measuring stations in the context of this study. Apart from the budgetary constraints, the choice of sites to be equipped must be primarily based on an identification of hydrological measures needs.
It is important to note that equipping a subset of the 20 priority hydropower sites with flow gauging stations does not mean that only this subset of sites will benefit from the measures campaign. In fact, amongst the 20 priority hydropower sites, some already benefit from the presence of nearby flow gauging stations; on the other hand, some proposed new flow gauging stations will benefit several sites (cascades of sites on the same river or in close proximity in the same watershed).
Therefore, the selection of sites to equip with flow gauging stations is based on the analysis of the following criteria:
Criteria n°1: Priority of development of the hydropower site resulting from the prioritisation process explained in the Hydro Planning Report: Amongst the 20 priority hydropower sites, the sites which are the most interesting for short and medium term development will be favoured.
Criteria n°2: Uncertainties of the available hydrological information based on the hydrological study results presented in section 8. Sites which currently have little reliable information will be favoured.
Criteria n°3: Presence of sites on a cascade. It would be useful to install a gauging station on a river whose measures could benefit the development of several sites.
The table below summarizes, for each of the 20 priority hydropower sites for which the selection process is explained in the chapter 10, the selection criteria of sites to be equipped with a flow gauging station.
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Prioritisation Code Name Group River Water Basin Criteria 1 Criteria 2 Criteria 3 for Comments equipment* Kagera and Lake The station 5A2 (Ngono) at Muhutwe Bridge must be M-121B Kitogota Falls Group A Kitogota Yes Victoria equipped Malagarasi and Lake SF-187 Muyovozi Group C Muyovozi No Ungauged river basin Tanganyika Malagarasi and Lake Gauged river basin (Luegele at Lubalisi). Data must be SF-022 Luegere Luegere No - Tanganyika further analyzed. Group D Malagarasi and Lake Regionalization of data available from the Luegele river SF-178 Mgambazi Mgambazi No Tanganyika gauge. M-288 Kelolilo Group G Kelolilo Lake Nyasa Yes - Gauged river basin (Kitewaka at Muhumbi - 1RB4A) M-070 Momba II Momba Lake Rukwa Yes - Gauged river basin (Mtembwa at Luasho/Kapoma) SF-082 Lukosi Lukosi Rufiji Yes - Gauged river basin (Lukosi river at Mtandika - 1KA37A) Group H The gauging could additionally support the irrigation SF-294 Kigogo Kigogo Rufiji Yes development. Close to Mufindi Pulp and Paper Mill (60,000 t/year). Ungauged river basin. The alternative of the Ruvuma and rehabilitation of the Miesi (Mikele) river gauge (adjacent SF-277 Mbagala Group I Mbagala Southern Indian No watershed) located on a bridge must be carefully Ocean Coast analyzed. Gauged river basin (Mngaka at Road Bridge - 1RB6). Data M-299 Luaita Luaita Lake Nyasa Yes - must be further analyzed. Group J Ruvuma and Ungauged river basin but regionalization is possible N-010 Kitandazi II Mbinga Southern Indian No through two adjacent similar water basins. Ocean Coast The river basin is gauged at Ntatumbila (3CC2), at SF-020 Mfizi II Group K Mfizi Lake Rukwa Yes - Parawame (3CC3) and Useveya (3CB2) Gauged river basin (Mtembwa at Luasho/Kapoma and at SF-017 Momba I Momba Lake Rukwa Yes - Chipoma - 3B15A) Ungauged river basin but regionalization is possible Malagarasi and Lake SF-019 Lwazi Lwazi No through an adjacent similar water basin (Samvia at Tanganyika Yunga). Ungauged river basin. The gauging station could be SF-206 Chulu Chulu Lake Rukwa No Group L located on a bridge located at the end of the fall. Malagarasi and Lake SF-214A Kalambo I Kalambo Yes Ungauged river basin. The gauging station which benefit Tanganyika to 2 potential sites could be located on a bridge located Malagarasi and Lake SF-214B Kalambo II Kalambo Yes two km upstream of the site. Tanganyika SF-217 Samvya Samvya Lake Rukwa Yes - Gauged river basin SHER s.a. in association with Mhylab Small Hydro mapping report - April 2015 Page 119 of 181 Small Hydro Tanzania REA / The World Bank Contract n°7169139 - Recommendations for the hydrological campaign -
Prioritisation Code Name Group River Water Basin Criteria 1 Criteria 2 Criteria 3 for Comments equipment* Ruvuma and Ungauged river basin. The gauging station could be SF-266 Muhuwezi Group M Muhuwezi Southern Indian Yes located on a bridge located 5 km upstream of the site. Ocean Coast Ungauged river basin but regionalization is possible M-295 Myombezi Off-grid Myombezi Lake Nyasa No through an similar water basin (Kitewaka at Maboga - 1RB9). Total 7 * Key: : priority sites for equipment of flow measure Total 4 : non-priority site for equipment of flow measure Total - - : site for which flow measures already exist
The result of the prioritisation process of sites to be equipped with hydrometric stations classifies these sites into three categories:
(i) Priority sites for hydrometric station equipment (legend key: ). These gauging stations will reduce the hydrological uncertainties hence the estimation of the technical and economic parameters of the potential hydropower sites that are the most attractive at the short- and medium-term.
(ii) The non-priority sites for hydrometric station equipment (legend key: ). These sites have less interest for immediate equipment with hydrometric stations; it would be anyway interesting to equip them in the long term outside the framework of this study.
(iii) The sites already benefiting from information coming from close hydrometric stations (legend key: -). For these sites it is nevertheless important that the maintenance, processing and validation of the hydrological data programs continue.
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Based on the aforementioned criteria, we suggest the installation of 7 flow gauging stations on the following rivers: Kitogota, Muyovozi, Kigogo, Mbagala, Chulu, Kalambo and Muhuwezi. It is important to emphasize that these proposed 7 stations will directly benefit 8 sites (cascade sites on the same river) and indirectly many hydropower sites proposed in the context of this study or already considered in previous studies. In fact, these new flow gauging stations are found in watersheds more-or-less close to other priority hydropower sites and will therefore improve the quality of the spatial extrapolations for these hydropower sites.
Figure 34 illustrates the location of the 7 sites that will directly benefit from the proposed new gauging stations during the hydrological measure campaign as well as watersheds associated with these sites.
11.4 RECOMMENDATIONS FOR TECHNOLOGY TRANSFER
As previously mentioned, it is essential that the collection of hydrological measures continues over time, beyond the duration of this study. It is also true for the data processing and quality assessment, as well as for regular checks and updates of flow rating curves.
To this end, the Tanzanian counterpart who will accompany the Consultant and/or the Contractor for the installation, maintenance and follow-up of gauging stations will be suggested by the Tanzanian Institution to which the property and responsibility of these stations will be transferred. In this way, the infrastructure and data appropriation process will be started from the beginning of activity 4 and will hence maximise its chances of success.
It is important to remember that these 7 flow gauging stations are an addition to an existing monitoring network, currently managed by the Water Resources Division from the Ministry of Water which has the following attributions: "To collect hydrological. Hydro-geological and hydro-meteorological information, and disseminate such information and associated services to other Government institutions and the public". It is important that the management of the hydrological information be centralised, meaning that the data be collected, processed, validated and distributed by the same institution. This contributes to ensure the consistency of acquisition, supervisions and consequently the quality procedures.
For the aforementioned reasons, we recommend that the Water Resources Division from the Ministry of Water will be appointed as the institution which will be entrusted with the responsibility of the new 7 flow gauging stations which will be installed in the context of this study.
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Figure 34 7 sites that will directly benefit from the proposed new gauging stations
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12 Implementation plan of the Phase 2 /3 - Data collection and validation / Small Hydro Atlas
12.1 RECOMMENDATIONS FOR PHASE 2
The main objectives of Phase 2 are to achieve, for the 20 prioritized hydropower sites: (i) the stream gauge measurements of a selection of rivers, over 18 months, for which the available flow data are very insufficient, (ii) preliminary investigations of topography, (iii) surface geology and (iv) socio-environmental risks.
12.1.1 Hydrological measurements campaign The hydrological study done during previous activities, shows that the available hydrological data on the rivers of interest are generally insufficient. Based on the results of this study, the consultant suggested the installation of gauging stations (measurement of the water level) on 7 rivers that he considers as priority and on which a survey will enable to substantially improve the hydrological knowledge of areas in Tanzania that haven’t or are slightly gauged. The selection process of these 7 rivers is explained in the section 11.3.
The definition of requirements concerning the gauging stations (specifications) and the follow- up and supervision of implementation of works of these stations will be carried out by the team of the Consultant. As described in section 11.2.4, a rating curve for each site must be prepared to be able to convert head data into flow. The installation of gauging stations will be entrusted to a service provider with relevant experience in installation of gauging stations in developing countries. The establishment of flow rating curves associated with gauging stations is an integral part of the mission of the service provider. A minimum of 10 measurements at different flows is considered as the minimum to validate a flow rating curve. The consultant will be responsible for the follow-up of flow measurements taken by the service provider aiming for the creation of the flow rating curve, this to validate the acquisition and processing of hydrological data. An explanatory diagram is given in Figure 35.
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Figure 35 Responsibilities and interactions in the implementation of a hydrological network
The necessary activities for the implementation of the gauging stations network are detailed below:
Hydrological The Consultant Administrative Indicative Activities services (SHER) documents dates provider Writing of terms of reference of the hydrological Terms of service provider and the indicative - April 2015 reference characteristics of gauging stations Restricted tender (3 service providers) launched Restricted - May 2015 by the Consultant tender folder End of Non-objection notice from the World Bank - - Mail May 2015 Preliminary mission for the definition of the final June characteristics of gauging stations and of the Mission report 2015 equipment list Implementation of the gauging equipment - Subcontracting June-July Follow-up of gauging station implementation - Site minutes 2015 Hydrological Establishment of flow rating curves July2015 report November Supervision of hydrological measurements for Follow-up - 2016- the establishment of flow rating curves report June 2015 Guarding Facilities security and guarding - November contract 2016 November Hydrological report - Report 2016 Transfer of the Equipment at the end of the Transfer December
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Hydrological The Consultant Administrative Indicative Activities services (SHER) documents dates provider study agreement 2016 Table 20 Activities for the implementation of a gauging stations network
As previously mentioned, the location choice of a gauging station must be done very carefully. In fact the measurements and records quality will depend on the choice of the location of used technology. This is why it will be important to organise a preliminary mission for the service provider, with the Consultant, to carry out a prior inspection of sites which could take gauging stations. The objective of these site visits is to ensure that the physical and hydraulic characteristics of the planned location comply with relative prescription to the application of flow measurement methods that are planned to be used and to define the latter according to specific conditions of the site.
Despite the installation should be in the dry season, the risks exist that the service provider must put back one of the installations by a few weeks/months because of a too high water level in the rivers to carry out the installation in good and safe conditions.
12.1.2 On-site training for the collection and processing of hydrological data The engineers and technical staff proposed by the REA and the Ministry of Water will be trained to carry by the service provider to use the new flow measurement tools.
In addition, a theory and practice training concerning the different aspects of a gauging network will be given by the service provider. This training will aim to acquire installation, maintenance and operating autonomy of the hydrological acquisition network.
The subject addressed will include:
Theoretically
Identification criteria for a site,
Selection of gauging appropriated technology to local conditions,
Preview of different gauging technologies at the river,
Basic approach of data recording technologies,
Data acquisition process,
Establishment of the flow rating curve,
Head-flow conversion,
Telecommunication systems for transmission of data from “slow” phenomena,
Maintenance operations of a gauging station,
The hydrological database,
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SCADA systems,
Data handling and validation.
Practically
Familiarisation with the electronic measurement equipment (Voltmeter, ammeter),
Measurement of electronic signals generated by sensor,
Connection of sensors to an acquisition device,
Configuration of an acquisition device,
Connection of an acquisition device to a GPRS telecommunications system,
Preventive periodic maintenance,
1st level corrective maintenance,
Collection and transfer of saved data by an acquisition plant,
Gauging - state of the art,
Use of a rating software,
Management of a database,
Handling data,
Data authentication,
Data consultation.
12.1.3 Extra preliminary investigations in topography The aim of the topographical campaign on the 20 prioritized sites is to confirm gross head and to confirm the technical feasibility of the schemes suggested in Activity 1. The measurements will be done with a DGPS or with a total station depending on the conformation of sites (canopy, slopes, deep valey, etc.). The topographical team will take some important points including altitudes concerning planned infrastructures (dam, intake, canal or penstock, forebay, surge tank, powerhouse, etc.).
12.1.4 Extra preliminary investigations in geology and geotechnics The aim of the extra preliminary geological and geotechnical investigations at the 20 prioritized sites is to check and describe at a reconnaissance level:
local geology;
soil conditions;
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soil stability at the dam, at the waterways, at the powerhouse;
to check soil permeability at the main works;
to describe seismic risks in the project area;
to check the risk of landslides;
to check the availability of construction material.
12.1.5 Description and assessment of social and environmental risks The consultant will carry out a visit or the 20 prioritized sites with a socio-environmentalist expert who will determine the future constraints which could result from planned facilities and, when appropriate, highlight the elements that should be taken into account in future studies (prefeasability, feasibility, environmental and social impact study, resettlement plan, etc.). The expert will be particularly attentive to the World Bank safeguards policies.
12.2 PRODUCTION OF VALIDATED SMALL HYDRO ATLAS
The Consultant will consolidate the results from the hydrological monitoring and site investigations, and use this latest data to update the small hydropower potential mapping outputs from Phase 1. A draft validated Small Hydro Atlas swill then be delivered in the format of a stand-alone report, slide pack, and relevant GIS layers. The Small Hydro Atlas report will provide a summary of the methodology and process, references to the previous report and data outputs, and high quality representations of the final mapping outputs. It will be delivered in electronic format suitable for print and web publication.
12.3 PRE-FEASIBILITY STUDIES ON THE 4 THE BEST SITES
The Consultant will carry on studies on the 4 most promising sites. The pre-feasibility studies will assess the costs and risks involved in such a projects, and the challenges to be faced for their development. The scope of works consists of the following main tasks:
a) Review of the existing data and GIS information;
b) Site visit of each 4 sites and main load centers / national grid connection;
c) Based on the field visits, identify any major environmental and social impact that needs to be addressed at feasibility level;
d) Preparation of a Simplified Topographic Survey;
e) Preparation of Preliminary Surface Geological Report;
f) Update and verify the hydrological data;
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g) Preparation of a Schematic Layout of Hydro Power Plant, weir or dam (when applicable), waterways and Transmission Lines to the main load centers / national grid connection;
h) Preparation of a Budgetary Cost Estimate and Electricity Generation Estimate for a range of installed capacity;
i) Preparation of the draft Prefeasibility Report including the output of the above activities ;
j) Preparation of the final Prefeasibility Report.
According to additional information such topography, the Consultant will verify the site suitability and, in case, made locally changes of the axis location, in order to achieve better morphology, easier accessibility, higher water head and stable geological conditions. During site visit the Consultant will prepare a topographic survey, a schematic layout and a preliminary geologic appraisal, together with the relevant report, as below described.
During the field visit, the Consultant will assess possible environmental and social impacts of the potential SHP project, such as household’s resettlement, forest or agricultural land flooding etc. The assessment will list and made a rough estimate about these impacts.
For the 4 potential sites, the Consultant will revise and consolidate the schematic layout prepared during site visit, producing a final preliminary project layout. The layout shall contain all necessary structure dimensions for making a preliminary quantity estimate: such dimensions will conform to the hydraulics computations usually made at preliminary level for defining a hydropower scheme. Hydraulic computation will be in accordance with hypothesis and assumptions pertaining to the standard practice for hydropower design criteria. Based on the above, for each project, the Consultant will prepare a cost estimate in US$ currency. The cost estimate will be composed by summing the major items cost plus a percentage of finishing and miscellaneous, to take in to account all minor items not directly computed, plus engineering costs (including estimated cost of access roads to sites) and contingencies.
The Electricity Generation Estimate will be calculated taking into consideration the installed capacity of the identified power plant and will be based on the assessed hydrological data.
The cost per kW/h will be assessed based on the cost estimate and on the electricity generation range and will show different cost estimates in US$/kW installed and US$/kWh generated per each site.
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12.4 WORK SCHEDULE PHASE II AND PHASE III
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13 Training and capacity building
During the study on hydropower mapping - Tanzania, SHER sa (the consultant) has created both a Google Earth and a GIS (geographical information system) database which serve as the backbone for all the information we gathered and cleaned about the potential small hydropower sites in Tanzania.
This training will introduce and detail how to retrieve information from this database and how to update it.
13.1 DATABASE PRESENTATION FOR MANAGERS
The first part of the training session will be dedicated to a non-technical audience and will focus on especially deciders and managers of related institutions (duration: half a day). During the training, the database and results of site visits will be presented on Google Earth. The Google Earth database will contain a summary of information for every site considered during the study. Google Earth, a freeware, is user friendly and accessible to everybody.
The capabilities of the GIS database and software will be presented in a way that allows the deciders to assess the potential of the database.
13.2 CONTENT
Every session will start with a short theoretical introduction and a demonstration followed by practical exercises to develop critical thinking skills. The 5 sessions (half a day each) will focus on:
The first session is aimed at a non technical audience including deciders and managers:
General presentation of the Google Earth small hydropower database for managers and technical staff (easily accessible to non professional) - presentation of the capabilities of the GIS database.
The following sessions aimed at engineers and technical staff:
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Software installation, introduction to GIS, introduction to the main layers and shapefiles,
Consulting and updating (editing) the database,
Updating the database from Google Earth data, from GPS data,
According to the participants level, the last session might be focused on
o more exercises on layers, consulting and editing the database o creating maps o using GPS/smart phones o possibilities of GIS for hydropower studies (presentation)
13.3 TRAINING SESSION FOR ENGINEERS AND EXECUTIVES
The second part of the training (2 days) will be aimed at the engineers and technical staff, who will manage, share, consult and update the GIS database.
13.4 DATES AND DURATION
The training session will be organized on 2.5 days and will be held during the month of March right after the working session of phase 1 (2.5 consecutive days in March 2015).
13.5 PLACE AND PRACTICAL INFORMATION
Location and practical aspects of the training are to be determined by REA and the World Bank.
13.6 REQUIRED LEVEL OF TRAINEES
No previous experience of GIS is required, only a good overall knowledge of MS Windows and Office.
13.7 REQUIRED HARDWARE OF TRAINEES
Each participant should bring his personal computer (Windows 7 if possible), considering that the software will be installed on the computer and most of the activities will include practical exercises.
13.8 SOFTWARE'S
Two software will be installed on the participants computers:
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GoogleEarth
Quantum GIS
Both software are free, Quantum is moreover an open source software. It is recommended (but not required) for the participants to install both software prior to the training session. (http://qgis.org/en/site/ and https://www.google.com/earth/).
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14 Working Session in Dar-es-Salam
A Working Session is foreseen in Dar-es-Salam to present and discuss the results of the first phase of the study and to discuss the phase 2 and 3 which concerns the implementation of hydrological measuring stations, collection of site data (hydrological, geological, topographical and socio-environmental) and to construct the structure of the future Small Hydro Atlas. The table below presents an indicative calendar for this Working Session.
Date Hour Subject
Main event
09:30 Welcoming of participants
10:00-11:00 Presentation of the Small Hydro Mapping report and discussions
DAY 1 11:00 Coffee break
11:30-12:30 Presentation of the Site Investigation report, results and discussions
12:30 Lunch
Presentation of planned activities in Phase 2 – site data collection and 14:00-15:30 validation, and discussions
9:30 Welcoming of participants
10:00-11:00 Presentation of the GIS database for managers
DAY 2 11:00 Coffee break
Training session
Beginning of the training session for engineers and technical staff 11:30 Software installation, introduction to GIS, introduction to layers and shapefiles Training session - day 2 DAY 3 9:30 Consulting and updating (editing) the database Updating the database from Google Earth data and from GPS data Training session - day 3 More exercises on layers, consulting and editing the database creating maps DAY 4 9:30 Training on how to use GPS/smart phones to collect and store the georeferenced information Possibilities of GIS for hydropower studies (presentation)
One of the objectives of this workshop is to discuss about the activities foreseen in phase 2 which will enable the confirmation/validation of advanced figures collected during the site visits. This means additional reconnaissance of topography, geology, natural and social
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environment and hydrological measurements on targeted watersheds through gauging stations.
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15 Policy recommendations
In order to scale up the investments in renewable energies in general and in small hydro in particular, we suggest the following recommendations for Tanzania:
Implement at the short-term the amendment of the Electricity Act which aims at dismantling the Single Buyer Model (Electricity Act, 2008 particularly Section 41(6)) to allow private power producers to supply power directly to bulk off-takers. This reform is an integral part of the Strategic Reform Document and Roadmap. It would allow small independent power producers (IPPs), including hydropower producers, to sell directly to bigger eligible customers without necessarily using the TANESCO tariffs and, IPPs would in addition be allowed to install and operate small off-grid distribution networks.
Further on the reform of the off-grid small distribution networks with IPPs, it should be possible for private distributors to build and operate small rural distribution networks (under a concession agreement for example), buy at negotiated wholesale tariffs (with standardized PPP agreements) electricity produced by TANESCO or imported from abroad (and in this case supporting the regulated wheeling charges). This proposed reform is in accordance with what is already included in the Strategic Reform Study, but it would further accelerate electrification in rural areas, with new private capitals, and better quality of services at the most competitive costs.
As pointed out in the “Annual Review of Government of Sweden and Norway Financing Support to Capacity Development Project and Rural Energy Fund (November 2013)”, access to electricity is often impeded by the lack of financial resources of the rural households to pay for the connection fees to the electricity network. Hence, the electricity access rate would increase in rural areas if the legal and regulatory frameworks would allow private investors to build and operate small grids, connected or not to TANESCO, where connection fees and in- house installations could be financed through access to credit lines supported by development partners. This mechanism of access to credit lines to finance connection fees and household electric installations has been in practice in various countries across Africa to accelerate the electrification in rural areas.
In a context of growing demand for energy, it is strongly recommended that the future energy development plans give a comprehensive and integrated overview of all the power generation options for Tanzania, including the 36 hydropower sites already studied at an advanced stage (refer to section 7.1.4 for more details on those sites), the 20 prioritized potential small hydropower sites selected in the context of the present study as well as the other sources of renewable energies (solar, wind and biomass). This would create a comprehensive portfolio of relevant RE generation alternatives. Moreover, it is recommended to visit and review part of the 36 hydropower sites in order to evaluate and/or update their production costs (LCOE) to eventually make relevant comparisons with the 75 potential sites analyzed in the present study.
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Also, we strongly recommend to further explore the possibility to develop reservoir hydropower schemes having the capabilities to daily or seasonally regulate the river flows, hence the energy generation. This would allow for more flexibility in the management and operation of the power system to meet the variable demand.
Finally, the expansion of the existing interconnected grids should continue. This must be done in a transparent way, using maps, clearly highlighting the priorities and timeframes for their development. This would allow to not jeopardizing the development of some remote potential hydropower sites which are generally smaller and less competitive, partially due to the high costs associated with the development of their transmission lines. Those high costs could be put into perspectives should the expansion plans of the power grids be better known.
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16 Conclusions
All the information related to the hydropower sector in Tanzania having geographical references has been compiled into a geographic information system (GIS). More specifically, the original database of potential hydropower sites is the result of the integration of information from different sources: it contains a total of 455 potential hydropower sites amongst which 281 coming from the literature and 174 newly identified by SiteFinder, a spatial analysis tool that identify river stretches featuring a high hydropower potential based on rainfall and topography data (tool developed in house by SHER Ingénieurs-Conseils). Note that the cleaning and validation processes of the spatial database will be finalized with the assistance of REA and associated organizations during Phase 2 and 3 of the study for the final production of the Small Hydro Atlas. We suggest to discuss the detailed approach and methodology during the workshop.
Alongside to the potential hydropower sites selection process, the hydrological study revealed that, in general, available hydrological data in Tanzania are sparse and / or non-existent for some watersheds. For the vast majority of the potential hydropower sites in this study, there is no or little accurate information on their hydrological regime. Therefore, we developed and applied a methodology to estimate the statistical characteristics of river flows at sites of interest, based on data available at other gauging stations in Tanzania. We also attributed to each site a confidence index to the estimates.
The 75 promising sites (and 11 existing sites) were visited between March 2014 and January 2015. Site visits enabled to validate the information and the assumptions made during the desk study phase and to propose relevant hydropower schemes layouts adapted to the local constraints of the sites environments. The data acquired during the sites visits are included in dedicated reports: Sites Visits Report - Potential Sites and Sites Visits Report - Existing sites.
Chapter 12.4 of the report includes the proposed detailed planning of Phase 2 and 3 related to the data collection and final validation. This activity aims at validate key parameters of the 20 prioritized sites through additional investigations related to the topography, geology, natural and social environment and hydrological measurements. Regarding the hydrological measurements campaign, it is proposed to install flow gauging stations (measurement of water level) on 7 rivers over a period of 18-months. These additional measurements will substantially improve the knowledge of rivers located in areas that have not been or only sporadically gauged in the past. It is important to note that it is only by further expanding and maintaining the existing network of flow gauging stations (and the new stations that will be installed as part of this study) that hydrological data will contribute to a better development of hydropower projects in Tanzania. As mentioned previously, the 455 potential sites database will be validated during phase 2 and the HydroAtlas of Tanzania will be published.
The mapping of the hydropower potential of Tanzania reveals that the country owns a great potential which is currently largely untapped. The country benefits from a good relief and favourable rainfalls, particularly in the Western part of the country and other mountainous areas. Development opportunities cover the entire power range, from small to large
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hydropower schemes. The development of this potential, however, is hampered by the poor quality of the transportation network (particularly tracks and roads), the scattering of urban areas and is also challenged by the size of the country. Soil degradation and subsequent erosion due to unsustainable agricultural practices, gold panning and artisanal mining activities in some areas of the country are worrying and might jeopardize the viability or even the technical and financial feasibility of some hydropower projects. These watershed degradation and sediment load problems should be taken into account in the planning and development of every future hydropower projects, whether large or small. Generally speaking, any new hydropower development should be part of an integrated river basin management plan (RBMP) developed in accordance with the Integrated Water Resources Management (IWRM) principles in order to preserve this sustainable and natural resource.
The production of the HydroAtlas that will be delivered at the end phase 3, including the spatial databases (GIS) described in this report are appropriate operation tools to facilitate the planning process undertaken by the Tanzanian agencies responsible for the latter. Indeed, the HydroAtlas will be a unique tool that integrates all the (validated) information from the different institutions involved in the hydropower sector. It provides an overview of the sector, in terms of existing and potential assets that allows a better visualisation of the portfolio of possible future supply options that could meet the increasing demand. It is worth mentioning that the HydroAtlas and its spatial databases are dynamic and evolving tools that must be updated according to future developments of the hydropower sector in Tanzania and the increasing availability of information (hydrological measurements, updated site surveys, etc.).
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17 Afterword
The content of this report reflects the study process before the workshop, held in Dar-Es- Salaam, on March the 17th, 2015.
During the workshop and concomitant meeting, it was decided that additional site visits amongst potential site already studied at a certain level shall be foreseen in activity 2 to improve the portfolio of potential small hydropower sites.
The added value and the level of risk concerning the installation and monitoring of gauging equipment was also debated. It was decided together with REA and the World Bank to skip this activity and to improve the hydrological information by carrying out a more detailed hydrological analysis on the 20 prioritized sites in order to further reduce the uncertainties associated with their preliminary design (installed capacity, firm energy generation, etc).
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18 Annexes
18.1 ANNEXE 1 : BIBLIOGRAPHY
Title Author Date Tanzania Rural Electrification Study Sweco 2005 Africa Renewable Future IRENA - Global Atlas for Solar and Wind Energy_abstact IRENA - Global Solar and Wind Atlas IRENA - Implementation Strategy For a Global Solar and Wind Atlas IRENA - Mini-grids based on Mini Hydro Power(MHP) sources to augment rural electrification in UNIDO - River basin planning and management EJ.Manongi - Rural Energy Agency and Innovation in Delivery of Modern Energy Services to Rural Areas REA - Tanzania_Overview of The Electricity Sector Unknown - Tanzania_Power Sector Situation Unknown - Master Pan and Programme Report decon 2005 The Rural Energy Act 2005 REA 2005 Electricity Act 2008 TANESCO 2008 Power system Master Plan-Apendix C-Extended Steamflow Seres TANESCO 2008 Guidelines for Developers of Small Power Projects in Tanzania Draft 2009 Power system Master Plan 2009 Update SNC LAVALIN 2009 Rural Electrification Plan-Tanzania_V5 Suma SHP 2009 Target Market Analysis_Tanzania's Small-Hydro Energy Market Hankins_GTZ 2009 Joint Energy Sector Reviw_Final Report MEM 2011 REP_Financing Windows For Rural or Renewable Energy Development in Tanzania REA 2011 The organization Struction of the Ministry of Water Minister 2011 Power Report Master Plan_Interim Executive Summary Report MEM 2012 Visions, Scenarios and Action Plans Twards Next Generation Tanzania Power System Kihwete et al 2012 IRENA_Stecher et Biomass Potential in Africa al_DBFZ 2013 Capacity Development Framework-Renewables_V1.1 Met Office 2013 Energy Lab Report Executive Summary TdV25 2013 Mini-Hydro for Rural Electrification in Tanzania DIT 2013 Power System Master Plan 2012 - update May 2013 MEM 2013 Tanzania Hydropower Sustainability Assessment-Fnal Inception Report SWECO 2013 Existing Studies Hydro Iventory.V2 Unknown - List of GVEP-supported Small Hydropower sites in Tanzania Unknown - List of Selected Projects for Feasibility Study Unknown - List of Various Studies TANESCO - Summary of Identified Small and Medium Hydropower Potential in Tanzania and their level Study Unknown - Inventory of Mini-Hydropower Potential Sites TANESCO 2005 Inventory of Mini-Hydropower Potential Sites TANESCO 2005 List of Mini-Hydropower Potential Sites in Tanzania TANESCO 2009
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Title Author Date List of Mini-Hydropower Potential Sites in Tanzania-Update TANESCO 2010 List of Mini-Hydropower Potential Sites in Tanzania-Update TANESCO 2010 List of Mini-Hydropower potential sites in tanzania TANESCO 2012 Projectpipleinelist_v2 REA 2012 Small and mini-hydropower potential sites in tanzania TANESCO 2012 Summary of SPP Developers Unknown 2013 Iringa Phase II_Summary of the reconnaissance study findings Unknown - Project Records updated REA - Reconnaissance study findings_Kagera,Iriringa,Ruvuma Region Unknown - Surverys and Investigations SwedPower 1998 Small Hydro INVENTORY TANESCO 2002 Micro-Hydropower for Rural Electrification in Tanzania and Identification of suitable Local Facilities UNIDO-TaTEDO 2005 Potential hydropower sites in the Usambara Mountains TaTEDO 2005 Reconnaissance Study_Mini hydropower Potential Sites-Rukwa Region TANESCO 2006 Reconnaissance Study_Mini-Hdropower Potential in Kagera Region_Draft Report TANESCO 2006 Reconnaissance Study_Mini hydropower Potential Sites in Mbeya Region TANESCO 2007 Reconnaissance Study_Minihydropower potential Sites-Iringa Region PhaseII TANESCO 2007 Reconnaissance Study_Minihydropower Potential Sites-Iringa Region PhaseIII TANESCO 2009 Annex 10_Reconnaissance Study_Mini-Hydropower Potential Sites_Morogoro Region_Draft TANESCO 2012 Identification of biomass potential in Tanga region_Tanzania IED 2012 Identification of Potential Hydropower Sites in Morogoro Region_Report of Field Mission IREP 2012 Reconnaissance Mission_Development of the Pangani and Kiwira Hydropower schemes Vala Associates 2012 Annex 10_Pre-faisability study of sites visited by Tanesco team in the south Morogoro region tanesco - Electrification of Muze village TANESCO - Feasibility Study _Micro-Hydro Plant on Yongoma River Unknown - Potential hydropowersites in the Pare Mountains TaTEDO - Pre-Feasibility Study of Upper Ijangala Small Hydropower Plant ELCT - Pre-Feasibility Study _Kitewaka Hydropower project_6p Unknown - Tanzania Zeco Hydropower Reference List Unknown - The Potential for Job Creation and Productivity Gains Trough Expanded Electrification Unknown - Feasibility Studies_Ruhudji Hydropower Project_Final Report_Executive Summary SwedPower 1998 UNP_ESMAP_Pre-Investment Report on Mini-Hydropower Development-Rukwa region_Case Mtambo River SECSD(P) 2000 UNP_ESMAP_Pre-Investment Report on Mini-Hydropower Development-Ruvuma region_Case Muhuwesi River_185p Unknown 2000 Limkerenge Feasibility Study NINHAM SHAND 2002 Tanzania -Mini Hydropower Development-Case Studies on Malagarasi, Muhuwesi, and Kikuletwa Rivers-VolI-The Malagarasi River ESMAP 2002 Tanzania -Mini Hydropower Development-Case Studies on Malagarasi, Muhuwesi, and Kikuletwa Rivers-VolII-The Muhuwesi River ESMAP 2002 Tanzania -Mini Hydropower Development-Case Studies on Malagarasi, Muhuwesi, and Kikuletwa Rivers-VolIII-The Kikuletwe River ESMAP 2002 Wino Development A proposal for a rural transformation project in wino and mahanje Association 2004 Norwegia, Support to Implementation for SHP_Assessement and Prioritization Study NORPLAN 2009
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Title Author Date Ruhudji Hydropower Porject_Complementary Hydrologicaly Studies_Interim Report SWECO 2009 Hydropower Prefeasibility Project Potential Along Kiwira River in Tanzania MeS 2010 Ruhudji Hydropower Project_Design Hydrology Report SWECO 2010 The Report on Pre-Feasibility Study of SHP Schemes in Morogoro, Iringa, Ruvuma and Mbeya Regions-Tanzania Y Dar Es Salaam Institute of Technology(1) 2010 The Report on Pre-Feasibility Study of SHP Schemes in Morogoro, Iringa, Ruvuma and Mbeya Regions-TanzaniaY Dar Es Salaam Institute of Technology(2) 2010 The Report on Pre-Feasibility Study of SHP Schemes in Ruvuma and Iringa Regions- Dar Es Salaam Institute Tanzania of Technology(1) 2010 The Report on Pre- Feasibility Study of SHP Schemes in Ruvuma and Iringa Regions Dar Es Salaam Institute Tanzania of Technology(2) 2010 The Report on Pre-Feasibility Study of SHP Schemes in Ruvuma and Iringa Regions- Dar Es Salaam Institute Tanzania of Technology(3) 2010 Annex2_Prefeasibility study report for the potential demo sites UNIDO 2011 Kiwira River 10 MW Small Hydropower Project_Draft Feasibility Study EA Power 2011 Pre-Feasibility Studies for SHP project-Draft Final Report_PartII_Nkole SHPP ENCO 2012 Pre-Feasibility Studies for SHP project-Final Report_PartI_Zigi SHPP ENCO 2012 Feasibility Assessment for the Innstallation Of Hydroelectricity in Momba District SKY Energy 2013 Inception report_feasibility study of six mini hydropower project in Tanzania_Intec 2013 Modelling the Mtera_Kidatu Reservoir System to Improve IWRM Yawson_et_al 2003 NationalWater_Sector Development Strategy 2006 Water Ressources Assistance Strategy-Improving Water Security for Sustaining Liverlihoods and Growth WB 2006 Rufiji Basin IWRMD Plan_Draft Interim ReportII-Volume2 Water Management Options WREM International based on National Development Policies and Sectoral Plans Inc. 2007 Rufiji IWRMD Plan_Draft Interim Report VolumeI-Water Resources Availability WREM International Assessment Inc. 2007 WREM International Water Sector Status Report Inc. 2010 Rufiji Basin IWRMD Plan_Draft Interim ReportII-Volume1 Climate and Hydrologic WREM International Modeling and Assessments Inc. 2013 Rufiji Basin IWRMD Plan_Draft Interim ReportII_Volume3 Stakeholder Participation, WREM International Capacity Building, and Communication Plan Inc. 2013 Climat Change Adaptation in the Pangani River Basin IUCN - Climate Projections for United Republic of Tanzania Jack_UCT - Pangani River Basin-Tanzanie WANI Case Study IUCN - The Economics of Climate Change in Tanzania-Water Resources Noel(SEI) - UNDP Climate Change Country Profiles C.McSweeney et al. - Population and Assets Exposure to Coastal Flooding in Dar es Salaam(Tanzania)- Kebede and Vulnerability to Climate Extremes Nicholls(UK) 2001 National Adaptation Programme of Action(NAPA) URT 2007 Climate Volatility and Poverty Vurnerability Ahmed et al. 2009 Climate Volatility deepens poverty vulnerability in developing countries Ahmed et al. 2009 Agriculture and Trade Opportunities for Tanzania-Past Volatility and Future Climate Change Ahmed et al. 2010 An assessment of future emissions growth and low carbon reduction potential SEI 2010 Climate change modelling for the Pangani Basin to Support The IWRM Planning Porcess UCT 2010 Climate Change Vulnerability and Adaptation Preparedness in Kenya CAMCO 2010 Climate Change Vulnerability and Adaptation Preparedness in Tanzania CAMCO 2010 Climate Change Agriculture and Poverty Hertel et al. 2010
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Title Author Date Synthesis Report-The Implications of Climate Change and Sea-Level Rise in Tanzania- The Coastal Zones Kebede et al(UK) 2010 Agriculture and Trade Opportunities for Tanzania-Past Volatility and Future Climate Change-Ahmed et al WIDER 2011 Climate Change, Agiculture, and Food Security in Tanzania-Arndt et al WIDER 2011 Climate Variability and crop production in Tanzania Rowhani et al 2011 National Claimate Change Strategy and Action Plan URT 2011 Technical Assessment for Potential Community-based Micro-Hydropower potential in Muheza, Korogwe and Lushoto Districts-Technical Report CAMCO 2011 Climate Impact and Crop Agriculture ine Tanzania- DECAR Project "Climate Volatility and Poverty in Southern and Eastern Africa" Ahmed 2012 REMP_Technical Report Upstream Upstream Downstream Workshop IUCN 2001 SAGCOT_Strategic Regional Environmental and Social Assessment Draft Report ERM 2012 Analyse_population_villages Fact sheet - Briefing_DP_Mapping Fact sheet - Links to national statistics Fact sheet - Min i-Grids_Tanzania Fact sheet - NBCBN_Hydropower Development Research Cluster Kassana et al 2005 Tanzania National Panel_Survey Report 2008-2009_Round 1 NBS 2009 National Sample Census of Agriculture_preliminary Report NBS 2010 National Strategy for Growth and Reduction of PovertyII MFEA 2010 PPP BILL JULY 2010 Fact sheet 2010 REA Annual Report REA 2010 REA Annual Report For The_Financial Year Ended June 30th2010 REA 2010 African Country Factsheets_Africa Modelling KTH 2012 African Country Factsheets_Renewable Potential KTH 2012 Renewable Energy Projects available for Investment in Tanzania REA 2012 Tanzania National Panel_Survey Report 2010-2011_Wave 2 NBS 2012 Annual Review of Government of Sweden and Norway Financing Support to Capacity Development Project and Rural Energy Fund 2012-2013 REA 2013 Email from stakeholder in Ruha e-mail 2013 PAD_Capacity Build WB 2013 Permission letter for data request TANESCO 2013
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18.2 ANNEX 2 : SITEFINDER : A TOOL TO DETECT SMALL HYDROPOWER POTENTIAL SITES
Site Finder is a Python program developed by SHER whose objective is to detect small hydropower potential sites. The software needs a DEM (Digital Elevation Model: a numeric topography model) and the mean annual rainfall map.
The program simulates runoff in the area and deducts river flows. That, combined with the topography layer, allows the program to compute the specific potential (i.e. power potential per unit length) on the whole river path. The process output is a GIS layer highlighting the high potential of the rivers of the covered area. It allows the operator to analyze the results in a convenient way by enabling a cross-check with other GIS data such as topography map, satellite images, etc.
Below is an example on two rivers in Tanzania nearby Mahale Mountain National Park.
The map shows the river path on a topographic map. It also shows the results of SiteFinder on this river, with high power potentials in orange-red colors.
The following graph shows the discharge crossed with the elevation profile. Both the discharge and the elevation profile are computed by SiteFinder.
The program then computes the specific power potential on the river (potential per unit length). The high potential sites are highlighted by red-colors on the map. The operator is then able to navigate through the project area and to record (manually) every detected site in a GIS database.
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1,4 1400 1,2 1200
1 1000 0,8 800 0,6 600 0,4 Discharge 400
Discharge[m³/s] 0,2 Elevation 200 0 0 [m] Elevation 0+000 2+000 4+000 6+000 8+000 10+000 12+000 14+000 Chainage [m]
Figure 36. Example of computation realized by SiteFinder, showing the river elevation/discharge profile
18.2.1 Input data: Rainfall The 2 sources of mean annual rainfall maps have been found in Tanzania land resource for coffee map (funded by the STABEX program of the European Union 1998 - left), and the Mean Annual Rainfall Map (ODI, "Rethinking natural resource degradation in semi-arid sub-Saharan Africa: the case of semi-arid Tanzania" 1966, reproduced in the IREP reports, - right). Although those maps have a significant difference in production date, they are rather closely matched.
Figure 37 Mean Annual Rainfall
18.2.2 Topographic Data: Digital Elevation Model The 2 sources of DEM used are ASTER and SRTM20.
SRTM
The Shuttle Radar Topography Mission (SRTM) is an international research effort headed by the U.S. National Geospatial-Intelligence Agency (NGA) and the U.S. National Aeronautics and
20 Source of the following information: www.wikipedia.org
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Space Administration (NASA). It obtained digital elevation models on a near-global scale from 56° S to 60° N, to generate the most complete high-resolution digital topographic database of Earth prior to the release of the ASTER GDEM in 2009. SRTM consisted of a specially modified radar system that flew on board the Space Shuttle Endeavour during the 11-day STS-99 mission in February 2000. In November 2013, LP DAAC released the NASA Shuttle Radar Topography Mission Version 3.0 (SRTM Plus) Product collection with all voids eliminated.
The data resolution is three arc second (90 m - but up to 1 arc second in the US).
ASTER
ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) is a Japanese sensor which is one of five remote sensory devices on board the Terra satellite launched into Earth orbit by the NASA in 1999. The instrument has been collecting superficial data since February 2000.
During October 2011 version 2 of Global Digital Elevation Model was publicly released. This is considered an improvement upon version 1. These improvements include increased horizontal and vertical accuracy, better horizontal resolution, reduced presence of artefacts, and more realistic values over water bodies. However, although showing a considerable improvement in the effective level of detail, some experts still regard it as being at an 'experimental or research grade' due to presence of artefacts.
The data resolution is 30m.
Resolution
The ASTER resolution is about 9 times that of SRTM: where SRTM has 1 elevation value (1 pixel is 90mx90m), ASTER has 9 (1 pixel is 30mx30m). This is highlighted on the figures below.
Figure 38: Resolution of ASTER (left) and SRTM data (right), on an area in Mbeya region.
Artifacts (errors) on the project area
ASTER is known to still have some artifacts (local errors). If most of the project area has a satisfying quality, others have many local errors. Below is an example on tile S11E037 (Eastern Tanzania).
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Contours lines issued from SRTM are shown in red. Contours lines retrieved from ASTER are shown in blue. Most of the contour lines are similar, even on the hills shown on the upper left and right parts of the image. However, on the picture center, many 'small hills' are shown only with blue contour lines. Those hills do not exist in reality; they are local errors of ASTER DEM.
Figure 39 Local errors of ASTER DEM
Areas filled with SRTM data
On some areas in Eastern Tanzania, parts of ASTER DEM have been filled up with SRTM data. The 2 figures below represent the same area. The first one is ASTER only, and one can see a huge difference in resolution between the center and the sides of the picture. The second one shows the 2 DEM contour lines, where the image center has almost exactly the same contour lines for both.
Figure 40 ASTER DEM and SRTM DEM comparison
Other remarks
A subtraction between the 2 DEM gives other details.
Some tiles show significant differences between the 2 DEM, following the satellite track. Here follows a subtraction on tiles S06E030 and S11E037, where the typical satellite track angle is visible.
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Figure 41 Example of subtraction between ASTER and SRTM
Again, if most of the country has a satisfying quality for ASTER DEM, (for example below on the left), some areas are very polluted, with huge differences between both DEM (below on the right, subtraction on tile S11E037).
Figure 42 Subtraction on tiles S06E030 and S11E037
SRTM quality has been widely recognized. ASTER has a better resolution, but still lacks the quality of SRTM.
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All the ASTER errors shown above might have an impact on the SiteFinder process, resulting in sites being mistakenly detected or other mistakenly omitted. However, with its much higher resolution, ASTER would allow the software to detect sites located in more complex topographical features.
For such reasons, both DEM have been used in the software. Possible mistakes in site detection are possible due to the resolution and quality of the DEM.
Therefore at the end of the process a thorough manual site assessment and visual check, using the 1:50,000 topographical maps, was carried out on the pre-identified sites.
18.2.3 Program Simplification As indicated below, the SiteFinder process has been particularly time and computer consuming. It was therefore decided to simplify the process by dividing the country into several main watersheds and by simplifying the hydrological input. Even so, more than 20 nights were necessary to complete the process with the ASTER data.
18.2.4 Work flow The workflow has been organized as follow:
Input data quality check : The focus of quality check was mainly the DEM, whose quality has been compared to the SRTM's. See paragraph 18.2.2 for details.
Detection process : SiteFinder needs 2 major calculation steps in its process: river path creation and hydropower computation, whose complexity is directly proportional to the DEM resolution and the area extents.
SiteFinder SRTM processing
A merged national SRTM DEM has been created for this analysis. Each major step needed a 12 hours computer calculation.
SiteFinder ASTER processing
ASTER DEM for the whole country takes 2.5 GB of space disk.
Resolution here was too high to create a national DEM, given the size of the country. Therefore, the country has been divided into water basins. Then, SiteFinder was applied on each major basin. This process was particularly time and computer consuming since 12 areas were created, and each area needed 2 nights of computer process for the 2 major steps, meaning that around 24 nights were required to cover to whole country with ASTER DEM.
Every detected site is recorded in a SiteFinder database by our engineers.
Manual site assessment and visual check : a final check and potential assessment is then undertaken. This is made possible by reviewing topographic maps, which give more accurate information about the head. The hydrological database also gives a (rough) estimate of the discharge to be expected.
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Topo Maps check
The sites are checked on the 1:50,000 topo maps and a value for the expected head is assessed based on the map contour lines.
Hydrological estimation
An estimated value for the mean annual discharge is extrapolated from the hydrological database.
The 2 previous parameters allow us to assess the expected power potential of the sites.
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18.3 ANNEX 3 : METHODOLOGY USED FOR ECONOMICAL EVALUATION
18.3.1 Objective The main objective of the economical evaluation is to define the Levelized Cost Of Energy (LCOE). The LCOE is a stream of equal payments, normalized over expected energy production periods that would allow a project owner to recover all costs, an assumed return on investment, over a predetermined life span.
LCOE has the following basic cost components:
Fixed costs, such as initial investment (construction, environmental and social mitigation, interim replacement costs, decommissioning, etc.).
Variable costs, such as operations and maintenance (O&M) and fuel.
The LCOE is defined for all sites and allows an easy comparison of the potential schemes profitability.
Moreover, the SREP21 has defined the LCOE values for different power generation systems, namely:
Small hydropower plant,
Biomass power plant,
Isolated diesel generator,
Solar photovoltaic with battery,
Hybrid system between diesel generator and solar photovoltaic with battery.
They were compared based on an economic discount rate of 10%. The lifespan of the different systems is not defined in the report. Below are two tables comparing the basic assumptions related to the calculation of the LCOE in the SREP report and in the current report as well as LCOE values obtained from SREP.
SREP Hydropower atlas Actualisation rate 10% 10% Life span Unknown 50 years Operation and maintenance costs 5% annual capital cost 10$ / kWh / year SHP installed capital cost 3000 $ / kW Calculated based on quantities Table 21 Basic assumptions comparison
Small hydro Biomass Hybrid Diesel Solar PV 0.23 $ 0.29 $ 0.53 $ 0.59 $ 0.71 $ Table 22 : LCOE calculated by SREP
Additional information obtained from the Investment Plan for Tanzania concerns the cost for private diesel generation, which the fuel cost is expected to exceed 0.35 $ / kWh.
21 Scaling-up Renewable Energy Program (SREP), Investment plan for Tanzania, 2013
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Hence, the economical evaluation will enable an identification of the most promising schemes and of schemes presenting an acceptable LCOE (lower than 0.5 $/kWh).
18.3.2 Global methodology The objective is reached after processing data collected during the field mission. These data concern some geometrical information and comments on the site situation. Based on these, the global design of the scheme is defined.
Data are then processed in a dedicated software developed by SHER which allows the definition of energy production and project costs. LCOE is obtained from those results.
18.3.3 Type of schemes designed Three types of schemes are designed:
- Run of the river schemes,
- Daily operated reservoir schemes,
- Regulation reservoir schemes.
Run of the river schemes are supposed to be operated 24 h a day while daily operated reservoir are supposed to be operated at least 6 h a day at full capacity. The sites topography is supposed to enable enough storage volume to run reservoir schemes (daily operated or regulation). Hence, regulation reservoirs are supposed to be operated at full capacity 24 h a day all the year long. Regulation reservoirs with daily fluctuation are not considered.
18.3.4 Hydrology Hydrological parameters are obtained by regionalization of available hydrological measurements. A theoretical rated discharge curve is defined for each site and different return-period discharge values are extracted from this curve to feed the software.
Discharge values used for installed capacity definition are: Q2.5%, Q30%, Q50%, Q65%, Q90%, Q95%. Discharge value used for flood determination has a return period of 100 years (Q 100 year).
Discharge available 95% of the time (Q95%) is called “firm discharge” and is used to determine the firm capacity and the firm energy generation.
18.3.5 Design of Works Project implementation costs are mainly related to Civil Works. Main civil works comprised in a hydropower scheme are: the dam, the spillway, the desilting basin, the intake and headrace (canal or tunnel), the forebay or surge tank, the penstock and the powerhouse.
Other elements also essential for a hydropower scheme are: electromechanical equipments, access roads and transmission line. The last two however are often considered separately as they are of public interest (roads and transmission lines are part of a country’s development plan) and might be financed by public institutions.
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The following section will highlight the main assumptions used for the design of Works (Civil Works and others).
Dam
Several dam types were considered:
- Concrete gravity dam
- Masonry gravity dam (with a maximal height of 20 m)
- Rockfilled embankment dam
- Earthfilled embankment dam
To prevent seepage, embankment dams are planned with a clay core. Other techniques exist (bituminous core, concrete facing,…) but are not considered at this very preliminary stage.
Dam dimensions and type are defined after the field mission observations. If no indication is given about the dam type after the field visit, the choice is made after considering the following elements:
- The shape of the valley:
Wide : an embankment dam is preferred
Narrow : a gravity dam is preferred
- The overall geology of the dam area:
Rocky : a gravity dam or a rockfill dam is preferred
Loose : an earthfilled dam is preferred
When the dam is to be placed on a permeable soil (sand, cracked limestone,…) jet grouting is foreseen.
Spillway
For gravity dam, the spillway is ungated and ogee shaped. The spillway might be as large as the dam itself, in which case the dam is called a weir.
Embankment dams are planned with an ungated sill with spillway and stilling basin. Guide walls, spillway and stilling basin will be made of concrete.
Gates will only be foreseen for extremely large flood discharge. For micro-hydropower schemes, shaft spillways are not considered.
Desilting basin
Desilting basins are among the most important Works for a hydropower scheme, especially when solid transport in the river is high. The more important the sediment load, the larger the desilting basin. Desilting basins are designed with two tanks so as to keep the turbine running even when a flushing is required. They
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must be large and long enough to cause settling of solid particles but not too much so as to allow an easy flushing; if sediments stay too long in the desilting basin, they might start to consolidate and flushing becomes extremely complicated (it requires large amounts and velocities of water, or even cleaning by hand).
The water turbidity (expressed in NTU) gives a hint about the global solid transport. The higher the turbidity, the higher the solid transport. Although the field measurement is an isolated measure, it can be used to define whether a desilting basin is required or not.
It is assumed that a desilting basin is required if the turbidity exceeds 100 NTU. Observations on site will allow the definition of the desilting basin size to be implemented. Similarly, if the turbidity is lower than 100 NTU but field observations indicate high amounts of sediment deposition along the river, it might be decided to design the scheme with a desilting basin. Each tank of the desilting basin is equipped with slide gates at entrance and end as well as with a flushing gate.
Intake and headrace
Intake is equipped with trash rack, trash rack cleaning device (manual or automated) and a slide gate. A gravel trap is planned in the intake vicinity to prevent gravels from entering the headrace. A flushing gate is foreseen through the dam to eliminate debris and prevent them from obstructing the intake. Stop logs slots are planned upstream of the intake to allow its dewatering.
Two headraces are considered: open canal and underground tunnel. They might be combined.
When the ground transverse slope is higher than 45°, it gets risky to pass with a canal. Hence, tunnels will be preferred each time that the mean transverse slope is higher than 45° on the whole projected canal length. In other situations, a canal might be projected. If the canal trace crosses sections with a high transverse slope (>45°), retaining structures and stabilization measures will be planned.
Forebay
A forebay tank is the junction between the headrace canal and the penstock. It might also serve as auxiliary desilting basin (and be designed as such, long and wide enough to allow sedimentation). The penstock must be submerged to such a depth that no vortex is formed. The vortex is air that enters the penstock and could cause cavitation. Hence, the forebay is composed of two sections: a settling section (for sediments) and a head pond (where the penstock mouth is located).
The forebay is equipped with slide gates at the end of the settling section to isolate it from the head pond. A flushing gate is foreseen in the settling section. A trash rack and trash rack cleaning machine are also provided before the penstock mouth, to prevent particles from entering the pipe, so as to avoid damaging the turbine.
Surge tank
The surge tank is the junction between the headrace tunnel and the penstock. It is open air and built in reinforced concrete. It avoids damages related to water hammer issue when quick opening and/or closing of the turbines.
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Penstock
The penstock is the link between headrace works and the powerhouse. It is usually a high pressure pipe. It is made of steel and its diameter is defined to keep head losses to a reasonable value. Nowadays, other types of pipe might be used for penstocks (GRP, PEHD). They are not considered at this very preliminary stage.
The penstock might either be aerial, buried or both. Aerial sections are placed on slide blocks. Anchor blocks are placed at each bend in the pipe.
Given the range of hydropower schemes studies (0 to 10 MW), only one penstock is foreseen. If several turbines are foreseen, a bifurcation (or trifurcation) will distribute water to all turbines.
Powerhouse
The powerhouse will be above ground. Underground powerhouses are not studied at this stage.
The powerhouse will be equipped with stop logs downstream of the turbines, in the tailrace canal.
Electromechanical equipments
Three types of turbines are considered:
- Kaplan turbines: for low heads and high discharges
- Francis turbines: for medium to high heads and high discharges
- Pelton turbines: for high heads an low to medium discharges
In order to ensure a satisfying production curve, at least two turbines are placed in schemes exceeding 1 MW of installed capacity. It ensures redundancy of equipments, economies of scale on spare parts and the possibility of partly operating the scheme, even during maintenance.
The choice of turbine is conducted based on the next figure. It indicates the discharge and head ranges in which a particular type of turbine might be operated. Following criteria 22 were considered:
- Kaplan turbine : H < 12 m Q > 10 m³/s and H < 30 m - Francis turbine: 30 m < H < 60 m Q < 10 m³/s and H < 30 m Q > 0.5 m³/s and 60 m < H < 100 m - Pelton turbine :
22 These criteria are relevant for small hydropower schemes and must be reviewed if intended to serve for schemes with an installed capacity exceeding 10 MW. Other types of turbines (presented in the figure above or not) might also be used and must be analyzed in further studies.
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H > 100 m Q < 0.5 m³/s and 60 m < H < 100 m
Figure 43 : Turbines operating range (Layman. 2005)
Access road
Access road concerns both sections of road to rehabilitate and sections of road to create to enable access to the scheme (mainly dam and powerhouse sites). Their width is taken to 5m.
In some case, they might contribute to enhance the national network and their costs might be covered by public funds.
Transmission line
The main objective of transmission lines is to:
- Connect the scheme to the closest grid (national grid or mini grid) if it is supposed to be connected.
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- Connect the scheme to final users (hospitals, industries, load centers, households,…) if it is supposed to be isolated.
18.3.6 Costs estimate Two kinds of works were considerate for costs estimates:
- Dam and waterways works (canal, tunnel, penstock)
- Dedicated works (desilting basin, forebay, surge chamber, powerhouse,...)
Quantities required for the first group are easily computed. An estimative bill of quantities is then easily realized, and hence costs might be estimated. For the second group however, quantities are more difficult to define, mainly because of the complexity of the works. Costs of dedicated works were then estimated after benchmarking over 50 hydropower schemes in Central Africa and Madagascar. Costs were actualized to 2013 $. Hence, costs of dedicated works were derived from interpolation on one of the scheme’s characteristic (capacity, head, discharge,...), depending on the work treated.
Electromechanical equipments costs were also defined after regressions (cost versus capacity), defined for each type of turbine.
Additional costs were also taken into account. They consist in;
- 20% for Civil Works contingencies
- 15% for Electromechanical equipments contingencies
Engineering and supervision of works is estimated at 10% of the total cost.
18.3.7 Electrical production Installed capacity depends on the type of scheme and on the demand. Demand is correlated to the connexion that is planned.
Indeed, if the scheme is isolated, the purpose of the hydropower plant is to produce electricity all the year around with as few variations as possible, hence the operating discharge must be close to the firm discharge of the river.
On the other hand, in a connected grid, hydropower plants are often used for peaking. Hence the operating discharge is chosen to provide as much energy as possible over a given amount of time. For example, the plant runs at full capacity during the rainy season, but only at half of its capacity during the dry season.
18.3.7.1 Operating discharge As highlighted above, operating discharge is chosen according to the demand. Indeed, installed capacity depends mainly on operating discharge and head. Head depends on the site topography and is then a fixed parameter. Operating discharge might be chosen.
Below is a table indicating the operated discharge selected for each case.
Isolated Connected
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Run of the river scheme Q90% Q30% Daily reservoir scheme 4 Q90% 4 Q30% Regulation reservoir scheme
18.3.7.2 Firm capacity, firm energy and installed capacity Run of the river scheme
The capacity [kW] of a hydropower run of the river scheme is determined from the following equation:
with the global efficiency (estimated at 85%), the water density (1000 kg/m³), H the net head and
the scheme operating discharge (m³/s).
The firm capacity [kW] is the capacity reached with the firm discharge ( :
The firm energy [kWh] is the amount of energy produced on one year if the scheme works at firm capacity.
It is then obtained by multiplying the firm capacity by 8760h :
Daily reservoir scheme
The capacity [kW] of a hydropower daily reservoir scheme is determined from the following equation:
with the global efficiency (estimated at 85%), the water density (1000 kg/m³), H the net head, the width of active storage volume and the scheme operating discharge (m³/s).
As daily reservoir are supposed to be operated 6 hours a day, the firm discharge is The firm capacity is the power delivered by the turbines under the lowest operating conditions (when the water level is the lowest). In such case, turbines are not working at their best efficiency. This effect is taken into account by modifying the discharge according to the new head conditions . For the firm
capacity, . The firm capacity [kW] is then given by :
The firm energy [kWh] is the amount of energy produced on one year under the lowest operating conditions23. It is given by:
23 The head considered is the mean head because a daily reservoir is only operated part of the day, so it has time to re-fill up to maximum level during non-functioning periods.
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Regulation reservoir scheme
The installed capacity is calculated the same way as for daily operated reservoir. The firm capacity [kW] is calculated based on the same formula as for daily operated reservoirs:
The only difference is that the firm discharge is the operating discharge. It is due to the fact that the storage volume is considered sufficient to allow a regulation all over the year. Turbines will thus be operated all the year round at the same discharge; the operating discharge.
The firm energy [kWh] is the amount of energy produced on one year under the lowest operating conditions:
18.3.7.3 Energy production Run of the river schemes
The energy production [kWh] is calculated based on the “operation flow duration curve”. It is defined by the union between the operating flow and the flow duration curve, as shown on the diagram below.
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Flow duration curve
Operation flow duration curve
Operating discharge curve
The operation flow discharge curve is then multiplied by , so as to obtain an “operational power duration curve”. The energy production is obtained by integrating the area under this last curve.
Daily reservoir schemes
The principle is the same as for run of the river schemes, except that the flow duration curve must be multiplied by a factor corresponding to the opposite of the portion of time during which the scheme is supposed to be working:
As the hypothesis was taken that the plant is supposed to be working at full capacity at least 6h a day, the factor value is 4.
Regulated reservoir schemes
For regulation reservoir, the available discharge is defined based on the total storage volume. Here, we suppose that storage is enough to absorb all discharges, except discharges higher than . The total volume of water is obtained by integrating the area under the flow duration curve, from 2.5% to 100%.
The available operating discharge [m³/s] is then
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The yearly energy output [kWh] is given by :
18.3.8 LCOE estimation As explained earlier, the LCOE is defined based on investment costs (Capex - Capital Expenditure), Operational costs (Opex - Operational expenditure) and the annual energy production.
Capex are related to:
- Engineering and supervision of works (10% of total investment costs)
- Investment costs specific to Civil and Electromechanical Works
- Relocation and environmental mitigation measures (10% of total investment costs)
Access roads and transmission lines are not considered in the Capex.
Opex are annual costs and are related to
- Replacement costs for spare parts : 0.25% of investment costs specific to Civil and Electromechanical Works
- Operation and maintenance costs : 10 $/installed kW
- Insurance costs : 0.1% of investment costs specific to Civil and Electromechanical Works
The LCOE is defined as :
The NPV is the “Net Present Value” and is calculated as with n the “actualization rate”, taken at 10%.
The levelized cost of energy might be calculated over whatever period of time, here 50 years. Decommissioning costs at the end of the economic life are taken to 10% of investment costs specific to Civil and Electromechanical Works.
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18.4 ANNEX 4 : PARTICIPANTS TO THE KICK-OFF MEETING (NOVEMBER 7, 2013)
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18.5 ANNEX 5 : PARTICIPANTS TO PRESENTATION OF PROGRESS REPORT (NOVEMBER 20, 2014)
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18.6 ANNEX 6 : PARTICIPANTS TO THE WORKING SESSION ON SMALL SCALE HYDRO RESOURCE MAPPING
(MARCH 17, 2015)
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18.7 ANNEX 7 : PARTICIPANTS TO THE TRAINING SESSION ON SMALL SCALE HYDRO RESOURCE MAPPING
(MARCH 18, 2015)
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18.8 ANNEX 8 : MAPS
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