Solu Khola (Dudhkoshi) Hydroelectric Project – 86MW

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.

Salient Features:


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)


Project Progress and Present Status:

  • Survey License obtained.
  • Feasibility study completed.
  • Connection agreement signed with NEA.
  • Generation License obtained.
  • PPA signed with NEA.
  • Syndicated Credit Facilities signed with NIBL as lead bank along with 10 other banks and investment company as consortium members.
  • Transmission Line Survey License obtained.
  • Detailed Engineering Design being carried out by Hydro Consult Engineering Ltd.
  • Physical Model Tests carried out in Hydro Lab.
  • IEE for Transmission Line Approved.
  • Camp construction completed on headworks and powerhouse.
  • 2 Bailey bridges installed at project area.
  • Access road to headworks and powerhouse completed.
  • Civil construction work completed.
  • Hydromechanical work completed.
  • Electro-Mechanical work completed.
  • Transmission Line work completed.
  • COD, March 2023

 Strengths of the project:

  • Smaller intake and waterway structures.
  • Shorter tunnel length.
  • Higher percentage of dry energy compared to other projects in Nepal.
  • Connection agreement signed for a nearby substation (<14 km)
  • Minimum length of access road to be constructed (<15 km)
  • Minimum socio-environmental impacts
  • Satisfactory social support to the Project.
  • Dedicated Transmission line in Double Circuit 132 KV transmission line to Lammane Substation.
  • All expenses will be borne by NEA for construction of Substation.
  • Stable rock and good land area for penstock alignment.
  • Hydrology is very reliable and is justified with various hydrological data.
  • High head with low design discharge.
  • Flow of semi snowed river- dry season discharge is maintained


Project Gallery

  • Roadway
    1. Kathmandu to Banepa - 27.2 Km, Araniko Highway
    2. Banepa to Khurkot – 115.3 Km BP Highway
    3. Khurkot to Ghurmi – 65.5 Km Madhya Pahadi Highway
    4. Ghurmi to Okhaldhunga –41.7 km Harkapur Okhaldhunga Road
    5. Okhaldhunga to Ramitey-31 Km, Black Topped Road.
    6. Ramite to Intake- 7.3 Km, Track Road
    7. Intake to Powerhouse- 20.71 km, gravelled road

    Tribhuvan International Airport to Phaplu Airport, 30 minutes
    Phaplu Airport to Headwork via roadways, 18 Km, 30 minutes