Khimti I Hydropower Plant

Khimti HEP - Powerhouse
Powerhouse The underground (6500 cubic metre) powerhouse of the Khimti I Hydropower Plant in Kirne Dolakha
Khimti HEP - Powerhouse
Powerhouse The underground (6500 cubic metre) powerhouse of the Khimti I Hydropower Plant in Kirne Dolakha

Khimti I Hydropower Plant is built with private sector funding as a “BOOT” agreement (Build, Own, Operate, and Transfer) with HMGN. Construction commenced on 12 Asadh 2053 (26th June 1996) and the date of Commercial Operation is Asadh 27, 2057 (11th July 2000).

Himal Power Limited operates the plant and sells electricity to Nepal Electricity Authority (NEA). The banks and investors will be repaid during the operation. The plant will then be transferred to HMGN at the end of the 50 year license period. At the end of the first Power Purchase Agreement the NEA will purchase a 50% share in the Power Plant at Kirne for a nominal fee.

The Khimti I Hydropower Project site is located in the Janakpur Zone, Central Development Region some 100 km east of the Kathmandu. Khimti Khola forms the boundary between Ramechhap and Dolakha Districts.

The plant is a “run of the river” hydro-electric power generation plant designed for an installed generating capacity of 60,000 kilowatts and annual production of 350 million kilowatt-hours of electrical energy (350 Gwh).

The site is located in Dolakha and Ramechhap District. The power plant will utilizes a drop from 1,270 to 586 meters above sea level in Khimti River, a tributary to the Tamakoshi River about 100 kilometers to the east of Kathmandu.

Access to the site is by the existing Jiri road 175 kilometres from Kathmandu. HMGN has constructed a road (22 kilometres long) from Nayapul to the power house site at Kirne.

Construction work on the Khimti I Hydropower Project was started in early 1993 by the Butwal Power Company Limited and then gained momentum as soon as the Financial Closure occurred in June 1996. The major structures of the project include the Head-works (intake, de-silting basin), 7900 m long headrace tunnel with 4 construction audits, 1000 m long penstock tunnel, 900 m access tunnel and 1470 m long tailrace tunnel through and a 6,700 m3 underground Power house.

The civil design and construction works of the project were carried out under a contract by a consortium of NCC Tunnelling, formly Statkraft Anlegg (Norwegian company) and Himal Hydro (Nepalese company). A consortium of Alston Power, formerly ABB Kraft and Kvarner Energy along with Nepal Hydro & Electric (Pte) Limited carried out the electro-mechanical works. Similarly a consortium of Statkraft Engineering and BPC Hydroconsult had carried out the project management on behalf of HPL.

The Project holds the record for achieving the highest national tunneling productivity; it has the longest headrace tunnel and penstock in the country. It is also the first project in Nepal to implement a Total Quality Assurance Scheme during construction. Above all, it is the first major hydropower project in Nepal to be completed within the original schedule despite very difficult tunneling conditions and other problems encountered.

Salient Features 

Hydrology (Intake)
Catchment Area 358 km2 Average Precipation (Jiri) 2,212mm
Average flow at intake 31.5m3/s Minimum daily discharge 3.5m3/s
Probable maximum flood (PMF) 3,900m3/s Firm flow (90% exceedence) 4.11m3/s
Head-works (Intake)
Diversion weir crest elevation 1,272 m Diversion capacity 11.65 m3/s
Diversion height ~ 2.5 m De-sanding chambers 2 (two)
Chamber dimensions 90m x 12m x 2m
Waterways
Headrace tunnel – Length 7,885 m
Steel lined penstock – Length 1,000 m (inclined) Steel lined penstock Diameter 1.8-2.0 m
Tailrace tunnel – Length 1,433 m Access tunnel – Length 890 m
Powerhouse, Turbine, Generators etc.
Powerhouse Underground
Pelton turbines Generators
Number of Units 5 Number of units 5
Rated capacity 12.5 MW Rated capacity 14.2 MVA
Running speed 750 rpm
Maximum static head 677 m Transformers
Design head (net, full load) 660 m Number of units 3
Rated flow at design head 2.15 m2/s (2 x 28.4 MVA and 1 x 14.2 MV)
Power and energy output
Installed capacity 60 MW (net capacity after auxiliary use.)
Energy 350 GWh/yr (approx annual energy generation)

Source : Himal Power Limited Website