25218 Volume 3 ESHAPTEMOCAL IAPER TazaDuicr -Mign Hydropower Develo meA (Cae Studies on The Ma gar$as M hgwes'9 ad Kf2ew dverso .I~~~~~~~~~ I =- -~~~~~~~~~~~ M't /1 f , , ; 9,9 99~~~~~~~~~~~~~-,:s Energy Sector Management Assistance Programme April 2002 Papers ST qa $ P and au Ea TOhnD1co $roes are dDscussDon docueuqs, n¶$ ¶ gona piro ecq reporqs0 'They aire suinbDect qc the mel zcEpyrogDhs as oDgle25 BI1SHA ObHcaqoons0 JOINT UNDP / WORLD BANK ENERGY SECTOR MANAGEMENT ASSISTANCE PROGRAMME (ESMAP) PURPOSE The Joint UNDP/World Bank Energy Sector Management Assistance Programme (ESMAP) is a special global technical assistance partnership sponsored by the UNDP, the World Bank and bi-lateral official donors. Established with the support of UNDP and bilateral official donors in 1983, ESMAP is managed by the World Bank. ESMAP's mission is to promote the role of energy in poverty reduction and economic growth in an environmentally responsible manner. Its work applies to low-income, emerging, and transition economies and contributes to the achievement of internationally agreed development goals. ESMAP interventions are knowledge products including free technical assistance, specific studies, advisory services, pilot projects, knowledge generation and dissemination, trainings, workshops and seminars, conferences and roundtables, and publications. ESMAP work is focused on three priority areas: access to modern energy for the poorest, the development of sustainable energy markets, and the promotion of environmentally sustainable energy practices. GOVERNANCE AND OPERATIONS ESMAP is governed by a Consultative Group (the ESMAP CG) composed of representatives of the UNDP and World Bank, other donors, and development experts from regions which benefit from ESMAP's assistance. The ESMAP CG is chaired by a World Bank Vice President, and advised by a Technical Advisory Group (TAG) of independent energy experts that reviews the Programme's strategic agenda, its work plan, and its achievements. ESMAP relies on a cadre of engineers, energy planners, and economists from the World Bank, and from the energy and development community at large, to conduct its activities under the guidance of the Manager of ESMAP. FUNDING ESMAP is a knowledge partnership supported by the World Bank, the UNDP and official donors from Belgium, Canada, Denmark, Finland, France, Germany, the Netherlands, Norway, Sweden, Switzerland, and the United Kingdom. ESMAP has also enjoyed the support of private donors as well as in-kind support from a number of partners in the energy and development community. FURTHER INFORMATION For further information, a copy of the ESMAP Annual Report, or copies of project reports, etc., please visit the ESMAP website: www.esmap.ora. ESMAP can be reached by email at esmapD_worldbank.ora or by mail at: ESMAP c/o Energy and Water The World Bank 1818 H Street, NW Washington, DC 20433 U.S.A. TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION JOINT UNDP/ESMAP TANZANIA KILIMANJARO REGION PRE-INVESTMENT REPORT ON MINI HYDROPOWER DEVELOPMENT CASE STUDY ON THE KIKULETWA RIVER FINAL REPORT MARCH 2000 PREPARED BY SECSD (P) LTD. SECSD (P) Ltd 1-1 Klfminal.doc Copyright © 2002 The International Bank for Reconstruction and Development/THE WORLD BANK 1818 H Street, N.W. Washington, D.C. 20433, U.S.A. All rights reserved Manufactured in the United States of Amnerica First printing April 2002 ESMAP Reports are published to communicate the results of the ESMAP's work to the development community with the least possible delay. The typescript of the paper therefore has not been prepared m accordance with the procedures appropriate to formal documents. Some sources cited in this paper may be informal documents that are not readily available. The findings, interpretations, and conclusions expressed in this paper are entirely those of the author(s) and should not be attributed in any manner to the World Bank, or its affiliated organizations, or to members of its Board of Executive Directors or the countries they represent The World Bank does not guarantee the accuracy of the data included m this publication and accepts no responsibility whatsoever for any consequence of their use. The Boundaries, colors, denominations, other information shown on any map in this volume do not imply on the part of the World Bank Group any judgement on the legal status of any territory or the endorsement or acceptance of such boundaries. The material in this publication is copyiighted. Requests for pernmssion to reproduce portions of it should be sent to the ESMAP Manager at the address shown in the copyright notice above. ESMAP encourages dissemunation of its work and will normally give pernussion promptly and, when the reproduction is for noncommercial purposes, without askmg a fee. "ESMAP Values your Feedback If you have found this report useful, or would like to provide comments on our reports and services, please log on to our website at www.esmap.org and leave your feedback. In this way we can better understand our audience's needs and improve the quality of our knowledge products. Thank you. ESMAP Management" °PIWPII !p TPll (d) Os93s gj, ..edW/ l UQGJUO.IAU3 lA J@Rd ., flW ............... ..LWe5. ... pue I..u.Jss..L 'unuole u u9 A pod 9............. hA.A..... .............. ... ... 9nPdn4S IND Al d . ..,.-{.-....-. ....... 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I!npuoo Jmod 1 Pod NOIDU ObVrNVINI1l)1 aRnis 83MOdObOAH INIVN-VINVZNVi TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION CHAPTER 13 ECONOMIC AND FINANCIAL ANALYSIS ........................................., 13-1 SECTION 1 DESCRIPTION ....... ........ ........................................................................................ 13-1 SECTION 2 ASSUMPTIONS .... . ........................................................................................... 13-2 SECTION 3 METHODOLOGY . .... ................................................................................................ 13-3 SECTION 4 RESULTS.. .. ................................ SECTION 5 SENSITMITY ANALYSIS. .... ..................................................................... 13-7 CHAPTER 14 IMPLEMENTATION ASPECTS . 14-1 SECTION 1 GENERAL . . . 14-1 SECTION 2 SUPPLY OF MATERIALS AND EQUIPMENT . 14-1 SECTION 3 O RGANISATION . ...... ..... .1 .................................................................................... 14-2 SECTION 4 CONSTRUCTION SCHEDULE .....14-2. . ..............................................................14-2 Part I Prelimineries. .. ................. . ............................................................ 14-3 Part I1 Preliminary Works ... . . ...............I.......................................... 14-4 Part 11 Diversion Weir. .1.. .....4 I.......................I5............. ...14-5 Part IV Waterway ... .... ................................................... 14- Part V Power House . .... ............. .................................................................................. 14-0 Part VI Tailrace. ... 14-7 Part VII Switchyard.4.... 1-7 Part VilI Transmission .... 14-7 Part IX Final Works .... 14-7 CHAPTER 15 CONCLUSIONS AND RECOMMENDATIONS .................................................. 15-1 CHAPTER 16 PHOTOGRAPHS. REFERENCES, ABBREVIATIONS ...................................... 16-1 SECTION 1 RERFERENCES .................................................... 16-2 SECTION 2 ABBREVIATIONS .................................................... 16-3 LIST OF TABLES TABLE 2-1: POWER DEMAND AND SUPPLY BALANCE FOR ARUSHA, KILIMANJARO AND TANGA REGIONS. 2-3 TABLE 2-2: ENERGY DEMAND AND SUPPLY BALANCE FOR ARUSHA, KILIMANJARO AND TANGA REGIONS2-4 TABLE 3-1: SUITABLE SMALL HYDROPOWER SITES IN THE KILIMANJARO REGION .................. ................ 3-6 TABLE 4-1: FEATURES OF KIKULETWA STAGE - 3 HYDROELECTRIC PROJECT ..................................... 4-9 TABLE 7-1: OBSERVED FLOW AT GAUGE SITE 1 DD54 ................. .................................. 7-9 TABLE 8-1: POWER STUDY IN AN AVERAGE YEAR ................................................... 8-10 TABLE 8-2: POWER SIrUDY IN WET YEAR ................................................... 8-11 TABLE 8-3: POWER STUDY IN DRY YEAR ................................................... 8-12 TABLE 1 0-1: SPECIFICATIONS OF ELECTRO MECHANICAL EQUIPMENT ............................................. 10-10 TABLE I 1 -: PERFORMANCE OF 33KV LINE ................................................... 11-10 TABLE 11-2: SPECIFICATIONS OF ELECTRICAL WORKS ................................................... 11-11 TABLE 12-1: IMPLEMENTATION COST .................................................... 12-7 TABLE 13-1: ECONOMIC AND FINANCIAL ANALYSIS .. ...... ............................................................... 13-9 TABLE 14-1: IMPLEMENTATION SCHEDULE ........................... 14-9 SECSD (P) Ltd. v Kkfbl.doo TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION LIST OF FIGURES FIGURE 1 -1: F LOW CHART OF STUDY METHODOLOGY ....................................................1-4 FIGURE 1-2: SECSD STUDY AREAS AND EXISTING GRID .................................................... 1-5 FIGURE 2-1. MAP OF PROJECT AREA AND KILIMANJARO REGION .................................................... 2.5 FIGURE 3-1 PROJECT DESIGN AS PER JICA SHEET 112 .................................................... 3-7 FIGURE 3-2 PROJECT DESIGN AS PER JICA SHEET 2/2 ................I8...... 3- FIGURE 4-1. LAYOUT OF STAGE-1 PROJECT .................................................... 4-11 FIGURE 4-2. LAYOUT OF STAGE-2 PROJECT .................................................... 4-12 FIGURE 4-3: LAYOUT OF STAGE-3 PROJECT .................................................... 4-13 FIGURE 4-4' LAYOUT OF STAGE-4 PROJECT .................................................... 4-14 FIGURE 4-5 TOPOGRAPHY OF PROJECT AREA ..................................................... 4-15 FIGURE 4-6 LONGITUDINAL PROFILE OF KIKULErWA WITH CASCADE PROJECTS ............... ................ 4-16 FIGURE 6-1: GELOGICAL PLAN OF PROJECT AREA .................................................... &7 FIGURE 8-2 GEOLOGICAL LOGS OF TEST PITS FOR CONCRETE AGGREGATE ....................................... &8 FIGURE 7-1: HYDRO METEOROLOGICAL STATIONS IN THE CATCHMENT ............................................ 7-10 FIGURE 7-2. ISOHYETAL MAP OF THE REGION .................................................... 7-11 FIGURE 7-3: FLOW DURATION CURVE IN AVERAGE YEAR . .................................................... 7-12 FIGURE 7-4: FLoW DURATION CURVE IN A WET YEAR .......... .......................................... 7-13 FIGURE 7-5: FLOW DURATION CURVE IN A DRY YEAR . .................................................... 7-14 FIGURE 8-1: RESERVOIR AREA AND CAPACITY CURVES . .................................................... FIGURE 9-1: GRAVITY CU M ARCH DAM DETAILS ..................................................... -8 FIGURE 9-2: PLAN AND PROFILE OF WATERWAY .. .................................................. 9-9 FIGURE 9-3: PLAN OF POWER HOUSE AT DIFFERENT ELEVATIONS ................................................... 9-1 0 FIGURE 9-4. CROSS SECTION OF POWER HOUSE .................................................... 9-1 1 FIGURE 1 0-1: DIMENSIONS OF ELECTRO MECHANICAL EQUIPMENT .........................1........9.......... .. 10 9 FIGURE 11-1: CONTROL, PROTECTION AND MONITORING SCHEMATIC ............................................. 11-9 FIGURE 13-1: SENSITIVITY ANALYSIS CASES I TO 6 ........................................ 13-10 FIGURE 13-2: SENSITIVITY ANALYSIS CASES 7 TO 12 .........................................1. 1.1 LIST OF BOXES BOX 1 -1 SUMMARY OF ENERGY OUTPTS ......................................... 1-13 Box 2-1 EXISTING AND PLANNED PROJECTS IN THE BASIN ......................................... 2-2 Box 3-1 IMPLEMENTATION COST OF JICA's PROPOSAL ........................................ 3-2 Box 3-2: FUNDS DISURSEMENT SCHEDULE ......3.................................. 3 Box 3-3: ECONOMICS OF JICA'S PROPOSAL .........................................3-3 Box 3-4 VARIATION OF B/C VERSUS CAPACITY ........................................ 3-3 Box 3-5: FINANCING ALTERNATIVES AND RATE OF RETURN ............ ............................ 3-4 Box 4-1: PROPOSED CASCADE DEVELOPMENT OF KIKULETWA ................. ....................... 4-2 BOX 4-2 PROJECT AT A GLANCE ......................................... 4-5 Box 5-1: EXTENT OF SURVEY AND MAPPING BY JICA ........................................ 52 Box 6-1. COMPOSITION OF VOLCANIC PRODUCTS ......................................... 1 Box 6-2: SOURCES OF CONSTRUCTION MATERIAL .............. . ........ ............. ... .......8................... -.5 Box 6-3: TESTS ON CONSTRUCTION MATERIAL ....8...-... ...... . .................................................... " Box 7-1: TOPOGRAPHIC SHEETS FOR DRAINAGE MAP ..... ..... ......................................................... 7-1 SECSD (P) Ltd. vi Kil.doo TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION BOX 7.2 PERCENTAGE EXCEEDANCE OF FLOWS . ....................7.... ............................................. 7-3 Box 7.3 FLOOD ESTIMATES .. ... .. .. . ............ .................................................7...................... 74 BOX 7-4: MONTHLY EVAPORATION IN MM .7-5 BOX 7-5. WATER QUALITY ..7-5 Box 7-B: NORMAL SCOURING VELOCITIES .7-7 Box 8-1 SUMMARY OF ENERGY OUTPUTS .......................... ........................................................... 8-.7 BOX 8-2: WATER ULIZATION FOR GENERATION ............................................................................. 8-7 BOX 8-3: PLANT LOAD FACTOR ...................................8 8 BOX 12-1 COMPONENTS OF IMPLEMENTATION COST .12-1 BOX 13-1: CASES FOR SENSITIVITY ANALYSIS. 13-7 BOX 14-1' CONSTRUCTION RATE .14-3 LIST OF PHOTOGRAPHS PHOTO 16-1. VIEW OF DrVERSION WEIR SITE FROM DOWNSTREAM .................................................. 16-1 PHOTO 16-2, VIEW OF POWER HOUSE SITE. 16-1 SECSD (P) Ltd. vii MIWna.doo TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Chapter 1 Executive Summary Section 1 Introduction This report and accompanying studies present the findings of a smalUmini hydropower study aimed at developing cost effective design of such schemes. It has been carried out for the Government of The United Republic of Tanzania. The Government of Sweden through ESMAP financed the study which forms the mini hydro component of the World Bank's assistance program to Government of Tanzania. The studies are intended for the benefit of Tanzania's state owned electric power utility TANESCO which is involved in generation, transmission and distribution and is administered under the Ministry of Energy and Minerals. The primary objective of the study is to look for economical and reliable alternatives for meeting the growing electric power demand in the Kilimanjaro, Kigoma, Rukwa and Ruvuma regions of Tanzania. These regions with the exception of Kilimanjaro are very remote and are not yet electrified by the national grid. The existing local grid supply in the last three of these regions is from diesel engine driven generators owned and operated by TANESCO. The present supply situation is however not reliable and the diesel units are expensive to operate and maintain. These diesel sets were Initially Installed to provide for rapid electrification of the regional capitals and important towns. However, there was continuous rise in power demand due to realiation of the benefits of electrical energy in these towns and regions as well as rise in population. TANESCO is facing difficulty in meeting the demand for electric power adequately and reliably due to constraints on the installed capacity of diesel sets, fuel availability, long distance fuel transportation, adverse operating conditions and frequent outages of the diesel generating sets, some of which have reached the end of their economic life. These factors have also hindered the expansion of the regional grids with the resul that most areas in these regions, with the exception of the respective regional capitals and surrounding areas are not electrified or are wihout electricity due to considerable load shedding which is practiced. Although in some regions demand side management studies can be done, the capacity released is unlikely to be significant in the short term due to the fact that electricity in these areas is mostly used for lighting and other domestic needs. SECSD (P) Ltd. 1-1 KJk&.doc TANZANIA-MINI HYDROPOWER STUDY ICLIMANJARO REGION All regions considered in this study are endowed with perennial streams and rivers with many potential sites suitable for economically developing small hydropower projects (upto 10 MW). To effectively meet the load demand in the short term from these projects, implies that effort and time spent on the phases in a conventional approach to small/mini hydropower development such as planning, investigations and tendering should be reduced by simplified designs and layout so that implementation czn commence quickly, and the construction period limited to one or two years. The towns/regions referred to SECSD and the study methodology adapted come under two categories shown in figure 1-1. In the first category are the potential schemes in the region which have already been investigated to feasibility stage by TANESCO and other agencies, but were not Implemented. These existing studies need to be updated by improving the planning, layout and design approach so as to minimize Ihe implementation cost and construction period. Some factors which suggested this approach are the very high level of Investment cost per kW and lotnger construction period. Due to these aspects, the projects provided only marginail economic and financial benefits. Most of the estimated costs of such candidate projects in these regions ranged from about US$3000 to $8000 per kW rendering the sites rather uneconomial for development as originally planni id. Some of the key factors contribAing to such high level of Implementation costs directly or indirectly in the category one schemes are * Increase in quantum of civil works due to inappropriate planning principles and certain features incorporated in the designs such as long waterways for getting additional marginal increase i i head. * High unit costs in civil wcrks estimate, even for indigenously available construction materials and equilpment. * High Electro mechanical equipment costs. * Alternative layouts for the schemes formulated and studied before selecting the final altemative on techno-economic grounds needed a closer look and review. SECSD (P) Ltd 1-2 KIdliuJdoe TANZANIA-MINI HYDROPOWER STUDY KLIMANJARO REGION e Planning development of a river in its lower reaches ith very large catchment (where the river is wide, shallow with considerable flood magnitude) for a power station with very small installed capacity as the load demand Is very small. * Planning of power stations on a stream on isolated basis without doing planning of the entire stream or river basin. * Inadequate reconnaissance and investigation of alternatve sites in the vicinity of a demand center. * Non availability of adequate observed river flow records with the result that potentially good streams have not been selected for development. In such cases synthetic hydrology has to be developed using elaborate models. * Vast distances between towns In a region with the resuft that expenditure on transmission lines becomes abnormal If a single power station is selected to supply all towns. In such a situation development of local grids has to be done using mini hydro on nearby streams. In the second category, there are many sites which have been identified by various agencies on the basis of concentrated drops or steep gradients In Fte river bed. From the preliminary information available on these potential sites, it appears that these sites however are not close to the existing rural demand centers. Many such sites occur in reaches of streams where access is difficult or the drainage area is insignificant, with low and erratic flows, as a result of which power generation may not be reliable and has a large variance from year to year. Because of these factors, these sites call for substantial expenditure on acces roads and transmission. Hence, instead of selecting sites to serve an area from the existing inventory, an alternative approach of thoroughly studying other streams and rivers in the vicinity of the demand center to identify promising sites in terms of access, hydrology and other factors but not necessarily planned for development on the basis of a naturally occurring concentrated head was undertaken. A series of such viable potential sites have been identified to meet the demand at an early date. They have been studied on toposheets exhaustively and reconnoitered well. Simultaneously, a total river basin development for SECSD (P) Ltd. 1-3 KNmi.doc START)--- ES~~~--- -- -------_ -- ESMAP/ -ANfSCO DECIII:E I I I ~~~~l?fA_ 'Ier1 F tj,-lERccT 4," COLLECI ILL I ! \ STAPT i~-IU TAs'DOECuYE S-lIDIES AVAILABLi | ROI WA & PUvIAMA PE--.NS ' FOR T--- E AREAS |STvlD' EXIST7IN 'FEAIJE,iIr |ES FEASIIOLTY SY1101 NO REVIEWz ExclSTiNG INVENTOF'R< REPOR I Ey/TS FLR F'iOTENv71AL - OF F'OTEN7,AL tWTS t UTI11-R vE)/U7NSL TA .'/'- T iN 1HE AREA *- o-T OF v~~~~~~~~~~~~~~~~~~~~ -S =- SUITAClILE IN O 7500 TO -,'00 k' TERM5 OF .-' IIFhLMEEN1A70i; 'LnIDD ' iES lEG - ACCES', 2 * YEARS GOCO ,V I S ---- - - I .92 TRANSM4ISSION ROTL- I I;III .AR ~ jp * '3 IMPL EMEN T4 BON t ;t9 SUITA8.-- FtiR SDp ,-- | I s J-i WATER RI(HT - l PARi101PA lION . '5 COST i r.;¢: fi | ~~~~~~~~NO ! ! IILWROVE DESitv b' IRFEDUSINC WATERWA Y STUDY OFA TO/'OCRAPl'-!C 2 SPLIT7ING IN7C' STAGES SNEElS, OIf 4REA TO iDEIVTIFY ALTERNATI1F 3 REVISINC UNIF RATES RVR LS ODMN J USlNGt LOCAL TECHNOLOGY RIVEp _ CLttZj TO OEM4Nd ,______ ) I 'lNTRE h ~~~~~~~~~~~~~~~~~~~~~~~~~~~~_ ____ I - ' | UFDA TED DESIGN I ' STUD4 THE SELECTED ' LEADS TO A SERiES RIVER BASIN CLOSE TC! OF PROJECTS #N j DEMAA CENT' AND CASCADE j IDENTIFY 4 SEPIES OF 'I TES SITE VISITS TO CONFIRMf V- , _ SITE WSITS WIH BRIEF PLANNING ' TOPOGRAPHIC SURVCEY --___ _ __------~ ~~'~~~~~~ S COLLECT HYDROLOGICAL DA TA ETC 7| SELEt T O X7NC CAYEJT -|i- fx _rq JECTFRQM C45AQF_ ,- IROJECT FROM CASCADE , I ES <: HIO)ROLOGIC DATA '--------- ! - ~~~~~~~~~~~~~~AVAILABLr _.- HYDROLOCICAL STUDIES ' , I _-- (____,_ ___ I- W T , | | ~~~~~~~~~~~~~~~NO POWER AND ENERGYDtEO STUDIES _ J K rfl'ELOP ! ----------- -- t ~~~~~~~~~~SINTHrETIC HYDROLOGYt (CIVIL VORKS DES15+N AND i . __ _ ~OUANTITIES ELECTRO MECHANICAL DEVELOP PRE-INVESTMENT EOUIPMENT SELECTION - REPURT I X l_ ~~~~~~~~~~~~~~~~~~~~~~~~~~RECOMMEND WsE AS 50iTA8L - / S TOP FOR DEVELOPMENT 8X IPPs r ( UNIT RATE, 4ND R OR TANESCO A _ ) COST ESTIMATES BMRIEf EN VIRONMEN TAL MINI HYDROMWER DEVELOPMENT STUDY ~~IMPC 'UD_ _____. )TU i- I___ _FLOW CHAFrT OF STUDY METHODOLOGY , 4 ECONOMIC AND FOP ESMAPTESO -' t K ~~~FINANCIAL ANAL YSIS - ASN LNII.DSII A l L _ - _ z- _ ~~~~~~~~~~~~~~~~~~~~~DWG NO 1PLANNINC, DESt(;NS & CAL)B 13, Flr~t- I-I SIVACIURU ENERG' CONSULTANTS PAGE 1-4 30 32 34 36 38 40- UGANDA /-- - . _ ___ /- N LAKE ,_ ----K _' Y (aWBA FUVlNZh LL lABORh Ma Q KNAAYA STASGT m MAJOR GENERATING STATION. EXISTING 4 4 OR UNDER CONSTRUCTION /~~~~~ ~O SUP Y FOSPPYO MPID .. GOOMFA Si MEZBR. OS /RE FSUYB ES ULU > \ . PLANNED MAJOR GENERAlING STATION, AtINIDA TI OR PREFEASIBILITY/FEASIBILITY SITE 0 60OABORA F KILMAWLZAR. REGION TANGA .EXISTING DIESEL STATION 1M 'ALL MTEKONDO KIXULETWA RIVER F EBIBA ISN S ES I TO 3 RUKWA REGION FORSUPPLY.MOSNI HALE AND / 6' _UAM Y RI V ANER (GRIDA ONNE,TED) PA GANI_ FDR SUPPLY TO DMDPMAFALASZANZIBAR TOWN/AREA OF STUDY By SECSD Li ACHAMANO HYDROPOVWER STATION PROPOSED __MBEYAKIWE A MA MIPWAIPWA BY COD n Z ~~~~A IAo _Lb°°" > I & ¢ _ y NJOMBEFORSVPPLYTOTVNDUCHALI TOWN/CITY T A N ZAN I A 1I0RO.ORO \ OAR ES SALAAM MTERA ' BG INDIAN TOSMANGJANGA' -, IKWIRIRI AKE RUKIVA -O OS T EIIRINGAST-NG KIDATU RIAFIA IS _____ ______ -_ ___ ___l _- F1 SV5R NEC OSLA1LL _0 \ACADJSUM YANS11FAKARA SUMBAWANGA, ~~~~~~~~OLUPIRO 6HIL)FIND ~ ~ ~ C OCEAN 6c) K MA(U II LW~A< SONG) SONGO IS "'loIAAUV% MPANGA MAS( ?~,j~UKUY I RUNIAKALIA .RUFUDJI RUVUPAAREGION I-j TUI 1382 E a it :dCamp tiona -<' s?7*o A --~an Q~~~~~~~~~~~~~~~~~~~~~~K t~~~~~~~~~~~~~~~~~~~)~~~~Slr 0w- T.; .\e Camp ai I u do A, 6 43~~~~~~~~-o ShrUl61 ~ LK h ~~>.ITArJALr.A H.S.O E F?ET so N:~~~~~~~~~~. O 2 S * lR I VT ~ O .O m T 4 s ON _____ ) OY.hI~ P CCC & (6. .~' ~ r ai:r'~~n *.~:-----~~ FI'3:2-1 PU C [P Ct IJi Lodg TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Chapter 3 Review of Previous Proposals (JICA) Section 1 General In 1989, The Japan International Cooperation Agency (JICA) carried out a feasibility study on development of mini hydropower in the region. The study explored and ranked nine sites identified previously by TANESCO which are given In table 3-1. As can be seen from the table, the Benefit Cost ratio of the potential projects is very low and implementation is not worthwhile. The study finally recommended a rehabilitation of the Kikulotwa No. I station and the construction of a new power station called Kikuletwa No. 2 downstream of the existing Kikuletwa No. 1 power station. An outline of the Kikuletwa No. 2 project as proposed by JICA is given in figures 3-1 and 3-2. Section 2 JICA Project Features The main project features of the proposed project were 1. A concrete dam of 13m height and 105m crest length on the Kikuletwa river which creates a regulating pond of 209,000 m3. The high water level is 81 7m. The dam is to be located about 2.2 km downstream of the existing Kikuletwa No. I power station. 2. An intake structure which admits water to a 2250m long headrace culvert built on the left bank. 3. The headrace culvert is followed by a 1050m long open canal which conveys water to a forebay. 4. From the forebay, a surtace penstock of 2.6m diameter descends on the steep banks of the Kikuletwa river to the power house located adjacent to the river. The length of the penstock is 835m. 5. The total length of waterway works out to be about 5 km. 6. The total gross head available is 86.1 m and the available net head for the power station was 78.20m, with FSL of 81 7m and TWL of 730.9m. The maximum flow was fixed at 17.90 cumecs. SECSD (P) Ltd. 3-1 KIdinL.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION 7. The power house would consist of two vertical shaft Francis turbines coupled to synchronous generators rated at 5800 kVA. 8 The generated power was to be transmitted by a 33kV double circuit transmission line between Kikuletwa 2 and the Kiyungi substation. The length is 14km, 9. The implementation cost in 1989 was USD 49.4 million and the period required for construction is 48 months. The estimated cost of the installed capacity was $4,490 per kW. The cost components of the project are given in Box 3-1. 10. The annual energy output from the scheme was predicted to be 67.8 GWh. At 10% annual costs the cost of energy would be 7.28 cents per kWh. 1 1. The Benefit Cost ratio of the project was calculated to be 1.1 74 as compared to alternative thermal generation using a discount factor of 10%. Box 3-1: Implementation Cost of JICA's proposal Work Item Local Foreign Total MUS$ MUS$ MUSS Preparatory Works Access Road 0.915 2.135 3.050 Camps 0.800 3.200 4.000 Miscellaneous 0.350 1.050 1.400 ClvIl Works Dam and Intake 0.220 1.252 1.472 Headrace 1 768 9.848 11.616 Head Tank 0.110 0.710 0.820 Penstock 0.218 1.401 1.017 Power House 0.240 1.576 1.81B Miscellaneous 0.200 0.800 1.000 Hydraulic Equipment 0.143 2.362 2.505 Electro-mechanical Equipment 1 073 9.657 10.730 Transmission 0.160 0 640 0.800 Administration and Engg 0 620 3 463 4.083 Contingency 0 682 3 809 4.491 Grand Total 7.497 41.903 49.400 SECSD (P) Ltd. 3-2 Kk&ml.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION The expected disbursement schedule of the funds during the construction period is given in box 3-2. Box 3-2: Funds Disbursement schedule Year-I Year-2 Year-3 Year-4 28.70% 31.24% 25.06% 15.0% The study calculated the economic benefit of the project as the present worth obtained by discounting all costs of an equivalent diesel station minus that of the proposed hydro. The result is given In Box 3-3. Box 3-3: Economics of JICA's proposal PRESENT WORTH KIKULETWA 2 DIESEL POWER PLANT Investment 32 112 9.259 Operation and Maintenance 5.136 3.452 Fuel Cost 25.708 Lubricating Oil Cost 5.321 Total Cost 37.248 43.741 Thus Surplus Benefit obtained by implementing hydro over thermal was shown to be 6.493 M USD. Hence the Benefit Cost was calculated to be 1.174. The economic values of the benefit cost ratio for different Installed capacities are given In box 3-4. Box 3.4 Variation of B/C versus capacity Capacity (kW) 12700 11000 9300 8500 Energy (GWh) 67.30 67.09 64.50 63.29 B/C 1.150 1.174 1.153 1.148 The financial analysis of the project studied two major source of funds for implementation. The first was a Government based soft loan from a cooperating country and the second being a Commercial project loan from an Intemational SECSD (P) Ltd 3-3 I(krinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Financial Institution. The following are the conditions assumed for each of the two financing options. * Foreign Govemment Loan with an Interest Rate of 1.5% p.a, repayment period of 30 years with a ten year grace period. * International Financial Institution Project Loan with an Interest Rate of 7.64% p.a, repayment period of 15 years with a five year grace period. For the above cases, the rate of return was computed os shown in box 3-5. Box 3-6: Financing Alternatives and Rate of Return Item Foreign Government Loan International Financial Institution Initial Investment 49.400 49.400 Interest During Constructton 1 636 8.335 Total 51.036 57.735 Depreciation Cost 1.020 1.154 Net Income 57 404 27.041 Rate of Return 5 58% 2.22% The project was however not implemented. The primary reason was probably inability to secure the requisite funds. The economic and financial analysis also appear to be far from satisfactory. In fact the feasibility study Itself recommended implementation of the project with the help of a soft term government to government loan from a cooperating country. With the conventional funding from an International Financial Institution, the cash flow during the loan period was shown to be negative. Also the corresponding rates of return were very low. The following are extracts from the report. Page 13-5: "Hydro power plant construction requires a large investment, while the turn-over ratio of the total assets is low. It is therefore desirable that construction be financed at a low interest rate and with a long repayment period..." SECSD (P) Ltd. 3-4 KklnaI.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Page 13-7 a) "For the case of the foreign government loan, the cash balances for both projects (Klkuletwa No.1 and 2) will be favorable every year from commissloning...." Page 13-7 b) "In the case of the International financial institution project loan, the cash balances for both projects will show deficits every year throughout the repayment period...." Page 13-7 c) "The project is financially justifiable based on the equalizing discount rates and on the rates of return. However, the financial burden will be very large if the required funds are financed by loans from International Financial Institutions. It is recommended that the project be financed by a government to govemment based soft term loan from a cooperating country." Section 3 SECSD Observations The above discussion clearly rules out implementation by TANESCO, the participation of IPPs and even funding from World Bank. Another point to be noted is that the Beneft Cost ratio compared to an altemative diesel station is only 1.174 thereby favoring the thermal alternative. A study of the cost components in Box 3-1 shows that the cost of water conductor system (Head race, Head tank, Penstock) is US$ 14.053 M or 28.5% of the total cost, The cost of Administration, Engineering and Contingencies is US$ 8.5M, and expenditures on Access, Camps and Miscellaneous Is US$ 8.45 M. Thus a total of about US$31 M or 62% of the cost is spent on items which can be considerably reduced if design is simplified so that project execution period is reduced. In updating the above feasIbIllty study, SECSD have revised the layout as per the guidelines and findings enumerated earlier with the objective of reducing the implementation cost and considerably improving the economics. This revised layout is discussed briefly in chapter four and elaborated further in the remainder of this report. SECSD (P) Ltd. 3-5 KUWA00 TABLE 3-1 SUITABLE SMALL HYDROPOWER SITES IN THE KILIMANJARO REGION SL PARTICULARS UNIT Kikuletwa No 1 Kikuletwa Himo No 1 Bombo Rehabilitation No 2 Rehablitation Himo No 2 Rehabilitation Hingilili Ndungu Hiridi Gulutu 1 Name of river Kikuletwa Kikuletwa Himo Himo Hinigilili Hingilil' Yongoma Sesseni Sesseni 2 Catchment area sqkm 2,200 2,280 174 183 1 8 53 5 57 181 3 190 3 Annual inflow MCM 410 421 52 54 6 0 56 28 3 30 1 64 3 67.4 4. H W.L m 830.47 818 00 1,025 5* 885 00 1470 00 900 00 1071 00 690 00 600 00 S Headrace length km 3.20 1 00 160 0 40 0 40 0 90 1 80 1 00 6 Penstock length m 20.00 834 50 82 00 200 00 400 00 1600 00 1100 00 120 00 220.00 7 TWL m 817.40 730.90 954 20 837 00 1380.00 585 00 532 00 617 00 545 00 8 Gross head m 13.07 87.10 71.20 48 00 90 00 315.00 539 00 73 00 55 00 9. Effective head m 12.70 78.20 67 60 43 70 84 50 299.00 512.00 67 00 51.20 10. Max discharges m3/s 15.40 17.90 0.43 0.43 0 09 0 80 1 00 0 96 1 00 11. Firm discharge m3/s 10.53 17.90 0.13 014 - 0.12 0.15 1.24 0 25 12. Type of turbine S-Type Francis Cross Cross Cross Pelton Pelton Francis Francis Tubular Flow Flow Flow 13. Installed capacity kW 1,500 11,000 220 140 50 1,830 3,940 480 380 14. Frim capacity kW 1,055 11,000 66 43 0 270 575 120 96 15. Annual Energy GWh 10.53 67.09 1.49 1 02 0.06 10.00 21.50 3 60 2.90 16. Transmission line length km - 9.00 1.00 1.50 0.50 1.00 13.50 17.00 12.00 17. Total project cost MUS$ 7.20 49.40 1.07 3.71 0.44 9.56 16.29 7.29 5.11 18. Energy Cost US$/kWh 0.68 0.73 0.69 2.43 7.08 0.73 1.83 1.61 19. Benefit / cost ratio 1.27 1.17 1.08 0.21 - 0.70 0.87 0.34 0.39 20. EIRR % 13.30 12.30 11.30 less than 6.63 8.52 0.96 1.97 0.1 Note: * High water level at head tank. kilste is Sll SECSD (P) Ltd. 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CI SQ.1~~~~~~~~~~~~~~~~~~~82 825 8 , / __ l '-4 LAY~~~~~~~~~~~~~~~~~~~~~~~~~~~ONUIT OF .¶vTAGE-GlI 82,5 -8300P52R345S P SCAl OUE ae to ic PSINIC ___________ _____ _____________________ _______ ______(RUINED)_______ I342 SIcUFI ~AD0sJA~aD1s ___________________________ _________________ _______________________________2____ ;77slSfllnsNcl` )t1e83N3 nlfldOvAlsl T_r fl Qs.7t1+ -... - n:i3rfOWd U9MOdOUGA,H VM131JI;5MN 0v w ifo sfsw SS5e5o< e (ut) 3T#os 9.R k056 \f'. 05 JlO osYlDdllr l_9.JH11)45 sigi~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ei c.orztel ^^)lrxali :w .91W7 i,-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~f ^6nd °K+tze.ffiS.v U .).IM/d l.wwoola a3 *--Dd Je qi)s; ~ ~ ~ ~ ~ ~ ~ 65' .to«s-aseaUs w (OnIS @ '\4 \ - X / 9 / / s ) \ KAhuletwo No 2 ond No 3 FSt r ovi H O Hr aOfiACE PEtI ~~~STA re6p-NRG (rnJ ,39n _ ~~~~ _ SIAGE-3 80S O 740 0 65 0 2d 0 2 x 5500 325 1 Sv /20n} 65 0 1 50000 SCAt EAGE- PL94~~~~~~~~~~~~~~~~~~~~~~~~~ SHOWINGN VtRAPTW STAGESE I TO 4> - . , . nE iS iM, ;U@, 1> mt /y, CAQJOBS\~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~LRE TAN7 TANN)AI __ORAH.VP h /~~~~~~~~~~~~~~~~~~~~~~ 00 CI STAC-E-3 805 0 740 0 65 i* 50 2 9120 1 ( h l* A.~~~~~~~~~~~~~~IUETAHDRPWR RET STGE4 74 0 78 1 0 2 h0 i8 '0~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~LGTO SAE O4 SA ti', A ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ A.h A.' 840 ElEVA TION p,os' EXIS TEWi AKiKEL TWYA O1EERS0hIO E 1(1 FSL 630 46 E~ISTINJG K WARE DIVERSION KIIR KIEIILE TWA CANAL I (SI ~~~~~~~~~~830 46 830 (I 11 IAEAA IIEADEANK KW~~~~~IARE RIVER NEW STAGE-2 CANJAL PROPOSED KIKULEIWA STACE-3 0 20 c,g',s DIVERSIOIY REIR 820 r~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~SL 805 0 -I [~~~~~~~~~~~~~''~~~~~~~~ ~~KIKULELTWA STAEE-3 POP/VAGE CUT ANtI COWiR CONDUIT 810 EX(ISTING KIKULETTA2200n3 P02SR STA TICS? (RUINED) - (N600,W + 1,400AW f 1,d60kill 800 ~~TM 817 40 800 ~~PRO,POSED RTHABxLITA T,II1 0 = 20 cun/s PROPOSED STAGE-2 2 A1000,W POKER HOUSE ~PNECS2 IS,d 790 I 00PtSOK ~d PROPOSED IKIELElTWA STAGE-2?,UfW IE DIVERSION WEIR 760 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~PROPOSED STAGE-4 POKER HOUSE TKLt 730 4 P 2 00 W 770 PROIPOSED STAS(-3 POKlER HOUSE lTI 740 0 760 0 =20 wmr/s 750 PROPOSED KIULE TWA STAGf-4 IvTRpSIoTI 1EP rSL 7400 740 730 . . . . . I .~~~~~~~~~~~~~~~~~~~~~ . . . C C DISTANCE (ni) FROM EXISTING KIKULE TWA DIVERSION WEIR LONGITUDINAL PROFILE OF IQKULETWA RIVER SHOWING PROPOSED CASCADE DEVELOPMENT KiK(ULETWA RIVER HYDROPOWER PROJECTS (STAGES 1 TO 4) PROFWILE WVITH CASCADE FEATURES FOR: THE WORLD BA(ITANESC DWG, NO PLANNING. DESIGNS & CAD BY _FIG 4-6 ISIVAGURU E1NERGY CONSULTICNTS TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Chapter 5 Topographic Features and Surveys Section 1 Topography The Kikuletwa sites are located in the Mount Kilimanjaro area. The project area is located on a vast plain, which has an elevation of 700 to 800 m, at the south- southwest foot of the 5895m high Mount Kilimanjaro. The sites are approximately 45 km from the peak. The rivers Himo, Karanga, Weru Weru and Kware , the sources of which are near the summit, flow down the southern slope of the mountain in a fan-like pattern. These streams ultimately drain into the Kikuletwa River south of the city of Moshl. The Kikuletwa River, after passing the Nyumba Ya Munga Reservoir, becomes the Pangani River which empties into the Indian Ocean south of Tanga. Mt. Meru (EI,4,566 m) is located about 70 km west of Mount Kilimanjaro, and also has a fan-like pattern of streams flowing down its slope. One of these streams is the main tributary of the upstream portion of the Kikuletwa River. The proposed projects on Kikuletwa are located in the vicinity of the confluence of the Kware River, flowing from Mt. Kilimanjaro and the Kikuletwa River, flowing from Mt. Meru. The main topographic feature of the project area is the deep valley which the Kikuletwa river has cut and the rather steep slope of the river bed. At some places the depth of the valley is over 30m with nearly vertical sides. On both banks the terrain is almost flat tableland of elevation of about 800m. Section 2 Survey The project area is mapped by Survey of Tanzania topographic sheets in 1:50000 scale with contours at 20m intervals. The map index number is 56/3 fitled Sanya Chini. An extract of the relevant area of interest is given in figure 4-5. The stretch of the Kikuletwa river was photographed from the air, extensively surveyed and mapped by JICA in 1989 as per details below. SECSD (P) Ltd. 5-1 Kikfnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Box 6-1: Extent of Survey and Mapping by JICA SL ITEM SCALE QUANTITY 1 Aerial Photography 1:20000 longitudinal 300 sqkm 1:8000 transverse 2 Flight Courses 9 3 Longitudinal Mapping 1:1000 30 sqkm 4 Transverse Mapping 1:1000 9 km 5 Topographic Maps 1:5000 6 Topographic Surveys 1:500 182500 sqm of Kikuletwa I and 2 I I The 1:20000 aerial photographs were used to prepare the 1:5000 topographic maps for an area of approximately 300 sqkm. 1:8000 aerial photographs were used to prepare the 1:scale longitudinal and transverse profiles Ground surveying was used to prepare the 1:500 topographic maps for the main structure sites of the originally envisaged Kikuletwa No. 1 and 2 schemes. Section 3 Results All the revised project features proposed by SECSD are within the limits of the survey information available in the JICA report. Hence for the new layout no additional surveying is required to be done. Requisite Information has been extracted from the available sheets and is presented in figures 4-1 to 4-6. Additional information inferred from the above include the following which are presented in the relevant sections of this report. 1 The cross sectlon of the river at the proposed diversion site to bring out the longitudinal section of the diversion weir. 2. The reservoir area and capacity data to be used In the hydrology, power and energy studies. 3. The ground profile along the waterway to compute the quantities of civil works and penstock alignment. 4 Lake spread with any potential environmental impacts. SECSD (P) Ltd 5-2 Kkfilnai.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Chapter e Geology Section 1 General The geology of the site is considered from the available geological information to be adequate for the construction of a diversion weir upto 20m height. Also the formation of the proposed impoundment will not give rise to any major slips or settlements in the bed or banks of the reservoir. Section 2 Regional Geology The area Is chiefly composed of the volcanic products of Mount Kilimanjaro. The origin of these volcanic rocks is thought to be between 13 to 15 million years so that Kilimanjaro's volcanic activity might have started between the Miocene and Pliocene eras. The frequency of activity gradually decreased from Pleistocene to the Holocene eras. Present day activity is limited to local eruption. The past activity can be divided into three stages which formed the three peaks with Shira being the first and Kibo the most recent. The composition of the lavas is given below. Box 6-1: Composition of volcanic products STAGES COMPOSITION OF VOLCANIC PRODUCTS Shira Lava with pyroclastic rocks Mawenzi volcanic products such as basaltic lava, tuff breccia and agglomerate Kibo volcanic rocks or porphyry such as trachyandesite trachyte, phonolite, and rhomb porphyry in addition to a deposit known as Lahar. The proposed project sites are located in the area of the Kibo volcanic product distribution. The volcanic products are of the Rhomb Porphyry Group partially overlayed with Lahar. Section 3 Engineering Geology Part I General The results of the JICA team's aerial photo interpretation, detailed geological field surveys, and core drillings indicate that the geology of the Kikuletwa Project Area may be summarized as follows: SECSD (P) Ltd. 6-1 Kik".doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION * The sub-area upstream of the proposed site for the Kikuletwa No. 2 intake dam. This area includes Kikuletwa No.1 project area. * The sub-area from the proposed ste for the Intake dam to the proposed powerhouse site for JICA's Kikuletwa No. 2 (SECSD stage 4). * The sub-area downstream of the proposed site for the JICA's Kikuletwa No. 2 powerhouse (SECSD stage 4). The topographical differences within the project area are considered to be due to the geologies which formed them. The geologies concerned are those of the Kibo "Rhomb porphyry Group" and of the "Lahar" The former within the project area, consists of dark grey tuff breccia, with part of the top layer containing limestone. The "Lahar' is itself of reddish brown color; the "Lahar studied In the surface reconnaissance and core drilling, however, had a high degree of consolidation, and presented the appearance of tuff breccia. This consolidated Lahar contains numerous blocks, which appear to be phonolite characterized by mega- phonocrysts. The Rhomb Porphyry Group will be referred to Tuff Breccia (2); and the geology containing Lahar will be referred to as Tuff Breccia (1). Part II Origins and Stratigraphies It is thought that Tuff Breccia (2) was accumulated in the volcanic activity of Mt. Kilimanjaro and was subsequently subjected in part to the sedimentary environment of limestone. Tuff Breccia (1) is considered to be a secondary deposit of volcanic products and is thought to have covered Tuff Breccia (2) in the form of filling valley topography when flowing down the slopes. In the project area studied, the thickness of Tuff Breccia (2) is greatest in the vicinity of the midpoint of the headrace planned by JICA for Kikuletwa No. 2 which is very near the modified stage 2 project site where it Is estimated to exceed 50 m. Part liI Hydrogeological Conditions Springs which flow into the Kikuletwa River are located about 2 Km upstream of the existing TANESCO Hydropower Station, in an area of Tuff Breccia (2) distribution. The volume of spring water is comparatively stable throughout the SECSD (P) Ltd 6-2 Klkftnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION year This, together with the fact that the existence of confined water has been recognized in Tuff Breccia (2) through core drilling investigations at the Kikuletwa No.2 intake dam site, downstream of the spring location, make It seem quite likely that some part of the Tuff Breccia (2) layer is in aquifer. Talus deposits and alluvium are present as unconsolidated deposits overlying the basement rocks. These deposits are either distributed over small areas, or are thinly and widely distributed. No prominent fault structures, landslides or slope failures have been recognized in the project area. The intake dam and the powerhouse site for the Kikuletwa stage 3 Hydropower project are located approximately 3 km approximately 3.8 km, respectively, downstream of the existing TANESCO power station. The topography from the r stage 3 Intake dam site (Including the regulating reservoir area) to the powerhouse site is that of a gently sloped tableland, of elevation from 800 to 840 m. The section from the intake dam site to the powerhouse site excluding the reservoir area shows a predominance of small mounds on the table- land. The Kikuletwa River flows down the tableland from the commencement of the reservoir, from the stage 2 intake dam site toward the stage 3 powerhouse site, gradually descending to form a "V\ shaped valley and meandering slightly. The average river bed gradient in the regulating reservoir area (Including the intake dam site) is 1/500. The gradient between the intake dam and powerhouse site is 1/50. Part IV Geology of Regulating Reservoir The regulating reservoir and intake dam site are composed of Tuff Breccia (1), Tuff Breccia (2) and limestone. The Tuff Breccia (1) thinly over-lies the Tuff Breccia (2) almost horizontally, with limestone interbedded at the boundary between the two. The limestone lens is limited to the vicinity of the intake dam site. All of the bedrocks are generally hard, and except for Tuff Broccia (1) at the surface layer of the right bank of the intake dam, the permeability coefficients are SECSD (P) Ltd. 6-3 Kkansl.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION 104 to 105 cm/sec. The groundwater level at the tail end of the reservoir is EL. 813 m, approximately 2 m above the water surface on both banks of the Kikuletwa River. Unconsolidated deposits, consisting of talus deposits and alluvium overlie the basement rocks. These deposits, however, are extremely thin. Part V Geology at Diversion site The important drill holes for the stage 3 project are KD-4 which is in the regulating reservoir area, KD-5 which is very near the diversion wier site and KD-6 which Is downstream of the diversion site. The geology at the diversion site is assumed to be close to that met with in KD-5. The drill hole showed the material to be Tuff Breccia with phonolite and good values of RQD. The geology along the headrace route of JICA is Tuff Breccia (1) overlain at parts by very thin talus deposits of not more than I m. It is assumed that the same conditions are met with on the opposite bank of the river also. So far as ascertained in core drilling, the Tuff Breccia (1) is well-consolidated and hard to a depth of 20 m from the ground surface. Blocks thought to be phonolite, which exist in large numbers in the bedrock, are very hard, and their hardness differs from that of the fine material surrounding them. For all drill holes, permeability coefficients at depths over 10 m from the ground surface were found to be 105 cm/sec or less. The groundwater level Is highest near the midpoint of the proposed headrace, which it is about the same as or lower than headrace elevation in the vicinities of the intake dam located upstream, and the head tank, located downstream. Part VI Geological Engineering Assessment ft is expected that excavated high slopes will be formed at the proposed headrace because of topographical features of the route. The propertles of the Tuft Breccia (1) indicate that the cut slopes will be stable. As the headrace route runs through a gently-sloped tableland, there is little risk that of debris and loose soil from the surrounding ground surface will slide into the canal. SECSD (PI Ltd 6-4 IkAnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION The above studies on engineering geology have shown that the bearing capacity for all the proposed structures is adequate and no major problems are likely to emerge. Section 4 Construction Materials A thorough investigation of source of construction materials has been done by JICA. The main results are given below. The locations of the sources are given in figure 6-2. Box 6-2: Sources of Construction Material SITE LOCATION MATERIAL QUAnTY REMARKS KITETO 7 km SE of Medium to coarse grained sand 10,000 cum stage- 1 of crystalline schist and gneiss of pre cambrlan sedimentary origin from tributary of Kikuletwa NYM 90km SE of medium to coarse grained sand of 100,000 stage-i pre cambnan schist and gneiss of cum pre cambrian sedimentary origin HAI 15km North basaltic rocks from volcanic Existing crusher of stage-1 products produces In sizes from 0.25 to abov 1 Inch R KARANGA 12km NE of sand gravel orglnating from stage-1 basaltic rocks of volcanic actMty TPC 3km South of Voicanic alkaline Fairly large 5m over burden R Karmnga site basalt Is to be removed The test results are summarized in box 6-3. SECSD (P) Ltd. 6-5 KLUM .doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Box 6-3: Tests on construction material SPECIFIC ABSORPTION ABRASION SOUNDNESS ORGANIC CRUSHING ALKALI GRAVITY IMPURITY REACTIVITY KITETO 2.60 to 10 7 to 14.2% 8.4 to 14 i LIGHT WITHIN 2 73 FINE YELLOW LIMITS NYM 2.71 5.2 LIGHT WITHIN YELLOW LIMIITS HAI 2.54 to 1.9 to 2.8% 22.3 to 2.3 to 3.2 DARK 22% HIGH for size 2.57 FOR 24.9 BROWN c 5mm COARSE R. 2.43 to 152to 25.2 to 4.8 to 7.2 DARK 15% HIGH for size KARANGA 2.46 24.1 FOR 27.2 2.7 to 3.0 BROWN 5m MIXED coarse tP rC- 2.52 BARK_ HIGH for size II__ I II BROWN i_< 5_ _ SECSD (P) Ltd. 6-6 KIIla.doc siflYil(lS9ii) Ai-dJN] r8f)YAIS -9 91J af..wa .., .S ,w kg OV3 9 SN'JISM3 9ONINN9ld Ot 9A4q ;w o ; 4 t ) _ ~~OOeS3NYJMJYWJtIdltOM-dO. ZrDOJ)1' 3 "f' F2ZJ 5irw 15t0s 7 L1y V3iW103P@dd: i)3rJd JO Nld 0030 C \v e 1OO bJ rAl. III i53I'Od 3aMOdQllaAH VAL'll3)li> 0 15 'J .1 Jt hS ~~ ~~ a ~SIION (w) 31YO SJt ____________________ _ X+ ISJ.J 6) P-Md 'W".041"~~~~~~n-AcJ. 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X-D p- PXI .f 0 0 0 LL93ANI 31.V03UDFjV313U3N0j' mo aqw,) 6jv., ild-ISM.40 8001 -6 0 0 0 zi WI S10:4r0)Jd H3hl0d0UQAHvhwin)om 1-0 0 0111, -9 0 0 0 L ON .9 1 0 0  ON AGJIIS VJlf JO e-P-P 3dhOIJ UO 03SVO - aps 4-0 1. .,y Q-)folvq = Is 1-0 9 9 9 I ON I d I 'I; I'd f'-Pd-S Z_; Io F- I -9 ON i'd P 0"'Af I opt "'Ll 00 f-c-ti .91 co -5-,v d o zz- 7.1 00 -N e-P ou 1 _P ON Ii" e-9 -ti I OUT at" N . I------ I - - X, r I Opt El -ti el ON, if -ti Of OUT 6 ON P (10 'I if ON 4- --emr - 1, = .1 I-rot -C ONT 1-f OV 1-fo 0 W, 1-d 14 wdo I Ip/ 9 -NV Z 014 9 ON f pp, ON .6.0,0)4' Jdi ('u zm - 4". oove 'VII I ON f ON \0 (&)fw=Is 91 ON OM X, 01, S/d -.m-'oo ON wat % Opt I N ION wl ON - "q I N Z-1 oti I- 1-i ONv 1-1 O', obuojoy a TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Chapter 7 Hydrology Section 1 Drainage Network The catchment area of the Kikuletwa river is drained by a large number of streams and rivers which form a close and dense network at the higher elevations but are sparse in the plains. The river is formed from three major tributaries Kware and Sanya running down the south slope of Mount Kilimanjaro and Usa running down the southern slope of Mount Meru. The drainage network and hydro- meteorological stations in the catchment are illustrated in figure 7-1 titled Hydro- meteorological stations in the basin. The map was constructed by using the following topographic sheets of 1:50000 scale. Box 7-1: Topographic Sheets for Drainage Map SL SHEET No. NAME 1 55/1 OLDONYO SAMBU 2 55/2 NGARE NANYURI 3 55/3 ARUSHA 4 55/4 USA RIVER 5 56/1 WEST HAI 6 56/2 KILIMANJARO 7 56/3 SANYA CHINI 8 56/4 MOSHI 9 71/2 MBUGUNI 10 72/1 LOSSOITO 11 72/2 ARUSHA CHINI The drainage area is fan shaped. The figure shows the drainage network for the main stem of the Kikuletwa river till it joins the Ruvu river and then flows into Myumnba ya Munga reservoir. From here the river is known as Pangani and it flows southwards for a considerable distance through an arid plain and then tuMs east and empties into the Indian Ocean. The sub networks for the three major tributaries the Kware, Sanya and the Usa have been shown. The drawing also shows the rainfall stations in and around the catchment with altitude and the various river gauging stations with their identification numbers. The catchment area is covered with the porous products of volcanic activity from Killmanjaro. A significant portion of the rainfall is thus absorbed and reappear as springs in the area such as Rundugai and Chemka. Locations of some of the important springs are also shown in the drawing. SECSD (P) Ltd. 7-1 Kkfiral.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Section 2 River Flow Data Observations of runoff for the major streams and rivers of the region Is done by Water Resources office at Moshi, From the point of view of the hydropower studies for the proposed site, the most important flow data is that obtained from gauging station IDD-54 which is located about 300m downstream of the existing TANESCO Kikuletwa 1 power station. The data was collected from Ministry of Water in Dar-Es-Salam. The daily observed data with analysis of the data Is given in the separate volume annexure A. Section 3 Observatlons The catchment area at the gauge site is 2220 km2. From the measured flow data, the average run off is found to be 14.35 cum/s corresponding to a runoff depth of 204 mm. The average precipitation over the catchment is 800mm giving a run off coefficient of 25%. The observed records include the runoff from water sheds of Mount Meru and Kilimanjaro, and the Rundugai and Chemka springs. In addition the runoff from Kware and Kikuletwa together with the amount of waif- which was being diverted for power generation by Kikuletwa 1 power station and released back is included in the measurements. Duration curves based on the above data have been prepared and are presented in the annexure volume. The following important observations can be made. The river hao a constant base flow. The ratio between 95 day discharge and 355 day discharge is small. The annual range of fluctuation in discharge is small. The pattern of flow is ideally suited for production of hydropower. Section 4 Yield at Kikuletwa site The proposed diversion site is located a little downstream of the gauge site. The catchment area at the proposed diversion site is 2280 sqkm representing an increase of only 2%. No major stream or tributary joins the Kikuletwa between the gauge site and the proposed diversion site nor is there any abstraction of water in this reach. Hence the yield at the diversion site is taken to be equal to the measured flow. The error involved in the assumption will be less than 0.1%. Analysis of the flow data by duration curve gives the exceedance values given in box 7-2 which are partly reproduced from table 8-1 of annexure A. SECSD (P) Ltd 7-2 KI(nal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Box 7-2: Percentage Exceedance of Flows S% | JAN FEB MAR APR I MAY JUN JUL AUG SEP OCT NOV DEC 10 15.23 14.32 16 71 30.46 29 78 20,17 15.55 13.75 15.71 13.31 14.51 18.58 20 12 94 13.02 13 39 23 51 22.98 17.59 13.89 12.35 12.12 12.14 12.91 12.94 40 12.16 1214 12.43 18 35 20.27 14.12 12.73 11.79 11.68 11.84 12.18 12.12 80 11 56 11.61 11 65 12.86 15.77 12.63 11.75 11.45 11.44 11.50 11.57 11.67 80 11 34 11.35 11.37 11.67 13.24 11.57 11.42 11.22 11.19 11.24 11.25 11.43 100 6.08 9.29 7.32 10.26 11.22 8.94 4.00 9.12 7,34 9.20 9.20 8.97 From the above, It Is seen that the months April and May have the highest flow. The discharge exceeded 40% of the time in these months is 18.35 and 20.27 cumecs respectively. Section 6 Flood Studles The maximum daily discharge recorded at the IDD54 gauging station for each year is given in annexure A. Study of precipitation records at Arusha (No. 933-633) and Kikuletwa (No. 933- 769), where data collection is comparatively sufficient, shows that precipitation was extreme in the years 1963, 1968, and 1978 - a cycle, at both sites, first of 5 years and then of 10 years. Yearly variations in river runoffs for the Kikuletwa River flowing from Mt. Meru and Mr. Kilimanjaro, has shown that the high water years were 1968 and 1974 - a cycle of 6 years. It is said that a large flood occurs in the Kilimanjaro Region about once every 10 years. According to the above records, the cycle for medium-scale floods Is approximately 5 years, while large-scale floods have a return period of close to 10 years. The largest flood remembered by personnel at the existing TANESCO power station occurred in May 1978. On the basis of high water marks and river cross section, the flood water level is estimated to have been EL. 820.80 m, and the flood discharge estimated to be approximately 200 m3/sec. The probable flood discharges, as estimated by fitting various probability distributions are given in annexure B, based on the daily maximum discharge record for the 16-year period. The main results are given in box 7-3. SECSD (P) Ltd. 7-3 Kkftal.doc TANZANIA-MiNI HYDROPOWER STUDY KILIMANJARO REGION Box 7-3 Flood Estimates RETURN FOSTER FOSTER HAZEN'S PEARSON LOG GUMBEL INTERVAL T'PE-1 TYPE-3 PEARSON 1.01 15.8 111 .67 5.0 15.8 1.05 16.8 14 6 12.9 11.6 1 9.9 7.0 20 59.2 58.2 68.e 84.5 90.1 94.2 100 113.8 118.5 119.2 110.9 136.8 129.2 1000 1391 168 0 168.8 145.1 225.1 178.7 10000 155 5 196 8 223 7 174.2 351.0 228.0 The May 1978 flood discharge observed at the existing TANESCO power station, mentioned in the preceding section, is estimated to have been from a flood with a magnitude corresponding to a 1000-year return period. For the design of the spillways a discharge of 200 cumecs is fixed. For the construction, a design of 100 cumecs Is fixed corresponding to 20 year flood. Both are based on Log- Pearson distribution. Section 6 Climatology Temperature, humidity, evaporation, and sunshine hours are recorded at the Moshi (EL. 854 m) and Same (EL. 872 m) observatories in the Kilimanjaro Region, and compiled at the Directorate of Meteorology in Dar es Salaam. Part I Temperature As is to be expected in a tropical country, temperatures are high, with little variation from year to year. February is the hottest month with a mean temperature of 33.1TC. August is the most pleasant month with a mean temperature of 15.40C. Part II Rainfall The Kilimanjaro Region, which borders Kenya and is situated approximately 450 km northwest of Dar es Salaam, enjoys considerably more rainfall than the semi- arid regions which make up most of the country. At the higher elevations on the slopes of Mt. Kilimanjaro's, annual precipitation exceeds 1,800 mm. On the higher areas of Mt. Pare , annual precipitation exceeds 1,000 mm. Piecipitation decreases at lower elevations, however, and low-lying areas receive less than 500 mm of precipitation each year. Figure 7-2 shows an isohyetal map of the area. SECSD (P) Ltd 7-4 Knfinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION This region generally has two rainy seasons. A heavy rainy season from March to May, and light rainy season in November and December. Part Ill Humidity The region is characterized by mild or moderate temperatures and very low relative humidities of about 40 to 60 percent. Part IV Evaporation Evaporation is fairly substantial even in the rainy season (with a value of about 300 mm in March). The mean monthly evaporation rates is given in Box 7-4. Box 7-4: Monthly Evaporation in mm MONTH JA IFEB I MARI APR MAY JUN -JUL AUG I SEP OCT NOV DEC TOTAL EVAP 276.2 281.1 305.8 184.7 126.4 108.2 126.4 136.2 171.2 114.5 213.4 244.7 2290.8 Section 7 River Water Quality Water samples were collected from the Kikuletwa and other rivers by JICA. Analysis carried out at the Soil & Water Laboratory in Maji Ubungo showed that water in the rivers flowing down Mt. Kilimanjaro is alkaline, with pH values slightly higher than 7. No abnormal physical or chemical properties were recognized in any of the samples analyzed. The suspended loads and discharges of the Klkuletwa, Weru-weru, and Pangani rivers, are given in box 7-5. Box 7-6: Water Quality River Station Area Discharge Suspended Load (km2) (m3/S) Kikuletwa IDD-1 3840 14.8 to 90.1 9 to 184 Weru-Weru IDD-5A 146 6.2 to 60.6 19 to 698 Pangani ID-8 9037 16.8 to 96.9 21 to 133 Using the discharge - suspended load relationship for the Weru-weru River, for which the suspended load is comparatively high, the following suspended load SECSD (P) Ltd 7-5 Kkcflnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION and discharge are found for 1970 by JICA team, for the year of average runoff condition at gauging station No. 1 DD-54 on the Kikuletva River. River Station Suspended Load Discharge Kikuletwa IDD-54 28 7.65 300 30.97 Based only on the above data, the total suspended load is calculated to be approximately 24,505 m3, against a total annual flow volume of approxlmately 41.1 million m3. This corresponds to 11.04 cu.m per square kilometer annually. The Kikuletwa River, for the 72 km stretch from Msitu Wa Mbogo near Arusha to its confluence with the Karanga River, may be considered to be a transitional area. The average river gradient in this stretch Is approximately 1:300. The suspended load, instead of being deposited in this transitional area, is carried down and deposited in to the plan area, or else is carried further down, to the Nyumba ya Mungu Reservoir. Section 8 Sedimentation The expected sedimentation consists of the suspended load and the bed load. The suspended load consists of silt which for this purpose has been defined as a material that obeys Stokes law and has effective mean diameter of less than 0.08 mm. The bed load comprises boulders, pebbles, gravel, and sand. The rate of translatory movement varies inversely to the size of the particles, so that a sorting process by the river Is taking place where the particle size ranges from boulders In the hills to fine silt in the lower reaches near the sea. The process of size reduction is aided by extremely slow dissolution, by the abrasion, particularly where the velocity of flow is great and the material comprising the bed load is large. Large boulders move only under extreme flood conditions and in general so slowly that they are never found very far from the hills. Pebbles, rounded by abrasion, also progress intermittently and very slowly, while gravel travels much faster, especially where the depth of flow is small. SECSD (P) Ltd 7-6 Ki(dinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Sand movement takes place in ripples or under extreme conditions by sheet movement. With ripples, the coarser particles tend to settle at the bottom of each trough and may not move on when exposed to the action of flowing w"ter. Slightly finer particles roll up the sloping face and drop into the succeeding trough, repeating the process as each ripple passes. Still finer particles jump from ripple to ripple, while yet finer particles are thrown into temporary suspension, returning to the bed some considerable distance downstream - these two processes are termed saltation. Experiment indicates that the bed load is most important in those stream sections with sandy bed, where the size of the material in suspension approaches the size of the bed material and where the quantity of the suspended material is small. As the difference between the size of the sediment In suspension and the size of the material in the bed increases, the relative importance of the bed load decreases. The following scouring velocities may be given: Box 74: Normal scouring velocities. SL MATERIAL VELOCITY VELOCITY ft/s mph 1 Fine Clay and mud 0.25 0.17 2 Fine sand and silt 0.50 0.34 3 Coarse sand (peas) 1.00 0.68 4 Fine gravel (beans) 2.00 1.3e 5 Coarse gravel (1 in) 3.00 2.04 6 Pebbles (1 5 in) 4.00 2.72 7 Heavy Shingle (3 in) 5.00 3.40 In the case of the Kikuletwa project, silt load is likely to be more important than bed load and more attention must be paid to this matter in the future control. Preliminary reconnaissance studies indicate that there is no great danger of sedimentation to the Kikuletwa reservoir. However, the matter will have to be watched in future, especially the silt load volume. Changes of the river channel and Its bottom have to checked. It Is especially necessary to reduce the rate at which the products of land erosion removed by the rivers that is to say by soil conservation in the basin. The method used for predicting sediment inflow and deposition amount in the SECSD (P) Ltd. 7-7 K*lal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION reservoir is outlined below, The first method which can be used is the prediction of an annual average sedimentation volume using an empirical formula based on surveys of existing reservoirs. However, there are no such records for Nyumba ya Munga reservoir which is downstream. Method of comparlson with known annual average sedimentation In similar river basin. This method is also inapplicable, as no measurement records are available on annual average sedimentation at other river basins with similar geology, topography, vegetation, and precipitation. However, a group of U.S. geologists (Witig, Brune-Allen, Brown-Jarvis, Churchill, and Borland) have derived the following general equation from sedimentation data of storage reservoirs where there is a mixture of bed load and suspended load, qs = K x (C/F) 0.569 where qS average annual sedimentation ratio (cu.m/sq.km/yr) C storage capacity (cu.m), F Is the catchment area (sq.km), K = 0.501 as average value Applying this equation to the Kikuletwa site results in the following estimate: q = 0.501 x (151,000/22,20) 0.569 = 5.53 cumisqkmlyr Q5S = qs x Catchment area - 5.53 x 22,20 m 12,273 cu.m/yr Most of this suspended load will be carried along the restricted width of the pondage and through the spillways. For working out the deposition in the reservoir, the capacity inflow ratio may be computed. Cr = Reservolr volume/Average annual inflow = 1511,000/452x106 = 0.000334 As per Brune's relationship diagram, the trap efficiency of the reservoir is found to be about less than 0.5%. Thus annual sediment trapped = 0.005 x12,273 = 62 Cubic meters Over a period of 40 years, total sediment volume = 2480 cubic meters or about 2% of the gross storage of the reservoir. However due to the operation of the gates, regular flushing of the deposits near the diversion structure will occur and the actual trap efficiency will be much lower. SECSD (P) Ltd. 7-8 Kilchnal.doo SITE 10054 TABLE 7-1 UNITS m3(s STREAM KIKULETWA OBSERVED FLOW AT SITE 10054 CATCHMENT 2,220 km' BASIN KIKULETVVA - _- _ _ _ANNUAL YIELD DATE JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC MEAN (MCM) 1967 NNA 10 37 lo 5 10 9a 13 79 12 20 10 60 10 66 10 81 10 66 11 94 12 33 11 3 3278 1968 1 144 1176 13 85 24 25 24 32 25 52 14 82 12 61 1126 1143 14 43 17 54 t5 80 483 1 1969 12 16 13 42 13 21 12 56 13 89 12 37 1172 1191 1191 1133 12 23 1211 12 39 390 8 1970 12 59 12 50 12 95 19 63 19 31 1265 11 53 11 29 1060 11 44 1057 1120 1302 410 7 1971 17 49 20 86 11 48 20 59 26 65 10 92 10 39 9 95 10 23 9 86 9 91 9 37 13 89 434 5 1972 1061 10 16 1327 1604 1901 1492 1195 11 17 1222 1249 1321 1231 1312 4148 1973 12 46 12 42 1169 14 44 18 77 12 25 12 44 1184 11 58 1140 1139 1149 12 69 4001 1974 12 22 13 06 11 49 33 78 15 57 11 83 11 68 11 29 11 49 11 60 11 18 11 43 13 86 437 0 1975 11 20 11 30 11 09 1247 14 13 1295 1148 11 32 11 49 11 38 11 14 1141 1178 3715 1976 1123 1142 1148 1176 1163 1129 1141 1136 1137 1128 1136 1133 1141 3608 1977 11 39 14 20 11 82 17 68 13 61 12 29 11 54 12 23 1229 1269 13 57 12 78 1299 409 5 1978 12 54 13 13 14 14 19 82 21 68 17 33 13 95 19 34 22 94 17 37 16 34 15 62 17 03 536 9 1979 13 08 13 52 15 20 25 81 58 90 55 24 41 91 27 72 19 29 14 64 12 69 11 72 25 88 816 3 1980 1139 11 59 11 98 11 90 24 33 NA 1391 11 75 11 24 11 27 11 74 11 94 1302 3780 1981 11 50 11 80 11 77 13 55 16 95 12 77 11 51 11 50 11 56 11 53 11 43 11 44 12 28 387 2 1982 1121 11 24 11 44 13 91 15 29 13 00 11 74 N A N A 12 06 14 86 16 69 13 26 3310 1983 1178 11 46 11 35 11 55 1639 1506 11 48 11 42 11 45 11 63 11 42 NA 1228 3543 1984 1143 NA 1165 1242 1595 1222 1229 1152 1380 1220 NA NA 1268 2684 1985 1 178 1213 22 46 27 51 22 86 19 54 1614 12 64 1195 11 84 12 29 ¶5 56 16 41 517 5 1986 19 97 13 64 11 97 22 07 33 32 20 24 13 82 12 12 11 74 t1 54 1229 12 28 1627 513 0 1987 1988 1219 14 16 16 71 18 16 14 00 13 10 12 85 11 96 1 I 44 11 46 12 71 12 40 13 42 424 4 1989 ¶990 12 37 12 84 N A 31 62 21 78 18 34 15 25 N A 12 85 12 19 16 62 26 69 18 08 473 4 1991 2537 2362 2040 NA NA 1727 1462 1213 NA NA 1181 1215 1711 3593 1992 11 71 11 63 11 44 28 57 21 07 18 67 13 72 N A NA NA NA N A 16 67 306 8 MEAN I I 14 45 421 1 YEARS 23 23 23 23 23 23 24 21 21 22 22 21 269 MAX 25 37 23 62 22 46 33 78 58 90 55 24 4191 27 72 22 94 17 37 16 62 26 69 58 90 MIN 10 61 10 16 10 53 10 98 11 63 10 92 10 39 9 95 10 23 9 96 991 9 37 9 37 MEAN 13 00 1314 13 19 18 74 20 57 16 61 13 86 12 75 12 55 1197 12 50 13 32 14 35 VOLUME 34 83 31 79 35 32 48 56 55 10 43 05 37 13 34 15 32 52 32 07 32 41 35 69 452 64 RUNOFF 15 69 14 32 15 91 21 88 24 82 19 39 16 73 15 38 14 65 14 44 14 6 16 07 203 89 NOTES MAX MIN MEAN in curnecs, VOLUME sn MCM, RUNOFF & MASS In mm MEAN FLOWS (AVERAGE YEAR) 100 T JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC MONTHS MEAN FLOWS (WET YEAR) 100 . . ... ... ............ ...... . ........ . .. . . . .. .................. JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC MONTHS MEAN FLOWS (DRY YEAR) 100 .*LoI I1..... .. JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV OEC MONTHS SECSD (P) Ltd Page 7-9 Ka3fto(mean) (I A.~~~~~~A. , 1'0' ~~~~~~~~~~~~~~~~ ~RAJN GAUGE CODE 1.Vi;: (344 I .4 1106~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~OHI(HIA(O) ROUW I KILE3JA-4149N1 933- 745 J33/ln,2 IDC-,A I 1)~~~~~~~~~~~~O ~~~~~~~ .!~~~~~~~~~" ~~~~SISAL ESTATE I 933.- 7,3i 27o;.,,2 1OC- 3A .4 Ila, A ~~,s/ I HAI ?I01tER 100 * .4 ,~~~~. ,~~. i rJos'Es 933--7134 20.2 IC 5~~~~'5 '~~~~~~~~ g ~~~~HAI LOAIBO - 13 24~,,,2 1011 I. p. 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ISS1C(V SCHOOL 933- 706 411CR a ~~~~~~~~;I1 I~11(0RS KES FRK .4~~~ r~~3.~~-) ,~~~'! / - 'A / I I 1'~~~~~~~~ M08A4i3 HA! 933- 72/ (16s .0.10) 100-1HA0(1s md) ID - 1 1110.'A .4 I [CA 13U110I3 ~~~~~~~~~~~~~~~~~~~~~~~0SAW A JaU .4 .4~~~~~~~~~~I, 4 M,L e.UC A. - ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C~~~~~~~~~~~R10E14AN 933- 74 7 (44S m,,e) IDD- 13 .4 - I .FARM - - 1~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~~~LM 'A~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A4 A R.4 e' ~~~ I8~~~~~8u~~~~.f~~~~tA5wAALAk~~~~~~~~~~~~T .4 I I,':o~~~~~~~~~~Tblo,,es & .4.4 ~~~~~~~~~~~ 8 ~~~~~ANY CA P LA I ii4 5 NT % ~0L* *, .* I '9Aogm e(foco Slaoc- Secoadory E, n '' "' , I~~~~~~~~~~ A,r Photo Pr'nc,pol Pc.rt Ss SItf4 .01".u2, Isit , r . No - RA A I ( A c o. dOA CSA .4.4 ~~~~~~~ThAc' oc'. 00 0.8~~~~~~~~~~~~~~+ ,,. c',,Oroq s/col'n .4 A ., ,.,~~~~~~~~~~~~~J.5, .1* - .455 5'~~~~~~~~~~~~~~~~~I REFERENCE .455 .4, .4.4 Icc':~~~~~~~~~~~~~~~~~~~~~~~~e- Sheet No' 72/2 56/4.56/7.72,/. 71 '2 .4 ~~~~~~~~~55/4 56/' 355/.56/3 .4' :0' ' .4~~~~~~% : I 'SCO I I AP AA X, sr Y~* A MUNGA CATGHMEN1T AREA OF KIKULETWA RIVER UPTO 1'JYUMBA YAMUA W I REEVI THE KIKULEGWAL HYDROPOERPOJC (3008.80eq km.) elHD-MMXGCLTP * FOFLrWOF.D BAN4KJ'TANE30 O. 1/ 1. PANN,/IG DE15AA A 1*','! 5,,1.., -& . Is '-. 1.00511(0151(51 CCAS1AlATll .: ' '''slhJo jSch) i / / /RsW~~. Q) soinbu Mo t( /1 t;p0-15 tor ?o sawe < S;< _ __ 0~~~~(Aft 4eIra u (iS.o)5 93 706) ej s --| -- .---i 1 X, . /t / w _ . | z D \ / gtl wa % 93 - 7w36 j SO 1JGAL MAP OF K~~~~~~~IIAJR REom 2/ o rtkl,~~~~ 3 3 - 710 7~~~~~, | lXlKiTe*>t{DFit0'+E6 {15§E-0T Arusho~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~SHEA MA FTEPO.T RA( Air~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~FR Pori WORL BAKTAEC _M I o D2GtO ILAtIGDSIN NA B O FO 'N1 >1 >1072 |91ZAGURU EtJERGY CONSULIrtJlS _ _, SITE 10054 FIGURE . 7-3 YEAR 1971 STA KIKULETWD A FLOW DURATION CURVE IN AVERAGE YEAR FLOW DURATION CURVE (semi log) 10 t e *R ag e - ? ~~~~~~~~PERCENTAGE EXCEEDANCE FLOW DURATION CURVE 80 E I 8, U 4 20- ( __ PERCENTAGE EXCEEDANCE SECSD (P) Ltd. Page - 7-12 KF3FLO.LDs(71grd) SrTE I1W54 FIGURE 7-4 YEAR 1979 BASIN KIKULETWA FLOW DURATION CURVE IN A WET YEAR FLOW DURATION CURVE (semi log) 100 - 0 m I n 1L. d. 0S 0 o o o o PERCENTAGE EXCEEDANCE FLOW DURATION CURVE 80 60 L E t 40 LC.) 10 *20 o- O 0 . ......... . _ _I............ 0 0 a 0 0 R O o ~ ~ ~~N ,, S8 PERCENTAGE EXCEEDANCE SECSD (P) Ltd Page. 7.13 KI3FLO.xIs(79-grd) SITE ID054 FIGURE 7-5 YEAR 1976 TASRIN KIKULE1WA FLOW DURATION CURVE IN A DRY YEAR FLOW DURATION CURVE (semi log) 100 . .-- ------ ---.-- E i 10 9a i o o o 0 PERCENTAGE EXCEEDANCE FLOW DURATION CURVE 15 ----------- -- - --. - -- ~~~----.. -......... ........ . . 10 E .2: w o 0 * C, 5- ar O na 5t R ,aR aOe ffi PERCENTAGE EXCEEDANCE SECSO (P) Ltd Page 7-14 Ki3FLO.xds(76-grd) TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Chapter 8 Power and Energy Studies Section 1 Description The power and energy studies are carried out to predict the pattern of power, energy output of the plant, estimate losses and arrive at the optimal installed capacity of the power plant based on the available flow at the project site. Other features of the study include formulating operating strategies of the power plant. Section 2 Reservolr Characteristics For carrying out the power and energy studies, the reservoir characteristics were calculated from the 1:5000 aerial topographic maps which are existing. The contours on the map were digitised and the contours were further interpolated to contour intervals of 1 m by use of a Digital Terrain modelling software. The area enclosed by each contour at the diversion weir site was calculated. The incremental storage between any two levels hi and h2 is given by the following cone formula. A = A1 + A2 + 'I(A1A2) where A1 and A2 are area in m2 at elevation hi and h2 respectively, AV = A (hi -h2)13 cubic meters. V = EAV cubic meters. The area/capacity characteristics are given in figure 8-1. Section 3 Methodology The methodology adapted for deriving the inflow sequence at the Kikuletwa dam site has been dealt with in chapter 7. Here we discuss how this sequence has been used to compute the power and energy output of the power station. A continuous period of at least ten years with no missing data is taken to be representative of the hydrological conditions which are likely to recur during the lifetime of the project. This representative period is the hydrological years 1970 to 1979. The average yield of Kikuletwa for this period at the proposed site is 14.61 cumecs with a yield of 451.1 MCM. A set of extreme conditions in the above period were identified to carry out the power and energy studies. SECSD (P) Ltd. 8-1 Klflnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION The year with maximum yield was 1979 with a yield of 814 MCM and the year with minimum yield was 1976 with a yield of 359.8 MCM. The year in which the yield was closest to the mean with monthly distrlbution of runoff corresponding to the average of the ten years is 1971 with a yield of 450.9 MCM. Thus 1971 is an average year, 1979 is a wet year, and 1976 is a dry year. In any actual year, the energy output from the plant would be between the extreme values as determined from the above. Thus the evaluation was carried out according to the series of daily average discharges available for the 1 0-year period 1970 tol 979. The installed capacity and the choice of the number of units was fixed so as to minimize the spill in an average year as well as to use some of the extra flows available in a wet year. The number of units was decided by the pricing of the turbines and generator as well as to provide flexibility in operation. Various sets of calculations on energy output were performed with different installed capacities. Based on above it has been decided that for an optimum development the installed capacity should be 11 MW and the power station will consist of two units. (2 x 5.5MW). As a drawdown of about 3 to 4m is permitted, considering the fairly uniform head which will be obtained during the year, vertical shaft Francis have been preferred and shown in the design drawings. Section 4 Important Features of the Calculations The power and energy studies have been carried out with a computer program which uses the daily flow data series at the diversion weir site. The program models all the important conditions and constraints which are likely to be encountered during actual operation of the project. Some of the key features of the software include: 1. Use of daily flow data In working out the power and energy computations. This is necessary as the reservoirs or pondages are quite small and the water levels increase rapidly for moderate inflows thus giving rise to rapid increase in head. Use of monthly models which assume linear variation of head during the month as well as those based on calculating the area under the duration curve underestimate the average head severely and consequently gives a pessimistic value of the power and energy. SECSD (P) Ltd. 8-2 I(lUfnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION 2. Accounting for the efficiency variation of the turbines which is a function of head and discharge. This was accounted by using model test characteristics obtained from equipment manufacturers and adjusting them to prototype values. 3. Operating constraints on power output caused by head which dictates the maximum discharge which the turbine can allow. 4. Accounting of all hydraulic losses which would occur in the waterways such as Intake, canal, penstock, draft tube and tailrace. 5. Operating the power station to maximize the energy production from available flows. This is achieved by operating the units at best efficiency operating point during the dry season and full gate position during the wet season. The determination of the best efficiency and full gate position in case of projects with long waterways is obtained through the solution of non-linear simultaneous equations. 6. Giving due consideration to all other conditions such as evaporation from lake, mandatory releases for downstream users, irrigation requirements etc. 7. Accurate prediction of spill volume on hourly basis and spill hours which is used in predicting the high tail water level as this affects the power output. 8. Summarising the daily computation results, into monthly aggregates for easy comprehension. The summary tables of the power study provide the starting and ending values of the water levels, heads and storages for each month and the true average of various levels, heads and power taking into account the non-linear variations in these parameters during the month. It was noted that the difference In energy output between the conventional monthly computations and the daily computations is as much as 30%. Thus in effect a simulation of the entire system has been performed giving an accurate picture of the power and energy output which would be obtained during actual operation. SECSD (P) Ltd 8-3 Kiklnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Section 6 Case Studios The following case studies for the power and energy output were done. They are indicated below. 1. Operation of the Klkuletwa power station In a typical average year 1971 with an installed capacity of 2 x 5.5MW. 2. Operation of the Kikuletwa power station in a typical wet year 1979 with an installed capacity of 2 x 5.5MW. 3. Operation of the Kikuletwa power station in a typical dry year 1976 with an installed capacity of 2 x 5.5MW. Section 6 Results Detailed performance and operating tables are presented in tables 8-1, 8-2 and 8-3 for the average, wet and dry years respectively. Each table brings out among other things, the following basic twenty five quantities summanzed to monthly values which are sufficient to completely describe the operation of the power plant. 1. Start Volume: The volume of water available in the reservoir on the first day of the month in MCM. 2. Start Level: The level of the lake calculated from the level vs volume characteristics of the reservoir given in figure 8-1 for the start volume of water above. The value is given in masl. 3. Inflow Volume: The total inflow into the reservoir in MCM for the month as determined from the section on hydrology. This includes the flow of the river as well as the regulated power station discharge of any upstream stations which are included in the model, 4. Turbine Volume: The total quantity of water routed through the turbines in the entire month for power production in MCM. SECSD (P) Ltd 8.4 Kflmai.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION 5. Lake Surface: The mean surface area of the lake during the month in square km. This influences the quantity of water which evaporates from the surface. 6. Evap Volume: The total quantity of water which evaporates from the free surface of the lake during the month in MCM. This is dependent upon the climatological conditions and are fixed through the pan evaporation data. 7. Irrigation release: This gives the quantity of water abstracted for Irrigation from the lake either through lift or gravity. This is assumed to be nil in this study as the project is designed mainly for power production. 8. Mandatory release: This gives the quantity of water which must be released for downstream uses. Assumed to be nil in this study as the projects are run of river and the design and operation is such that no change in flow pattern of the river is contemplated. 9. Spill Volume: The volume of water which have to be let out over the spillways in MCM due to limitation of the turbine capacity and absence of incremental storage in the reservoir. This is also the quantity which at the present stage cannot be economically routed through the turbines. 10. Sgill Hours: The number of hours for which this spill occurs in a month. 11. Finish Storage: The volume of water available in the reservoir in MCM on the last day of the month after distributing the inflow between the power station and spill, storage and accounting for evaporation. 12. Finish Level: The water level in the reservoir on the last day of the month corresponding to the above computed finish storage. Values are given in masl level. 13.Change In Storaae: The net volume change In the reservoir for each month. Positive values indicate that the reservoir was built up and negative values indicate that the reservoir was drawn down. 14.Average Station discharge: The discharge through the turbines in the particular month in cubic meters per second. SECSD (P) Ltd. 8-5 Kiinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION 15,Hours Run This indicates how many hours the power station could be operated in any day of the month at the particular station discharge above. In the wet season this is 24 hours and the station generates continuously. In the dry season a value of 6 hours indicates that the inflow is stored for 18 hours and used through the turbines in 6 hours for peaking. The total operating hours is given in the last row. 1 6. Units Run: This indicates the number of machines which are on load. 1 7.Averaae Gross Head: This indicates the gross head available to the turbines. ft is calculated as the difference between the reservoir level and the tailwater level. 18.Averaae Loss: This indicates the sum of the hydraulic losses in the waterways. Typically this includes the intake, trash rake, draft tube etc but does not include the losses in the turbine. 19. Start Net Head: The net head available to the turbine on the first day of each month 20. Finish Net Head: The net head available to the turbine on the last day of each month 21 .Averaae Net Head; The mean net head during the month. This value is not the average the quantities 18 and 19 as the variation of net head may not be linear during the month 22.Averaae TWL: This is the average tailwater level during the month given in meters above sea level. 23.Averaae Rower: This value gives the average power output avallable from the HT Terminals of the step up transformer in MW. This is calculated by computing the mechanical power output of the turbine as per the net head and discharge, then subtracting losses in generator to get generator output. A further one percent of this is subtracted for consumption within the power SECSD (P) Ltd. 8-6 final.aidoc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION house for various auxiliaries. Then the losses in the power transformer and bus is subtracted to give the net power available. 24. Energy: This gives the monthwise production of energy in GWh. 25, Not Storage: The net change in the reservoir volume for the year. This should be as small as possible so that the cycle may be repeated in the following year. In the last row of the table, the mean and sum of various quantities are given. The above figures are sufficient to fully describe the performance of the plant in any particular type of hydrological year. From the above results the following may be inferred. Section 7 ConclusIons The results of the studies are summarized below. Box 8-1 Summary of Energy Outputs Installed Capacity Mean Year Wet Year Dry Year (MW) (GWh) (GWh) (GWh) 1 x4.0 36.0 1 x6.0 54.1 2x4.0 59.7 2 x 5.5 65.0 82.0 55.9 2x6.0 66.2 The annual energy production in an average year is about 65 GWh. The annual inflow volume and utilization for generation for each year is given below in Box 8-2. Box 8-2: Water Utilization for generation Year Wet Year Average Year Dry Year Inflow (MCM) 816.3 448.9 359.7 Utilization (MCM) 526.1 414.4 359.7 Percent Utilization 64.45 92.31 100.00 SECSD (P) Ltd 8-7 ftcfnai.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION The plant load factor for each year is given in Box 8-3. Box 8-3: Plant Load Factor Year Average Wet Dry Plant Load Factor 67.45 85.10 58.50 Further from the tables 8-1 to 8-3, It Is seen that In an average year, 11,000 kW can be generated continuously in the months February to May. In the other months one unit can be on full load. As initially, the power plant will be the only generating plant operating near Moshi into the existing grid It is anticipated that the power station will give peaking facIlIty and voltage support. Also surplus energy can be utilized in neighboring areas easily. SECSD (P) Ltd. 8.8 Kfkfinal.doc FIGURE 8-1 RESERVOIR AREA AND CAPACITY CURVES Kikuletwa Stage-3 Reservoir Area Characteristic 810 00 >805 00.,_ @ 80000 o ______ I 795 OC_ i0-_ , 790,00 - 785.00 = _______ 780 00 0 5000 l0000 15000 20000 25000 30000 Reservoir Area (sqm) Kikuletwa Stage-3 Reservoir Capacity Characteristic 81000 ....... -- -.--. W0 00 _ -800,00 -----i - W 795.00 - 785 00 0 50000 100000 150000 200000 250000 300000 Reservoir Volume (MCM) SECSD (P) Ltd. Page: 8-9 lakacp.)dsgraph-1 0l AVlj ,MdEtPI 0-a 4&8 Pil id) COS30S SHINoOi SHINOW I3833.Omod a _______________ ~d3S VWt mnr NnIr AVn l08w OvOl 033 PTw 330 AON iOo d00 0%0v inr 081? AVN 08 I OW l SOi1d ,jvr 1SgN V 3MOdkjHlNNoWI 0St NO 13A"1 0AOAH3S3O -__ --109 . -H M - . -- 0l 0IM 03a A0 100 ds ofw nr Mr AV" ud ti - - 08y 0I0~~~~~~ NO )2V~~~~~~~~~~~H is 3 AN 30 NOtw InrZ Wl AV 8V 319M3 V _ _ - - - - - I~~~~~~~~~~~~~~~~~~~~~~~~~~~Oza lOs 5,i 15001>1 fg jO:OO io:o IJI Z6tO - 000010 1001 000 066600 0100 01800 000 000 000 000 01815 50055 '0 105 :00 01051~ ~~~~~~~~~~~~~~~~~~~ 295~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~0 05) 01 11 IOJO~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~90 II11 096 .1 5 1 9 L _ I 9 I 6 g 0 g e I C C O115 N6Z 60 DE 1 _B u_a__ ___Po ___Ito____Pt_at,__ ____ 03s01ii j boo SG ElZ0 I) s ION 000 9 01 00 0110 88 0 IOt IVIS Gi 50) 0fl0 0 slol C 0 1900I 0090100 00 13 DO9r 0 zoo 0 0W S0A 09,101 10" Los i'i30 0600 , 00A]10wAv00 41.1 195 OVOOOYOsSN' 004 00090)90 biS 'ld 90111 1ISINi 0 Go 0 06 891 009 CZi SI MOSIN io).' j0 1S 1 AO"9 Ss s 9: D'. .9 zi ". 6S 0 Z,iiMhO9 '0 004P 916 0063Acoo0,s 50 A 0fI0OM0dA6000ZE 1idd0091Vi'SAi'I'0 [Z a S B" S, I- P. S. C9 09 0 m ~~ Z 00 Z Sfi. 10f008 0'399 to 9A0IfleOiO0 no0 o O 1 S ~ 89' LTK o t s ;f .. 5, Eg S6 9 19 0 as Z9 00 11 1: :t zoo 00~~~~~~ 0 0901 0 t e P0 0 ua 00 1 ,9 3 TABLE 8-2 KIKULETWA STAGE-3 PROJECT MoTHlY SUMMARY OF OPTIMIZED DAILY POWER STUDY NA TYPICAL WET YEAR FOR 2. sSMtJI 9791 MONTH START START INFLOW TURBINE LAKE EVAP IR R 8V04 FlNiSH FINISHi SPILL SPILL CHANGE AVEPAGE HOURS LiiTS AVERAGE AVERAGE START FWSH AVERAGE AVERAGE AVERAGE ENERGY VOLUMtE LEVEL |VOLUME VOLUME SUIRE.E E VOLUME RELEASE RELEASE STORAGE LEVEL VOLUME HOURS IN STATION RINMPER RUN GROSS LOSS NET EET NET TWL POWER AREA tORAGE DISCH DAY HEAD HEAD) HEAD HfEAD I CUM Ium) t |M CUM, IM CUM, 50 KM ,M CUM, IM CUM IN CUM) /M CUMIM (1 IM CUM IMCMI 1M01H (-I I., (-I 11111 I (MAIl 1GWv JAN o0 I s0000 3s03 3501 0o o 00 00o0 000 01o S 4 65 000 000 -0 01 1301 24 00 640l 102 5366 6321 6364 74034 743 5 5 FEB 015 804065 32 71 32 71 0 0. 301 0 00 000 014 804 31 000 0 00 -0 01 13 52 24 00 2 64 30 100 63 21 6255 63 21 140 35 701 5II MAR ol4 804 31 4071 40 71 002o 001 000 000 0 13 80394 00o 0o00 001 1520 2400 2 6393 130 62 s5 61 13 6255 740 38 841 6 lb APR 013 803 94 660 o 51 64 0 02 0 0o 0 00 0 00 0o5 800 00 1o 04 719 20 0 02 20 00 24o 2 63 4 2 36 61 13 0 219 61 13 740 4 11 04 705 MAY O1's 8o0 15 Z7 53 57 o 02 0o00 000 0o00 0o15 800 0 41 74400 00 2000 24 00 2 64 5 2 36 62 10 6210 5219 74045 113 8 21 JIM 010 80500 143W1 s o 14 D0 0 00 0 00 00 015 8000 W 134 720 00 00 W6 20 20 0 2 O 450 230 6 2 1 9 6216 62 39 74040 1113 60 JUL 015 8050 DO I12Z25 53 57 0 02 00 000 0 00 0Go 0l 80000 58 66 7"406 000 20 00 24 00 2 64005 2 36 62 19 62 16 6219 7404 : 1 113 -20 AUG 015 60500 7421 03057 0 02 000 0 00 0 00 010 8DS080 20 67 744 00 000o 2000a 2400o 2 64055 236 62 19 6230 62 19 74045 Il 630 SEP 010 8000 50so00 49077 03l 000 000O 000 010 801500 0 23 720 00 0 00 102'I 24 00 2 64 56 216 6238 8330 62 30 74044 108go 770 OCT 015 0 500 39 121 39021 0 2" 000 000 015 048 0 00 0 00 000 4 164 2400 2 64 83 1 28 63 35 635 8330 740 37 932 19 NOV oIs a0406 3260 30913 02 000 000 000 0 14 04 59 0o00 000 000 269 24 00 2 64 52 097 63 56 6345 6306 14033 721 1 DEC 0o4 8B0409s 31 39 31 39 302 000 0w00 0 00 014 S04 53 00 W 00 0 00 11 72 2400 2 64 27 83 63 45 64 53 63 45 740 32 6 71 49 ____- ____ - ____ ____ -- t -_ __ ___ _ - NET ___ iMEAN0 TOTAL, TTOTAL, MEANI t01. TO3AL. TIOTAL) (OMEAN) ITOTALI ITOTALU ORAGE (MEAN) (TOTALI (MEANI IMEAN A 1MEAN4 IMEANi (MEAN4i IMEA I (IMEANI TOTAL, I II 80478 e8 16 28[ 52610 02 004 000 0o00 04 74 2901 430120 -0 01 6 67 6760 -_ 64 38 1 71 62 67 82 74 62 67 740 40 634 818 WATER UJIL-ZATION - NET HEAD ON 15th I 61) ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~-6 t -oT40 l-- 64 ----- -- |~ ~ ~ ~ ~ ~ ~ ~ ~ ~~ ~~8 -__°°_____R_____--__-_-___I_E_E3____ 120 80 | JANE FEe MAR APR MAY JIM JUL AUG# SEP OCT NOVr DEC 8 0 l l I ~~~~~~~~~~~~~~~~~~~JAN FEB MAR APR MAY JIM1 JUL AUG0 SEP OCT NOV DEC |~ ~ ~ ~ ~ ~ ~ ~ ~MNH ID INFLOW D TURBEINE 0 EVAP E0 SPILL |I |MONTS | ~ ~~~~~RESERVOIR LEVEL ON. 1r MONTHLY POWERS&ENERGY 60~~~~~~~~~~~~~~~~~~~ JAN FEB MAR APR MAY JIM JUL AUG0 SEP OCT NOV DEC 6 JAN FEB MAR APR MAY J-IM JUL AL2G SEP *OCT NV -DEC MONTHS 8 INLW UB MONTHS|tI R SECSDO OR) Ltd P.ge 8 01 AI3POIAOOREORNNWE TABLE 8-3 K(ILILE TWA STAGE 3 PROJECT MONTHILY SUMMARY OF3IM1' DAILY POWER STUDY IN ATYPICAL DRY lEAP ~O 2 SM", 1976, MONITH START START INJFLOW TURBINE LAKE IE"A.P IPR MAlID vIIS'4 j SPILL SPILL CHANGE AVERAGE HOURS 1l'lTSl4 0EAEAO START FINISH AVERZAGE AVERAGE AVERAGE ENERGY VOUELEVEL VOLUME VOLUME SURFA-E ~'.,J,MF RELEASE RELEASE SIOAAF tO FL VOLUME HOURS IN STATION fRUN,PERl RuN GROSS I OS ET NET NET TW POE FEB 015 60465 2763 2763 ARE~~~~~~~~~~~~ A ___ 00 00TORAGE OISCH OAY HEAD jHEAD HEAD HEAD) IMCUMI iml IMCM cu)imCUMI SOKM, M'UAd m :-uM MpCUM, lM.U, I~ KACUMI imcmI 011 (CUM)II- , Inl (Ml (mI IMTl (MWI 1099111 JAN 0 15 405 00 30 06 30 04 102 Qz l io 65 0 00 0 00 001l 11 23 24 01 2 64 65 076 63 93 63 56 63 93 740 31 6 41 4 77 FEB 0 15 04 65 2763 27 63 .1 12 1. 34) -411 0 0 001 11 42 740.1 2 64434 0)76 635S6 63 20 63 56 740 31 6 46 4 35 MAR 0 14 604 31 30 75 30 75 012,, I, 1.1 13 3'4(Il) 000u -0 01 11 40 740 2 6399 I,7 63 20 62 79 63 20 740 31 6 47 4 82 APR 0 13 803 94 30 46 30 48 12.1 - '.12,1 11. 1 12.3 ~ 00 0 00 0 00 11 76 24)21J 63 2 0)83 62 79 62760 62 79 740 32 6 60 4 75 MAY 0 13 803 73 31 is 31 10 I 22 .,.)I 1,1 12101) 1) 31 0005 o ) 0Oa 00 11t63 74121 0 1 63 4' 06 1 62 60 62 51 62 60 740 31 6 51 4685 JUN 0 13 603 58 79 '6 7 f)9 6 '17,2 .1 >VI '11 21 4, II0, 00 12 24.11 2 !332 0 '7 67 51 62337 61 743 61 44 JUL 113 803 46 30356 30 56 '' LI '11 I '2 2 00) 0 00 11 41 24 1.3 13'5 176 62 37 67724 62 37 740 31 6)16 4 73 AUG 012 80332 3043 3043 >121 ~~~~~~~~~ >~~1,1 11.3 7 2 1)3 71212 000 13424,1,11 2 33.1 114 6774 6709 6224 74021 63262 4702 2 740 1 6 3 4 7 SEP 0 17 803 17 29 47 247, 11"0 Lj 1 '2 1.1 7 61*,0 62 0 'Ll 00 072 000 1137" L'74 6 6- 0 6190 620 470311 6 310 5 OCT 0 12 802 99 30 48 30 48 Li2 '~ ' '2 2 I 00 00G 0 00 11 36 2471 1 36 0' 61090 6162 69 43 3 6 NOV 0 12 802 87 247 76 021 2 .111 131 I; 0 00 00 1 240'I 2 25n 075 61682 63 616 7431 615 44 DEC OI 61 02 64 3056, 30 56 .117 .1.1 1,L1 .l13 1100 000o 000o I14 -37113 I 5 61 99 62 60 61 55 740 31 6 34 4 72 NET IMEANI TOALI TOTL, MA, 71" 701AL, TOA, OAE (M.A I 'I,AI MAN, MEANI MEANI (MA,MEANI IMFAN (MEANI,TTL WATER UTILIZATION NET HEAD ON 15th 1 20 ---- ~- -J 63 - -""-""-l--- to- -_ ~~~ 15 - -~~~~~~~~~~~~~~6 JAN FEB MAR APR MAY JUN JUL AUJANGEB MR AR MASJUN JULTUGNEPVOTDNO DE MONTHS 0 NLO TURBINE 13 VP 3MONTHS RESERVOIR LEVEL ON 1st MONTHLY POWER & ENERGY 805 7 604~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ W 63 802 1~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 801 iJAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DECPOE NRG MONTHS MONTHS [F- jE ~ I SECSO IF) Utd Page 8-12 ki3POWI2R res TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Chapter 9 Civil Works Section 1 Description The major components of civil works involved in the construction of the hydroelectric project will be 1 Construction of an access road to the proposed diversion weir and power house areas. 2. Preliminary preparation of the site including setting out, surveys, erection of storage areas for materials and area for personnel. 3. Excavation for diversion weir and construction of the non overflow and overflow sections. 4 Construction of the intake structure for the waterway. 5 Construction of waterway comprising cut and cover conduit and penstock. 6 Excavation for the turbines, their installation and subsequent concreting to form the substructure of the power house. 7 Erection of super structure of the powerhouse for accommodating auxiliaries, controls and protection. 8. Excavation of the tailrace and concreting which will afford passage of water after exit from the turbines back into the river. The preliminary design and scope of works involved for each of the above components is discussed more fully below. Section 2 Access Road For the construction of the project, the access road is of primary importance. Fortunately the site is located such that the works required will be limited to improvement of an existing 8km stretch. Other works involved are the improvement of existing second class road which is to be made suitable for transport of the machinery, especially through provision of some small culverts across streams. Therefore, it will not be necessary to seek permission to develop new roads. The access road will be used to transport all the equipment required to construct the project. The road is proposed to be 7.20m wide with shoulders I m wide. The proposed elevation of the access road is at EL 830m so as to be above the elevation of the high flood expected downstream of the diversion site. Two main branches are provided, one leading to the top of the dam which is at 812m SECSD (P) Ltd. 9-1 Kk&W.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION and the other descending to the power house machine hall level which is at 740m. The power house access road requires some grading of the left bank of the river so as to have a gradlent suitable for descent of vehicles. A simple bridge has to be provided to cross the river to the right bank where the power house is located. Section 3 Preliminary Design Part I Diversion Weir The diversion weir is a concrete gravity cum arch structure 20m in height and curved in plan. Considering that the diversion site is very narrow about 25m wide at the base and about 40m wide at the crest, an arch type of design Is considered to reduce the amount of concrete. Centrally situated is an uncontrolled overfall ski jump spillway. There is a weir of suitable shape at the top of the dam. The average inflow at the intake dam site described in the section on hydrology exceeds the 20 m3/sec maximum power discharge for about 40 days in an average year. The surplus water will be discharged downstream by the ungated spillway. Before placement of concrete the foundations and abutment should be consolidated by low pressure grouting through suitable holes. After completion a line of holes should be drilled partly from gallery in the dam and partly from the heel thereby forming a grout curtain to minimize leakage and uplift pressures. Near the base of the dam are two outlet conduits each controlled by a high pressure hydraulically operated slide valve. The height of the non-overflow section of the dam Is obtained by the following equations If the design water level is normal high water level then h,= hw + h. + h. but if the design water level is design flood water level h, = h The larger of the two values above is to be adopted, where, hi : addition to required water level (m) h: wave height due to earthquake (m) hw: wave height due to wind (m) ha addition depending on existence or non-existence of spillway (0.5 m) a) Wave Height due to Earthquake SECSD (P) Ltd 9-2 Qlkflnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION he = 1/2 ( kr/ 7t) (4gHl-) where, k horizontal seismic coefficient (0.15). r period of seismic wave (1 sec). Ho water depth of regulating pond from normal high water level (15 m) Substituting he ' 1/2x((0.15x1)/'n)x'I(9.8x15) = 0.289m b) Wave Helght due to Wind Hw = 0.0086 V " F0°46 where, F is the fetch (- 50 m) V is the 1 0-minute average wind speed (30 m/sec) Hw: 0.0086 x 301.1x 500°45 = 2.108m Height of Non-overflow Section Where design water level is normal high water level hf - hw + hi + ha hf = 2.108 + 0.289 + 0.5 - 2.897m Elevation of non-overflow section = 805 + 2.89 = 807.89m. The elevation of the top of non-overflow section is fixed at 812.5m due to approach considerations. The features of the diversion weir are given in figure 9-1. Part II Intake The intake structure is located in the immediate vicinity of the diversion structure. it is designed to be an independent structure with control for admission of water to the power conduit. The structure is founded on the hard rocks which form the banks of the river. The flow should be controlled in such a manner that air should be prevented from entering into the conduit. There is provided a trash rack structure to prevent any debris from entering the conduit. Admission is controlled by means of a slide gate operated by a hoist. The design of the structure is conventional. SECSD (P) Ltd 9-3 Kkftal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Part IlIl Power Conduit The power conduit consists of a D section cut and cover section as shown in figure 9-2. The overburden to be removed is very small except for a short stretch where the ground level is about 822m. The width of the conduit is 2.5m and most of the excavatlon Is soft rock. The total length is about 325m. The conduit is made up of reinforced concrete in a trench which is excavated and backfilled after construction. At the end is embedded a 2.5 to 1.5 m dia steel bifurcation from which two penstocks covey the water to the power house. The hydraulic loss was estimated with the Manning's formula with L=325m, A = 5.579 m2 , P = 8.926m, v = 3.58m/s, n = 0.015. The loss at maximum flow Is 1.75m. Part IV Penstock The penstock is the final component in the waterway. Two penstocks of diameter 1 .5m each are provided. They are laid on an excavated trench with 1:2 side slope. They are supported on anchors. Each penstock is made from steel plates of 10mm thickness. The total length of the penstock is about SOm. Loss was estimated by the Scobey's formula with K = 0.34, v = 5.65 m/s, D = 1.5m. The loss at maximum flow is 0,755m. Thus total loss in the waterway is 2.505m without taking into account losses in intake. The features of the waterway are shown in figure 9-2. PartV Power House The power station building is to be situated in the valley in which the Kikuletwa river flows about 1 km downstream of the diversion welr and intake structure. The power station building consists of a cylindrical tower built inside a circular excavation in the slope of the right bank of the river. The cylindrical structure is 9.5m in diameter. Alongside this on the upstream side is another shaft which houses the terminal section of the penstocks and bend. The entire power station equipment is contained within this structure which is divided Into three floors housing the various equipment. The access into the structure is from EL 743. The bottom of the tower is founded in sound bedrock. The plan of the power station at various elevations is shown in figure 9-3. The bottom structure of the power plant (from the foundations up to the turbine floor level) is formed of mass concrete founded on solid rock. The top structure is formed by a 12 m high cylindrical reinforced concrete shell. This shell which also forms the peripheral walls will be dimensioned so as to resist the water pressure if SECSD (P) Ltd 9-4 KUfidnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION the downstream water level rises to an elevation + 740m. On the downstream wall is provided a hoist for operating the draft tube outlet gates by means of a crane. The power plant consists of the machine hall, service bay, substructures, control room and space to house all auxiliaries. The access to the power plant is from a branch of the main access road going along the left bank of the river and descending to the river at a point near the power house from 820m to 745m. Final access to the power house is by means of a bridge across the river. The bridge leads to the approach area which is at elevation of 743.70. In front of the entrance a wide level space is provided to enable vehicles to turn and to temporarily stock unloaded articles. Access to the shaft is by a 2.5m wide gate from the western side. The whole structure due to its design is capable of withstanding the 1000 year high flood level as seen from figure 9-4. Additional protection from flooding of the power plant up to a flood level of 1000 years occurrence is possible by propping the entrance gate and sealing its joints so as to make it watertight. The bottom most floor level which Is at EL 737m Is the turbine floor. The spiral casings of the two turbines are installed such that they are symmetrical in plan about the longitudinal center line. Also accessible from this floor are the main inlet valves by means of a stairway leading down to the valve pit, the bottom of which is at EL 735.3m. This pit also houses the valve servomotors. Located centrally between the two units is a sump pit to collect all waste water and pumps which pump it to a level above the tailwater. This floor also houses the pressure oil and cooling system and the wicket gate servomotors. To enable lifting of equipment from this floor there is provided in the centre a column which houses the lift shaft as well supports a circular crane beam on which runs an overhead crane such that its path describes an entire circle. Thus items may be picked up from any floor and delivered to the unloading bay situated at EL 743.70m The generator is supported on a concrete generator barrel which also houses the shaft and the coupling. Access is possible into the barrel from the turbine floor for inspection of the guide vane apparatus. The top of the generators is at the machine hall floor which is at EL. 740.20. The piers of the draft tube extend upto this level. SECSD (P) Ltd. 9.5 Kflnai.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Iron gratings which can be removed are provided to remove the inlet valves from this floor thereby avoiding waste of space. Alongside the machine hall is located the control room which is below the unloading bay. This arrangement will provide a clear view of the machine hall and the service bay. The wall facing the machine hall will be fully glazed. Above this level is the unloading bay and entrance gate which are at EL 743.70m The floor has been extended such that it becomes rectangular thereby increasing the area available. Stairs are provided on the periphery for descending down to the machine hall. The roof of the power house is made of reinforced cement concrete slab at EL748.40m. It has a provision for the lift room as well as space for the two power transformers from which the line goes to the 33kV switchyard located adjacent to the approach road on the left bank. A standby diesel set and air conditioning equipment is also installed on the roof. All the above features are shown in the plan of the power house at different elevations in figure 9-3. Under the control room is a cable compartment and an 6.6 kV switch room. A13o located at this same level is a storage battery associated with its corresponding charger. The elevation of the centre line of the turbine runner will be 738 m, a value determined in consideration of the normal tailrace water level (EL. 740.0 m) and the draft head. The cross section of the power house is shown in figure 9-4. Part VI Tailrace The draft tubes are shut off by 4 vertical-lIft gates placed In position by a 3-t hoist traversed along the flood platform at an elevation of +741 m. The draft tube outlets can be closed by means of four stop logs measuring about 2m x 2m. A open tallrace channel of trapezoidal section with 1:2 slope will be excavated along the right bank. It will be about 13 m wide at the top and about 20 m in length. It will be lined. It is expected that most of the excavation involved will be soft rock excavation. A service road is provided on both sides. A berm is provided 0.6m above the normal water level of 740.00m. SECSO (P) Ltd 9-6 KkIinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Part VIl Reservoir and Bank Erosion The Kikuletwa reservoir submerges about 20,000 m2 at FSL 805m and extends for 1500m with a maximum width of about 40m. It is appropriate to consider the reservoir as a small lake contained in a narrow and deep gorge. Due to steep gradient of the river bed, the flow in the form of rapids has probably scoured the river bed and hence the flow is in a deep gorge of 25 to 50m depth. Bank erosion has not been noticed except at only one place on the left bank (photograph ). The upstream lake (stage 11) will absorb the floods which is limited to 200 m3/s (1 in 1000 year frequency). The lake is also formed in fairly a flat reach of the river bed. Hence the flow velocity In the lake gets reduced due to increased waterway width at FSL thus eliminating the chances of bank erosion. The surface water level is almost steady at the weir crest (805m) and fluctuates within 3 m during spill in February to May of a wet year only. There is negligible scope for water seeping into the bank with return flow to induce slides/slips. Hence it could be concluded that erosion of the river bank in the lake spread area will not occur. Moreover, the annual precipitation in the project area is hardly 800 to 1 000mm for sheet or bank erosion. This is also confirmed from the following field investigations by JICA. Drill hole data at the dIversIon welr site, Intake, water conductor system, head tank, penstock and power house (appendix 1111), (b) Physical and chemical water analysis (appendix 11-7), (c) Record of permeability test in drill holes (appendix 111- 2) and (d) Record of water levels in drill holes (appendix 111-3). The conclusions drawn from the results of the above investigations are * There is fresh rock at various depths along the left bank (4 to 5km) with core recovery percentage upto 99% in the head pond and penstock area of JICA's proposal. This area forms SECSD's proposal (stage 111). * Negligible suspended/dissolved material in water confirming nil erosion. * Low permeability of the order of 9.34x1086 to 1x10-3 cm/s along the left bank in the reach from diversion weir to power house (about 5km). The above reasoning coupled with the presence of Tuff Breccia all along the river banks/project area confirms that bank erosion or sloughing is very unlikely. Hence stabilIty of the river banks in the lake area is assured. However, sultable bank protection in the form of pitching or Gabion mesh anchored and strengthened by Guniting or shotcreting at required places could be considered at the time of execution of the project, SECSD (P) Ltd 9-7 KI(nal.doc N 8Jwp 75Nsd' KIOT wSUsW \~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~1 5\R 4 6 6 ,/ E \I: 825 - \ ' SECTIONTHPAUGHt>LET OtOUIT - 1- r - lt~~~~~~~~~~~~824 80 _ " : Abulmen/ ¢eSbor 2 Srr-prsp scf':*cy bucSel. ! Soclwc\ Irclrs9 rol1, 4 Air .ents rrb4~~~~~~~~~~~~~807 _ ~ 2 T tlSI 5 Vosve ccnU.DI ecct, e1 6 Pc6e sonlDer 7 rf)socul,¢ DOIt 8 Szl* so Sp9 ylLe,, t~~~~~~~~~~~~~K 2 U CRnftns gy 1>D>U>g 795 ~ AssumedfundolicnHoeL ff t4-!- < r/g:Alu 1 to L 4 1 8 27ntA4 _ (round rl,^nLe.d) + a 7ss 1 /+ rJPo,.r G %; . 15\_ ~ rsrs rrssIlk 785 T 7 - r | | | ~ l l l l | T--r-I l l l ll | / | ^' \' . ' . @ CXe!r4 Q~~~~~~~~AR \\0 I' 30,I01 6 0 9 eo IQ 1 . .' UPT7,NL'bT0 V¢TtC r)Hls{fTD:sAlv, - \ 1 Sp.S/*y <.rsl Servlc ihotl 3Acesl ollrri, 4t;cle ter ber. Oullet 6 Spv^o 1rz7/a 5 Wool ECTIGHTROU(> RlARULNt6 It~TYIA 797IO 5StN _.- A~ ~~~~~~~~RUIgAOCANG OESa K Lr E7C OWRPtNC 795 G -ll 4~~~~~~~GAIfCMAR HDt-EAL ; FO .2WRDA7(TcN _ 7-9° SlA5F NEG -SIL^l _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _~~~~~~R L 91 6 _-3de dco _ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~9 835 33 T\t IIS RAIITNC IS IC) BE B,i\~ X r j , <~ UtSED FiS OR ESTIA TE PURPOSES 2 2z I----------V V l I \| \| 830 - ScAIr u F *v- EL7EVA9T0PJ (n)osL .D 840 > - 8 \ \\ I \ \ ) ELEV TIO Cms; / ;Ig I \ [' i-I,-7 840 mlPLAN OF WATER CONDUCTOR SYSTEM P 830 -s4 -- 820 _ROUND LEEL I F- TFO.TE WOELD TEMIATES 81 , - . dERE B-. o800 AFT -~~~~~~~~~-----'~~~~~- ----.-- £'IFURCA lION 2500 TO 1502 DIA~~~~~IFUCATIO 200 O 500DI 790 A N ~25 10 0o TUNINEL (0-SECTION) - SODASUFC ESO OR CUIT ANO CO" R CONDOUIT 2500 d, CUT AND CO SUFAEPERTC 750 - y~~~~~~~, -X if' ONUi T BACK ILL IS REDUCE) COTDIDI OR S,URFACE ~ENS70Cre -OR CUJT & COIEP CONDUIT 780 /'-' '>'/ ~~~~~~Y,TO, Sm 0 LONGITUDINAL CL OF P11 4' '7 ~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~C CAN4 BE SHlF TED SUCH 770 - - /')~~~~~~~~~~~~~~~~~~ ~~~~~~~ -'~~~~~~~~~~~~ ~~ THAT POllER HOUSE TVELL '7>' C..' *~~~" IS EUIIRELY U, SOUXND 760 (-~j.~ OCCK 750- 740 - IL'0.. 730 - _____ A_ _______ _____ o 50 100 15~~~~~~~~~~~ 0 0o 25 000.J'N 0 --v UACfxt PROFILE, OF WAE ODCO YTMPLAN. DISTANICE ALONG WVTERK4I FRENI WNAKE STRUCTUFE ~~~ / I "2~~~~~~~~~~~~1,0 Jo, tv 1 O SCAMNT~~5, fl,.'Av4lfD ~~POIL ATR ODUTO YSE SLOPE) SETQICCI if RO ,-C--- KIKULEMWA HYIROPOWER PRCJEC~TS (STAGE-111 _ _______ / ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~PLAN & PROFILE OF WATERWAY FOR. THE WORLD BANKITANESCO- SECTI~~~~~~~~4A-A ~ ~ ~ ~ ~ ~ ~ so ~ ~ ~ ~ ~ ~ ~ em~~~~.c I/lIT~~~~~-6, liD P~LANNI/IC OLSICN & CALD By ____________ __SECTION _ A _____A___ __SECTION_______________Be _ _________________________________ ______T' q-2 1IVALIJRIJ ENELII TONSULlAtIIS . . . .1 . . ., a ' $,35 e7 I~~~~~~~~~ - I* -4F --- I L ~ ~~~~LLIFT- L-LI~ ,-/~~~~~~~~~~~ ~~~~ S' ,,,,.. , ,/,/ L _ $, _ 8 ty I j] _______ fl \ \': 'I ii Fit6 1 11 1 , \ \ i l I [ , X . i - X . I TUIRBINE FLOOR K * 1 ~~~~~~~~~~~~ ~~~~RUNNER 736 0 4XX ,/ /7 tI ] '<92 + ^ t VIN SITU 0 5 f-L 735 3 f 4 1 , [ | . v * i v - _,=> - * r ~ ' ff g^ 4 TOP OF DT1735 5 SCALE (me'ters) EL 735 3 I ROCK- (l f ALL LIiEiNSIoNs iN I>( j *' \ X t 2 ~ ~ ~ ~ ~ 14- ALL ELEVATIO.9 IN noii I' j ~ * _ ; ---Er362 KIKULETWA HYDROPOWER PROJECTS EL 73 '1- - - - ~(STAG,£ EL 733 65 , * |-- * .L _.--.* ~ ~ ~ |CRosS SECTION OF POWER HOUSE FOR IhE WOVRL AW rMiKWS ONG NO 9 PANiNING DESICNS & CAO BY _______________________________________________________________ ~ ~ ~ ~ ~ FIC 9-4 ISIVAGURU ENERGY CONSUJLTANISI a~ TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Chapter 10 Electro Mechanical equipment Section 1 Description The main electro-mechanical equipment consists of the turbine and generator, Also included in the scope are the equipment necessary for controlling the waterways to the turbine, and control of the bottom outlet gates of the diversion weir. The electromechanical equipment of the power plant was selected based upon the results of the power and energy studies. The preliminary dimensioning was carried out with a set of equations as well as database of turbine data obtained from various manufacturers. The equipment outline based on these dimensions are shown in figure 10-1. Section 2 Turbine Part I Dimensions On the basis of detailed hydrological studies it has been decided that the power plant will consist of two units of 5.5 MW each so that maximum energy can be produced. The maximum net head for the plant at full load is about 64.1m. The minimum operating head will be about 60.15m. The most Important factor In the dimensioning of the power house are the size of the turbine and generator. For the given parameters Q, H,,,, Hmin obtained from the power and energy studies, a Francis type hydraulic turbine is considered. The adoption of this type is advantageous from the operational point of view wlth the small variatlon of the head and discharge as compared to the types with adjustable runner blades, as high orders of efficiency are achieved, regardless of service conditions at much lesser cost. Safe design is made with respect to cavitation resistance of the runner blades, this undesirable effect is prevented by placing the runner at a sufficient depth below the downstream water level. The required value has been safely figured through manufacturer's model tests. In the present design, the runner center line has been placed about 4m below the minimum tallwater level. The type of turbine chosen for installation places more exacting demands on the draft tube which conveys the water coming from the blades of the runner. By model investigation it is possible to determine exactly the optimum shape of the SECSD (P) Ltd. 10-1 Kikfinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION draft tube, so that the flow is uniform under any service conditions and shows no irregularities whatever. The draft tube profile shown in the drawing is as per current practice. The operation of the turbine will be smooth and quiet, without oscillations that would adversely affect the electric power output of the generator. The dimensions of the turbine were calculated from experience curves. The resulting dimensions were then compared with actual equipment manufactured and installed for similar hydraulic conditions. The results were in close agreement. Any further small final changes in the dimensioning of the equipment will not materially affect the civil works quantity estimates which are used to work out the implementation cost. The trial specific speed Is given by n.'= 2334/4hd = 2334/V64 = 291.75 rpm (typical values for Francis units) A trial specific speed of 291.75 rpm was fixed. Trial speed n' = n.' x H1"4 / VP where P is in metric horsepower. A turbine output of 5500kW corresponds to 7275 mhp where H = 64 m, P = 7275 mhp So n' - 614.4 rpm Nearest synchronous speed = 600, 750 rpm for poles = 10 or 8 The 600 rpm running speed was selected. Thus Design Specific speed = nS = (n x VP)IH6G = 282.71 rpm Discharge coefficient 4= 0.0211 n.W = 0.9261 Diameter = 84.47t-1Hln -1.043m. SECSD (P) Ltd 10-2 Kkmnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Based upon the operating conditions which are to be met it has been decided that the turbine will have a runner of 1 000mm diameter The other parameters are estimated as follows. Wrunnvr = 607Dm.x2 75 kg = 607 kg Wturbin 15175Dma2"33 kg= 15.1t Shaft diameter = (7OPd/n) in = 7.15in = 180mm approx Flange diameter = 1.75 x 180 = 320mm Flange thickness = 0.20 x Flange diameter = 65mm Thoma's Cavitation coefficient ca = n1I4/50,324 0.208 The elevation of the power house area = 740m Atmospheric pressure Ha - 9,476m of water at elevation 740m. Mean temperature of river water = 250C Vapour pressure H, = 0.324 m of water Barometric pressure Hb = He - Hv = 9.476 - 0.324 = 9.152 m of water. Hcr - critical head - 64 m cYp = (plant sigma) = 0,20 (In the final design stage when the manufacturers sigma is obtained the plant sigma may be fixed). However this will not result in any major changes in the excavation volumes for the power house. H. (suction head) = Hb - up Hcr = -4.15m Now average minimum tailwater level = 740.40m from power study. Elevatlon of turbine runner = TWL +Hs = 736.25m. The elevation is fixed at 736m SECSD (P) Ltd 10-3 K1I1nal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Part II Specifications The runner consists of crown made of mild steel which incorporates the coupling face and a stainless steel assembly forming the flow passages. The crown and skirt are separate castings made of 18/8 Nickel Chromium steel. The crown and skirt are machined over the flow surfaces and the vanes are separately ground to the box templates. The entire stainless steel assembly is stress relieved. The assembly is then fixed to the mild steel crown by high tensile bolts and after final machining the stainless steel sealing rings are shrunk fit. The guide vanes are cast In 13/1 Nickel Chromium staInless steel. The guide vane end sealing plates and throat ring below the runner are clad with stainless steel thus the whole of the flow passages in the region of high velocity from speed ring to draft tube are of stainless steel. The turbine g0ide bearing is of a self lubricating type in which metal pads are rigidly secured round the shaft journal. The spiral casing of steel plate fabrication is welded to a cast steel speed ring. The spiral casing is stress relieved with internal ribs. An access hatch is provided. The casing is embedded in concrete at the site. The shaft is made of forged steel with integrally forged flanges on both sides for coupling with the runner and the generator rotor, The main shaft seal consists of shaft seal body with labyrinth, a clamp ring of stainless steel, lip ring of Perbunan rubber, seal ring with ceramic overlay and maintenance seal. The bearing system is made up of two-bearing arrangement; turbine guide bearing and combined thrust guide bearing on the generator side, the thrust guide bearing being designed for axial thrust in both directions. The bearings are oil- pressure lubricated, the lubricating oil will be pumped from the oil sump tank to the overhead oil tank and supplied to the bearings. This arrangement guarantees the lubrication of the bearings even if a failure of the DC emergency system occurs. Oil is cooled by use of an oil-air cooler. A high pressure oil pump Is installed for start-up or shut-down of the unit. Quantity of oil for the individual bearings is adjusted by regulating valves. SECSD (P) Ltd 10-4 Kikfimadoc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION The gate mechanism consists of fabricated wicket gates; stems and trunnions supported in self-lubricated bearings; operated by the regulating ring through levers and gates links. The draft tube liner is made of welded steel plates. It will be sectionalized as required for transportation. There will be a machined flange for mounting a flexible connection to the discharge ring. Apart from these usually included in the scope of supply will be drainage system, cooling water and oil supply system and one set of special tools and equipment. Part Ill Control The generating unit will be equipped with an automatic control enabling start up or shut-down through depression of a single push button. This automatic control also permits a shut-down of the set in case of any breakdown which might call for such an immediate shut-down, These controls are normally integrated into the governor which will be of the electronic digital hydraulic type with electronic speed sensing and stabilizing circuits and hydraulic valves to control the position of the servo motors. The regulators which control the turbine are designed to warrant a uniform and balanced run of the turbines under any service conditions, at an equivalent rated speed. In case of important and rapid alterations of the turbine load, temporary alterations of speed wlthin specified limits must be allowed for. The regulators themselves are envisaged to be of an electric type with an electronic hydraulic converter to the power part of the regulator which acts upon the control equipment of the turbine. The response of the regulators is high, so that the generating unit immediately responds to the slightest alteration of conditions in the system. As an accessory equipment of a regulator there are pumping sets including pumps and air chambers with a reserve of regulating oil in such a quantity as to safeguard a shutdown of the turbine under even the most unfavourable conditions. In some cases of variant design, where it would not be advantageous to install quickly operating emergency gates on the intake, the regulating SECSD (P) Ltd. 10.5 Klkinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION mechanism is fitted with an additional safety air chamber which might replace the emergency gates. Section 3 Generator The generator parameters are determined by the outlet output of the turbine and by the needs of the power system. Excitation for the generator will be obtained by rectification of the generator ac voltage by means of electronic three phase rectifiers. The generator shall be designed by taking into consideration the voltage conditions of the system to which the power plant will be connected, all estimated power station consumption and thelr average power factors. On the basis of these, the proposed generator power factor is cos y = 0.85. This generator power factor also corresponds to the demand on compensation of the 132 kV system in a given place, at the same time. The generator will duly secure a supply of the required compensation capacity. The generator is driven by the turbine and located above the turbine. All forces and torques occurring are transmitted into the concrete structure by the barrel. The generator will be of the three phase synchronous type running at 600 rpm. Each will be direct driven by the turbine. As the speed of the units is high, the umbrella type of installation will be unsatisfactory due to vibration. Hence the suspended type of arrangement is contemplated. The thrust bearing will be located on the generator stator on cross brackets. One guide bearing will be located below the generator. and also supported on cross brackets. Further specifications are given in the table 10-1 on electromechanical equipment. The actual dimensioning of the generator will be done by the manufacturer in consultation with the turbine manufacturer. The preliminary dimension obtained here and used for the sizing of the power house are based on empirical formulae. Section 4 Transformer Both the units will work into unit power transformers. The power transformer will be three phase step up 6.6kV/33kV rated at 6.5MVA. It will be installed outdoors on the roof of the power house. Under the transformers a sump will be provided to trap the oil which might leak out of the transformers. The HV bushing will have the CT built in. A short 33kV aerial line will connect the transformer to the switchyard. SECSD (P) Ltd 10.6 ftkfnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION The transformer will be oil immersed and cooled by air. A surge arresting device will be provided at the transformer to protect the transformer. Section 5 Intake Equipment The intakes to the power conduit are fitted with coarse and fine screens. Cleaning of the fine screens is afforded by a screen rake traversed along the intake structure crest. Emergency shut-off of the intakes is provided by vertical-lift gates, suspended in the grooves provided for them in each intake. The gates are operated by a hydraulic cylinder hoist. For manipulation of the mechanical equipment of the intakes, hoisting mechanisms and devices are provided (trestles used for erection, stoplog cranes or similar equipment). Section 6 Auxiliaries The correct operatlon of a turbine Is assisted by accessory mechanical equipment installed within the premises of the power plant. This equipment comprises the following units: 1. Lubrication system consisting of oil pumps, oil filters etc. Lubricating oil, which, durlng its passage across the surfaces of the bearings of a generating set removes the heat produced there, is cooled down as it continues its passage, filtered and restored to the bearings. In the case under review the lubricating circuits are designed separately for the thrust bearing of the generating set including the upper guide bearing of the generator. The bearings are even submerged In an oil bath, a perfect and close contact between the oil and the contact surfaces thus being fully ensured. The turbine bearing has also a separate lubricating system designed to warrant a safe and trouble free run of the hydraulic turbine. 2. The coollng system serves to cool down the heated-up lubricating oll, take over its heat and remove it, by way of the water discharged to the stream bed. Heat transfer is accomplished by contact of the cooling water in the pipes with the oil coming from the bearings, this direct contact between the two elements being produced in coolers. SECSD (P) Ltd 10-7 Kikfmnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION 3. The cooling water should be free from any sort of contamination. In our case it is obtained straight from the penstock, since the existing pressure is sufficient to ensure an ample flow volume for cooling. Prior to being put to this use, the water is passed through water filters. 4. The system of draft tube unwatering by pumping involves primarily the pumps situated in a shaft into which there is channelled the water from the draft tubes whenever an inspection of the mechanical equipment has to take place. The pumps have been dimensioned so as to obtain the dewatering of the draft tube in the time specified, under consideration of seepage past the gate joints. 5. The equipment for dewatering the power plant premises primarily comprises the pumps situated In the lowermost compartments of the power plant to which all seepage water from the power plant premises is drained. The equipment works automatically according to the seepage water level in the shaft. The water is then evacuated by pumps to the downstream river tract. 6. The oil system comprises, In the first place, oil reservoirs for lubricating and regulator oil and vaseline storage. The oil conservation system comprises portable oil pumps, filtering equipment etc. The extension of this system is not determined directly by the size of the generating set and no detailed design of the same has been undertaken in the study; in the next design stage it will be shown in more detail. 7. The compressor plant contains, as the main item, a high-pressure compressor with an air chamber, where there is provided a pressure air reserve for the first charge of the air chambers of the pumping sets. Compressed air Is also put to other uses, such as cleaning the equipment, etc. SECSD (P) Ltd. 10-8 Klkfinal.doc LINE METERING PANEL TO SUBSTATION AT KIYUNGI NOTES Aw A A~) This droweng shows the single Ime dogram or the A AA f* t} Kkuletwo Power stoan w,th the control protteltio and metering strategy A briel descripto, is g9,en below ,- . r The generator Is connected to the generator bus , VJ _~ t hrough o generotor circuit ireoker This brcsk,r wit be tripped in cose of overvolloge, Tault withic the Mach,c" 'oSs of encltlotiocetc StOtOo, sero,ce w,It :WI VAr 4AStill be ouarlole through the momn power transfornnr W I/Ar k -~~~~~~~~~~~~~~~~~ I ~~~~provided grid Supply enisto Toe transformer is diffetentiao protected with a crtcu,t breoher on 29 -~~~~~~~~~~~ LL ~~~~~~~~~~ ~the HV side A temperoture and pressure rean o VAr.0 .. otso trip this breaker The station service trJnsformer Wit VAr /s connected lo the generotor ternnmols Stotaon consumption con be metered with ao energy meter Th's rtonsformer vs protected by on over current reloy on the Z~~~~ H~~~V o,de The swilchYard wilt be of toe dloubte bus type out the generctor crcuit is Prouided nith a bypass isolator _with prossin to seroce the transformer otrcu bSmker Thus ace of the Buses Can aCt as a transfer bus j r- A double circuit tine to ith receivIng station oa Kyungi is shown Impedaoce type reloYIng Is considered adequate for the protection of the tmes 33kv B ' 1 Both generotot Dower Os welt as otl Ie incoming and outgoing tine ttows ore monitored with each ponet 33Pv GUS-2 ~ ~~~~~~~~~~~~~~~~~~~Contoning Ammeters, Vottrmeter indicating woitmetero 33kV 6US-2 a [ , ond vormeters, recording wattmeters ond vormeters and SWt al?YARD 4 Q X o recordng energy meter SIl0TH A RD \ \' 110V DC LEGEND Sii} ] -/- ISOLATOR 17 _- - CIRCUIT BREAKER CONTPOL POWER i{ 2 WNDING PT FROM STATION 4- 2 NNGP GENERAOR AdETERiNG SINGLE Y/tNDING PT PANEL T 2 WtNDING CT S IMPEDANCE RELA Y | 66h I | l m6Ek V/33hV lXo}W OVERVOLTAGE PELAt STEP UP 6 25 MVA OIFFERENTtAL RELAY I | | tW VAr 4 l l X@ AIR CIRCUIT BREAKER 'W | FE-9 3 0 l , | AMMETER v VOLTME TER I | Ml' 6Y6Ar V. 50Hz s WI ] w|INDtCATING WATTMETER ,8 L e ; TINDICA TINC VAIOME TER 7 | , 1 4 t ¢t i ; RECOROtNG WATTMETER C o -) v - T (t) 0 VAi, RECORDING VARMETER | I~~~~ ~ ~~~~~ ~~ ~ ~~ ~~~~~~~~~~~~~~~~ ~ ~~~~~~ AVM R ~S ECO OING ENERGY g t f UNI T- 1 17 MER UNI M l | 66kV 625MtiVA ) | . j 66 kV. 625 MVA J- - BA TTERY CENERATOR |_I+_ >, '_ POWER TRANSFORMER IV DC | |CDD400V 5OHz 1OOkW POllER STATIONV DCt STATION SERVICE MF4Ai rMrpfNT 4 LtGCTNlNG ARRESTOR CONTROL f ; STATION 01/S | i 9/400V 50z 1 ! LKIKULETWA HYDROPOWER PROJECTS _____ I I ; I J [lll L T - STAGE-W11 ! L X T ||~~~~~~~~~~~ TO LN I I-2 ( o) tookl s S| OL tINE= DI GR M WIH O TR L I0 LTONIT- 1T FOUR THE WOAkD BAVANESCO1 TO SWITCHYARD AUYIL/ARIES DtESEL SET DWG NO PLANNING DESIGNS & CAOD I C \ACADJOBS\GHANA\O6U\OB-Cp 11~~~~~~~~FG t-t I SIVAGURU ENERGY CONSULTANTS C \ACADJOBS GHANiP\OBU\OB-CP _. . - ~PAGE ii- g TABLE 10-1 STAGE-3 PROJECT SPECIFICATIONS OF ELECTROMECHANICAL EQUIPMENT EQUIPMENT PARAMETER DESCRIPTION Turbine Type Francis type verbtal installation Number of Units Two units Maximum Oro" Head 67.0 meters Maximum Net Head 64.14 molers Minimum Net Head 60.14 meters Design Had 64.0 meters Rated Head 62.0 meters Rated Discharge 10 cubic meters per second Turbine Rating 5500 kW nominal Overload 5% continuous Runner Diameter 1000 mm Speed 600 revolutions per minute Spcfic Speed 282.71 revolullons per minute Au&Jiiarles Hydraulicalty operated servomotors Governor Type Electronic - Digital Type Inlet Gates Type Butterfly or disc Size 1000mm Draft Tube Type Cone of Welded structural steel. Liner reinforced by suitable ribs Generator Typo Three Phase AC Synchronous Generator Frequency 60 cpyles nominal. Rating 6.25 MVA Voltage 6.6kV (final ohoice left to manufaoturer) Power Factor 0.85 Speed 00 rpm Poles 10 Cooling Water cooled Coupling Flange coupling Number of Units Two unns ExcKation Type Brushless Exciter (as recommended by supplier of allemator) Power Transformer Type Three phase Cooling Oil immersed and cooled by air. Rating 6.25 MVA Number of Units Two units HV Terminal 33kV bushing vith CT built In 13ESPOISheell SECSD (P) Ltd. Page: 10-10 TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Chapter 11 Electrical Works Section 1 Description The electrical works consists of all the works associated with connecting the generator to the step up power transformer, transformer to switchyard and switchyard to the grid interconnection. The scope also includes design, supply and erection of the equipment required for control, protection and metering of the power station, iighting, and unit auxiliaries etc. In the power plant are installed two generators of 6.25 MVA coupled to Francis turbines. Two 6.5-MVA, 6.6133 kV transformers are located on the roof. General features of the electrical works are given in table 11-1. Section 2 Generator Part I Description The generator Is embedded In the machine hall. It may be inspected by means of removable segmental steel covers. The cooling will be by forced means. A low voltage circuit breaker and isolator will be installed for disconnecting one of the generators from the generator bus for service or inspection and located beneath the control room. Each generator is connected to the 6.6kV bus through a generator circuit breaker. Each generator neutral may be connected to earth by a reactor if necessary to limit the short circuit currents. The generator windings are protected differentially. Part II Protection The following system of protection is considered sufficient for the generator. 1. Differential relay, common also for the block transformer and also working when an inside as well as outside short-circuit fault of the generator occurs in the protected section i.e. the section between the current transformers. 2. Instantaneous over current relay which serves as a back-up protectlon for the differential relay. In order to prevent a faulty operation of this relay in case of an outside short circuit its operation is interlocked by an under voltage relay, SECSD (P) Ltd 11-1 Kinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Chapter 11 Electrical Works Section 1 Description The electrical works consists of all the works associated with connecting the generator to the step up power transformer, transformer to switchyard and switchyard to the grid interconnection. The scope also includes design, supply and erection of the equipment required for control, protection and metering of the power station, lighting, and unit auxiliaries etc. In the power plant are installed two generators of 6.25 MVA coupled to Francis turbines. Two 6.5-MVA, 6.6/33 kV transformers are located on the roof. General features of the electrical works are given in table 11-1. Section 2 Generator Part I Description The generator Is embedded In the machine hall. It may be Inspected by means of removable segmental steel covers. The cooling will be by forced means. A low voltage circuit breaker and isolator will be installed for disconnecting one of the generators from the generator bus for service or inspection and located beneath the control room. Each generator is connected to the 6.6kV bus through a generator circuit breaker. Each generator neutral may be connected to earth by a reactor if necessary to limit the short circuit currents. The generator windings are protected differentially. Part II Protection The following system of protection is considered sufficient for the generator. 1. Differential relay, common also for the block transformer and also working when an inside as well as outside short-circuit fault of the generator occurs in the protected section i.e. the section between the current transformers. 2. Instantaneous over current relay which serves as a back-up protection for the differential relay. In order to prevent a faulty operation of this relay in case of an outside short circuit its operation is interlocked by an under voltage relay, SECSD (P) Ltd 11-1 KDkflnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION 3. Over voltage relay operating during a sudden generator voltage increase e.g. when over speeding or a failure of the voltage regulator, occurs in the generating set, 4. Time over current relay to protect against an overload of the generator and signal a dangerous current overload of the generator, 5. Field ground relay signals the occurrence of the first dead earth of the generator rotor, 6. Ground fault voltage relay. In addition to these the generator will be provided with a field circuit breaker. This extent of protection is proportionate to the protected machines with fully automatic operation. In view of the relatively small machine output it is not necessary to have other protection (for instance split winding protection, double ground fault voltage relay, back-up watt relay). Section 3 Transformers Part I Power Transformer The block transformers are only fitted with lighting arresting device. The remalning instruments of the outlets, particularly the switch and the disconnecting switches, are installed in side the 33 kV switchyard. Part II Protection The transformer will be protected by 1. Differential relay (Fl), 2. Instantaneous over current relay which is considered as a back-up protection for the differential relay, It is completed by an interlocking under voltage relay. The instantaneous over current relay is connected to the current transformers on the 33 kV side, 3. Oil pressure relay (Bucholtz protection), which acts when gases form in the transformer tank (for instance when the transformer temperature, is excessively raised or when trouble occurs inside transformer) and reacts even SECSD (P) Ltd. 11-2 Klkfnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION to the pressure of air in the transformer tank. It acts in two steps in the first of which it only signals and on the second switches the 33 kV circuit breaker off. Part Illi Station Transformer The station transformer is fed from the generator bus. In view of the small output of this transformer the Engineer recommends a protection by fuses on the H.T. side and a thermal over current coil and duly rated fuses on the L.T. side. Measurement of energy, current and power for station service is proposed at station service consumption transformers. Section 4 Control Protection and Monitoring The one line diagram of the power station is shown in figure 11-1 titled Control, Protection and Metering strategy. The main step up power transformers are connected between the 6.6kV bus and the 33kV bus. It is differentially protected with the other usual protection arrangements. The control room is separated from the machine hall and is situated with a view of bringing the entire electrical equipment together, an arrangement which involves notable operational and economic advantages (for example, the lengths of the connecting cables are kept down to a minimum), and the operators can readily and promptly effect an inspection and checkup of the entire equipment. The separation of the control room from the machine hall facilitates its air conditioning and thus creates an amenable working environment for the personnel and for the more sensitive instruments of the control board and the relay switchboard. For clear visibility and orientation, the control board is U-shape in plan. In front of the control board a desk is installed for the operator. At the sides of the control board are installed auxiliary switchboards with protective devices, registering instruments and the automation gear. For an easy and clear arrangement of the cable connections there is, under the control room, a cable compartment linked up to a cable gallery that extends along the entire machine hall. Into this gallery are brought all cable lines coming from the machine control panels, from the switchboards of the generator outlets, as well as all the cable connections coming from the block transformers. SECSD (P) Ltd 11.3 Kkftlm.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION The main station service panel is situated in an unoccupied part of the cable room under the control room. The electrical equipment for power supply to the auxiliary equipment of the generating set, together with the essential measuring and control instruments directly related to the operation of the generating set, are installed in two machine panels. The power part of these control panels is also in the unoccupied part of the cable compartment under the control room, opposite the respective generating sets. For an emergency coverage of station service consumption a 100 kVA diesel electric set is installed on the roof. For provision of D. C. voltage an alkaline storage battery is also installed. It is necessary to ventilate the machine hall of the power plant in order to remove the part of waste heat of the generator which passes to the interior of the hall through convection and radiation. On the basis of the general solution and control of the 33 kV power system in Tanzania and on the basis of local conditions, consideration was given to the possibility of the power plant operation with permanent attendance as well as without it. It has been decided to operate the Kikuletwa water power plant with permanent aKtendancG for the following reasons: a) the mechanical and electrical equipment of the water power plant are relatively complicated and need continuous maintenance, b) In view of the size of the installed capacity and location. On the other hand the 33 kV switchyard by its proximity to the power plant by its method of operation and by its relative simplicity will operate without permanent attendance and by remote control from the power station control room. For these reasons the control of the power plant and the 33 kV switchyard will be centralised in the control room of the water power plant where all control, SECSD (P) Ltd 11-4 Kildinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION signalling, measuring apparatus and instruments necessary for the operation control of the power plant as well as of the switchyard will be installed. According to current practice, the operation and control of water power plants is either semi or fully automatic. In the first case the personnel carry out a large part of the operations by hand, i.e. starting the generating unit, connecting it with the power system, loading and shut down. The generating unit is provided with control devices which in the case of emergency, signal a trouble state and when the trouble is serious the operator stops the generating unit. In the latter case however the starting and stopping of the generating units are automatic. This is achieved by an automatic equipment on receipt of a single control impulse. When the control of a generating unit is fully automatic the operation of the generating set Is also controlled by automatic devices which signal trouble and If necessary shuts down the machine set. In both cases the operation of different auxiliary drives and equipment is fully automatic, for instance the pumping of leaking water or oil, the pressure boosting into the air-oil reservoirs of governors and into receivers of compressor stations, the charging of accumulator batteries etc. After considering both options it is recommended to adopt a fully automatic control of the Kikuletwa water power plant. This control has following advantages: a) Better machine safety as automation eliminates trouble caused by improper handling by the personnel. b) Improved power system operation by reducing undesirable machine trouble. c) Increase of power plant operation ability (i.e. flexibility) (for Instance by decreasing the time needed for running up the generating set), possibility of remote control of the power plant from a secondary dispatcher's office at a later stage. d) reduction in the number of the service crew and lower demands on their qualification. The price dlfference between a fully automatic and semiautomatic generating unit is minimum. In other countries there are a great number of water power plants with fully automated operation running reliably. SECSD (P) Ltd 11-5 KUdinai.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Fully automatic operation of the generating unit requires an automatic synchronising equipment, an alutomatic voltage regulation of the generators and a reliable auxiliary supply for the power station. The automation of the machine operation will make it possible to centralise the generating unit control into the control room, and to establish a system for remote control of the power plant operation from the dispatcher's office in future. The extent of the measuring and recording of electric values may also be seen on drawing 11-1. This is in accordance with current practice and gives a complete survey of the immediate condition of the electric equipment for use of the local operation control. The control room will also have an alarm system with an audible and visual signalling of defects in the water power plant as well as in the switchyard. Preference will be given to a simple well-tested system which is modest in demands on space. Electric machines, the 3witchyard and the transmission line will be protected by electric protection relays which will assure the safe switching off of the outlet the moment any kind of trouble occurs and thus reduce the extent of possible damage to a minimum. The operation of protection relays will at the same time be signalled visually as well as audibly in the power plant control room. The extent of the protection is dealt with under each category of equipment. The overall strategy is given in figure 11-1. Section 6 Swltchyard The most suitable site has been chosen in order to make possible a connection with the power plant by means of a free line and to decrease the necessary ground work to the smallest possible extent. The power inlet to the 33 kV switchyard is by a short overhead transmission line. The outgoing conductors are anchored to the machine hall building. The switchyard is located as shown in the drawings showing the various project features. The switchyard is designed for 33kV operation. The schematic of the switchyard is shown in figure 11 -1. The double bus arrangement is preferred with a coupling arrangement between the two buses to enable changeover on load from one bus to another. The control power will be supplied by means of a cable SECSD (P) Ltd. 11-6 Kikflnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION from the power station. The entire switchyard will be fenced off and the fencing adequately earthed. Facility is provided to monitor the line flows. The design of the switchyard will have to be done in accordance with rules and regulations of TANESCO . In view of the proximity of the switchyard to the power plant it is recommended that the switchyard be remote controlled from the power plant. This switchyard will in the final construction contain two inlet lines from the power plant and one outlet field to Kiyungl substation. Further enlargement Is not envisaged till stage 1,11 and IV projects are taken up. The service consumption of the 33 kV switchyard is fed by a 400 V voltage from the power plant by cables. The auxiliary electric equipment is located in an one- storey building of minimum size. There are a L.T. panel, auxiliary panel for protecting devices, a D.C. equipment, a compressor station and accessories for the compressed-air control of switching devices of E.H.T. The switchyard operation is by remote control from the power plant control room. The emergency local control of the 33 kV equipment will be possible from outdoor control boxes located in each switchyard field. The panel control board or the control desk will be provided with a diagram and status indication of the switching device position as well as with control devices. In practice the status indication can by means of two signalling lights of different colours and with a separate control switch, or by a combined control and signal switch by a light-dark method. In view of the small switchyard it is recommended to adopt the simpler light-dark method or another simple system of signalling. To switch the outlets which have to be synchronised the Engineer recommends the use of automatic synchronising equipment which eliminates all possible mis handling and makes possible the use of remote control of breakers. The manual synchronising will be required only exceptionally. The connection by control, signal and measuring cables Is done in cable Is done in cable ducts from the switchyard to the single level building, and further to the power plant, in a cable trench. The main grounding system will be grid type made of steel strips galvanised in fire. The total ground resistance will be less than 1 ohm. In the cable routes SECSD (P) Ltd 11-7 Mkfinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION between the switchyard and the power plant, the outgoing earthing strips will be laid in a length of about 150-200 metres from the power plant in order to decrease an induced voltage occurrence at one-phase short-circuit faults, as well as their introduction by metal cable sheaths into the power plant. The whole area of the switchyard is to be fenced off. Inside the switchyard a safety fence is also proposed in places accessible to the staff during operation time and where the safety clearance to the energised parts was not maintained. Section 6 Transmission Part I Description The 33kV line starts from the switchyard The rough route was fixed on the basis of maps as well as field reconnaissance. For most of the length of 14 km, the route follows the existing old line from Kikuletwa No. 1 station. The towers will be built of wood poles. In the design of the line due consideration has to be given to relability. Hence a double circuit line is preferred. Also in determining the size of the conductor, provision is made for transmitting the power from stages 1, 2 and 4 of the cascade through the same switchyard as that of stage 3. With the above in mind, the performance of the line as well as parameters are given in table 11-1. Earthing conductor will be provided at the top for protection against atmospheric disturbances. Part II Protection of the Line With regard to the short line sections the protection by distance relaying is sufficient for all line troubles. It is not necessary to supplement it by anothier back- up protection. Section 7 Grid Interconnection It is recommended that the Kikuletwa power station be connected to the grid in the vicinity for maximum operational benefit. Also it is considered beneficial to connect all the plants of the cascade to the grid. Several alternatives were considered for the network connection of the plant with the grid. It appears that the best way to accomplish this is to connect to the receiving substation at Kiygungi to which power from all the upstream and downstream projects will be transmitted. SECSD (P) Ltd 11-8 KIIdm.doc LIfts ME TLRiNG! PANESL IC'SUS T N 4.'i YNt / NTCt iA ~A I(A) Iitoe o Pows', ps/hon, sr lho control rorio e rriete-wgt. st-rieav 4 t;rier cefs-rpto, Is q,v~ belowi The r00oeeoto s La.'e Aee: C thk q-s"'ohr Ous V~ ~ ~ ~~~~~~~~~Z 1.rrr't,qh v rj-rreroT, seti ot -Je, Thr5 treec, r wi he 1kipdwcasof o,,e-6hoqe rop:D1 enNhui Tht OiOCi-hrse ros- o' -Crao,iti,c Si tO,l- -er-e sri V/t1 /Arj IT f~~~~~~~~~~~~~~~~~~~~ri'Jeo grid stippif t-is 7n' 5001so'n,lre dlt t-rehot protcc/en with o cr'JniDis/ikC,- Li ~~~~~~~~~~~~ ~~~~~~~~~~~~~~~the H/V 5de Atempnerorre Lino tire5esr iet/oy cto, ueso ct'p B/ii, b:okehtr rio stoty, 3r-rC- rrrfrs Is, co-nected 15tic,h povilonro r5'-5rrtis staiis $tvo'miptror Can be ic/si d nit ua i -cr , se, Thi- trr$!rulr.5 0kC td hy 5,5 h-r Cnifrr,I Foni OPtheI Tie 'If?hor ot ho I)! Its' goC. irsoss i 5 but thh' cief-tocor on,r, ur Is prci,dra Or's a 91S 5O -ni, PtsrI,s servic~ Iri,norrr,rco> e,v Otius cno of t!re otises Coii I,: Os I rirrr,cion DSo for thre 'prsecttor C;i the titles 3-41, v 2US- I ~~~~~~~~~~~~~~~~~~~~~outaomorgine ftowd ore rhnirtrored wilt,erich iocc Momitsrsrs irrielees Volts,ete' orOrr vn&I/iit __ _ _ __US_ _ __ _ _ _ __ _ _ _ __ __2__ _ _ _ __ _ _ ord csrfmeters rscordnrr wsttrhete- 550 cnrrsrtter, old 32hh BUS-? I , I ns~~~~~~~~~~~~~~~~cersnrg energy rester I ~~~~~~~~~~~~LEGENALI I iov 1I irR -1-i SŽTCI Fcc sNCy'ThItiit PT GENERA70 tthMETEINOC, 'A N4EL WINi2OeTDttO I ~ ~ ~ ~ ~ ~ - L Ft Iti~~~~~~~~~~~~~~~APCDANCE RL yA) )r$EsV//irtt' i~~~~~~~~~~~~~~~~~~) ~ ~ ~ ij l~~~ItEitcGL TA CE ISLAAI K (v" --~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~PF EFN iAt REt 4' Fy IA~~~~~~ AiR OCRCUsT B/tEAr~Ei L!t ---- - -S TSr-I .~~~~~~~~~~~~~~~~~~~~~r' ~~ IAI ItNDECA VIIA trO 4PVE TFt I ~~~~~~~~~-/ I !~~~~~~~~~~~~~~~~WI thD/ ,Tth WATTAIETER REC OR,iGWTTIII 2Kc~~~~~'r-i--T I tr,t~~~ECOON VRMETER I '' ~~~~~~~~~~~~~~~~~RECORDINC, ENERCy Ii-.? ~~~ TA'oT-2 GA h/META UjqI-,- t UNIT-~~~~~~~~~~~~~~~~~~~F CtWEF CT'T Its/Tm GUS ( i)r 4vh' 5/tU "tOO6.(W CONTRO 25 -- VA ~ tTOV 517 I SERVtcE MEAS/IREM0RT L~~~~~~~~~~!-I &ATESiR)rGARSO 711 'I I 401k KIULETWA HYDROOWER PROJECT I ThEWO!ILDBAN~~~~~~~ANESCO E(CA70 ;COJBSG1k\OU06P 1otter-2 ( )tO tGT~Sr/,tttUNECtO(vTAT Lttt&L SET0/hG C PLANING t$IGN ti COYR 5Rf0RE TABLE 1 '-1 PARAMETERS OF TRANSMISSION LINE AND PERFORMANCE CALCULATION _____ Parameters Line Voltage kV 33 Frequency Hz 50 Electrical syslem Double Circuit 3 phase 3 wire Base MVA MVA 10 Receiving End power kW 5500 Receiving End power factor 0.85 Line Length miles 8.75 Conductor Code Word Conductor cross section area cmils 266800 Resistance per mile of Conductor Ohms 0 567 Inductive Reactance per mile of Conductor at Ift Ohms 0.484 Capactive Reactance per mile of Conductor at 1ft Mohms 0 134 Equivalent Spacing of conductors ft 5 55 Inductive Reactance per mile at equivalent spacing Ohms 0 173271406 Capactive Reactance per mile of Conductor at 11 Mohms 0 061017139 Current Carrying capacity 50 deg C temp of cond Amps 340 Aluminium strands No 6 Strand dia in 0 188 Steel strands No I Strand dra in 0 188 Ultimate strength lbs 8420 Weight of conductor per mile lbs 1542 Outside diameter In 0 563 Insulators Type Pin Type Supporl Steel towers typical illustration shown in drawing with double circuit vertical arrangement Base Impedance Ohms 108 9000 Base Current A 174 9546 Line Resislance Ohms 4 9613 Line Inductive Reactance Ohms 5.7511 Line Capactive Reactance Mohms 1.7029 Line Resistance in per unit per unit 0 0456 Line Inductive Reactance in per unit per unit 0 0528 Line Capactive Reactance in per unit per unit 15637.2816 Line Impedance in per unil 4 55578512396694E-002+5 28110634216794E-002i Receiving End Voltage per unil 1 Receiving End Current A 113 2059 Receiving End Current Vector Re per unit 0 8500 Receiving End Current Vector Im per unit -0.5268 Receiving End Current Mag in pu per unit 0 6471 Receiving End Current Phasor per unit 0 85-0 526782687642637i Receiving End Current per unit 0 55-0 340859386121706i Series Drop per unit 4 30579648401663E-002+1.3517263675346E-002i Sending Voltage per unit 1 04305796484017+1 3517263675346E-002i Sending Voltage Magnitude per unit 1 0431 Regulation percent 4 3148 Loss per unit 0 0572 Loss MW 0.5722 Efficiency of Transmission Line percent 90.5763 Provision made in conductor for further 6Mv from ________________________________________________ slages 1, 3 and 4 ktrdes.xdsSheetl1 SECSD (P) Ltd Page 11-10 TABLE 11-2 ELECTRICAL WORKS SPECIFICATIONS Equipment Category Units 1 Bus Bars Type Copper bus bars in bus ducts Voltage kV 6 6kV Current per phase A 1150 Protection Differentially protected 2 Generator Circuit breaker Type None Rating MVA To be selected in design stage No of breakers 2 3 Swltchyard Location Exlernal and located about 100m from power house Voltage kV 33 Design As per TANESCO guidelines Type of Arrangement Double bus bar type Incoming Lines Two incoming lines from Power Station Outgoing Lines One outgoing line to the Kiyungi Substation Circuit breaker type Vaccum circuit breakers No of Circuit breakers 4 Isolators Motorized post mounted rotary double break type No of isolalors 8 Earthing Switch Earthinh blade inlegral with isolators Lightning Ariestois Post type mouled on insulator post Current transformers Post type mouted on insulalor posl Potential transforrners Capacitve type Control power V 110 V DC supplied from power station by cable 4 Earthing Generator Noulni o 'idly earthid Stition A Swviir hv idi Giidi ril vjiii thsitablo .oninociins ti Il elortricat Ur.ruipmirrnt and melal parts Unit Auxlitaries Ausiliaries Supply v 400 V 50 Hz ac Auxiliaries sourcp 6 6kV!400V step down from generator terminals Type of scheme Sinqle slation service translormer Type of distribution LT distribution panel wilh individual circuit breakers Metering Voltage kWh and current 6 Emergency Equipment Battery 1 10V sealed maintenance free battery system Charging system Elecironic conlrolled charging Lighting V 110 V DC supplied from batteries in battery room Black start Diesel Electric set 100 kVA mounted outside station 7 Protection Turbine Overspeed, Bearing temperatures, Oil temperatures Generators Lo%s oh exciation, Negative sequence. stator faults Oveirspeed. Field short circuit Transloinirvi Dfirnrriotirl protection, Bucholz, lank grounding Tiansmission Distanice protection 8 Transmission Voltage kV 33 Type Double circuit towers Final Receiving Stalion Kryungi substation for interconnecting with grid Lenglh km 14 Conductors 106 sqmm ACSR ki3ELE01 xIsSheetl SECSD (P) Ltd Page 11-11 TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Chapter 12 Implementation Cost Section 1 Descrption To compute the Implementation cost of the project, the cost of civil works and equipment are estimated on the basis of the quantities of works required for the project and aggregated unit prices applied to the main categories of works and equipment. The direct construction costs, and the estimated contingencies, are added to the environmental impact mitigation cost, engineering and administration costs, to yield the total implementation cost. The breakdown of the implementation cost Is therefore as follows Box 12.1 Components of Implementation Cost Item Amount CIVIL WORKS A Miscellaneous and contingencies 10 % 0.10 A TOTAL CIVIL WORKS 1.10A EQUIPMENT B Miscellaneous and contingencies 5 % 0.05 B TOTAL DIRECTCONSTRUCTION COST D=1.10A + 1.05 B OTHER COSTS Engineering (Investigations, Detailed Design and Construction Supervision ) 5% 0.05 D Administration 3% 0.03 D TOTAL OTHER COSTS 0 =0.08 D TOTAL CONSTRUCTION COST C = D +O ENVIRONMENTAL IMPACT MITIGATION E TOTAL IMPLEMENTATION COST T = C + E SECSD (P) Ltd. 12-1 Kikfinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION The different elements of this table are described hereafter in each section. The cost estimate was based on the conditions prevailing in August 1999 and the currency of the estimates is US Dollar. Section 2 Clvil Works The cost estimate for the civil works is confined to the major items of work involved in the diversion weir, waterway, power house, tailrace etc. Miscellaneous items of work such as painting, doorwork, windows, lintels, decoration, false ceiling, flooring are simply taken care of in contingencies for Civil Works. It is of the opinion that these items of work are negligible compared to the major items and their detailed inclusion at this stage is not necessary. The contingency allowance provided for these items is considered to be more than adequate. The aggregated unit prices used for the cost estimates of civil works include all direct costs of labour, use of construction equipment and materials increased by overheads and profit, costs of any temporary storage facility installation and clearance. The aggregated unit prices result from a collection and review of costs extracted from actual construction costs prevalent in the region. The prices reflect the geographical location of the site and its relative remoteness from main centres of economic activity. The actual quantities of works have been taken into account, and some variations of unit prices have been considered according to the quantities of works. The aggregated unit prices for the cost estimates are presented hereafter in table 12-1. Section 3 Electro-mechanical Equipment The cost of the main generating equipment i.e Turbine, Generator, Electronic Governor and static excitation system, was calculated, based on budgetary prices and offer obtained from reputed manufacturer's for the same type of equipment (2 or 3 units, of turbines of the Francis type, vertical axis) increased by overheads to account for cost of transport from country of manufacture to port in Tanzania and then to project site. The offer was lumpsum and did not give break up of the price. The scope of supply includes SECSD (P) Ltd 12-2 Kikfinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION * Design, manufacturing, transport, delivery, installation, start up and testing of the following main equipment, all conforming to the relevant latest International standards such as ISO, ASME, SAE, DIN etc and provided with performance, cavitation, pressure and speed rise guarantees as per IEC. * Turbine - 2 units of Francis type turbine rated at 5.5 MW at 64 m speed 750 rpm complete with runner of 13%Cr & 4%Ni, main shaft, main shaft seal, guide bearing, wicket gate mechanism, gate operating ring, discharge ring, draft tube, oil supply head, oil piping, drainage and dewatering system, instruments and devices and complete set of platforms, ladders and stairs, drawings showing details of foundation requirements, embedding of supports and anchors in first and second stage of concrete. * Generator - 2 units of synchronous generators rated 6.5 MVA, 6.6kV, 50 Hz, cos phi 0.85, 750 rpm complete with cooling system, oil system for bearings, brake, bearing supports. * Governor - 2 units of electronic-hydraulic type with manual and automatic modes complete with speed sensing, stabilizing circuits, adjustable rated speed, permanent and temporary droop with dead band. The supply also includes hydraulic oil supply, hydraulic valves, pressure tank, compressed air supply system, instruments and devices. * Excitation system - 2 units of microprocessor controlled static thyristor excitation system complete with voltage regulator, excitation transformer, cooling, rotor over voltage protection with digital sequencing and installation in cubicles with all operating panels and displays. * Supply of one set of relevant spare parts and tools for above equipment * Adequate corrosion protection during transport to site. As the equipment is imported, as per Government of Tanzania rules any import duty and further taxes which may be levied are not taken into account. Section 4 Auxiliaries The following equipment and works are outside the scope of supply of electro mechanical equipment and are classified as auxiliaries and are separately accounted in the table 12-1. The items are SECSD (P) Ltd. 12-3 Klfinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION All electric connecting cables, bus bars and ducts. * Overhead crane, * Control Panels * Protection system * Ventilation, cooling and air conditioning * Synchronising equipment, * Station service transformer, Emergency lighting, illumination and black start power, * UPS and Battery system * Fire fighting The cost of the auxiliaries in the plant including all mechanical and electrical equipment of the power plant from the power intake to the power plant switching station (included) was calculated based on prices prevailing for similar equipment. Section 6 Hydro-mechanioel Equipment The cost of the intake gates and bottom outlets and inlet and outlet gates was calculated on the basis of the area of fixed parts and moving parts, and on the following unit cost of metal work: The main groups of equipment to be installed within this section are: 1. Bottom outlets with operating mechanisms 2. Inlet Valves. 3. Draft tube gates The unit costs used for the equipment cost estimates include manufacturing prices, transportation and installation costs. Gates etc. - $800 per sq.m. Section 6 Switchyard The costing includes the cost of land, land clearing, fencing, earthing, lighting, fire fighting, Main power transformer, Auxiliary transformer, switchgear and all other SECSD (P) Ltd. 12-4 I(Wnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION equipment required for the proper and reliable operation. The swithchyard is 33kV. Section 7 Transmission The costing includes the transmission lines and equipment for connection to the existing substations or new substations. The cost of connection to the Kiyungi substation includes the cost of new transmission lines and new line bays to be added to the existing substations for the connection . The total transmission is about 14 km Section 8 Miscellaneous and Contingencies The cost of construction is calculated by applying unit cost estimates to the calculated quantities of the works identified as the main components of the project. The total cost resulting from these calculations should be increased by a contingency allowance of 10% for the civil works, 5% for the hydro-electric equipment. These contingency allowances represent the miscellaneous expenses that have not been listed in the table on quantities and implementation and that which might not have been identified properly, especially when the topographical and geological conditions of the site, as well as the design of the works, have not reached the level of precision of later stages. Section 9 Engineering and Administration A provision of 5% of the total direct construction costs has boen considered for engineering services until the end of construction. This amount includes further topographical survey, geological and geo-technical investigations, feasibility and detailed design studies, environmfiental impact assessment and resettlement program, supervision of construction etc. The cost of administration of the project by the Owner was estimated to be 3 % of direct construction costs. Section 10 Environmental Mitigation Further detailed topographic surveys are necessary to accurately assess the environmental impact. Prima facie it is evident from site visits that no significant impact will occur. At this stage a lumpsum amount of US$50,000 has been provided for environmental impact cost. SECSD (P) Ltd 12-5 KWkhinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION The percentage of the environmental costs for project will not exceed 1% of the total implementation cost. Section 11 Total Implementation Cost The total implementation cost as determined with the item wise break up is given in table 12-1. The implementation cost should still be regarded at this stage to incorporate a certain range of uncertainty . which has two origins: i) an uncertainty on the unit costs, which is related to the high variations in the actual tender prices commonly observed, and to the economic conditions that will prevail until the time of construction, and ii) an uncertainty of a technical nature related to the exact natural condttions which prevail on the sites (with a particular influence of geology), and which will gradually be better known as investigations and studies proceed until the time of construction This range of uncertainty is estimated to be from - 15 % to + 20 %. The project is economically and financially viable even with this range of uncertainity with respect to the implementation cost. SECSD (P) Ltd 12-6 Wkfina.doc KIKULETVVA STAGE-3 TABLE 12-1 QUANTITIES AND IMPLEMENTATION COST I CIVIL WORKS Unit Unit Price Quantity Cost Total Item Cost Totat Cost USo I USO USo USD a Access Road Improvements km 20 000 101 200,000 200,000 b Construction Camp lumpsum 50,000 50,000 50,000 c Diversion Weir Preliminaries IRiver Diversion lumpsum 50,000 1 50,000 Is Site Clearing and Grading m2 3 564 1 691 51,691 d Diversion Weir Non Overflow Section Soft Rock Excavation m3 8 865 6,920 is Rock Excavation rmr3 13 736 9,568 Ill Mass Concrete m3 300 1355 406,500 iv Backfill m3 1 6 250 4,000 v Grouting & Drainage m 300 100 30,000 456,988 e Spillway I Soft Rock Excavation m3 8 497 3,976 ii Hard Rock Excavation m3 13 428 5,564 iii Mass Concrete m3 300 6250 1,875,000 iv Reinforced Concrete m3 384 500 192,000 v Grouting & Drainage m 300 100 30.000 2,106,540 Total Cost ot Diversion Weir . __. 2,616,219 f Intake & Water Conductor I Land Clearing and Preparation m2 3 4050 12,150 it Soft Rock Excavation m3 8 11700 93,600 sit Backfill m3 8 4270 34.160 iv Reinforced Concrete m3 384 1114 427.776 v Mass Ccncrete m3 210 200 42.000 vl Penstocks etc Inclusive cf fabrication t 5,000 55 00 275,000 884,686 gPower House I Soil Excavation m3 4 200 800 is Soft Rock Excavation m3 8 100 800 It Hard Rock Excavation m3 13 1205 15.665 iv Mass Concrete m3 210 100 21,000 v Reinforced Concrete m3 384 350 134,400 172,665 h Tailrace I Soil and Soft Rock Excavation m3 8 1965 15,720 Is Rock Excavation m3 13 0 0 is Concrete m3 210 174 36.566 iv Rei,nforced Concrete m3 384 135 51.840 104,126 TOTAL CIVIL WORKS COST 4,026,696 2 ELECTROMECHANICAL EQUIPMENT a Turbine S Generator kW 500 11000 5,500,000 b Auxiliaries kvv 50 11000 550,000 c Inlet Gates lumpsum 75,000 2 150,000 d Bottom Outlets m2 800 20 16,000 e Connection to National Grid km 30,000 14 420.000 6,636,000 - TOTAL ELECTROMECHANICAL COST 6,636,000 3 ITOTAL CONSTRUCTION COST |______ [ 10,662,696 4 OTHER COSTS _ r_ _ a Engineering percent 5 533,135 533,135 b Administration percent 3 319,881 319,881 5 CONTIGENCIES a Civil Works percent 10 402,670 402,670 b Electromechanical & Others percent 5 331.800i 331,800 6 ENVIRONMENTAL IMPACT COST lurn sum ______ 50,000 50O00 _ _ _- _ _ 7 ITOTAL IMPLEMENTATION COST I _ __._ 12,300 182 8 tCOST PER kW INSTALLED lUSo I i 1,1181_ SECS0 (P) Ltd Page. 12-7 kl3cost.xisSheetl TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Chapter 13 Economic and Financial Analysis Section 1 Description The economic analysis is carried out to evaluate the viability of the project from the viewpoint of Tanzania's national economy. The Benefit Cost ratio method is used to evaluate the economic feasibility. The benefit Is defined as the discounted value of all future net profits without considering taxes and the cost is defined as the discounted sum of all expenditures incurred in planning, designing, constructing and operating the project over Its economic lifetime. The benefit from the project Is from the sale of energy which it generates. For comparing this with the costs incurred and deriving the economic benefit cost ratio, it is necessary to fix a suitable monetary value for the energy which is produced. Usually for small hydro projects, it is fixed as the avoided cost of energy produced by the next least cost option which is usually from a diesel set providing an equivalent capacity and energy which would have to be implemented instead of the proposed hydropower project. Another fact to consider is that the project is likely to give other benefits such as fisheries, recreation etc. But from the point of view of the IPP these are considered as intangibles and the benefit is considered to be insignificant. The benefit cost must be at least one for the project to be economically viable. In the present case the area is already served with grid supply, and hence the price of the least cost option is that of obtaining energy from the grid. Thus economic value of the energy is fixed at present average tariff in the area. As the project may be implemented on non recourse financing in which the lenders and investors treat the project assets as a collateral, the financial analysis is carried out to determine cash flows and is the most important study for the project developers, the lenders and investors. The financial analysis hence shows the pattern of cash flow which the project provides over its economic life. If the project is built to serve an area without existing grid supply, the energy which can be sold will gradually increase every year from a low base year demand. Hence the market demand will influence the financial analysis. This demand growth pattern also determines the ability to pay SECOD (P) Ltd 13-1 Kikflnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION the dobt service, operating and maintenance cost streams and brings out any cash flow deficits which may arise. Ideally the net cash flow should be an inflow as otherwise other short term loans have to be negotiated to cover these deficits during project operation. In evaluating the cash flow, all expenditures such as debt service, operation and maintenance, depreciation, income from sale of electricity are lumped into end of year payments Section 2 Assumptions The main difference between the economic and financial analysis is the price of energy in each case In the first case it is usually fixed as the cost of producing and equivalent amount of energy from an alternative source and in the second case it is the price at which energy is sold. In the present case under study, both are equal to the average tariff prevalent in the area as the area is served by the grid. Hence the economic and financial analysis are identical. In the financial analysis, the consumer`s load and demand growth will not influence the revenue stream as the project will be grid connected and all the energy which is produced can be utilized by existing consumers who are connected to the grid This may give rise to conserving water at large storage dams for use in dry season. The assumptions in the analysis are given below. The Implementation cost of the project is US$ 12.3 million for 2 units of 5500KW which has been worked out in the statement on quantities and Implementation cost. Based on the 24 month construction period, the IOC is US$ 1.907 million. It is assumed that the entire cost of the project is met from borrowed capital . The interest rate is taken to be 10% and the loan return period is 7 years (typical values from International Financial Institutions for loans to project developers). Based on this the capital recovery factor is about 20.54%. The economic life of the project is taken as 30 years. The purchase price for electricity in the base year is taken as US$ 0.07 per kWh. An inflationary factor of 5% has been included in the calculations for the purchase price of electricity as well as the Operations and Maintenance costs. The annual operation and maintenance costs are taken as a lumpsum of 1% of the capital cost of the project. SECSD (P) Ltd 13-2 kltfial.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION For the financial analysis, the discount factor has also been taken as 6%. Thus all future receipts and payments are discounted to obtaln their present worth. All receipts and payments are assumed to be made at end of year. Based on the above, a computer program was used to perform the analyses and the results are presented in the table 7-1. The table brings out the debt service, depreciation, operation and maintenance and revenue flow as well as the discounted flows. Section 3 Methodology A brief description of the model is given below. The capital Cost of the Project is given by C as determined from the unit costs of materials and quantities For the project then C = 12.3 M$ (1) The Interest paid during construction is computed based upon the disbursement of the loan over the construction period as explained in the foregoing section IDC = 11 + 12 (2) where lI = C,i, where C, = 0.5C (3) 12 = (1 + C1 +C2 )i , where C2 = 0.5C (4) and i is the interest rate (cost of capital) = 10% pa. so that C, + C2 = C (5) Hence Total Capital Cost P=C+ i $ (6) The loan is assumed to be recovered in 7 equal payments. Hence the annual payment in the nth year is SECSD (P) Ltd 13-3 KkMna.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION L, = P i(1 + i)'7((1 + i)" - 1 ) $ for 1 c= n c= 7. Ln=0$forn >7 (7) where multiplier term above is also called as the capital recovery factor. The mean annual Energy Output as determined from the power and energy studies E = 65,000,000 kWh (8) The base price for electricity in the first year is T cents/kWh The escalation rate for the electricity price (e) = 5% Thus e - 0.05 (9) In any year n after commercial operation starts, annual revenue Rn = ET(1 + e)" $ (10) The annual operation and maintenance expenditure is 1% of the capital cost of the project = 0.01 escalating at the escalation rate (e) In any year n after operation starts OMn - 0.01 C(1 + e)n $ (11) Due to wear and tear of the equipment its necessary to account for depreciation. The depreciation is accounted by setting aside equal yearly payments into the bank such that at the end of the economic life the capital cost of the project is realised due to earning of interest. Dn = Ci/((1 + i)n- 1) where n = 30. (12) The total net income in any year Nln = Rn - Ln - OM, - Dn (13) SECSD (P) Ltd. 13-4 Kikbinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO RE1GION The present worth of any payment accruing in the nth year is given by multiplying the payment by the present worth factor PWF PWFn = 1/(1 + i)n (14) The present worth of the loan payment, depreciation, O&M and revenue streams are multiplied by the PWF to get the present worth of these future payments. These are then summed to get the total present worth of all these payments Thus total present worth of benefits from project B = ERnPWFn for 1 <= n <= 30 years (15) Similarly the total present worth of costs OM = QOM,PWFn for 1 c= n <= 30 years (16) The total lifetime costs S = P + OM (17) Benefit Cost Ratio = B/S (18) The Net Present Value NPV = B - S (19) The IRR is determined by trying various values of i such that NPV - 0. The unit cost of energy over the lifetime of the project is calculated by summing the present value of lifetime costs divided by c - (OM + D + P)/30E (20) The cost of generation in the first year is given by L1 + Di + OM1/65,000,000 $/kWh. For each year the cash flow is computed as Fn = Rn - Ln - Dn - OMn (21) SECSD (P) Ltd 13-5 Kkfinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION which when positive indicates net inflow and when negative indicates net outflow of funds. Section 4 Results The analyses shows that the Benefit Cost ratio of the project is 5.76. The average cost of energy based on the total life cycle costs divided by the energy produced over the life cycle in today's worth is 1 .11 US cents per kWh and the cost of energy produced in the first year is 4.5 US cents per kWh. If the project is financed by soft term loans (Interest rate 3%, payback 30 years) as obtained by governments, and which is probably the basis on which the economic and financial analyses of other proposed hydropower projects in Tanzania are calculated, then the economics of the project are BCC = 7.49 and cost of energy 1.60 US cents/kWh. Above calculations are presented in the table and a brief description is given here. Column labelled as %CC gives the percentage of total Implementation cost expended each year. Column 1 gives the amount to be invested each year during construction and during the operating period. Column 2 gives the IDC. Column 3 gives the uniform annual payments required to service the project loan and is worked out by the capital recovery factor method. Column 4 gives the depreciation amount to be paid. This is worked out by assuming uniform payments which earn interest to give back the capital cost at the end of the economic life. Column 5 gives the O&M cost each year taking into account the inflationary rate. The costs in columns 3,4 and 5 are added and divided by the annual energy to give the cost of production of 1 kWh. Column 6 gives the revenue earned each year starting from the specified base year tariff which is increased each year by the inflationary rate. Column 7 gives the net income each years by subtracting the sum of columns 3,4 and 5 from 6. Column 8 gives the present worth factor obtained by using the specified discount rate. Columns 9, to 11 give the present worth of each annual payment such as the annual cost, energy cost, revenue and cashfiow obtained by multiplying the corresponding value by the PWF. The last row of the table gives the total values in each column. The totals in columns 9 to 11 are the present worth of all future amounts. From these additional parameters can be computed as follows SECSD (P) Ltd 13-6 Kikfnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Total present worth of all operating costs is given in column 9 Total present worth of all Section 5 Sensitivity Analysis Since some of the conditions assumed for the analysis may vary in actual practice, sensitivity analysis as below was carried out to determine the variation. A sample calculation for case No. 1 is indicated in table 13-1. The results for the cases are presented in figures 13-1 and 13-2. All the cases show that very little on no cash flow deficits arise and the project is bankable. It should be noted that the tests are made with adverse conditions listed below * 100% Project loan at 10% Interest and payback in 10 years * Low price for electricity sold which is US 7 cents/kWh escalating at 5% p.a. Box 13.1: Cases for Sensitivity Analysis CASE PARAMETER COST LOAN INTEREST PURCHASE DISCOUNT PERIOD PRICE RATE 1 B/C RATIO 12.30 7 5% to 10% 0.07 6% 2 ENERGY COST 12.30 7 5%to 10% 0.07 6% 3 B/C RATIO 12 30 7 10% 0.05 to 0.10 8% 4 ENERGY COST 12 30 5 to 20 10% 0.07 6% 5 ENERGY COST 10-20 7 10% 0.07 6% 6 B/C RATIO 10-20 7 10% 0 07 a% 7 B/C RATIO 12 30 7 10% 0.07 6% to 20% 8 NPV 12 30 7 10%t 0.07 5% to 30% 9 LIFE CYCLE ENERGY COST 12 30 7 10% 0.07 5% to 30% 10 BENEFITS AND COSTS 12.30 7 10% 0.07 5% to 30% 11 NPV 12.30 7 5% to 15% 0.07 56% to 30% 12 B/C RATIO 12.30 10 5% to 15% 0.07 1 0% to 30% Following observations can be made on each of the cases above, 1. Case-1: Even for a high financing rate of 10% the project benefit cost ratio does not fall below 5.75 2. Case-2: Even for a high financing rate of 10%, the energy cost in the first year does not exceed 4.8 US cents per kWh. SECSD (P) Ltd 13.7 KI(Lnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION 3. Case-3. Even if the purchase price per kWh falls to 5 cents, the benefit cost ratio is 4.0. 4. Case-4: Even for a short loan payback period of 5 years, the first year energy cost is only 6.0 US cents per kWh. 5. Case-5: Even if the capital cost increases by 50%, energy cost does not exceed 7 US cents per kWh. 6. Case-6: Even if the capital cost increases by 50% benefit cost ratio is 4.0 7. Case-7: Even for a high discount rate of 20%, the benefit cost ratio exceeds 2.0 8. Case-8: Even for a high discount rate of 20%, the NPV is positive. 9. Case-9: The life cycle energy cost in present value is only 0.6 US cents per kWh 10.Case-10: The plot of benefits and costs versus discount rate Intersect at a discount rate more than 20%. Thus FIRR is high. 11.Case:1 1: Combined plot of NPV versus discount and interest rate shows that NPV is positive for all combinations 12.Case:12: Combined plot of BC ratio versus discount and interest rate shows that B/C ratio is greater than one for all combinations. Summarizing the project is highly feasible from economic and financial terms. Hence construction of the project as an alternative to support the existing grid is recommended. SECSD (P) Ltd. 13-8 Kikfinal.doc KIKULETWA STAGE-3 TABLE 13-1 ECONOMIC AND FINANCIAL ANALYSES Capital Cost 12 300 M US$ Interest Rate 10 percent Payback Period 7 years CRR 0 2054 Discount rate 6 percent Net Annual Energy 65 000 GWh Base Price of Energy 0 07 $/kWh Inflation Rate 5 percent O&M 1 percent IDC 1 907 M US$ IDC + Capital Cost 14 207 M US$ Economic Life 30 years I - PRESENT WORTH Years % Investment Sigma IDC Debt Depre- 0 & M Energy REVENUE NET PWF RUNNING ENERGY REVENUE CASH CC inv Service ciation Cost INCOME COSTS COST FLOW M US$ M LS$ M LIUSS M USS M USS S/kWh M USS M USS M USS S/kWh M USS M USS 1 2 3 4 5 6 7 8 9 10 11 -2 50 6 150 6 150 0 615 -1 50 6 150 12 300 1 292 (6)- (8)x (3+4+5) (3+4+5) (8)x(6) (1 0)-(9) 1 0 000 2 918 0 075 0 129 0 048 4 778 1 655 0 943 2 945 0 045 4 507 1 562 2 0000 2918 0075 0 136 0048 5016 1.888 0890 2784 0043 4465 1 680 3 0 000 2 918 0 075 0 142 0 048 5 267 2 132 0 840 2 632 0 040 4 422 1 790 4 0 000 2 918 0 075 0 150 0 048 5 531 2.388 0 792 2 489 0 038 4 381 1 892 5 0 000 2.918 0 075 0 157 0 048 5 807 2 657 0 747 2 354 0 036 4.339 1 986 6 0 000 2 918 0 075 0 165 0 049 6 097 2 940 0 705 2.226 0 034 4 298 2 072 7 0 000 2 918 0 075 0 173 0 049 6 402 3 236 0 665 2 106 0 032 4 258 2 152 8 0 000 0 000 0 075 0 182 0 004 6 722 6 466 0 627 0.161 0 002 4 218 4 057 9 0 000 0 000 0 075 0 191 0 004 7 059 6 793 0.592 0 157 0 002 4 178 4 021 10 0 000 0 000 0 075 0 200 0 004 7 411 7 136 0 558 0 154 0 002 4 139 3 985 11 0 000 0 000 0 075 0 210 0 004 7 782 7 497 0 527 0 150 0.002 4.099 3.949 12 0 000 0 000 0 075 0 221 0 005 8 171 7 875 0 497 0.147 0 002 4 061 3 914 13 0 000 0 000 0 075 0 232 0 005 8 580 8 273 0 469 0.144 0 002 4.022 3 879 14 0 000 0 000 0 075 0 244 0 005 9.009 8.690 0.442 0 141 0 002 3.985 3 844 15 0 000 0 000 0 075 0 256 0 005 9 459 9 129 0 417 0 138 0 002 3 947 3 809 16 0 000 0 000 0 075 0 268 0 005 9 932 9 589 0 394 0 135 0 002 3 910 3 775 17 0 000 0 000 0 075 0 282 0 005 10 429 10 072 0 371 0 132 0 002 3 873 3 740 18 0 000 0 000 0 075 0 296 0 006 10 950 10 579 0 350 0 130 0 002 3 836 3 706 19 0000 0000 0075 0311 0006 11 498 11 112 0331 0 127 0002 3800 3673 20 0 000 0 000 0 075 0 326 0 006 12 073 11 671 0.312 0.125 0.002 3.764 3 639 21 0 000 0 000 0 075 0 343 0 006 12.676 12.259 0.294 0.123 0.002 3.729 3 606 22 0 000 0 000 0 075 0 360 0.007 13.310 12 875 0 278 0 121 0 002 3 694 3 573 23 0 000 0 000 0 075 0 378 0 007 13 975 13.523 0.262 0.118 0 002 3.659 3 540 24 0 000 0 000 0 075 0 397 0 007 14 674 14.203 0 247 0 116 0 002 3.624 3.508 25 0 000 0 000 0 075 0 417 0 008 15.408 14 917 0 233 0 114 0 002 3 590 3 476 26 0 000 0 000 0 075 0 437 0.008 16 178 15.666 0.220 0.113 0.002 3.556 3 444 27 0 000 0 000 0 075 0 459 0.008 16 987 16 453 0.207 0.111 0 002 3.523 3 412 28 0 000 0 000 0 075 0 482 0 009 17,837 17 280 0 196 0.109 0.002 3 489 3 380 29 0 000 0 000 0 075 0 506 0 009 18 728 18.147 0 185 0.107 0.002 3 456 3 349 30 0 000 0 000 0 075 0 532 0 009 19 665 19 058 0 174 0.106 0.002 3.424 3 318 MEAN MEAN TOTAL 12300 1 907 20427 2243 8581 0016 317412 286.161 20516 0.011 118.246 97730 w-I _ _ _ PW of Total Life Cycle Benefits 118 246 M US$ PW of Total LCC (OM+Cap+IDC+E 20516 M US$ Benefit Cost Ratio 5 764 Average Cost of Energy 0 011 $/kWh Computed over lifetime energy Net Present Value 97 730 M US$ ki3ECF01 xis anlyse SECSD (P) Ltd Page 13-9 KIKULETWA STAGE-3 FIGURE 13-1 SENSITIVITY ANALYSES CASES 1 to 6 BC vs Interest Rate Energy Cost (1st year) vs Interest Rate 643 < . , 0 050. 63 62 6 2 \ 046 60 0 044 5 9 58 5 6 7 8 9 10 5 6 7 8 9 10 Interest Rate Interest Rate Case-i Case-2 Selling Price vs BC Energy Cost vs Loan Period 8~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 7 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~0 070 ................................... 7 _o ~ ~~~~ , ~~~0.060' _ 6 . 0__ ' _ _0 0 0 030 4 0 020 3 - 5 10 15 20 0 050 0 060 0 070 0 080 0 090 0 100 Loan Period (years) S/kWh Case-3 Case-4 Energy Cost vs Capital Cost I BC vs Capital Cost 0 070 7 6 0 060 -- .~0.050 0 040 ____ __4 '0030 3 _ _ _ __ _ _ _ 0 020 2 0010 1 0 000 ........ ....... ...0.4I 10 12 14 16 18 20 10 15 20 M USS MUSS Case-5 Case-6 ki3ECF01 xis sensgr SECSD (P) Ltd Page 13-10 KIKULETWA STAGE-3 FIGURE 13-2 SENSITIVITY ANALYSIS CASES 7 to 12 BC vs Discount Rate I NPV vs Discount Rate . . .. . .. _ 1 .. .... .; ..1.20. .- 80 L) 6 ____D_ _____l 60 * _ _ 2o I 0~ ~ ~ ~~~~~~~~~~~4 5D~~co~tRate1520 ~ ~7 i72 0 ~ ~~ ~~~~~~~~0 5 10 15 20 ° 5 lO 15 20 i ~~~~~~Discount Rate Discount Rate Case-7 Case-8 Life Cycle Energy Cost vs Benefits, Costs vs Discount Discount Rate 0012 140 ................................. 001i1 120 - - 100- _ _ _ _ 0010 4 \ ; en 80 0 009 60-__ _ -- __ 0 008 00071 _ _ _______0____ 0 006 0 5 10 15 20 0 5 10 15 20 Discount Rate Discount Rate Ire-|Benefit Cost Case-9 Case- 10 NPV vs Discount, Interest BC vs Discount and Interest 7 . _ _ _ . i C _ .g _ 1 , 1111 1E. , )5 5 _L0 8 5 8 ID1 14 17 20 Discount unt e 13 0 000-20.000 M 20 000-40 000 Interest (%) 0 40 000-60 000 Q 60 000-80 000 . 0 0 __ ._ 11180 000-lO00000 Cl l0100000 120 000 ' l fa30 000-2 000 1 2.000-4 000 04 000-6 000 6 000-8.000I Case-l 1 Case-12 SECSD (P) Ltd Page 13-11 ki3ECFO1 xlssensgrl TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Chapter 14 Implementation Aspects Section 1 General The successful Implementation of the project depends on close coordination between the various teams involved in the design, construction etc. Some aspects in which the construction team would be interested are discussed below. Section 2 Supply of Materials and Equipment The construction of the power station and the related transmission facilities will require the hauling in of materials and construction equipment, electro-mechanical equipment (turbines, generators etc) and hydraulic equipment (gates etc). The longest and heaviest construction items are assumed to be the following Heaviest Article Longest Article Prior to construIction -Breaker about 25 tons During construction - Travelling crane about 8m Generator rotor segments It is expected, that mechanical and electrical equipment shall be furnished In major items as follows: 1. Penstocks, Gates and Trashracks 2. Turbines, Governors, Cranes and Hoists 3. Auxiliary Mechanical Equipment 4. Spillway Gates 5. Generators 6. Transformers 7. Major Electrical Equipment 8. Equipment for 33 kV Switchyard. 9. General Materials These principal Items may be furnished on speclal contracts. The Items Involved will be procured from three major sources SECSD (P) Ltd. 14-1 Kkiftnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION 1. Imported Heavy Articles. This will consist of construction machinery, the electro mechanical equipment etc. All of these will be landed at the Dar Es Salaam harbour. Trucks and trailers or railway can be conveniently used for transport from the port to the site or from port to Rundugai railway station which is very near with intermediate storage if necessary. 2. Imported Light Articles These articles which would consist of any sensitive equipment will be flown to Kilimanjaro International Airport which is very near and subsequently transported by road directly to site. 3 Domestically procured Materials: All equipment and materials which are locally available will be procured at Arusha or Dar or other cities and transported to the site. Section 3 Organlsatlon The nature of the Kikuletwa Project is such that it is logical that it will be divided into major project features, perhaps separate contracts, If need be as follows taking due consideration of local contractors and facilities which exist in Tanzania: 1. Housing and Facilities of the Site 2. River Diversion, Care of the River and Unwatering 3. Dams 4. Spillways 5. Power Station 6. 33kV Switchyard 7. Tallwater Channel 8. Access Roads 9. Transmission Line 33 kV 10. Receiving bay at substation in Kiyungi Section 4 Construction Schedule There is a rainy season in the months of November, December and heavy rains from March to May. Consequently, it is necessary to adapt the sequence of constructional operations to these climatic conditions. The greatest advantage possible should be taken of the dry seasons, particularly in the months of June to October for the operations in the main river. SECSD (P) Ltd 14-2 Kilftal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION In order to shorten the time taken by the construction, it is necessary to accomplish, even during the rainy season, individual types of operations, such as rock quarrying, concrete work, grouting operations performed outside the foundation pit, and installation. It is necessary to take into account that during the rainy season the average construction output is reduced. The entire con5truction of the hydroelectric project, according to the tentative schedule is estimated to take two years. To achieve this a highly mechanized approach to construction is contemplated. The following are the maximum rates of progress adopted for the estimation of the construction period. Box 14-1: Construction Rate ITEM Units Rate Access Roads km/day 0.20 Open Excavation with power shovels m3/day 50 Rock Excavation m3/day 25 Dam Excavation m3/day 20 Concrete placing m3/day 20 Reinforced Concrete m3/day 15 S hotcrete m3/day 10 Backfill m3/day 50 Transmission works km/day 0.25 The sequence of construction of the hydroelectric project Is divided into the following items Part I Preliminaries It is assumed that either TANESCO will implement the project or it will be implemented by IPP. In either case, the implementation will involve the issue of a bid documents and evaluation of tenders. In the case of IPP participation, a formal structured RFP will be issued to which various IPPs will respond. Based on this about 12 months will have to be set aside for various negotiations and contractual SECSD (P) Ltd 14-3 Kikdinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION arrangements to be finalized, final feasibility report preparation which may be required by various lending institutions, additional field investigations etc. The time frame which these are expected to take is given in the preliminaries heading of the implementation schedule in table 14-1. The actual contract for Civil works and Electro mechanical equipment is assumed to be issued by the project company twelve months after the decision to go ahead with the project is taken. Part II Preliminary Works This consists of the construction of access road, construction site and the camps and clearing, excavation and grading of site. The required camps can be constructed alongside the access road as well as on road from the dam to the swltchyard Also includea will be any temporary roads required for working the quarries or borrow areas The area to be occupied by the principal structures, such as the dam, the power plant, the spillway and the appurtenances to be constructed, together with the surfaces of all borrow areas, shall be cleared of all vegetation the material being used as industrial wood or burned. The construction materials earmarked for the sections of the dam and proceeding from other sources than from the excavation required for the construction, shall be taken borrow pits designated in the final drawings. The pits shall be selected so as to lie as close to the point of utilisation as possible, in accordance with the results of the second phase of the survey. According to the results of the first-stage surveys, occurrence of landslides Is not likely. Nevertheless, the estimates include sufficient contingencies for this case A concrete batching plant of about 50 cubic meters per day capacity will be installed at the site Both stationary and portable air compressors will be used. Power can be obtained from the distribution system which will be setup to convey construction power to various points at site Water for construction can be pumped from the Kikuletwa river and stored in tanks prior to utilisation. Potable water may have to be brought by tankers from Moshi. SECSD (P) Ltd. 14-4 fkIinai.doc TANZANIA-MINI HYDROPOWeR STUDY KILIMANJARO REGION Adequate electric power will be required for the construction of the project. It is estimated at about 1000kW. The best method to obtain this power Is from a truck mounted diesel generator in the vicinity of the 5ite. Alternatively, the existing transmission line at Kikuletwa 1 to the national grid should be operated at 33kV with step down facility to obtain the construction power Part Ill Diversion Weir When preliminary works have been completed, a diversion tunnel near the diversion site taking advantage of the bend in the river in the left bank shall be excavated so that the diversion weir area is rendered dry. After the construction, the diversion tunnel shall be plugged with concrete. The diversion tunnel being rather small it shall be completed upon which the main river shall be diverted by closing the river channel both upstream and downstream of the dam baseline so that the minimum flow occurring in the months of Jun to October be admitted to the diversion channel and passed safely downstream, Immediately after diversion, the main dam area shall be de- watered and there shall be initiated, excavation for the foundation of the dam. All materials for the foundations, in accordance with the first phase of the investigation, are first classified as follows: Rock excavations include all solid rock that cannot be removed either by large power shovels or loosened by rippers without blasting. Standard excavations Include all the materlals outside those Included In the rock excavations, that is, earth, gravel, loose or shattered rock fragments and all other materials that can be removed by the excavating machinery without blasting. Excavations in the river bed include all materials other than rock, to be excavated from the natural river bed. Excavations by means of blasting shall be performed only to a limited extension. It is presumed that all suitable materials from the excavation required will be used in the construction of embankments, riprap, cofferdam blankets or fill material. Excavated materials which will be found unsuitable or will not be required for SECSO (P) Ltd 14-5 Kikfin~al.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION further construction shall be dumped in dumping areas shown in the final drawings. These disposal areas shall be arranged so as to have a neat appearance. Concrete placement for the spillway and non overflow sections shall be done continuously. A total of about 2000 cum of excavation and 8000 cum of concrete is required. The entire diversion weir can be completed in about nine months. Part IV Waterway The waterway requires excavation of about 16500 cum. It is estimated to take about 6 to 8 months Reinforced concrete of about 1300 cum is required. Concrete placement shall continue in parallel with excavation. The entire construction is spread over 14 months. The penstocks in view of short length can be erected when the conduit works are nearing completion. Part V Power House Immediately after the preparatory works are finished, there shall be erected around the power house site a temporary cofferdam built upto elevation of 742 m, The main river shall continue to flow in its original channel undisturbed. Simultaneously with the construction of the cofferdam, the excavation of power house shall be carried out The surfaces of all rock foundations, upon or against which concrete is to be placed, shall be conditioned so as to promote good bond between the rock and the concrete and to provide adequate and satisfactory foundations. The construction of the power house shall go undisturbed irrespective of the season. In three months the entire excavation is completed and the placing of the draft tube and welding of the structural components shall begin which will be the first items delivered by the equipment supplier. The entire concreting of the substructure shall take about 2 months. Subsequently, It will be possible to start intense work on the superstructure of the power house. In the course of the first stage of construction concrete shall be placed up to a minimum level of 740m for the power house, SECSD (P) Ltd 14-6 Kikfinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION At the time when the main works of the machine hall with have been finished, the assembly of the main crane and then the installation of the turbine runners, generators and the accessory equipment shall be started. The power house will be finished in about 17 months. Part VI Tailrace The tailrace involves relatively low excavation and concrete. It shall be initiated when power house excavations are complete. Concreting is expected to take about 4 months. Part VII Switchyard Another structure, the completion of which influences the commissioning of the power plant, is the switchyard. The earthwork shall be initiated while the excavations in the bedrock on the right river bank for the power house are in progress, in order to make possible the completion of the subsequent civil engineering part and electrical equipment installation at the time of the completion, that is, within the 18 months following the start of the work. Part VIII Transmission The transmission works can be done independent of the other works. It Is estimated that it will take a total of about six months to complete the work. Part IX Final Works At about the time when the project is nearing completion there shall be initiated an intensive clean up operation which shall clear all waste materials and restore the site to its original conditions taking into consideration replacing any lost vegetation etc in the vicinity of the site. The commissioning of the power plant depends on the successful completion of all the civil and electrical works. The attainment of the minimum water level is not a problem as the storage provided is small. Based on the economical rates at which construction activities can be progressed for a project of this scale a preliminary project construction schedule has been SECSD (P) Ltd 14-7 Kikfinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION drawn up and is presented in table 14-1. The construction period will not exceed a two years. TABLE 14-1 IMPITMIErTATION SCHEDULE 1~~O~ H tAR FEB ~~2 5 0 02__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _____ 4 _____________________A_ EB MAAR PR hAy iLUl JIUT AUG SEP OUT NOV DEC J4i.5 OE6 FlAR APR MLAY J,14 JUL AUJG SEP LCT1 UiIT DEC JU11 FEE iAP OPR MAY JLTI JUL OUG SEP OCT N-OVl DEC L _____ _ ________________________ OTY LOST I 2 _ 4 5 6 7 a 9 10 11 12 I -2 3 4 5 6 7 8 3 1 2___ 4 S 96 7 9 lo II 12 'a~PPJ8EtARRA1ION BID EVALUATION 0 FURTi-ER FILDl, INVESTIGATIONS ,LJLL FEASIBILITY REPORT jL,CENlSJG'& OTHER CLEARANJCES P iI3ER PURCHASE AGREE1AEIJTS iCt3PACKAGE 9 AILED ENGINEERINGA ST-UDIES Cl' ORKS CONTRIACT AWVARDED CAV> 311iATUAfRTO JRI ~C'ROMECH EGUIPORDERED 012.iITATOR SAND AUXILIARIES iit M N EDUIPLIENT _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 2 PRLIMIARY CML WORKS o A'cs Roads 14Io Ellivliicw,wte Wl t 1'. 5019.rC ColonIes ~35 o I o~air1000cr I C_OCiP`5 1311to a 1jd¶c.lh--I Ep- S WATER CO-NDUCTOR- a P-ehnoan- c E C--aior 16500tl c di -rt,ng 1300 ot _ _ _ _ _ _ _ _ _ _ _ 6 POWER House o Sit. PipItoo ot,voot 1500 11 * Coo-ietig 450 cl _ _ _ _ _ _ _ _ _ _ I Other El-tncal Woiti 7 TAILRACE a E-cvt-o 169 tri A Coilcetig and RrIi,hig 315000 6 JWITCKTARO a Prehooory Woktr o Ediopiet 9 1EA54SNSSION 14 oI_ Towe Erection 10 FM"A VWORKS a TesIt'i9oIPlator Cie-o ip arid othe nsncelem, -orS 11 TO&F ___ OT 2 3 4 S 6 A 9 tO1 2 1 4 15 16 1? 16 19 20 21 22 23 2 SECSD (Pi Lid P.g. 14-9 o.31TMOI llstini TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Chapter 15 Conclusions and Recommendations 1. The Kikuletwa river has a stable flow throughout the year. This is advantageous and obviates need for providing storage. This also implies that the river can give dependable capacity and hence can attract industrial customers for the generated power. 2. A feasibility study was conducted in 1989 by JICA on hydropower generation from the stretch of the river downstream of the existing Kikuletwa 1 power station. 3. The feasibility study by JICA recommended a diversion type development with an installed capacity of 11 MW (2 x 5.5MW) and an energy output of 68GWh per year. A long waterway of about 4.2 km total length (2250m headrace culvert, 1050 open canal and 835m penstock) was proposed to obtain a gross head of about 85m. All project features were planned to be on the left bank. The Implementation cost was estimated to be about $4920 per kW in 1989. 4. To obtain satisfactory cash flow and financial analysis, JICA recommended implementation of the project by securing a soft term loan from a co-operating country. The project has however not been implemented till date probably due to inability to secure funding under the desired terms. 5. As per the revised planning suggested by SECSD, the implementation cost and time required for construction can be reduced significantly by taking advantage of loops in the river course. This is achieved by splitting the development into stages which results in a reduction in length of the waterway to less than 400m for development of a head of 65m for the largest stage. 6. In the present modified proposal with an installed capacity equivalent to the original capacity fixed by JICA of 11 MW, 65 GWh of energy is generated with a very short water conductor system. Further the head on the plant is 65m as compared to 85m gross and 78.2m net head in the JICA proposal. This balance head of 13.2 m and loss of 6.8m in JICA proposal is utilized by two small power stations which can give additional capacity and energy. SECSD (P) Ltd 15-1 IkfRnal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION 7. From the view point of the present stato of power supply in the Region, it is more desirable to implement a medium hydropower project close to the demand centre The Kikuletwa Stage 3 will be able to meet most of the energy demand of the town of Moshi. 8. The principal structures will be the diversion weir, intake structure, short waterway, powerhouse above ground and tailrace. 9. The geological conditions for the various proposed structures are sound and have ample bearing capacity to support all the structures. 10. Comparison studies of alternative plans indicates that the optimum development capacity is 1 1 0kW. 11.The power house will have two Francis turbines of 5.5MW each and produce 65.0 GWh of energy in an average year. The plant capacity factor is 67.45%. 12.The total construction cost Is estimated to be US$12.30M and IDC US$ 1.90M. 13.Due to the revised planning, implementation cost will be reduced to $1110 per kW. The cost of energy from the project will be US cents 4.5 per kWh even with very stringent financing conditions. 14.The results of the economic evaluation show that the project is economically feasible. 15.The financial rates of return based on discount factor of 6% indicates that the project is financially sound. 16.The electric power produced at the Kikuletwa stage 3 power station will be supplied to the Regional grid and this will improve the electric supply demand and supply situations. 1 7. In order to expedite the implementation of this project, the layout is such that, the times required for the detailed designs. financing and construction are kept to their practical minimum. It will be possible to commence commissioning of SECSD (P) Ltd 15-2 Kikfinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION the Kikuletwa stage 3 project in late 2002. The project expenditure and size is such that it is suitable of being financed by many local companies who can become IPPs. 18.The Kiyungi and Njiro substations are at the end of the 132kV transmission system. The voltage drop is therefore great. The Kikuletwa-2 power station will give ample voltage support and increase the stability of this line thereby improving operating conditions in other parts of the system. 19.The construction of the reservoir will not result in the loss of valuable agricultural or grazing land. The lake will not inundate a populated valley necessitating the displacement of the population. Therefore the cost of moving the Inhabitants and of replacing the farm will not affect the total cost estimates. 20. The value of land and property in the area of the project, which is not in direct physical interference, will not be adversely affected by the construction of engineering works 21.The construction of dam and reservoir will not interfere with fishing rights. As far as fish and wildlife are concerned the creation of the reservoir can only enhance the value of the area. 22.During construction and later during operation of the project sufficient quantities of water will be released to the downstream bed of the river. The operation of the hydro power station will not lead to a reduction in the flow. On the contrary, the operation of the reservoir will ensure the regulation of flows to some degree. SECSD (P) Ltd 15-3 KI(dInal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Chapter 16 Photographs, References, Abbreviations Photo 16-1: View of Diversion weir site from downstream Photo 16.2: View of Power House site SECSD (P) Ltd 16-1 Kikfinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Section 1 Rerferences 1 Feasibility Study on Small Scale Hydroelectric Power Development in Kilimanjaro Region by Japan International Cooperation Agency Jan 1989 Vol-1 2 Feasibility Study on Small Scale Hydroelectric Power Development in Kilimanjaro Region by Japan International Cooperation Agency Jan 1989 Vol-2 3. Survey of Tanzania Topographic sheets on 1:50000 scale - 55/1, 55/2, 55/3, 55/4, 56/1, 56/2, 5613, 5614, 71/2, 72/1, 72/2. 4. India - Mini Hydro Development on Irrigation Dams and Canal Drops Pre Investment Study Volume - 1, Main Report, Report No. 139AJ91. Joint UNDPJESMAP study 1991. 5. India - Mini Hydro Development on Irrigation Dams and Canal Drops Pre Investment Study Volume - 2, Technical Supplement, Report No. 139B91. Joint UNDP/ESMAP study 1991. 6 India - Mini Hydro Development on Irrigation Dams and Canal Drops Pre Investment Study Volume - 3, Cost Estimates, Report No. 139C/91. Joint UNDPIESMAP study 1991 7. Submission and Evaluation of Proposals for Private Power Generation Projects in Developing Countries - The World Bank, IEN Occassional Paper No.2 April 1994. SECSD (P) Ltd 16-2 Kikfial.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Section 2 Abbreviations Institutions TWB The World Bank ESMAP Energy Sector Management Assistance Programme UNDP United Nations Development Programme UNHCR United Nations High Commissioner for Refugees GOT Government of The Republic of Tanzania TANESCO Tanzania Electric Supply Company JICA Japan International Cooperation Agency SECSD Sivaguru Energy Consultants & Software Developers IFI International Financial Institutions IPP Independent Power Producer BOOT Build Own Operate and Transfer Electrical W Watt kW kilowatt = 1 000Watts MW Megawatt = 10xl o Watts Wh Watthour kWh kilo Watt hour = 1000 Wh GWh Giga Watthours = 1x 100 kWh V Volt kV kilovolt = 1000 Volts VA Volt Ampere kVA kilo Volt Ampere = 1000 VA MVA Megavolt ampere = 1 xl 0 VA A Ampere kA kiloampere = 1000 ampere pu per unit LT Low Tension HT High Tension AC Alternating current DC Direct current SECSD (P) Ltd 16-3 Kikfinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION pf Power Factor Hz Hertz rpm Revolutions per minute rps Revolutions per second cmils circular mils Hydraulic cum cubic meter m3 cubic meter m3/s cubic meters per second cumecs cubic meters per second MCM Mllion Cubic meters = lxl08 cum FSL Full Supply Level H Water head in m TWL Tail water level masl meters above sea level EL Elevation Measurements sqkm square kilometers ha hectare = 0.01 sqkm m meter km kilometre = 1000m in inches ft feet = 12 inches 4 feet mm millimeter lbs pounds kg kilogram = 2.21 lbs t tonne = 1000 kg F Farenheit C Celsius SECSD (P) Ltd 16-4 Ikfinal.doc TANZANIA-MINI HYDROPOWER STUDY KILIMANJARO REGION Financial USD United States dollar TSh Tanzania Shillings IDC Interest during construction O&M Operation and Maintenance PWF Present Worth Factor BC Benefit Cost ratio NPV Net Present Value M million SECSD (P) Ltd 16-5 Kidfnai.doc Joint UNDP/Woild Bank ENERGY SECTOR MANAGEMENT ASSISTANCE PROGRAMME (ESMAP) LIST OF TECHNICAL PAPER SERIES Region/Country Activity/Report Title Date Ninmber SUB-SAIIARAN AFRICA (AFR) Kenya Field Performance Evaluation of Amorphous Silicon (a-Si) Photovoltaic Systems in Kenya: Methods and Measurement in Support of a Sustainable Commercial Solar Energy Industry 08/00 005/00 The Kenya Portable Battery Pack Experience T'est Marketing an Alternative for Low-Income Rural Household Electrification 05/01 012/01 Senegal Regional Conference on the Phase-Out of Leaded Gasoline in Sub-Saharan Africa 03/02 022/02 Swaziland Solar Electrification Program 2001-2010. Phase 1: 2001-2002 (Solar Energy in the Pilot Area) 12/01 019/01 Tanzania Mni Hydropower Development Case Studies on the Malagaiasi, Muhuwesi, and Kikuletwa Rlvers Volumes I, Il, and III 04/02 024/02 Uganda Report on the Uganda Power Sector Reform and Regulation Strategy Wot kshop 08/00 004/00 WEST AFRICA (AFR) LPG Market Developnment 12/01 017/01 EAST ASIA AND PACIFIC (EAP) Chma Assessing Markets for Renewable Energy Ui Rural Areas of Northwestem China 08/00 003/00 Technology Assessment of Clean Coal Technologies for China Volume I-Electric Power Production 05/01 011/01 Technology Assessment of Clean Coal Technologies for China Volume II-Environmental and Energy Efficiency Improvements for Non-power Uses of Coal 05/01 011/01 Technology Assessment of Clean Coal Technologies for China Volume III-Environmental Compliance in the Energy Sector. Methodological Approach and Least-Cost Strategies 12/01 011/01 Thailand DSM in Thailand A Case Study 10/00 008/00 Development of a Regional Power Market in the Greater Mekong Sub-Region (GMS) 12/01 015/01 Vietnam Options for Renewable Energy in Vietnam 07/00 001/00 Renewable Energy Action Plan 03/02 021/02 SOUTH ASIA (SAS) Bangladesh Workshop on Bangladesh Power Sector Reforn 12/01 018/01 Regioni/Country Activit/Report Title Date Numnrber LATIN AMERICA AND THE CARIBBEAN (LAC) Regional Electricity Markets Inteiconnections - Phase I Identification of Issues for the Development of Regionial Power Markets in South America 12/01 016/01 Population, Energy and Environment Program (PEA) Comparative Analysis on the Distribution of Oil Rents (English and Spanish) 02102 020/02 Estudio Comparativo sobre la Distribucidn de la Renta Petrolera Estudio de Casos- Bolivia, Colombia, Ecuador y Peru 03102 023/02 GLOBAL Impact of Power Sector Refom- on the Poor: A Review of Issues and the Literature 07/00 002100 Best Practices for Sustainable Development of Micro Hydio Power mn Developing Countries 08/00 006/00 Mini-Grid Design Manual 09/00 007/00 Photovoltaic Applications in Rural Areas of the Developuig World 11/00 009/00 Subsidies and Sustatnable Rural Energy Services: Can we Create Incentives W]thout Distorting Markets? 12/00 010/00 Sustainable Woodfuel Supplies from the Dry Troptcal Woodlands 06/01 013101 Key Factors for Private Sector Investmrent in Power Distribution 08/01 014/01 4/8/02 LSMIA D E<'L a it v II la The World Bank 1818 H Street, NW Washington, DC 20433 USA Tel 1 202458.2321 Fax 1.202522 3018 Internet www esmap org Email esmap@worldbank org 4w>~- - -b _,1- . A jomnt UNDP/Worid Bank Programme