Tarbela-IV extension project not functional for last 4 months

ISLAMABAD: Pakistan’s very important hydropower project of Tarbela-IV extension with capacity to generate 1,410MW, which was inaugurated on March 10, 2018, is no more functional for the last over four months on account of the extensive silting in the power house tunnels and turbines.

Top sources told The News that the damage caused to the tunnels and turbines was the result of the inauguration of the project in haste the month of March when the water level in the dam was very low and the temporary coffer dam made of mud was not removed at the time of first operation resulting in mud-debris inflow to the tunnels and turbines.

Now the Wapda’s top management has spent Rs15 million just to remove the silt. However, the story does not end here. The poor quality of work has also appeared that has resulted in perforation in the valves below the penstock. Sources said that dewatering has now become an uphill task. It is pertinent to mention that no holes have been seen for the last 25 years in Tarbela’s other penstocks.

The software that helps in making the project functional has also been found faulty as the alignment of the generators accessories should have been red, yellow, and blue but through software mistake of consultant, it was aligned as red, blue and yellow.

Shamail Ahmad Khawaja, Federal Secretary of Ministry of Water Resources, said that there are some issues in the project on which the authorities concerned are vigorously working.

He said the project is very useful and will generate annual energy of 3.84 billion units. “It will provide benefit of Rs30 billion per annum,” he said.

However, Wapda top officials said that at the time of inauguration in March 10, the water level was close to dead level, and the silt and debris inflows hit the turbines. They said that now the issues are taken care of properly and since the water level is going up in the dams with better water inflows, the management is considering making two turbines of 470MW each operational in couple of days.

Tarbela Dam was built with five original tunnels, with the first three dedicated to hydropower generation, and the remaining two slated for irrigation use. The fourth phase extension project uses the first of the two irrigation tunnels, while the fifth phase extension will use the second irrigation tunnel.

The project has been competed with three turbines with a capacity of 470MW each in Tarbela's fifth tunnel which was previously dedicated to agricultural use. Upon the full function of extension-IV, the total power generation capacity of Tarbela Dam will be increased to 6,298MW.