KATHMANDU: The West Seti Hydropower Project is a major storage-type hydropower initiative with an installed capacity of 750 megawatts, ranking it among Nepal’s largest planned power plants. Situated in the Sudurpaschim Province of Nepal, the project covers the districts of Doti, Dadeldhura, Bajhang, and Baitadi, with the dam constructed on the Seti River, a key tributary of the Karnali River system.
Unlike typical run-of-river projects that generate power only based on river flow, West Seti is designed as a storage hydropower project with a large reservoir. This allows water to be accumulated during the monsoon wet season and enables steady electricity generation throughout the year, including the dry months from December to May. This feature enhances the reliability and stability of Nepal’s national power grid.
Core infrastructure includes:
- A 195-meter-high concrete-faced rockfill dam.
- A reservoir approximately 25 kilometers long, inundating parts of the river valley and surrounding forests.
Project Summary
- Capacity:
- West Seti: 750 MW
- Seti River 6 (SR6): 450 MW
- Combined capacity: 1,200 MW
- Type: Hydroelectric storage project with a joint reservoir.
- Location: Seti River basin, Sudurpaschim Province, Nepal.
- Districts involved:
- Project sites: Bajhang, Doti, Dadeldhura, Achham
- Reservoir: Baitadi, Bajhang
- Transmission corridor: Doti, Dadeldhura, Kailali, Kanchanpur
- Elevation: 550–920 meters above sea level (Middle Mountains).
- Annual Energy Generation: Approximately 3,636 GWh.
- Project Cost: Estimated INR 80 billion (approximately USD 2.4 billion).
History and Timeline
- 1980-81: Preliminary surveys for a 37 MW run-of-river project.
- 1987: French firm Sogreah proposed 37 MW, later upgraded to 380 MW storage scheme.
- 1994: West Seti Hydro Limited, backed by Australia’s Snowy Mountain Engineering Corporation, received survey license.
- 1997: Construction license issued; Environmental Impact Assessment started and approved in 2000.
- 2008: Updated Environmental Impact Assessment aligned with Asian Development Bank standards.
- 2009: China’s CMEC agreed to invest but later withdrew due to investment environment concerns.
- 2011: Nepal government revoked WSHL license for lack of progress.
- 2012: Project awarded to China Three Gorges International Corporation; joint venture signed with Nepal Electricity Authority in 2017.
- 2018: China Three Gorges Corporation withdrew citing financial unfeasibility and resettlement costs.
- 2020: Nepal government planned internal development, scrapping Chinese deal.
- 2022: Investment Board Nepal signed Memorandum of Understanding with India’s NHPC Limited to develop West Seti and SR6.
- 2023: NHPC submitted inception report estimating project cost at INR 80 billion; Detailed Project Report due in 21 months.
Project Development and Agreements
- Ownership and Development Model: Public-Private Partnership led by Indian government company NHPC Limited.
- Power Purchase Agreement: Nepal receives 21.9 percent free electricity from West Seti; remainder exported via Power Trade Corporation India Limited.
- Survey and Licensing:
- NHPC to apply for survey license for West Seti within 45 days of Memorandum of Understanding signing.
- Survey license for SR6 within six months.
- Detailed Project Reports to be completed within two years after survey license.
- Construction timeframe: Approximately five and a half years.
- Investment: Approximately USD 2.4 billion combined for both projects.
Technical Details
- Dam and Reservoir:
- Concrete-faced rockfill dam, 195 meters high, with ungated chute spillway.
- Reservoir extends 25 kilometers along Seti River, total 28 kilometers including five tributaries (Chama Gad, Dhung Gad, Saili Gad, Nawaghar Gad, Kalanga Gad).
- Reservoir full supply level at elevation 1,284 meters.
- Land submerged approximately 2,202 hectares.
- Tunnels and Powerhouse:
- Twin diversion tunnels, 12.8 meters in diameter.
- Headrace tunnel 10 meters in diameter, 6.7 kilometers long.
- Pressure shaft 167 meters deep and pressure tunnel 365 meters long.
- Five steel-lined pressure conduits, each 3 meters in diameter, feeding turbine-generator units.
- Tailrace tunnel 620 meters long returning flow to reservoir.
- Re-regulation Weir:
- Located six kilometers downstream from tailrace.
- Area of 62 hectares.
- Regulates river flow fluctuations caused by power generation.
- Features slide gates and crest spillway.
Strategic and Economic Significance
- Classified as a project of national pride with strong government support.
- Majority of electricity is exported to India; Nepal receives nearly 22 percent free power.
- Expected to stimulate regional development in Sudurpaschim Province.
- Reinforces Nepal-India energy cooperation
- According to USAID studies, the project could generate billions in revenue between 2030 and 2045 through hydropower exports, depending on infrastructure investments and timely completion.
Access and Location
- Accessible via Mahakali National Highway 14 and Seti National Highway 15.
- Dam site is located 82 kilometers upstream of the Seti-Karnali confluence.
- Reservoir spans multiple tributaries in remote mountainous terrain.
Environmental and Social Aspects
- Comprehensive Environmental Impact Assessment, Environmental Management Plan, and Resettlement Action Plan have been prepared and approved.
- Impact assessments include effects on transmission lines and reservoir submergence.
- The project aims to balance energy generation with minimal environmental damage, following Asian Development Bank guidelines.
- Mitigation plans address displacement of families and potential effects on wildlife habitats.
The West Seti Hydropower Project stands as a flagship initiative for Nepal’s energy security and sustainable development. It is expected to create employment, reduce fossil fuel dependence, and position Nepal as a regional clean energy hub. By fostering deeper bilateral cooperation with India and contributing to carbon neutrality goals by 2050, West Seti promises transformative economic and environmental benefits for Nepal and the region.
