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

ParticularsDetails
Installed Capacity1000 MW (4 x 250 MW)
LocationTehri Garhwal, Uttarakhand
Round Trip EfficiencyMore than 75%
Commercial Operation DateUnit-1: 07.06.2025
Unit-2: 10.07.2025
Unit-3: 12.12.2025
Unit-4: 12.04.2026
Beneficiary States/ UTsUttarakhand, Rajasthan, Delhi, Haryana and Gujarat

KEY TECHNICAL FEATURES

ParticularsDetails
Upstream ReservoirTehri Dam Reservoir
Downstream ReservoirKoteshwar Dam Reservoir
Head Water LevelMaximum: EL 830 m; Minimum: EL 740 m
Head Race Tunnels2 × 8.5 m diameter; HRT-3: 932 m, HRT-4: 1,060 m
Upstream Surge Shafts2 Nos.; 20.92 m diameter & 145 m height each
Penstocks4 Nos. × 6.0 m diameter, steel-lined; total length: 1,389 m
Downstream Surge Shafts2 Nos.× 18.44 m diameter & 69 m height each
Tail Race Tunnels2 Nos.× 9.1 m diameter; TRT-3: 1,080 m, TRT-4: 1,190 m
Tail Water LevelMaximum: EL 612.5 m;
Minimum: EL 606 m (Pumping Mode); EL 603 m (Turbine Mode)
PowerhouseUnderground, Left Bank
Generating Units4 × 250 MW
Machine TypeVariable Speed Vertical Francis-type Reversible Turbine
Turbine Net Head Range122.8 m – 220.7 m
Pump Net Head Range132.8 m – 228 m
Design Head188 m
Design Discharge per Unit109.5 cumecs – Pump Mode
146.9 cumecs – Turbine Mode
Speed230.77 rpm (Synchronous Speed)
206 rpm - 250 rpm (Variable Speed)
Switchyard420 kV Indoor SF₆ Switchgear
  1. Peaking power of 1000 MW (expected annual generation of 2442 million units)
  2. Reliable means for efficient banking of surplus power.
  3. Provides Ancillary grid services.
  4. Contribution to 100 GW of PSP capacity required by 2035-36.
S.No.DescriptionPumping (MU)Generation (MU)
1Pumping/Generation during August 2026171.70156.49
2Cumulative Pumping/Generation during FY 2026-27 (up to August 2026)769.56617.61
Last Updated on 7/9/2026