Overview:
Commissioned in 2017, the Sainj HEP is a 100 MW run-of-the-river project developed by Himachal Pradesh Power Corporation Limited (HPPCL). It harnesses the flow of the Sainj River, a tributary of the Beas, using minimal surface disruption. With its underground powerhouse and carefully engineered tunnels, the project balances energy generation with environmental stewardship in one of Himachal’s most biodiverse valleys.
📍 Location & Key Details
| Attribute | Details |
|---|---|
| Coordinates | 31.783°N, 77.3352°E |
| District | Kullu |
| River | Sainj (tributary of Beas) |
| Installed Capacity | 100 MW (2 × 50 MW Pelton turbines) |
| Commissioned | 2017 |
| Operator | HPPCL |
| Project Type | Run-of-the-river |
| Powerhouse Type | Underground (near Suind village) |
🏗️ Engineering Highlights
- Diversion Barrage:
Located near Niharni village, it diverts up to 35.88 cumecs of water into the system. - De-silting Chambers:
Two underground chambers (145 m × 15 m × 7 m) remove silt particles down to 0.2 mm, protecting the turbines from abrasive Himalayan sediment. - Headrace Tunnel:
A 6.3 km-long, 3.76 m diameter modified horseshoe tunnel carries water to the surge shaft. - Surge Shaft & Pressure Shaft:
- Surge Shaft: 87 m high, 9 m diameter
- Pressure Shaft: 550 m long, 2.75 m diameter steel-lined pipe bifurcating to feed two vertical-axis Pelton turbines.
- Annual Generation:
Estimated at 322.23 million units (MU) in a 90% dependable year.
🌄 Environmental & Cultural Context
- Eco-sensitive Zone:
Located near the Great Himalayan National Park, a UNESCO World Heritage Site. The project was designed to minimize ecological disruption. - Community Impact:
Limited displacement due to underground design. HPPCL has supported local infrastructure and education initiatives. - Recent Challenges:
In June 2025, the project was temporarily shut down due to high silt levels following a cloudburst in the Sainj Valley.
🧭 Accessibility
- Nearest Towns:
- Larji (junction point for Sainj and Tirthan valleys)
- Banjar and Aut (on NH-3)
- By Road:
From Mandi or Kullu, take NH-3 to Aut, then branch into Sainj Valley Road toward Niharni and Suind. - By Train:
Nearest railhead: Joginder Nagar (narrow gauge) or Chandigarh (broad gauge) - By Air:
Bhuntar Airport (Kullu) – ~50 km from the project site
