Annex1_Siwa Khola
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GENERAL INFORMATION OF THE PROJECT Project Description of Siwa Khola Hydropower Project (SK-HP) 1.0 Background Nepal has more than 6000 rivers and rivulets belonging to three main drainage basins: Koshi, Gandaki and Karnali. Most of the rivers are perennial as they are originated in high Himalayas and are nourished by snow and glaciers. Water resources of Nepal have been regarded as nature's bountiful gift to the country. In fact, perennial nature of rivers and the steep gradient provide ideal conditions for the development of some of the world's largest hydropower projects in Nepal. The main reason for hydropower projects being the most attractive is due to reliable, safe and cheap source of energy. The total theoretical hydropower potential is 83000 MW with 43000 MW is technically and economically feasible potential. Potential mega-projects have failed to take shape in Nepal primarily due to the lack of adequate funds and the basic infrastructural facilities; in view of which, the development of medium scale and small hydropower projects are given high priority. Ministry of Energy, Government of Nepal license to encourage participation of Private Developers for development of hydropower projects in Nepal. Nepal Electricity Authority (NEA) has fixed the energy rates for small hydropower projects less than 25 MW capacity promoted by Independent Power Producers (IPPs). Domestic commercial banks are also interested to invest in hydropower projects as priority sector investment. In addition to this, GoN has announced the People's Hydro Program to promote the participation of local people and local institutions. Government of Nepal ( GoN) has allocated the budget to implement the People's Hydro Program. Among the various level activities of this program, the study of hydropower projects is one of the program to make projects available for the implementation. Department of Electricity Development ( DoED) intends to carry out the Detail Engineering Study of the project from the competent local consulting firms. 2.0 Project Information The proposed Siwa Khola Small Hydropower Project is located in Nalbu and Papung VDCs of the Taplejung district of the Eastern Development Region of Nepal. The project will have a generation capacity of 15 MW and will be able to generate 83.47 GWh(after outage and losses) of annual energy. The present feasibility study has been carried out to establish the economical, technical and environmental viability of the project. The
description
Hydropower design
Transcript of Annex1_Siwa Khola
GENERAL INFORMATION OF THE PROJECT
Project Description of Siwa Khola Hydropower Project (SK-HP)
1.0 BackgroundNepal has more than 6000 rivers and rivulets belonging to three main drainage basins: Koshi, Gandaki and Karnali. Most of the rivers are perennial as they are originated in high Himalayas and are nourished by snow and glaciers. Water resources of Nepal have been regarded as nature's bountiful gift to the country. In fact, perennial nature of rivers and the steep gradient provide ideal conditions for the development of some of the world's largest hydropower projects in Nepal. The main reason for hydropower projects being the most attractive is due to reliable, safe and cheap source of energy. The total theoretical hydropower potential is 83000 MW with 43000 MW is technically and economically feasible potential. Potential mega-projects have failed to take shape in Nepal primarily due to the lack of adequate funds and the basic infrastructural facilities; in view of which, the development of medium scale and small hydropower projects are given high priority.
Ministry of Energy, Government of Nepal license to encourage participation of Private Developers for development of hydropower projects in Nepal. Nepal Electricity Authority (NEA) has fixed the energy rates for small hydropower projects less than 25 MW capacity promoted by Independent Power Producers (IPPs). Domestic commercial banks are also interested to invest in hydropower projects as priority sector investment. In addition to this, GoN has announced the People's Hydro Program to promote the participation of local people and local institutions. Government of Nepal ( GoN) has allocated the budget to implement the People's Hydro Program. Among the various level activities of this program, the study of hydropower projects is one of the program to make projects available for the implementation. Department of Electricity Development ( DoED) intends to carry out the Detail Engineering Study of the project from the competent local consulting firms.
2.0 Project InformationThe proposed Siwa Khola Small Hydropower Project is located in Nalbu and Papung VDCs of the Taplejung district of the Eastern Development Region of Nepal. The project will have a generation capacity of 15 MW and will be able to generate 83.47 GWh(after outage and losses) of annual energy. The present feasibility study has been carried out to establish the economical, technical and environmental viability of the project. The construction cost of the project is estimated as US$ 203.74 million, and it is expected to be completed in 3 years period from the start of construction.
The intake of the proposed project lies near Pandalun village in Nalbu VDC about 13 km northwest of Taplejung, the district headquarters. The powerhouse is a surface type located on the terrace field at Chambrun village on the right bank of Mewa Khola. Currently, local trails from Taplejung bazaar link the intake site. The nearest airport is situated in Sukhetar, about 3 km southeast of Taplejung.
The headworks of the project is located at siwa Khola of Nalbu VDC. A 3.0 m high diversion structure is constructed across the river to divert the required flow towards the intake. Structures like gravel trap, undersluice, side intake, a two chambered surface desilting basin incorporating an emergency spillway are proposed at the headworks. Necessary structures for the convenience during operation and maintenance, and safety of the structures are also provided.
A 2180 m long inverted D-shaped headrace tunnel has the finished width of 2.5m and height of 2.95 m diameter conveys 5.9 m3/s design discharge from the headworks to a 1.45 m diameter of 531.02 m long penstock. Necessary lining is proposed along the tunnel alignment. Also, anchor blocks and saddle supports are provided along the penstock.
The two units of horizontal axis pelton turbine each of rated capacity 7.5 MW utilize the water for energy production before discharging back to Siwa River via a 23 m long tailrace canal. It is estimated that with aforementioned design discharge and gross head of 299.49 m, the project will be able to generate 83.47 GWh in an average year. The generated energy from the project is proposed to transmit to the 33 kV substations at Dhankuta by constructing 35 km long transmission line. During project execution, about 12 km access road will also be constructed to link the intake site to the nearest road head in Taplejung bazaar on the Phidim Taplejung road.
3.0 Salient Features of Siwa Khola Small Hydropower Project1. LocationRegion:Eastern Development RegionDistrict:TaplejungProject Area Boundary:Between Latitudes 270 27 30 N and 270 30 30 NLongitudes 870 34 00 E and 270 37 30 EHeadworks:Latitude 270 29 22 N, Longitude 870 36 18Powerhouse:Latitude 270 28 30 N, Longitude 870 36 42
2. Meteorology and Hydrology
Average Annual Precipitation:1960mmCatchment Area at Intake Site:138 km2Average Flow at the Intake Site:7.89 m3/sec90% Firm Flow:1.87 m3/secDesign (Turbine) Flow:5.9 m3/secProbability of Exceedance:41%Design Flood:1 in 100 years:211 m3/sec1 in 200 years:233 m3/secDiversion Flood1 in 10 years:13.28 m3/sec1 in 20 years:15.88 m3/sec3. Diversion Weir
Type:Ogee shaped free overflow spillwaySpillway Length:18mSpillway Crest:EL 1419.0mHeight:3.0m from river bed
4. UndersluiceLocation:At right side of the weirSection:With a single gate of 2.5m wide and 3.0m high separated by a 1m wide pierCrest Level:EL 1416.0m
5. IntakeLocation:Immediately upstream and adjacent to the underlsuiceInvert level:EL 1417.40mSize of Opening:3.0m wide and 1.6m high separated by 1.0m wide pier
6. Gravel Trap and Emergency SpillwayGravel Trap:7.0m wide, 7.5m high and 15m longSide Channel Spillway:15.0m longCrest Level of the Spillway:EL 1418.81m
7. Desilting BasinType:Dobule Chamber Hopper Type Surface DesiltingBasin with Provision of Continuous FlushingNumber of Chambers:TwoNominal Size of Trapped Particles:0.2mmLength:60m
8. Headrace TunnelLength:2,180 mShape:Inverted D-ShapeSize:2.5m wide and 2.95m highWater Flowing Section:2.5m and 1.7m high
9. ForebayLive Capacity:1,062 m2Effective Size ( L x B x H):42m x 5m x 5m with extra depth of 1mSpillway Length:7.0 m
10. PenstockLength of the Pipe:531.02m up to bifurcation and then 8.7mDiameter of the Pipe:1.45m abd 1.05m after bifurcationThickness of the Pipe:Ranges from 8 mm to 28 mm
11. PowerhouseType:SurfaceLength x Breadth x Height:29.12m x 11.88m x 18.40 mNumber of Generating Units:TwoType of Turbine:Pelton Horizontal AxisTurbine Center Line:EL 1119.51mTurbine Efficiency:90%Gross Head:299.49mRated Net Head:292.37mGenerator:Synchronous with Horizontal shaftGenerator Efficiency:96%Rated Capacity:2 x 7.5 MW
12. TailraceType:Cut and Cover ConduitInner Dimension:2.0m x 2.0mLength:23m
13. TransformerType:Single Phase, Oil ImmersedNumber of Unity:3+1Rated Capacity:6 MVA eachVoltage Level:11 kV/132 kV
14. Switchyard and Transmission LineSwitchyard Type:Outdoor, Conventional with area of 18m x 12m Transmission Line Length, Volatage,Circuit and Conductor type:29.9 km, upto proposed Kabeli-A Sub-station at Pinase in Taplejung District, 132 kV and Single Circuit with Wolf Conductor
15. Energy GenerationAnnual Average Energy Output (Gross):87.86 GWhAnnual Average Energy Output(After Outage and Losses):83.47 GWhDry Season Energy(Dec/Jan to Mar/Apr):15.42 GWhWet Season Energy(Apr/May to Nov/Dec):68.05 GWhFirm Eenrgy (after outage and losses)@Q90%:37.73 GWhMinimum Monthly Energy:1.560 km/ 5.695 km
16. Energy GenerationAnnual Average Energy Output (Gross):87.86 GWhAnnual Average Energy Output(After outage and losses):83.47 GWhDry Season Energy(Dec/Jan to Mar/Apr):15.42 GWhWet Season Energy(Mar/Apr to Nov/Dec):68.05 GWhFirm Energy (after outage and losses)@Q90%):37.73 GWhMinimum Monthly Energy:3.21 GWh
17. Access RoadAnnual Average Energy Output (Gross):1.560 km/ 5.695 km
18. Investment Costs1With Cost of TLWithout Cost of TLEconomic cost:NRs. 2,039,932,564NRs. 1,640,140,164Financial cost:NRs. 2,255,743,630NRs. 2,037,432,560
19. Economic and Financial IndicatorsWith Cost of TLWithout Cost of TLEIRR:16.1020.93B/C Ratio:1.471.82NPV:NRs. 1,265,960,000NRs. 1,786,930,000
Financial with dry season price if NRs. 7.00 per KWh and Wet Season Price of NRs. 4.00 per KWhIRR on equity investment (%):14.1017.00B/C Ratio:1.081.19NPV:NRs. 181,476,000NRs. 380,526,000
