Tehri Pumped Storage Project, Uttarakhand, India
The Tehri pumped storage project (PSP) is located on the Bhagirathi River, a tributary of the Ganges River, in Uttarakhand, India. It is one of the tallest dams in the world, with a height of 260.5 meters. The Tehri PSP, will provide peaking power to the northern grid of India, improving grid stability by balancing the supply and demand of electricity (during periods of peak demand).

Tehri PSP will add an additional 1,000 megawatts of power to the facility, bringing the total capacity to 2,400 megawatts. In a pumped storage project, water is pumped from a lower reservoir to a higher reservoir during periods of low energy demand, and then released back to the lower reservoir through pump turbines during periods of high energy demand to generate electricity.


The project is being developed by the Tehri Hydro Development Corporation (THDC), which is a joint venture between the Government of India and the Government of Uttar Pradesh. It is currently in an advanced stage of construction, scheduled to commence operations in couple of months.


SMEC undertook extensive design review, which required the development of an alternative design to mitigate challenging geological conditions. Oversized surge shaft chambers needed to be remodelled and reduced from 25m to 15m width to ensure the safe excavation conditions. A key innovation was to design a reverse flaring in Surge Shaft on top (a first of a kind solution in hydro projects). The solution was devised through extensive 3D analysis, including modelling rock bolting to replicate actual underground conditions.


The surge shaft protects the water conductor system from the damaging effects of water hammer by temporarily storing the excess water that surges back up the penstock after the turbine is shut down. The shaft acts as a buffer, allowing the water to slowly dissipate the energy and pressure.

One of the main challenges for the project was the need to manage the big cavern excavations through unstable geological conditions. This required the use of advanced geotechnical and rock mechanical analysis through sophisticated software, to ensure that the excavations are carried out accurately and safely. Extensive 3-D analysis of the underground caverns has ensured the safety of workers during construction, with round by round rock support and rock bolting modelled in the analysis to reproduce the envisaged ground conditions.
———— Prashant Agarwal, Head-Renewables

The Impact

Once complete, Tehri PSP will be one of the largest pumped storage projects in the world.

During the detailed design, SMEC undertook redesign of two large outlet structures, converting them into four smaller structures to control velocity and provide more equitable distribution of flow. Extensive 3-D analysis of the underground caverns has ensured the safety of workers during construction, with rock bolting modelled in the analysis to replicate ground conditions.

The project is designed to generate 1,000 megawatts of electricity, which will help to meet the growing demand for power in the region. The project will also help to improve the reliability and stability of the power grid, reducing the risk of power outages and blackouts. The project aids management of water resources in the area, which will help to ensure that water is used efficiently and sustainably.

Overall, the Tehri Pump Storage Project is expected to have several positive impacts, including the generation of electricity, improved water management, employment opportunities, economic development, and flood control.

additional power generation
enough power for 1 million homes
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 Renewables-SACA



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