Funding Agency: Asian Development Bank (ADB)
Client: Tanahu Hydropower Project
Date: May 2019 – December 2023
Lower Seti (Tanahu) Hydropower Project lies in Tanahu district of the Western Development Region of Nepal between longitudes of 84017’30” E and 84028’42” E and between 27047’30” N to 27055’00” N. The project lies in the Seti River of the Middle Hilly Region, which constitutes a broad complex of hills and valleys. The dam site is located about 19 km upstream of the confluence of Seti and Trishuli Rivers, while the powerhouse site is located towards the downstream end of Amdadabesi village on the right bank of the Seti River, approximately 2 km downstream from the confluence of Seti and Trishuli Rivers. The elevation of the intake site is about 255 m above the mean sea level (amsl), and that of the powerhouse site is about 200m amsl.
In accordance with the preliminary study, the proposed project with the installed capacity of 126 MW will produce a net average annual energy of 441.61 GWh with a minimum 6 hours peaking even in the dry season. The Seti River has a large tributary stream, namely the Madi River, joining the Trishuli River downstream of the intake dam. The river flows almost north to south downstream of the dam site. The catchment area upstream of the proposed intake point is approximately 2849 km2.
The major civil components of the project are as follows:
Headworks consists of a gated dam and a side intake on the right bank of the River. The crest length of the dam is 200m with four radial gates to pass the design maximum flood (1 in 10,000) of 7779 m3/s. The height of the dam, including foundation, is 45 m. There will be two numbers of intakes of size 8m *12m each.
The electromechanical equipment consists of two turbine units of Francis Turbines (Rated Power of 53,300 kW each), each coupled with a synchronous generator (Rated Power of 61.2 MVA). The governor is an Electronics PID type with speed droop adjustment between 0 and 5%. The generation voltage of 11 kV will be stepped up to 200 kV by two nos. of transformers of rated capacity 62 MVA each. The revised rated efficiencies for selected turbines, generators, and transformers are 93%, 97.5% and 99.5%, respectively.
The energy generated from the project will be injected into the Damauli- Bharatpur Transmission line to be constructed by Tanahu Hydropower Limited with the switching arrangements.
Overall Services provided:
The overall objectives of consulting services are to carry out the Detailed Engineering Design and preparation of Bidding Documents of the project, The scopes shall comprise, but not limited to, the following tasks:
