2.16 NAM POT HYDROPOWER PROJECT

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1 2.16 NAM POT HYDROPOWER PROJECT Nam Pot is a hydropower project of around 20 to 25 MW located in Xiangkhouang Province. Due to its size, location and economics, Nam Pot project is best suited to a domestic role, supplying the Central Grid. A mandate was awarded to VKS of India to develop the site but it is inactive. The Project is located appropriately 30km south-southeast of Xiangkhouang. A small dam is situated on the Nam Pot, a tributary of the Nam Siam, which in turn discharges into the Nam Ngiep. The dam site is located some 3.5km upstream of the confluence of the Nam Pot with the Nam Siam. Downstream of the dam, the Nam Pot falls through a height of 700m over a reach of 3.5km. Upstream of the dam, the river flows at a relatively shallow, wide bottomed gradient, although the area inundated by the reservoir would be very small and confined to a narrow northwest to southeast trending valley. The proposed power station site is on the left bank of the Nam Siam just upstream of its confluence with Nam Pot. The Project was studied by Knight Piesold to inventory level in The Consultant evaluated the Project using: Existing field data no new field data was collected; Updated hydrology (1966 to 2002 streamflow series); EVALS hydropower dimensioning and evaluation software; SESAMEE environmental and social impact assessment. The technical and economic characteristics of the Project are summarized in the following table. No project interactions were assumed in determining these outputs. The EVALS outputs are provided. Some environmental and social costs are accounted for in the EVALS evaluation and are reflected in the program outputs. The project s wider impacts have been assessed using SESAMEE and are internalized into the evaluations reported in Section 6 of Volume A, Main Report. Power System Development Plan August 2004 Final Report Vol C: Project Catalogue 35

2 Technical and Economic Data (Source: EVALS Output): Development: Installed Capacity Factor 1.75 Contractual status MOU (inactive) Level of study Inventory Access Roads: New road 22 km Rehabilitation 0 km Hydrology: Name of river Nam Pot Av. annual precipitation (dam site) 1,729 mm/a Ave. Reservoir Inflow 1.9 m 3 /s Reservoir: Full supply level (FSL) 1,140 m asl Minimum operating level (MOL) 1,127 m asl Max storage volume (FSL) hm 3 Active storage volume hm 3 Maximum reservoir area (FSL) 4.9 km 2 Reservoir filling time 7.5 months Dam: Main dam type RCC Gravity Maximum height 26 m Crest length 130 m Spillway: Spillway type Ungared Ogee Design discharge 340 m 3 /s Power Station: Type Surface Number of units 2 Turbine type Pelton Turbine rated head 673 m Transmission: Line Length 6 km Voltage 115 kv Output: Installed Capacity 20 MW Guaranteed capacity (95%) Average generation Primary generation (95% firm) Secondary generation 19.4 MW 92 GWh p.a. 89 GWh p.a. 3GWh p.a. Average plant factor 53 % Economic: Basic project cost (no esc. or IDC) mus$ Capacity cost Average energy cost Weighted energy cost 14 1,398 US$/kW 3.4 /kwh 3.4 /kwh 14 The calculation of weighted generation cost values secondary energy at half the value of primary energy based on a definition of primary energy as energy produced with 95% firmness. Power System Development Plan August 2004 Final Report Vol C: Project Catalogue 36

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7 2.17 NAM SANE 3 HYDROPOWER PROJECT The Nam Sane 3 Hydropower Project is located in Xiengkhouang Province on the Nam Sane. The location of the Project is shown in the attached plan. The Project as configured in the PSDP consists of a dam of about 45 m in the headwaters of the Nam Sane impounding a reservoir of about 6 km 2. A headrace tunnel of about 6 km in length conveys the generation flows to the powerhouse located on the right bank of the Nam Sane. The gross head created by the dam and river gradient is about 800 m. Output is produced by two Pelton units with an aggregate capacity of 60 MW. The Consultant evaluated the Project using: Existing field data no new field data was collected; Updated hydrology (1966 to 2002 streamflow series); EVALS hydropower dimensioning and evaluation software; SESAMEE environmental and social impact assessment. The technical and economic characteristics of the Project are summarized in the following table. No project interactions were assumed in determining these outputs. The Project economics are excellent but there is uncertainty about the number of people displaced by the Project. A prefeasibility study and Initial Environmental Examination should be conducted as a soon as possible to confirm the project hydrology, geology and topography, and to obtain data on the social and ecological characteristics of the project area. Due to its size, location and economics, Nam Sane 3 project would be well suited to supplying the Central Grid. If impacts are manageable, the Project should be evaluated in a system expansion context. The EVALS outputs are provided. Some environmental and social costs are accounted for in the EVALS evaluation and are reflected in the program outputs. The project s wider impacts have been assessed using SESAMEE and are internalized into the evaluations reported in Section 6 of Volume A, Main Report. Power System Development Plan August 2004 Final Report Vol C: Project Catalogue 37

8 Technical and Economic Data (Source: EVALS Output): Development: Installed Capacity Factor 1.75 Contractual status Non active mandate Level of study Inventory Access Roads: New road 8 km Rehabilitation 4 km Hydrology: Name of river Nam Sane Av. annual precipitation (dam site) 1,890 mm/a Ave. Reservoir Inflow 4.9 m 3 /s Reservoir: Full supply level (FSL) 1450 m asl Minimum operating level (MOL) 1428 m asl Max storage volume (FSL) hm 3 Active storage volume hm 3 Maximum reservoir area (FSL) 5.8 km 2 Reservoir filling time 3.5 months Dam: Main dam type RCC Gravity Maximum height 43 m Crest length 180 m Spillway: Spillway type Ungated Ogee Design discharge 845 m 3 /s Power Station: Type Surface Number of units 2 Turbine type Pelton Turbine rated head 807 M Transmission: Line Length 44 km Voltage 115 kv Output: Installed Capacity 60 MW Guaranteed capacity (95%) Average generation Primary generation (95% firm) Secondary generation 59.0 MW 286 GWh p.a. 269 GWh p.a. 16 GWh p.a. Average plant factor 53 % Economic: Basic project cost (no esc. or IDC) mus$ Capacity cost Average energy cost Weighted energy cost 15 1,092 US$/kW 2.6 /kwh 2.6 /kwh 15 The calculation of weighted generation cost values secondary energy at half the value of primary energy based on a definition of primary energy as energy produced with 95% firmness. Power System Development Plan August 2004 Final Report Vol C: Project Catalogue 38

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13 2.18 NAM SIM SMALL-SCALE HYDROPOWER PROJECT The Nam Sim is a project of under 10 MW located in Houaphan Province. Due to its size, location and economics, Nam Sim project is envisaged primarily for supplying Sam Neua, Vieng Xay and other centers in the vicinity of the Project. The location of the Project is shown in the attached plan. The Nam Sim is a tributary of the Song Ma river, originating in the Annamite Range in Lao PDR and flowing eastwards into Vietnam where it enters the Gulf of Tonkin at Thanh Hoa. The Project consists of a small dam to capture and divert the streamflow, a 1400 m headrace canal and steel penstock to convey the water to a powerhouse, and two horizontal Francis units to generate electricity. The gross head developed by the dam and river gradient is about 160 m. No exclusive mandate to develop the site presently exists. The Project was studied by Hydropower Office to inventory level in The Consultant evaluated the Project using: Existing field data no new field data was collected; Updated hydrology (1966 to 2002 streamflow series); EVALS hydropower dimensioning and evaluation software; SESAMEE environmental and social impact assessment. The technical and economic characteristics of the Project are summarized in the following table. No project interactions were assumed in determining these outputs. The EVALS outputs are provided. Some environmental and social costs are accounted for in the EVALS evaluation and are reflected in the program outputs. The project s wider impacts have been assessed using SESAMEE and are internalized into the evaluations reported in Section 6 of Volume A, Main Report. Power System Development Plan August 2004 Final Report Vol C: Project Catalogue 39

14 Technical and Economic Data (Source: EVALS Output): Development: Installed Capacity Factor 1.00 Contractual status No mandate issued Level of study Inventory Access Roads: New road 4 km Rehabilitation km Hydrology: Name of river Nam Sim Av. annual precipitation (dam site) 2,320 mm/a Ave. Reservoir Inflow 5.8 m 3 /s Reservoir: Full supply level (FSL) 638 m asl Minimum operating level (MOL) 636 m asl Max storage volume (FSL) 0.90 hm 3 Active storage volume 0.60 hm 3 Maximum reservoir area (FSL) 0.5 km 2 Reservoir filling time 0.5 months Dam: Main dam type Concrete Gravity Maximum height 7 m Crest length m Headrace Canal: Design discharge 5.8 m 3 /s Canal Length 1,400 m Top Width 3.4 m Bottom Width 1.9 m Lining Shotcrete Desilting Basin: Basin type Conventional No. of Basins 2 Power Station: Type Surface Number of units 2 Turbine type Horizontal Francis Turbine rated head 163 m Transmission: Line Length 29 km Voltage 22 kv Output: Installed Capacity 8.2 MW Guaranteed capacity (95%) Average generation Primary generation (95% firm) Secondary generation 8.0 MW 47 GWh p.a. 17 GWh p.a. 29 GWh p.a. Average plant factor 65 % Economic: Basic project cost (no esc. or IDC) mus$ Capacity cost Average energy cost Weighted energy cost 16 1,379 US$/kW 2.7 /kwh 4.0 /kwh 16 The calculation of weighted generation cost values secondary energy at half the value of primary energy based on a definition of primary energy as energy produced with 95% firmness. Power System Development Plan August 2004 Final Report Vol C: Project Catalogue 40

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19 2.19 NAM THEUN 1F HYDROPOWER PROJECT The Nam Theun 1 Hydropower Project is located on the Nam Kading on the border between Bolikhamxai and Khammouane Provinces. The layout of the Project shown in the attached plan relates to a reservoir FSL of 300 m asl as proposed in the 1995 Electrowatt feasibility study. It included a archgravity concrete dam of over 180 m and a power station incorporated into it. Both Halcrow (1998) and Electrowatt-Ekono (2002) have studied alternatives. These include Nam Theun 1F, based on an RCC dam and a FSL of 250 masl. This option is associated with a lower capital cost and fewer social and environmental problems, but the smaller reservoir cannot provide full seasonal regulation and the weighted generation cost suffers. The Consultant has evaluated several project alternatives using: Existing field data no new field data was collected; Updated hydrology (1966 to 2002 streamflow series); EVALS hydropower dimensioning and evaluation software; The results of the EVALS evaluations are presented in the following table: Project Configuration MW FSL (m asl) Average Generation Cost ( /kwh) Weighted Generation Cost ( /kwh) Nam Theun 1 F: w/- THB (210 MW) & Nam Theun 2 (1074 MW) Nam Theun 1: w/- Theun Hinboun (315 MW) upstream Nam Theun 1: w/- Theun Hinboun (315 MW), NT3 storage & Nam Theun 2 (1074 MW) The technical and economic characteristics of Nam Theun 1F are summarized in the following table and in the attached EVALS output. Project interactions assumed in determining these outputs include Nam Theun 2 (1074 MW) and Theun Hinboun (210 MW). Some environmental and social costs are accounted for in the EVALS evaluation and are reflected in the program outputs. The PSDP evaluation results for Nam Theun 1F contrast with those derived by Electrowatt-Ekono who calculates the average and weighted generation cost to be 2.97 /kwh and 3.63 /kwh respectively. The development of Theun Hinboun Expansion with upstream regulation storage at the Nam Theun 3 site would increase the diversion of flows from the Nam Theun basin at the Theun Hinboun power station and reduce the generation flows available to Nam Theun 1. Power System Development Plan August 2004 Final Report Vol C: Project Catalogue 41

20 Nam Theun 1F: Technical and Economic Data (Source: EVALS Output): Development: Installed Capacity Factor 1.30 Contractual status MOU Level of study Nam Theun 1F - Inventory Interactions NT2 (1074 MW); THB (210 MW) Hydrology: Name of river Nam Theun Av. annual precipitation 2,508 mm/a Ave. Reservoir Inflow m 3 /s Reservoir: Full supply level (FSL) 250 m asl Minimum operating level (MOL) 210 m asl Max storage volume (FSL) 918 hm 3 Active storage volume 664 hm 3 Maximum reservoir area (FSL) 23.4 km 2 Reservoir filling time 1.5 months Dam: Main dam type Concrete Arch Gravity Maximum height 133 m Crest length 285 m Diversion: Design discharge 1,140 m 3 /s Tunnel Diameter 10.5 m Tunnel Length 610 m Spillway: Spillway type Gated Ogee Design discharge 17,700 m 3 /s Power Station: Type Surface Number of units 6 Turbine type Francis Turbine rated head 95 m Transmission: Line Length 220 km Voltage 220 kv Output: Installed Capacity 400 MW Guaranteed capacity (95%) Average generation Primary generation (95% firm) Secondary generation 343 MW 1,332 GWh p.a. 425 GWh p.a. 906 GWh p.a. Average plant factor 38 % Economic: Basic project cost (no esc / IDC) 495 mus$ Capacity cost Average energy cost Weighted energy cost 17 1,541 US$/kW 4.9 /kwh 7.5 /kwh 17 The calculation of weighted generation cost values secondary energy at half the value of primary energy based on a definition of primary energy as energy produced with 95% firmness. Power System Development Plan August 2004 Final Report Vol C: Project Catalogue 42

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