Tshering Dorji

The Druk Green Power Corporation (DGPC) will take over the Mangdechhu Hydropower Project (MHPA) February 29 on ‘as is where is basis’.

The MHPA’s managing director, AK Mishra, said that the DGPC’s team had been running the plant since April and all minor issues were spotted and rectified.

“There are no contractual issue and we have ensured that all components of the project fulfil technical standards,” he said. In fact, in the peak season, he said that the plant is capable of running at 10 percent overload, meaning that the plant built to generate 720MW is capable of generating 792MW.

As a component of the royalty energy that the government gets, MHPA has started to load its power into the Trongsa and Bumthang grid.

AK Mishra said that he had requested the authorities to close the project. This will be another record in the hydropower history.

He said that usually took about two years to close the project because of contractual and technical issues. “But this is costing the project. For instance, my monthly salary for another two years is added cost to the project,” he said.

Of the total project cost of Nu 51B, he said majority (Nu 12B) was on account of payment to NHPC for the design.

However, he said a number of times, he had to deviate from the Detailed Project Report (DPR) and methodology, taking enormous risk. For instance, the design of pressure shaft had to be completely changed due to the geology. In some cases, he said it was done to save cost and, in a few other cases, deviation was made to save time.

While audit has raised concerns, he said as  long as the objectives are met and his conscience was  clear, it was not a difficult task to convince the authorities.

Problems at the powerhouse

Soon after spinning the turbines at four generating units, oil spillage put the generation to halt.

To cool down the components of the generating units, special oil is being used as a coolant. Oil leakage was observed in all the units. Once the shaft of the turbine rotates at 75 rotations per minute, oil oozed out.

AK Mishra said that the units were stopped immediately. The designers from Bharat Heavy Electricals Limited (BHEL) came and did some modification. He said that oil spillage is now minimal and below the allowable standards.

Even after that, something unusual happened in Unit-3. When it was run on manual mode brakes were applied leading to some wear and tear. “BHEL was of the view that someone might have turned the knob by mistake,” he said. Brake pads were burnt in the process.

As of last Friday, he said that pads were replaced and the unit was put to run. This did not have impact on the generation since at this time of the year only one unit run due to low water discharge.

“I take this responsibility because I waived off the testing time for BHEL, which is around a month,” he said, adding that this was done in the interest of generating revenue, which today amounted somewhere close to Nu 600M.

Was MHPA responsible for cracks in Kuengarabten?

No, said AK Mishra.

As soon as the report on cracks began circulating, AK Mishra said that MHPA formed a committee, separate from the one government formed. While it was difficult to ascertain the cause, findings points towards multiple factors, claimed AK Mishra.

He said that the geology in Kuengarabten and Samcholing comprised of clay and there is an overburden. On the project’s part he said the water discharge was monitored. The volume of water dispensed from the reservoir and the volume of water at the powerhouse indicated that there was no loss of water. This, he says, meant water seepage from Kuengarabten and Samcholing had nothing to do with the tunnels.

The crack was observed until the Trongsa-Gelephu highway and it did not reach the valley. AK Mishra said that there was no continuity and the cracks did not reach the river. He said that from Samcholing to the powerhouse there were paddy fields containing high water and clay.

It was also noted that there is a stream in Kuengarabten, which seep underneath the ground and does not come out from anywhere. AK Mishra said there could be an accumulation of water below the earth.

Moreover, another theory leads to the earthquake of magnitude 3 in Mongar on October 7, which could have disrupted the geology. “This is not ascertained, however,” he said.

The problematic area is between adit 3 and 4 of the headrace tunnel. He said that this part of the tunnel was shut and physical monitoring was underway.

“There was no water seepage,” he said. Plying of heavy vehicles was also attributed to the vibrations.

In the meanwhile, the project has installed sensors and survey points to monitor the cracks.

“But I’m 100 percent sure that cracks will not extend further and the problem will be arrested,” he said, adding that the project provided Nu 300,000 to each affected households as a part of corporate social responsibility.