Nathpa closure leads to a loss of over Rs 100 cr

The shutdown of the mammoth Nathpa-Jhakri hydel project since July 25 has resulted in a loss of over Rs 100 crore.

Power supply to all the northern states has been effected plunging several areas into darkness due to the complete closure of the 1,500 Mw project since the last week of July.

Nathpa is the largest hydel project of the country located in Himachal Pradesh's tribal Kinnaur district some 160 km from here.

Ever since the project was built over two years ago, power generation was effected seriously every year in July and August due to high silt levels in the swollen Sutlej upstream forcing the project's giant turbines to shutdown due to threat of damage to the machines.

At this rate the 1,500 Mw Nathpa project is unlikely to achieve the annual target of 6,400 million units once again. The total generation has been only 3,055 million units this year. The project turbines could comfortably operate with silt levels of up to 5,000 parts per million (ppm) but if higher, it could damage the machines.

Silt level rises in the Sutlej for about four weeks during the monsoon and also when excessive snow melting takes place in the high mountains of Tibet during the summer further effecting the power generation.

Project engineers are unable to say when the silt level would drop and warned it could take several days for normal power generation.

Builders of the project had expected the silt to rise for about a week in a year instead of several weeks in a year. A long term measure being considered is to build a dam upstream at Khab which will filter out the silt downstream at the Nathpa project and other upcoming projects at the Sutlej.

"Even though the silt rises considerably during this time, this year it is higher on the Sutlej river instead of in its tributaries in India," said officials.

Sources said it was a whopping 43,000 ppm as the river enters India from China at Shipkila, but reduces as the river moved down the Indian side.

Satellite images, including 'Google Earth' pointed to a lot of construction activities including a hydel project on the Chinese side which is effecting power generation on the Indian side of the river.

"We can avoid the construction activity on the Indian side, but are unable to do anything about growing construction activity on the Chinese side," said the Sutlej Jal Vidyut Nigam (SJVNL) Chief H K Sharma. SJVNL, a central public sector company, built and now runs the Nathpa project.

Barely a fifth of the catchment area of the Sutlej river falls on the Indian side. The Nathpa project was built at a cost of Rs 8,630 crore over two years ago.