Name and Location
Upper Trishuli-1 (UT-1) hydropower project, Nepal.
Client
Nepal Water And Energy Development Company (NWEDC).
Project Description
The project is expected to be the first large domestic independent power producer.
It involves the development, construction and operation of a 216 MW run-of-river hydropower plant on the Trishuli river, in Nepal, with the generation potential estimated at 1 501.4 GWh/y.
It will be larger than any of the operating hydropower plants in Nepal and will sell power under a long-term power purchase agreement with national utility company Nepal Electricity Authority for domestic consumption.
The intake is about 250 m downstream of the confluence of the Goshainkunda Trishuli and Bhotekoshi rivers, near Dhunche, the headquarters of Rasuwa district, while the underground powerhouse is located about 500 m upstream of the Mailung river confluence with the Trishuli river.
The design discharge of this project is 76 m3/s of water and the gross head is 340.89 m to 342.86 m.
The catchment area at intake is 4 350.88 km2 and the operation water level is 1 255 m.
The diversion weir has three radial gates 11 m wide and 16.5 m high. Each weir is also equipped with a submerged roller bucket spillway and intake, with two roller gates 5.5 m wide and 8 m high.
The water intake is conveyed to the underground desander through a 297-m-long, 6.5-m-diameter circular intake tunnel.
Three parallel desanders – 10 m wide, 24.13 m high and 115 m long, each with two bays – will settle and remove sediment in the water.
A 9 716-m-long, 6.5-m-diameter circular headrace tunnel will convey the water from the desanders to the 292.12-m-deep vertical shaft.
The shaft will be connected to a 40-m-long horizontal pressure tunnel, which will follow the 110.70-m-long penstock tunnel to reach the underground powerhouse.
The powerhouse cavern will be 83 long, 18.7 wide and 43.9 m high. Three 27.95-m-long draft tube tunnels will each connect the powerhouse with the 9-m-wide draft tube gate shaft.
The 238-m-long, 6.5-m-diameter circular tailrace tunnel will discharge the water back into the Trishuli river. The electricity generated will be evacuated to the Upper Trishuli-3B hub through a 10-km-long, 220 kV transmission line connecting the national grid.
Value
Not stated.
Duration
UT-1 will be built under a 35-year build, own, operate and transfer (including construction period) concession agreement with the Nepal government.
Latest Developments
The project’s engineering procurement construction contractors are Daelim Corporation (60%) and Kyeryong Construction (40%), through a single wrapped contract provided by Daelim Corporation; Kosep (operations and maintenance contractor); and Korea South East Power and Jade Consult (owner’s engineer).
Key Contracts and Suppliers
None stated.
On Budget and on Time?
Not stated.
Contact Details for Project Information
NWEDC, tel +977 1 4412229, fax + 977 1 4422775 or email admin@nwedc.com.np.
Daelim, tel +86 21 6237 0099, fax +86 21 6237 0019 or email cmkim@daelimcorp.co.kr.
Kyeryong Construction, tel +82 70 4470 7435 or fax +82 42 486 6829.
Jade Consult, tel +977 01 424 7237, fax +977 01 423 2171 or email info@jadeconsult.com.np.