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Likhu 2 Hydroelectric Project

Completed: April 2023

Likhu 2 is a run-of-river scheme that diverts 26.4 m3 of water through a 5.25 m high diversion weir and further through a 6.57 km underground water conductor system to the powerhouse. Here, utilizing a net head of approximately 229.53 meters, we are able to generate up to 60.5 MW (with overloading).

Project Description

Description Symbol SI Unit
Design Discharge Qd 26.4 m3 /sec
Gross Head 247.25 m
Net Head Hn 229.53 Meters
No. & Type of Units 2*22 MW + 1*11 MW 3 Horizontal Francis
Turbine Efficiency at QD ŋT 95 %
Generator Efficiency ŋG 97.5 %
Transformer Efficiency ŋTr 99 %
Result
Gross Power PG 55 MW
Annual Energy EA 242.37 GWh

Key Technical and Financial Feature

General
Total Project Cost NPR 1076.35 cr (US$ 81.54 M)
Unit Cost of Generation NPR 19.56 cr (US$ 1.44M) / MW
EIRR 12.15 %
Period of Construction 48 Months
Project Layout Right Bank of Likhu
Catchment Area 346 km2
Head Race Tunnel
Type Low Pressure Tunnel
Section Type Inverted D
Finished Diameter 3.4 / 4.2 m
Support Type Shotcrete / Concrete Lined
Ungated Weir
Weir Height 5.25 m
Length of the Weir crest 44.4 m
Design Flood (1 in 100 Yr) 479 m3 / sec
Power House
Type Surface
Size (L * W* H) 44 x 20.25 x 35 m
Tail race 299.14 x 5.5 x 3 m
Transmission Line 132 kV, Double circuit; 5.5 km with Li 1 & Li 2 sharing the cost.
Connecting Sub- Station Likhu A Switchyard

Salient Features

General
Period of Construction Months
Project Layout Right Bank of Likhu
Catchment Area 346 km2
Weir location Marbu
Powerhouse location Thado Khola
Head Race Tunnel
Type Low Pressure Tunnel
Section Type Inverted D
Length 6465 m
Finished Diameter 3.4 / 4.2 m
Support Type Shotcrete / Concrete Lined
Surge Shaft U/G, restricted orifice
Internal Diameter / Height 2.5×86/4.5×47 m/4.9×47.5 m
Leading to an Underground PPV
Intake
Type Side Intake
No. of Chambers / Size 3 No. / 3.25 * 3.2 m
Crest Elevation of Intake 1724.75 m
Feeder Channel is Open
Length of Feeder Channel 24.95 m
Desilting Basin
Type Open, Surface
No. of Bays 2 (Two)
Length 75 m
Total Width / Depth 16.5 m / 7.25 m
Transmission Line
Voltage 132 kV
Length 5.5 km
Conductor Type ASCR BISON
Ungated Weir
Weir Height 5.25 m
Length of the Weir crest 27.0 m
Foundation Level U/S 1719 masl
Minimum reservoir level 1723.5 masl
Silt Pressure is Upto 1720.6 masl
Weir Top Level [Design Flood] 1724.75 m
Tail water level (Min.) 1722.28 m
Design Flood (1 in 100 Yr) 479 m3 / sec
Pressure Shaft
Type U/G Inclined & Horiz.
Total Length 514.5 m
Diameter 2.5 m (steel lined)
3.5 m (excavated)
Bifurcation Length 12.5, 15.6, 15.5 m
Bifurcation Diameter 1.5, 1.5 & 1.1 m
Power House & Tail Race
Type Surface
Size (L * W* H) 44 x 20.25 x 35 m
Capacity 55 MW (Original Capacity)
Tail race of 299.14 m long Box Culvert
Tail Water Level 1477.26 m
Transmission Line 132 kV, Double circuit; 30.4 km with Li 1 & Li A sharing the cost
Connecting Sub-Station New Khimti
Electro-Mechanical
Turbine Horizontal Axis Francis
Number 3
Rated output capacity per unit 2 x 22 MW + 1 x 11 MW
Efficiency 95 %
Power Factor 0.85
Generator Efficiency 97.5%