The testing of the first generating unit of the Mangdechhu hydropower project was successful.

Managing director of the project, A K Mishra said the testing was done to record the rotation per minute (RPM) and possible vibration and noise on March 30. “We recorded 375 RPM. It was very successful,” he said.

Now it is possible to synchronise the generation with the Indian Grid and commission Unit-1 of Mangdechhu Project Bhutan. The managing director said another unit is also ready for testing.

Final touching is ongoing to ready the third and fourth units. Each unit is capable of generating 180MW of power.

To save time, he said the water available from the seepage was diverted to fill the pressure shaft, which hit the turbines.

The filling of the headrace tunnel will also begin tomorrow. The filling could consume about two weeks since it has to be done in a gradual phase to ensure that no air is left inside the tunnel.

Once this completes, all four units would be ready for generation as the 13.5Km headrace tunnel is connected to the pressure shaft, the water discharge from which will spin the turbines.

The project cost as per the detailed project report (DPR) was around Nu 28.9B at 2008 price level, which was later revised to Nu 40.20B. The cost was again revised to Nu 42.81B at March 2015 price level. Early last year, the cost was revised yet again to Nu 52.7B at December 2017 price level. This is including the cost of building transmission stations and lines.

The final cost per MW is around Nu 70M, which the managing director claims is the lowest in the region.

Tshering Dorji