Tehri Pumped Storage Project

Global

experience

leads

to

first-of-its-kind

solutions

The Tehri Dam is a rock and earth-fill embankment dam on the Bhagirathi River near Tehri in Uttarakhand, India. At a depth of around 800 ft, it is the highest dam in India, distributing 270 million gallons of drinking water per day, irrigating thousands of acres of farmland and generating electricity to Uttar Pradesh, Delhi and other areas.

The 1,000MW Tehri Pumped Storage Plant (PSP) is part of the 2,400MW Tehri Hydro Power Complex and is being developed by THDC India, a joint venture of the Indian Government and the State Government of Uttar Pradesh. Made up of four reversible pump turbine units of 250MW each on the left bank of the Bhagirathi River, its operation is based on the concept of recycling water discharged between upper and lower reservoirs.

SMEC has been working on the project since 2013, addressing design issues encountered by another consultant and proposing alternate and ultimately successful first-of-their-kind designs.

Year

2013-ongoing

Location

Uttarakhand, India

Client

HCC Ltd, THDC Ltd

Rather than adapt during construction, our use of 3D modelling enables us to anticipate issues and devise solutions in response… The project had faced challenges with safety issues previously, so our ability to foresee problems and prevent potential incidents has been highly valued.”

———— Neeta Arora, Director Design Centre

1000

project with all components underground

830

upstream reservoir level

615

downstream reservoir level

Geological challenges lead to a first-of-its-kind design

All the components of the Tehri Pumped Storage project are located underground, essentially inside one hill within the vicinity of the existing 1000 MW Tehri Hydro Power Project.

The upstream and downstream surge shaft chambers were proposed to be 20-25m wide. As can happen with such projects, as geological information became available, it was apparent that the geological environment was too poor to construct chambers this wide.

Through extensive 3D analysis, including modelling rock bolting to replicate actual underground conditions, we re-planned the chambers and a width of 15m was determined as the best solution. However, the hydraulic conditions made it impossible to reduce the surge shaft diameter.

With a team of global experts in hydropower, tunnelling, and dams on the project, we designed a surge shaft chamber with the surge shaft slanting inward, in inverted form. “This is the first time such a solution has been adopted in India, and potentially worldwide,” says Prashant Agrawal, General Manager, Hydropower and Dams “It was made a reality through the vast experience of the global specialist team.”