Tehri PSP is India’s first 1000 MW Variable Speed Pumped Storage Plant, designed to provide 1000 MW of peaking power, enhance grid reliability, and facilitate the integration of intermittent renewable energy sources such as solar and wind by utilizing surplus power during off-peak hours.
The project utilizes the reservoirs of Tehri Dam and Koteshwar Dam as the upper and lower reservoirs, respectively, and comprises four reversible units of 250 MW each housed in an underground machine hall on the left bank of the Bhagirathi River. A key technical feature is the substantial head variation of about 90 m between the maximum and minimum operating heads of the reversible units. Tehri PSP stands fully commissioned with its entire 1,000 MW capacity as on 12 April 2026.
GENERAL FEATURES
| Particulars | Details |
|---|
| Installed Capacity | 1000 MW (4 x 250 MW) |
| Location | Tehri Garhwal, Uttarakhand |
| Round Trip Efficiency | More than 75% |
| Commercial Operation Date | Unit-1: 07.06.2025
Unit-2: 10.07.2025
Unit-3: 12.12.2025
Unit-4: 12.04.2026 |
| Beneficiary States/ UTs | Uttarakhand, Rajasthan, Delhi, Haryana and Gujarat |
KEY TECHNICAL FEATURES
| Particulars | Details |
|---|
| Upstream Reservoir | Tehri Dam Reservoir |
| Downstream Reservoir | Koteshwar Dam Reservoir |
| Head Water Level | Maximum: EL 830 m; Minimum: EL 740 m |
| Head Race Tunnels | 2 × 8.5 m diameter; HRT-3: 932 m, HRT-4: 1,060 m |
| Upstream Surge Shafts | 2 Nos.; 20.92 m diameter & 145 m height each |
| Penstocks | 4 Nos. × 6.0 m diameter, steel-lined; total length: 1,389 m |
| Downstream Surge Shafts | 2 Nos.× 18.44 m diameter & 69 m height each |
| Tail Race Tunnels | 2 Nos.× 9.1 m diameter; TRT-3: 1,080 m, TRT-4: 1,190 m |
| Tail Water Level | Maximum: EL 612.5 m;
Minimum: EL 606 m (Pumping Mode); EL 603 m (Turbine Mode) |
| Powerhouse | Underground, Left Bank |
| Generating Units | 4 × 250 MW |
| Machine Type | Variable Speed Vertical Francis-type Reversible Turbine |
| Turbine Net Head Range | 122.8 m – 220.7 m |
| Pump Net Head Range | 132.8 m – 228 m |
| Design Head | 188 m |
| Design Discharge per Unit | 109.5 cumecs – Pump Mode
146.9 cumecs – Turbine Mode |
| Speed | 230.77 rpm (Synchronous Speed)
206 rpm - 250 rpm (Variable Speed) |
| Switchyard | 420 kV Indoor SF₆ Switchgear |
- Peaking power of 1000 MW (expected annual generation of 2442 million units)
- Reliable means for efficient banking of surplus power.
- Provides Ancillary grid services.
- Contribution to 100 GW of PSP capacity required by 2035-36.
| S.No. | Description | Pumping (MU) | Generation (MU) |
|---|
| 1 | Pumping/Generation during July 2026 | 184.95 | 144.32 |
| 2 | Cumulative Pumping/Generation during FY 2026-27 (up to July 2026) | 597.87 | 462.72 |
Last Updated on 24/8/2026
