Using the same resource again and again is a good idea. The PDC has done a fine job by running three power stations on the same water, of course with the help of favourable topography. A Kashmir Life report.
Of all the powerhouses that the JKSPDC owns, the Chenaini series of three projects is a perfect case of how water from the same sources can be used and reused for generation at multiple spots if the topography permits. The other distinction with this series of projects is that the main canal is a grand mix of different canal systems – it is cut and open at a few places, covered at one level, has the conductor running through wooden flumes at a few places and more recently has a part under tunnels as well.
The three-stage project is spread over around six kilometres in the outskirts of Udhampur districts running parallel to the Srinagar-Jammu highway. Its total installed capacity is 32.80 MW but some of its units have been functioning at de-rated capacity over the years and may require some investment for upgradation.
Chenaini-I
Conceived during the early sixties, the project’s electro-mechanical part was implemented by a Hungarian company, the Ganz Movag in collaboration with the Bharat Heavy Electricals or BHEL. Locals still remember how the Hungarian engineers would live in trying circumstances and work for long hours to see the project completed in time. The civil works were managed by some Jammu-based contractors. Work on the project started in 1968.
“In Kashmir, people know that Sheikh Mohammad Abdullah was once imprisoned in Chenaini at a place where there was no life and escaping from the place was almost impossible given the dangerously steep slopes from all sides,” said an engineer. “That place is the same hillock on which the project is located.” Now the spot where Sheikh was imprisoned for some time is accessible by road besides a staircase having around 500 steps. “The great thing about the place is that while you take the stairs and quench your thirst in the spring, once you return you will feel the same thirst.” That is Rajghad where the project’s forebay is located.
The project taps the water from Beni Sung, one of the main tributaries of Tawi, not far away from the Pokhlia village. From the head works, the water conductor takes off. It is a mix comprising open and covered lengths, partly tunnel and partly vintage wooden flumes. Right now 3.36 kms of the channel are covered, 6.06 kms is open and the rest 8.95 kms comprise tunnels and wooden flume. The conductor gets water to the top of the peak in the outskirts of Slada hamlet where the project’s forebay is located.
Engineers say the discharge in the rivulet varies in seasons as it is fed by glaciers. It goes to an all-time low of 45 cusecs in winter that can peak to 13900 cusecs during average floods. The normal peak season discharge is around 540 cusecs. The canal is designed to take around 300 cusecs to feed the two penstocks that run the turbines in the powerhouse at Laddan. Laddan and Slada are connected by an 8-km rough road.
With an average head of 356 meters, the two penstocks create an acute angle on the slope to feed five machines after bifurcating midway. Every machine has an installed capacity of 4.66 MW each. The Pelton turbines fixed in the vertical set-up bear the seal of Hungarian electrical giant Ganz Budapest with the manufacturing date of 1966. There are BHE generators attached to the shafts.
Prime Minister Indira Gandhi flew to the spot to formally open the project’s first three machines on September 6, 1971. The fourth machine went into generation on May 24, 1975, and the last one on June 21, 1975.
The project is located on and around Muree rock formations comprising purely clay shale, clay stone, blocky sandstone and thick debris. Two major slides of Nashri and Saroli are part of this formation. This formation is not considered sound owing to its poor lithological characteristics.
This is primarily the reason why sliding and sumping of water conductors remained a perpetual problem with the project. Authorities started reacting to the issue that cropped up during all these years. The project faced a severe crisis when a major breach of water conductor between D 51430 and 51700 ft occurred on Feb 26, 2005, due to incessant and unprecedented rains. The same slide that impacted the water conductor also washed away seven houses, a watermill and one primary school building at Pladha.
Along with the water conductor, the transmission and distribution system also collapsed. It impacted all the stages because it was the same source that fed all, barring the last one that later got an additional and parallel water source helping it to resume generation early.
After seeking expert advice from CWC and GSI, a number of options were considered and finally the option of having an 1100-meter-long D-shaped tunnel was approved. The contract was bagged by K K Chibber for Rs 8.6 crore as an additional Rs 10 crore was spent on related restoration works. while the project had cost the government Rs 18 crore when it was built in 1971. The project was re-commissioned in May 2008 after remaining closed for three years. Interestingly, the same portion of the water conductor was damaged in 1998 when massive rains lashed the area.
Apart from occasional minor issues, the project has a severe siltation problem. Last time, the forebay was cleaned; it had 14 ft of deposits. Though spares are still available, ageing does cost. Right now, only four units are working as one machine is being refurbished by a Delhi-based company and will be reinstalled in June 2012. PDC has already approved an RMU of Rs 39.14 crore that is being implemented phase-wise involving different electro-mechanical components and civil parts. The de-rated capacity is now 3.40 MW a unit but the engineers say the project will improve its generations once the RMU is over. The project currently generates 350 thousand units a day.
The success of the project involved human costs. In the powerhouse, there are three photographs of its erstwhile officials – two engineers and one electrical sub-staff, who were killed while working there. G M Dar, a Srinagar engineer died of an electric shock on April 7, 1985, and the next morning, Ashok Koul died in almost the same situation. A K Malgotra of Jammu was killed in an electric blast on the premises on June 20, 1988.
SERC has put its cost at Rs 82.34 crore and its tariff at Rs 0.81 per unit. The project generated 717.15 lakh units in 2010-11 and 872.11 lakh units in 2011-12.
Chenaini-II 1996
Located at the foothills, this stage is totally dependent on the discharge from the first stage. It has two horizontal Francis turbines of one MW each supplied by Faridabad-based Flovel Ltd. The Brushless generators have come from Baroda-based Jyoti Ltd. The discharge from the stage-I is enough but the limitation of the head impedes higher energy generation. Its penstocks have a net head of 31.11 meters. Both units have been in operation since they were commissioned in 1996. Currently, the powerhouse produces around 30 thousand units of electricity a day. SERC has put its cost at Rs 12.51 crore and its tariff at Rs 1.02 per unit. The project generated 64.02 lakh units in 2010-11 and 73.91 lakh units in 2011-12.
Chenaini-III 2003
Implementation of the third stage started in 1992 and the project was commissioned in 2003. It has three units of 2.5 MW each and all three are in operation generating around 90 thousand units a day. It cost Rs 50.25 crore and was executed by a number of contractors. Most of the electro-mechanical part was done with Krisloskar equipment.
It has a horizontal Francis turbine. Powerhouse is located in Dibber village as its headquarters are in Salmay. The basic design of the project envisaged tapping the discharge of stage II and taking in an ‘overhead, under-bridge’ canal to the other bank of the Tawi and then to the powerhouse, more than 5573 meters away. After the massive breach in the stage-I water conductor, officials managed an alternative water source from the Tawi so the station has dual water sources feeding the same water conductor.
The Francis turbines are functioning at full capacity and have not reported any problems in the recent past. Floval Ltd worked on the project alongside various local builders. Engineers at the site said they usually do not require much of the water from alternative sources as the discharge from stage II is adequate. Its water conductor is designed to drain 12 cumecs (423.7764 cusecs) of water. While the stage-II discharge is 7.12 cumecs, the remaining is taken from the additional source. During winters all the stages of the Chenaini series report low discharge availability and produce less.
PDC has already identified the fourth stage of Chenani but it does not want to implement it directly. Recently, it advertised this part for the IPPs. Once ready, it will offer 7 MW of clean energy.
SERC has put its cost at Rs 58.21 crore and its tariff at Rs 1.56 per unit. The project generated 72.68 lakh units in 2010-11 and 180.01 lakh units in 2011-12.
