Solu Khola (Dudhkoshi) Hydroelectric Project (SKDKHEP) is an 86 MW Run Of River (RoR) type of project located at Solududhkunda Municipality & Thulung Dudh Koshi Gaupalika (Former Tingla, Kangel & Panchan VDCs) of Solukhumbu District, Nepal. The project area is about 130 km (aerial) east of Kathmandu and is situated within longitude 86°37’35” to 86°41’15” East and latitude 27°21’53” to 27°25’15” North. The project utilizes a design discharge of 17.05m³/s from Solu Khola and the elevation difference between the proposed intake at Solu Khola and powerhouse at Dudhkoshi River for power generation.
The proposed headworks is located at Gairigaun village of Solududhkunda Municipality, about 600 m downstream of the suspension bridge over Solu Khola (River) at Sanghutar. Surface settling basin, headrace tunnel, pressure shaft tunnel passes along different places of Thulung Dudh Koshi Gaupalika. The proposed powerhouse, switchyard and tailrace canal all are located near Maikubesi of Thulung Dudh Koshi Gaupalika, on the right bank of Dudh Koshi River, about 1 km upstream of the suspension bridge over Dudh Koshi River at Jaleshwor Mahadev.and 3.5km upstream of the confluence of Solu Khola and Dudh Koshi River.
The project consists of a simple weir with undersluice, side intake, gravel trap, approach channel, an desalting basin, headrace tunnel, surge shaft, inclined pressure shaft and horizontal penstock tunnel, surface powerhouse and a tailrace canal.
| S.N. | Components | Description |
| 1 | Project Location | Solukhumbu District, Province 1 |
| Intake Site | Solududhkunda Municipality | |
| Powerhouse Area | Thulung Dudhkoshi Gaupalika | |
| Latitude | 27°21’53”N to 27°25’15”N | |
| Longitude | 86°37’35”E to 86°41’15”E | |
| 2 | General | |
| Name of River | Solu Khola | |
| Type of Scheme | Run-of-River | |
| Gross Head | 613.20 m | |
| Net Head | 598.09 m | |
| Installed Capacity | 86,000 kW | |
| 3 | Hydrology | |
| Catchment Area | 454 km2 | |
| Design Discharge | 17.05 m3/s | |
| Design Flood Discharge | 475 m3/s (100 Yr. Flood) | |
| 4 | Diversion Weir | |
| Type of Weir | Gravity free flow concrete | |
| Length of Weir | 34.8 m | |
| Max. Height of Weir | 13.50 m from foundation level | |
| Crest Elevation | EL. 1,262.00 masl | |
| 5 | Intake Structure | |
| Type | 3 no.s of Side intake | |
| Size (W x H) | 4.00 m (W) x 2.00 m (H) | |
| Crest elevation of Intake | EL. 1,258.00 masl | |
| 6 | Undersluice Structure | |
| Type and number | 3 nos with Gate | |
| Size (W x H) | 1.50 m (W) x 1.00 m (H) | |
| Crest elevation of Undersluice | EL. 1,256.00 masl | |
| 7 | Gravel Trap | |
| Type | Rectangular, RCC | |
| Size | 5.00m (W) x 5.00 m (L) | |
| Bed load size to trap | 5 mm | |
| 8 | Approach Canal | |
| Type and Number | Free flow box culvert, total 3 nos | |
| Size | 2.6 m x 2.6 m | |
| 9 | Desanding Basin | |
| Type | Surface | |
| No of Bays | 3 Nos | |
| Dimension (L x B x H) m | 85 m (L) x 9.00 m (W) x 5.00 m (H) | |
| Particle Size to be Settled | 0.15 mm (90% trapping efficiency) | |
| Outlet Water Level | EL. 1,259.30 m | |
| 10 | Headrace box Culvert | |
| Length | 34.50 m | |
| Size | 4.5m (W) x 4.5m (H) | |
| Numbers | 1 (One) | |
| 11 | Headrace Tunnel | |
| Section Type | Inverted-D | |
| Length | 4469.61m | |
| Size | 4.0m (W) x 4.25m (H) | |
| Support | Shotcrete, Ribs, Rock bolt | |
| 12 | Surge Tunnel | |
| Size | 4.0m x 4.0m of 375.0m length in slope | |
| 13 | Penstock Tunnel | |
| Length upto Bifurcation | 1867.17 m | |
| Horizontal section before Drop Shaft 1 | 220.0 m | |
| Drop Shaft-1 | 187.0 m | |
| Inclined Section 2 | 536.0 m | |
| Drop Shaft-2 | 251.7 m | |
| Inclined Section 3 | 672.47 m | |
| Internal Diameter and length | 2.50 m for 1st 1198 m length,
2.25m for next 268 m length and 2.1m for 396 m length (last portion) |
|
| Thickness of steel penstock | 12 mm ~ 46 mm with yield strength 350 to 460 MPA | |
| 14 | Powerhouse | |
| Type | Surface | |
| Size | 49.6 m x 15.2 m x 32.96 m | |
| 15 | Tailrace | |
| Type | Free Flow, Box Culvert | |
| Length | 70 m | |
| Size (B x H) | 4.6 m x 1.9 m | |
| 16 | Turbine | |
| Type | 3 no. Vertical Axis Pelton | |
| Speed of Turbine | 750 RPM | |
| Rated Output Capacity per Unit | 3 x 30.32 MW with 10% COL | |
| Efficiency | 91% | |
| 17 | Governor | |
| Type | Digital/Hydraulic with PID Control | |
| Adjustment for Speed Drop | Between 0 to 5 % | |
| 18 | Generator | |
| Type | Synchronous 3 Phase | |
| Rated Output Capacity per Unit | 34.6 MVA | |
| Voltage | 11 kV | |
| Efficiency | 97% | |
| 19 | Transformer | |
| Type | Out Door, Oil Immersed | |
| Rated Capacity per Unit | Three Phase 35 MVA total Nos 3 | |
| Frequency | 50 Hz | |
| 20 | Transmission Line | |
| Length | 12.0 km | |
| Voltage | 132 KV | |
| Interconnection Point | NEA sub-station at Lammane, Tingla, Solukhumbu. | |
| 21 | Power and Energy Generation | |
| Mean annual energy per year | 520.20 GWh (Dry- 100.27 GWh, Wet- 419.93 GWh) | |
