Mai Small Cascade Hydropower Project (8MW)

1. Project Background

The project lies in Ilam district of Mechi zone in Eastern Development Region of Nepal. The entire project components are located along the left bank of Mai Khola within Godak Village Development Committee. The intake site is at the left bank of the Mai Khola, approximately 1.6 km upstream of the Mai Khola Bridge. The location of the powerhouse is at approximately 700m downstream of the Mai bridge. The latitudes and longitudes of the project area vary from 870 54’ 43” – 870 56’ 11” to Northing; 260 51’ 39” – 260 52’ 36”.

 

Project area

Fig 1: Project Location of Mai Khola Hydropower.

 

2.Project Silent Features

 

Particulars Project features
Type of Project Run-off-the-River
Village Development Committee Godak, Chisapani, and Soyak VDCs and Ilam Municipality
District Ilam
Zone Mechi
Development Region Eastern Development Region
Flow diversion MKSHP and Puwa Khola tailrace outlet
Powerhouse Area Bathane phat, Chisapani VDC
River Mai Khola & Puwa Khola
Project Boundary (Survey License) Easting; 870 54’ 43” – 870 56’ 11”

Northing; 260 51’ 39” – 260 52’ 36”

Project Boundary (Newly Proposed) Easting; 870 54’ 43” – 870 56’ 11”

Northing; 260 50’ 50” – 260 52’ 36”

Hydrology
Flow availability MKSHP and Puwa Khola HEP tailrace, the catchment therefore related to those projects ‘intake
Design Discharge 14.46 m3/s (12 m3/s and 2.46 m3/s for MKSHP and Puwa Khola HEP
Probability of exceedance of Design Flow ~50 %
Compensation Flow MKSHP release as 0.444 m3/s
Flood (Not relevant to design headworks)
1 in 100 Years Design Flood at Weir 1765 m3/s
1 in 200 Years Design Flood at Weir 2065 m3/s
1 in 5 years Dry Season Flood at Weir 72 m3/s
1 in 100 years Flood at Powerhouse 1794 m3/s
Access Road
Access road to powerhouse area Up gradation ~5-9 km along Ilam-Sanischare grave road than construct about 1.3Km new road to reach powerhouse.
Invert level of existing Mai tailrace canal end 435.18m
 
Headrace Canal/Syphon
Canal Type Covered concrete Canal
Slope 1: 1000
Location of headrace pipe inlet pond ~ 2565 m from MKSHP tailrace, near Karphok Khola

 

Size of Canal  3.0mx 1.45m + 3.2mx 0.85m
Syphon 100m long, 1.5 m diameter steel pipe (to be crossed Mai River)
Headrace pipe inlet pond 5m x5m x 7m with flushing arrangement
Headrace Pipe
Length 450 m
Dia/thickness of pipe 3200mm/ 5mm
Nos of anchor block 9
Nos of saddle support 90
Headrace Canal after headrace pipe up to forbay
Canal Type Covered concrete Canal
Length ~ 1210 m

 

Slope 1:1000 up to forbay
Size of Canal (3.0m x 1.45m + 3.2mx 0.85m)
Forebay/spillway
Capacity 320m3
Effective Size 15 m (L) X 8 m (W) X 5.0 m (H)
Spillway 10 m long, operating head of 350 mm
Penstock
Material Steel
Diameter 2700mm (uniform diameter)
Length 143 m
Thickness 8, 10, ,12 mm
Powerhouse
Type Surface
Dimension 36 m (L) x 11 m (W) x 15 m (H)
Turbine Axis Level EL. 368.15 m
Floor Level EL. 367.10  m
Minimum tail water level EL. 365.45  m
Tailrace
Type Steel Pipe
Length 350 m
Slope 1:200
Size 3200 mm Dia
Thickness 8 mm.
Turbines
Type of Turbine Francis
No. of Units 2
Rated Net Head 65.9 – 69.00 m
Unit Discharge 7.23 m3/s
Speed 1000 rpm
Switchyard
Size 10 m x 15 m
Transmission Line:
Voltage 33 kV
Length ~ 3.5 km
Connection
Power and Energy Generation
Gross Head 71.45 m
Net Head 65.9 – 69.00 m
Installed Capacity 8000  KW
Annual Net Energy 48.97 GWh
Dry Season Energy 9.77 GWh
Wet Season Energy 39.20 GWh
Cost Estimate
Total Cost 1185.15 Million NRs.

 

3.Present Status of the project:Under Final Stage of Operation

– Survey licence issued for 8 MW on date 2070/4/30.

– PPA agreement with NEA on Falgun 2069

– Connection Agreement with NEA on Dec 2012.

– Date of COD on NEA 2074/12/26.

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