The Bhutanese Leading the way.
Water seepage from the roof of the power house means that there will be a three month delay in commissioning the units of the 1020 MW Punatsangchu II.
In the original plan two units of 170 MW each or 340 MW in total were supposed to be commissioned and start generating power from late September 2024 with generation continuing in October, November and December even though it would drop down to one unit of 170 MW in the winter months when river levels run low.
The revenue projection for the 2024-2025 Financial year had projected a very conservative Nu 1.7 bn that was to be generated in these three months from P II.
This means the three-month delay will cost, at the least, Nu 1.7 bn in revenue to this ongoing financial year.
However, over the medium term (for the 13th FY plan), the fiscal projection is expected to remain stable and Bhutan will be on track to contain the fiscal deficit within 3% for the 13th Five Year Plan.
The budget always makes very conservative revenue projections overall but especially so when it comes to hydro projects given their frequent delays and unexpected surprises like now. In addition to this, the Nu 1.7 bn loss is based on the most optimistic timeline of 3 months delay.
However, 3 months is just the time for the false ceiling and not any additional repair works that is uncovered when the dam water levels are lowered.
A calculation by The Bhutanese using the Mangdechu tariff rate of Nu 4.12 per unit or kilowatt shows a loss of around Nu 2 bn within 2024 itself.
As per the plan the two units were supposed to generate power from late september which is 340 MW or 340,000 units into 24 hours into the number of days in the end of September, days in October for which the two units would be mainly functional and few days in October and 30 days in November and 31 days in December when it would come down to one unit. This is then multiplied into the Mangdechu tariff rate of Nu 4.12 per unit.
The approximate figure is around Nu 2 bn plus in potentail generating losses in this time period.
It is sure that Bhutan will be negotiatig for a P II tariff rate with India much above the Mangdechu rate and so when that is incorporated the potential revenue loss will be north of Nu 2 bn.
The seepage
After initiating the filling of the water conducting system, the seepage was first detected in the Machine hall on 13th August 2024. The quantum was quite small which was around 4 litre per second. However, as the project raised the level of dam and completed charging of the water conducting systems, the seepage in the power house gradually increased.
An official from the Ministry of Enery and Natural Resources said seepage issues are not uncommon in the underground powerhouse, particularly during the initial charging of water conductor system, which typically subsides with passage of time.
As there are some risks of water falling on to control panels and electrical equipments, further testing of the units was suspended temporarily till completion of the false ceiling (mainly to channelize the seepages) in the machine hall.
The official said that for the long-term interest of the project, it is essential to install Electro Mechanical (E&M) equipment in a water and moisture free environment.
In the case of PHPA-II, considering associated risk to control panels and electrical equipment, the decision was taken in the Technical Group (TG) meeting, which was held on 5th September, 2024 in Thimphu to go for providing false ceiling in the machine hall first and continue with the E&M works thereafter.
The ministry said the water in the dam is lowered to de-water the Headrace Tunnel, Surge Shaft and Pressure Shaft. There is a huge quantum of water filled in the water conducting systems under pressure.
“We need to drain out these water as per the guideline and initiate inspections to find out any cause and carry out remedial measures as soon as possible, if any.”
The ministry said that if everything went as per the plan (with no seepage), it was planned to complete testing and commissioning of first two units, and generate power by the end of September 2024.
In terms of delay the ministry said in keeping with the decision of the recent TG meeting, implementation of false ceiling will take around 3 months. Only after the completion of the false ceiling work, installation of E&M works will begin for the remaining four units.
The timeline for resuming commissioning of the generating units will depend on the treatment measures that may be suggested after inspection of the emptied water conductor system.
The ministry said it is important to resolve the issue as seepage issues could affect the functionality of electrical panels and equipment and so it is important to ensure that seepages is adequately addressed before commissioning of the units.
The mechanical spinning of 1st two units was done on 15th August, 2024 and the wet testing of the units could not be continued due to seepage issues and no power is generated till now.
