Lower Likhu Hydropower Project (28.1 MW)
Technical Summary
Lower Likhu Hydropower Project (LLHP) was identified by Swet Ganga Hydropower and Construction Ltd. The Project is run off the river type with it’s headwork’s located on the right bank of Likhu Khola in Sirise of Saipu VDC, Ramechhap District just upstream of the confluence of Pokali and Likhu Khola. The entire Project area (headworks to Powerhouse area) is located on the right bank of Likhu Khola in Sirise Saipu and Bijulikot VDCs of Ramechhap district, Janakpur Zone, central development region of Nepal.
The general arrangement of project comprises headworks, water conveyance pipe and tunnel of around 5 Km length. The headrace tunnel is D shaped with internal dia of 5 metre. The tunnel section crosses two Kholsi areas at Seti Khola and Poku Khola. The project layout and Longitudinal profile is shown on the figures below ( Figure 1 and 2).
The Project utilizes 118 metre of gross head and design discharge of 29.75 m3/sec , resulting the Installed capacity of 28.10 MW .The average annual energy generation according to PPA with Power Trade Department of Nepal Electricity and Authority is 166.53 GWh among which the dry season energy is 30.43 GWh and the wet season energy is 136.10 GWh .
A 27 KM long single circuit 132 kv transmission line has been proposed to evacuate the generated power from switchyard at Larkhubesi, Ramechhap to proposed NEA’s New Khimti Substation at Chubratar, Dolakha.
The required commercial operation date (RCOD) according to power purchase agreement (PPA) is 1st Dec 2021 (15th Mangsir 2078) .The company has already received Generation License for 28.1 MW, Lower Likhu Hydropower project on 2072. 12. 28 for 35 years,. The connection agreement for the project was done with Grid Operation department, NEA on 11th Chaitra, 2072.
Salient Features of the Project:
| S. N. | Description | Value |
| 1 | GENERAL | |
| Project location | Saipu and Bijulikot VDC’s of Ramechhap District and Tarkerabari of Okhaldunga District | |
| Zone | Janakpur Zone | |
| Development region | Central Development Region | |
| Nearest road-head |
Up to Sirise at Headworks Up to Ratamate at Powerhouse |
|
| Climate | Sub-tropical | |
| Average temperature | Maximum : 36.3 0C in May | |
| Minimum : 4.30C in January | ||
| 2 | GEOGRAPHICAL COORDINATES | |
| Latitude |
270 22’ 47” N to 270 25’ 50” N (Generation license) |
|
| Longitude |
860 13’ 17” E to 860 15’ 38” E (Generation license) |
|
| 3 | HYDRO-METEOROLOGY | |
| Average annual rainfall | 1796 mm | |
| Catchment area at intake | 718 km2 | |
| Annual mean flow | 47.30 m3/s | |
| Maximum mean monthly flow | 151.36 m3/s | |
| Minimum mean monthly flow | 4.34 m3/s (April) | |
| Design discharge | 29.75 m3/s | |
| 90% firm flow | 9.16 m3/s | |
| Flood discharge | 870 m3/s | |
| 4 | WEIR | |
| Type | Concrete ogee | |
| Crest elevation | 743 m amsl | |
| Length | 63 m | |
| Max Dam height (from existing ground) | 5.5 m | |
| 5 | UNDERSLUICE | |
| Type | Radial Gate Mechanism | |
| Numbers | 2 | |
| B x H (m) | 6.0 x 6.0 (each) | |
| Sill level | 736.0 m amsl | |
| 6 | INTAKE | |
| Type | Side intake | |
| No. of opening | 3 | |
| B x H | 4.5 x 2.85 (each opening) | |
| Intake sill level | 739.40 m amsl | |
| 7 | GRAVEL TRAP | |
| Type | Surface | |
| L x B x H (m) | 8.0 x 4.5 x 6.0 | |
| 8 | SETTLING BASIN | |
| Type | Surface | |
| Numbers | 3 | |
| L x B x H (m) | 110 x 12.5 x 8.0 (each basin) | |
| Length of inlet transition (m) | 22 | |
| Particle size to be settled (mm) | 0.2 | |
| Normal water level | 742.1 m amsl | |
| 9 | HEADRCE PIPE | |
| Diameter | 3.75 | |
| Thickness (mm) | 12 | |
| Length (m) | 280 | |
| 10 | HEADRACE TUNNEL | |
| Type | Inverted U-shape | |
| Length (m) | 4960 (alternative 1, option A) | |
| Diameter (m) | 5.0 | |
| 11 | SURGE TANK | |
| Height (m) | 41 (from invert) | |
| Diameter (m) | 12.0 | |
| 12 | PENSTOCK | |
| Material | Mild Steel | |
| Vertical and horizontal shaft Length | 0 (surface) | |
| Exposed pipe length | 231 | |
| Diameter | 3.75 / 2.65 | |
| Thickness | 12 – 28 | |
| 13 | POWERHOUSE | |
| Type | Semi-surface | |
| Location | Bijulikot VDC | |
| Length x Width x Height | 27.3 x 22.0 x 24.47 | |
| Turbine setting level | 623.36 m amsl (center line) | |
| 14 | TAILRACE | |
| Type | Open channel | |
| Length | 145 | |
| Height | 3.5 | |
| Width | 5.0 | |
| Normal Water Level | 625 | |
| 15 | TURBINE | |
| Type | Francis, vertical axis | |
| Numbers | 2 | |
| Rated output capacity per unit | 14.1 MW | |
| Efficiency | 91 | |
| 16 | GOVERNOR | |
| Type | Electronic PID control | |
| Adjustment for speed drop | Between 0 to 5% | |
| 17 | GENERATOR | |
| Type | Synchronous, 3 phase | |
| No of units | 2 | |
| Power factor | 0.85 | |
| Voltage | 11 kV | |
| Frequency | 50 Hz | |
| Excitation system | Brushless | |
| Efficiency | Minimum 96 | |
| 18 | TRANSFORMER | |
| Type | Oil immersed, ONAN type | |
| No of units | 2 | |
| Rated output capacity per unit | 18 MVA | |
| Voltage ratio | 132/11 kV | |
| Efficiency | 99 % | |
| 19 | SWITCHYARD AND TRANSMISSION LINE | |
| Switchyard type | Outdoor, conventional | |
|
Transmission line length (New Khimti Substation) |
27 km | |
| Voltage level and circuit | 132 and single circuit | |
| Conductor | ACSR “WPLF” | |
| 20 | POWER AND ENERGY | |
| Head-water level | 743 m amsl | |
| Tail-water level | 625.00 m amsl | |
| Gross head | 118.0 m | |
| Net head at design flow | Approx. 111 m | |
| Net head at lowest flow | Approx 115 m | |
| Installed capacity | 28.1 MW | |
| Dry energy | 30.43 GWh | |
| Wet energy | 136.10 GWh | |
| Average annual gross energy | 166.53 Wh | |
| 166.54 |
No comment