Dechen Dolkar
The 1,020 MW Punatsangchhu-II Hydroelectric Project (PHPA-II) has resolved its seepage issues, and testing and commissioning of the units have begun.
During the meet-the-press session yesterday, the Minister for Energy and Natural Resources, Gem Tshering, said that following the decision of the 18th Technical Group meeting held on September 5, 2024, the dewatering of water-conducting systems began on September 7 and concluded on October 14.
After dewatering, seepage levels in the water-conducting system reduced from 1,200 litres per minute to 650 litres per minute.
An inspection by the Technical Group on October 17 identified no major seepage sources, but the group decided to undertake additional grouting at the surge shaft bottom, along with Penetron painting on the surge shaft and part of the Head Race Tunnel.
Lyonpo said that the false ceiling installation work is progressing on schedule and that remedial measures in the surge shaft bottom and Head Race Tunnel are set to be completed by December this year. “Once completed, the water-conducting system will be recharged, and unit commissioning will proceed.”
With the monsoon season concluded, river flow is expected to decrease, limiting operations to one unit during this lean period.
The Minister said that since generation had not started prior to the discovery of seepage in the powerhouse, estimating generation and revenue losses is impractical. “It is crucial that we adequately address seepage issues before moving forward with commissioning,” he said.
The minister said that the two governments are in discussions to finalise the tariff soon.
He said that seepage issues are common in underground powerhouses, particularly in the initial stages of charging water systems. PHPA-II’s commissioning was temporarily suspended to prevent seepage from affecting electro-mechanical equipment, pending the completion of the machine hall’s false ceiling, which will help channelize seepage.
Regarding PHPA-I, Lyonpo said that both sides are closely collaborating on solutions to complete the project.
He acknowledged the challenges posed by unforeseen geological conditions in both projects, highlighting the collective responsibility of both governments to complete the projects for Bhutan’s energy security and economic prosperity.
Lyonpo said that 198 piles were previously installed as part of the stabilisation measures, and additional stabilization is being requested for safety concerns. The Government of India has agreed to install an additional 48 piles. Some officials from Bhutan travelled to Delhi, where meetings were held yesterday and today to reach a final decision.