Tangedco invites consultants for Sillahalla dam bid preparation

CHENNAI: In a step toward the construction of the Sillahalla pumped storage project, Tamil Nadu Generation and Distribution Corporation (Tangedco) has invited bids for consultancy services towards the preparation of the Engineering Procurement Construction contract bid documents for civil, hydro-mechanical and electro-mechanical works and funding modality for the stage-I (4X250 MW) of the project.

The Rs 7,000 crore Sillahalla project would be implemented in two phases. The consultant to prepare bid documents for stage-I of the project envisages the construction of an upper reservoir across the Sillahalla River with a capacity of one thousand million cubic feet and a lower reservoir with 400 million cubic feet.

“Sillahalla Pumped Storage project utilises the water of Sillahalla River, a perennial stream, a tributary to River Kundah and in turn to River Bhavani, which remains unutilised to date. Tangedco contemplates utilising the water by constructing an upper dam across the Sillahalla stream and a lower dam across the Kundah River downstream of the existing Kundah Palam Dam. Both the dams are interconnected by the tunnel to the proposed Sillahalla Pumped Storage Project (PSP) area in The Nilgiris,” a Tangedco official said.

The detailed project report for the stage-I was done by consultant WAPCOS Ltd. The estimated cost of the stage-I project would be Rs 4,950 crore.

The official said that the consultant to be appointed for preparing bid documents would cover the construction of the upper and lower reservoirs, tunnels, caverns and civil works. It would also cover the hydro-mechanical and electro-mechanical works and connected civil works.

The Sillahalla dam would act as a balancing reservoir between the Avalanche-Emerald dam and the downstream Pillur dam. It is called so because water from Pillur will be pumped up to the proposed Sillahalla reservoir when the power demand is less normally during the night. Surplus power generated by various sources, particularly wind power would be used to pump water to the upper reservoir from the lower reservoir. The water stored in the upper reservoir will be used to generate energy to meet the morning and evening peak power demand. It provides flexibility to the state grid for operation. The Sillahalla project will come in handy to harness the full potential of wind power which otherwise goes untapped during the peak wind season.