NHPC, India’s principal hydropower company, has awarded a civil works contract to Gammon Engineers and Contractors, one of India’s leading civil engineering and construction groups, for the 500 MW Teesta VI hydro project on the river Teesta, in the northeastern state of Sikkim.
The contract, which is valued at INR 12.48 billion (about US$ 165.64 million), was awarded on 15 March for the balance of civil works by NHPC’s subsidiary, Lanco Teesta Hydro Power. The contract includes works for the underground powerhouse and transformer cavern, part of the two headrace tunnels, surge shafts, pressure shafts and adits, the tailrace tunnel and other associated structures.
The award of the contract follows the finalization of the takeover of Lanco Teesta Hydro Power, the project’s former private developer, by NHPC in October 2019 (see H&D Issue 6, 2019). The project will be completed in five years at an estimated project cost of INR 57.48 billion (about US$ 763 million) based on July 2018 prices), which includes INR 8.975 billion for the project’s acquisition.
The run-of-river project in Sirwani village, southern Sikkim, will include: a 34.5 m-high dam with four spillways and radial gates; four independent straight intake structures; four desilting chambers; two headrace tunnels; two underground restricted orifice-type surge shafts; two steel-lined pressure shafts; an underground powerhouse cavern housing four vertical Francis turbines, each with a capacity of 125 MW; and, two tailrace tunnels to discharge the water back into the river Teesta. The plant is expected to generate average annual output of 2400 GWh. Twelve per cent of the power produced is to go to Sikkim as a royalty, with the remainder being sold on the market.
AF Consult (now AFRY) has assisted NHPC in reviewing detailed project reports, system optimization, tender design and drawings for civil works, and basic design and engineering for the electro-mechanical and hydro-mechanical works. The company also prepared tender documents and will evaluate the bids.