Losses are Nu 199 mn from Mangdechu and Nu 188 mn from Chukha
Meanwhile Mangdechu unit repaired by an all Bhutanese team after 24 days
Bhutan’s rivers have been in full flow from the second week of June with the monsoon arriving early in addition to earlier rains, and all power projects should be generating at their full capacity.
However, a 84 MW unit or turbine which is one if the four turbines of the 336 MW Chukha project has been down since August 2019 last year and is not able to generate power.
According to the calculation of Chukha project the loss between May and June 2020 which has better hydrology is 74 mn units which is Nu 188 mn foregone.
The loss is calculated till the end of June as the fourth unit is expected to be repaired only by 30th June 2020.
Just between August 2019 and December 2019 the single unit’s inability to generate power caused the loss of 115 mn units or Nu 299 mn in hydro revenue in 2019 itself.
This is because June, July, August and September are regarded as high generation months when the rivers are in full flow.
The Druk Green Power Corporation MD Dasho Chhewang Rinzin said that repairs were hampered due to the COVID-19 lockdown in India and so some equipment and parts could not come in from the manufacturer Bharat Heavy Electricals Limited (BHEL).
BHEL was also unable to send in their people to help due to COVID-19 as the general practice is to always have a person from the manufacturing company be there when the turbine is being opened up.
He said that now some parts have come in and some parts have been manufactured in the Bhutan Hydropower Services in Gelephu and so the repairs will be done.
The MD said that in the case of Chukha the turbine was already 32 to 33 years old and as they get older certain faults come out. He said that rotor earth part of the turbine was damaged causing damage to the rotor.
In the absence of any staff from BHEL a Bhutanese team is working on the turbine and will finish the work by the end of the month.
Meanwhile, the troubled 180 MW third unit of the 720 MW Mangdechu has been repaired and is up and running after around 24 days.
A fault was detected on 31st May in the third unit and it was shut down on 1st June and was put back on line only at 10.36 pm 24th June. When the paper contacted the MD A.K Mishra on Friday evening or 26th June he said that the unit had been in operation for around 24 hours so far.
According to data from the Mangdechu project the third turbine was unable to generate 48 mn units in the last 24 days leading to a total loss of Nu 199 mn. The amount is higher in Mangdechu given its higher tariff rate compared to Chukha.
The MHPA MD said that the other three units of 180 MW each were generating at full capacity with 10 percent additional power coming to around 594 MW.
The MD claimed that there was not much spillage or left over water and so the loss was not much.
However, another person well versed with the Mangdechu project said that it is not true as the monsoon in the first week of June and a full river should ensure that all four units should not only be generating 720 MW of full installed capacity but even more.
The MHPA MD said that from 28th June 2019 to 31st May 2020 in a period of around 11 months the Mangdechu project had generated around 3 bn units and earned revenue of around Nu 9 bn.
The losses would have been even more had an all Bhutanese team not fixed the faulty unit.
The MD said that BHEL did not show up for two reasons, one was due to COVID-19 and the other reason was since the project had not released Nu 340 mn to BHEL due to various contractual issues with BHEL on certain incomplete work.
According to another source, BHEL also did not want to cover the damage under its two-year liability period of which even the first year is not over and wanted a purchase order for the repairs. The source said that negotiations around this would have taken too long during which the project was losing money.
Finally, an all Bhutanese Operation and Maintenance team of MHPA who are from the DGPC got into action and opened up the unit and conducted complex repairs involving a high level of technical expertise without any help from BHEL.
The team detected the fault with the rotator stator and found flaws on poles 11 and 16 of the 16 poles in the machine. They did work on the field coils and the windings.
Earlier expert Bhutanese divers were also involved in fixing a leaking gate problem at the dam site.
The O&M team joined the project in April 2018 and from then till June 2019 witnessed the erection of the turbines and the commissioning of the project.
Though Bhutanese O&M teams have also fixed turbines in Chukha and Tala they have usually been with some BHEL supervision and so this is the first time a team has achieved such a feat without any help from BHEL.
Coincidentally this third unit is the same one that applied in the brakes by itself while generating power in full speed in September 2019 and had to be repaird.
BHEL currently has to resolve some other issues in the Mangdechu project. One is the automated control of the project through the Computer Controls and Monitoring Systems. There are still some issues with some sensors not responding which means some manual control is required.
The other problem is the oil leakage from the units with it being resolved on unit 1 but units 2,3 and 4 are yet to be resolved with BHEL promising to fix it only after the Nu 340 mn is released.