GUWAHATI, 12 Jun: The NHPC’s much-delayed 2,000 MW Subansiri hydro project along the Assam-Arunachal Pradesh border has suffered “minor damages” during the recent monsoon rains though the main structure remained unaffected, the company said on Thursday.
The commissioning of the Subansiri Lower Hydro Electric Project (SLHEP) has been further delayed till May 2026 from the earlier announced 2023-24 fiscal end, which was already more than 10 years late from the original completion schedule of December 2012, the NHPC said.
The project cost has also been anticipated to escalate more than four times to around Rs 26,075 crore at the time of completion next year from the initial estimate of Rs 6,285 crore in December 2002.
“No such structural damage has occurred to the dam structure which may cause safety concerns. Only minor damages to the spillway lip portion have occurred during this monsoon season,” the NHPC said in a statement.
During the monsoon season, the river flow is accompanied by silt, wooden logs and boulders, it added.
“Rolling of the boulders and wooden logs causes minor damages on the upper surface of the spillway glacis and lip portion during the passing of the river flow from the spillway gates. The functionality of the dam is not affected by such minor damage,” the company said.
After the passing of the monsoon season, the area shall be inspected, and the minor damages shall be repaired and restored as a general practice in any hydroelectric project, it added.
The company asserted that there is no risk at all to the dam structure, which is 116 metres high from the riverbed level.
The SLHEP, which faced multiple bottlenecks since its inception stage, has been delayed several times and its deadline for commissioning has been revised on many occasions.
On its official website, the NHPC said, “Date of commercial operation (COD) – project is likely to be completed in May 2026.”
It also stated that the project cost has now been anticipated to be Rs 26,075.54 crore on completion compared to Rs 6,285.33 crore as per the initial estimate in December 2002.
According to a company estimate in January 2020, the cost of the mega project, which was originally scheduled to be commissioned in December 2012, had escalated to around Rs 20,000 crore.
On completion, the Subansiri project, which is a run-of-river scheme, will generate around 7,500 million units of power annually in a “90 percent dependable year” with the help of eight Francis turbines of 250 MW capacity each.
In June 2023, commissioning of the 2,000 MW hydro project was postponed till the end of the 2023-24 fiscal with more than 90 percent of the total work of the project completed by then.
The Assam government in March 2022 had informed the state Assembly that partial commissioning of the 2,000 MW project was postponed till August 2022.
In December 2020, the company had set a target of March 2022 for commissioning the project, being constructed at Gerukamukh along the Assam-Arunachal border.
The NHPC had commenced the construction work of the Subansiri project in January 2005 after obtaining forest clearance in October 2004.
Construction work of the project was stalled from December 2011 to 14 October, 2019 due to protests by locals and many groups fearing safety and downstream impact.
To address the concerns of the agitators, multiple committees were formed by the Assam government and the Centre. The outcomes of their reports varied from one to another.
After clearing all the legal issues by the National Green Tribunal (NGT), the NHPC restarted construction of the project from 15 October, 2019. (PTI)
