Exclusive: At least three hydropower projects of 2,210 MW affected in Sikkim flash floods

Sikkim Flash Floods LIVE: 14 people dead, 102 missing and 26 injured in the flash floods in Sikkim

At least three hydropower projects totalling 2,210 MW have been damaged in the Sikkim flash floods, the death toll of which has now risen to 14, while more than 100 people are missing.

The worst affected of the three is the 1,200 MW Teesta Stage-III hydro power plant which was the biggest operational hydropower station in Sikkim. It is operated by Sikkim Urja Limited of the state government. Visuals of the dam before and after the calamity showed a large section of the dam's wall is now missing, which officials confirmed was washed away in minutes. Along with it, a 200-metre bridge connecting the dam with the power station has also been washed away.

NHPC Ltd, India's largest hydropower public sector undertaking (PSU), has shut its 510 MW Teesta-V hydel plant due to the flash floods in Sikkim. While the PSU did not mention the extent of damages to the hydel station, senior officials told Moneycontrol it is likely to be "substantial."

Also Read | Sikkim flash floods: 10 dead, 22 army men among 82 missing, several injured

The third project - Teesta-VI hydroelectric project (500 MW) in Sikkim - was not operational, but is under construction. This project was executed by Lanco Teesta Hydro Power Limited, a wholly-owned subsidiary of NHPC Ltd.

"This is to inform you that considering the emergent situation, all units of Teesta-V Power Station have been shut down. Detailed assessment of losses/damages suffered will be carried out after the water level recedes. The assets and loss of profit of the power station are fully insured under the Mega Insurance policy. All assets/ works of the Teesta-VI hydroelectric project are also insured under a construction all-risk policy," NHPC Ltd said in a BSE filing on October 5.

A senior NHPC official said roads leading to the Teesta-V and Teesta VI hydropower plants have also been damaged. "The extent of damages is currently being assessed. But, preliminary assessment suggests the damages could be substantial," said the official requesting anonymity.

A cloudburst over Lhonak Lake in North Sikkim resulted in a flash flood in the Teesta River basin on October 4. At least 102 people are still missing, including 22 army personnel, as per the Sikkim government.

In its first statement issued late at night on October 4, NHPC Ltd said the sudden increase in the inflow of water due to a cloudburst in the Lhonak Lake, which is 90 kilometres upstream from Teesta-V dam, resulted in the water level rising by 19 metres above the normal level.

"The water overflowed from the top of the dam. Hence, power generation from Teesta-V power station has been stopped," NHPC said in a statement.

Lhonak Lake is a glacial-moraine-dammed lake, located in Sikkim's far north-western region. It is one of the fastest expanding lakes in the Sikkim Himalaya region and one of the 14 potentially dangerous lakes susceptible to Glacial lake outburst floods (GLOFs).

Officials at NHPC Ltd told Moneycontrol that as of 10:30 AM on October 5, other hydropower projects in the area such as Rangit (60 MW) in Sikkim, and Teesta low dam-III (132 MW) and Teesta low dam-IV (160 MW) which fall in West Bengal are operational.