MB Subba 

Tala hydropower plant successfully restored generation of electricity by one of the units yesterday.

The plant was shut down on July 19 after large chunks of debris clogged the gates of the intake tunnels due to heavy rain for days. Druk Green Power Corporation (DGPC) officials are working round the clock to restore generation to the plant’s full capacity.

“On completion of filling the reservoir, the desilting chambers and the short dewatered section of the water-conducting system, the first generating unit of the Tala power plant was started today,” DGPC’s managing director, Dasho Chhewang Rinzin, said yesterday.

The installed capacity of each of the six units of the 1,020MW hydropower plant is 170MW.

He added that since there could still be some air that is trapped in the water conductor system from the incident on July 19, loading of the first generating unit is being taken up cautiously step by step with all parameters at the dam, the surge shaft and powerhouse being monitored carefully.

The cleaning of the intake gates and clearing of the debris from the desilting gates chamber were completed on July 22. On completion of the scouring of the reservoir, the closing of the dam radial gates was started in the late-night of July 22 to fill the reservoir.

“It is being planned to start the second generating unit later tonight if there are no problems faced with the first generating unit,” Dasho Chhewang Rinzin said yesterday. The other generating units, he said, would be started depending on the success of the initial generating units.

On the issue facing the plant, he said that the problem was with the water-conducting system from the dam to the surge shaft and not with the generating units themselves.

The plant remained shut down for four days as of yesterday evening with a daily revenue loss of about Nu 55 million (M). This means that the total revenue loss amounted to about Nu 220M as of yesterday.

According to the DGPC, at this time of the year, the Tala power plant with the monsoon rains would be generating a total of 1,122MW, including the additional 10 percent overloading capacity. This is equivalent to a daily generation of about 26 million units.

On the causes of the damage, DGPC MD said that from the review of the sequence of events, it appeared that the penstock pressure loss and subsequent events could have been caused by air suction into the water conductor system due to choking at the dam intake gates.

All resources of Tala and Chhukha power plants have been mobilised for cleaning of the intake gates and to lower the reservoir level to get access to the intake gates. The desilting gates chamber is also being cleared of any debris to allow free flow of water into the headrace tunnel.

Edited by Tshering Palden