When will power generation begin at the Subansiri Lower Hydroelectric Project?
Power generation at the Subansiri Lower Hydroelectric Project, a significant run-of-river dam on the Subansiri River near Gogamukh on the Assam-Arunachal Pradesh border, is set to start in March 2025. Initially, the project will produce 750 MW, with full capacity of 2000 MW expected by March 2026. Over 93% of the construction is complete, and NHPC finalized the 116-meter-high concrete gravity dam in June 2023. Work on the powerhouse and hydromechanical components is progressing steadily.
How is NHPC preparing for the start of power generation?
NHPC, the National Hydroelectric Power Corporation, plans to start power generation in March 2025 after completing the remaining radial gates post-monsoon. According to PR Consultant A.N. Mohammad, NHPC is technically prepared to generate power. They will initially use three out of eight turbines, generating 750 MW. Two turbines are installed, with a third nearing completion, which will allow for the project’s initial generation phase.
What is delaying the installation of the radial gates?
NHPC initially planned to complete the dam by December 2024, but natural challenges delayed progress. Of the five essential diversion tunnels needed, only one remains operational due to natural disasters. A landslide on October 27, 2023, blocked this last functioning tunnel, delaying the installation of three remaining radial gates that control water flow. While NHPC had installed six out of nine radial gates before the monsoon season, the remaining gates will be installed after the monsoon.
When will the Subansiri Project reach its full 2000 MW capacity?
NHPC targets March 2026 to fully commission the project, with all eight turbines generating a combined output of 2000 MW. Completion of the radial gates was delayed during the 2024 monsoon due to water flowing over the dam, an issue exacerbated by the blockage of the only operational diversion tunnel. Despite this, two large turbines were installed in the powerhouse, and NHPC plans to install a third to enable an initial 750 MW power generation by March 2025.
Why was construction at the Subansiri Dam delayed?
The Subansiri project faced extensive delays due to public opposition. The Brahmaputra Board initially proposed the dam in a 1983 report, and NHPC received central government clearances in 2004. However, strong opposition from downstream residents and Assam-based organizations halted construction in 2011. An Assam government committee raised concerns about building the dam on the fragile hills of Gerukamukh in seismic zone 5. Construction was suspended from December 2011 to October 2019 and resumed only after securing approvals from the National Green Tribunal.
What is the estimated cost of the Subansiri Lower Hydroelectric Project?
As of March 31, 2024, the Subansiri Project was 93% complete, with a cost of Rs 20,834 crore. NHPC estimates the total cost will reach Rs 22,000 crore upon full commissioning with all eight turbines. Initially, in 2002, the project’s cost was estimated at Rs 6,285 crore, but extended timelines and additional requirements have significantly raised the budget.
