Kali Gandaki A
| Kali Gandaki A | ||
|---|---|---|
 |
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| location | ||
|
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| Coordinates | 27 ° 58 '46 " N , 83 ° 34' 49" E | |
| country |
 Nepal
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| place | Mirmi , Syangja District | |
| Waters | Kali Gandaki | |
| Height upstream | 524 m | |
| power plant | ||
| owner | Nepal Electricity Authority (NEA) | |
| operator | NEA | |
| construction time | 1996 to 2002 | |
| Start of operation | 2002 | |
| technology | ||
| Bottleneck performance | 144 megawatts | |
| Average height of fall |
124 m | |
| Standard work capacity | 592 million kWh / year | |
| Turbines | Francis turbines : 3 × 48 MW | |
| Others | ||
The Kali Gandaki A power plant is a run-of-river power plant in Nepal, which is located on the Kali Gandaki , a left (northern) tributary of the Ganges .
It is located in central Nepal near the village of Mirmi in the Syangja district of the Gandaki administrative zone . A few kilometers southwest is the small town of Tansen .
Barrier structure
The barrier structure consists of a concrete gravity dam with a height of 44 m. The length of the wall crown is 100 m. When the reservoir reaches its maximum destination , the river accumulates to form a small reservoir with an area of around 0.65 km², which holds around 3 million m³ of water. A 6 km long tunnel with a diameter of 7.4 m diverts the water to an engine house near the town of Beltari . A 45 km long loop of the Kali Gandaki will be shortened through the tunnel, resulting in a drop height of 124 m.
power plant
With an installed capacity of 144 MW , Kali Gandaki A is currently (as of March 2015) the largest hydropower plant in Nepal. The three machines have a maximum output of 48 MW each. They were put into operation one after the other in March, April and May 2002, but initially could not achieve their full capacity, as the 132 kV line to Pokhara was not completed until August. Both the Francis turbines and the associated generators were supplied by Toshiba .
The switchgear , from which two 132 kV lines branch off, is located next to the machine house . The first leads 61.4 km to Pokhara , the second 44.3 km to Butwal .
The power plant is owned and operated by the Nepal Electricity Authority (NEA). The annual production is stated differently: on average 592 million kWh per year or 621 million kWh in 2005 and 759 million kWh in 2007.
construction
A first feasibility study was carried out in 1979. This feasibility study was updated between 1990 and 1992 and, based on this, the design for the power plant was drawn up from 1992 to 1995. In preparation for the project, a 28 km long access road was built by NEA.
backgrounds
The electricity supply in Nepal is 86% hydropower. At the time of the final concept and design studies for the Kali Gandaki A hydropower plant between 1992 and 1996, Nepal was suffering from an acute power shortage, which led to power cuts or voltage drops for an average of 16 hours a day, although at that time only 10% of the population was anyway were connected to the power grid and the peak load in 1992 was only 215 MW.
With its planned 144 MW, Kali Gandaki A should make the power cut-off unnecessary and also serve to cover the daily peak load, especially during the dry season, which occurs in the evening between 6 and 11 p.m. It should use its small reservoir for this. However, this goal could not be achieved because firstly the deadline was missed by 21 months and secondly because the demand for electricity rose faster than the available supply. Therefore the problem persists.
In 2011 NEA estimated that up to 1,800 MW of in-house generation capacity was available at companies in Nepal because the public electricity supply in Nepal is still unreliable. The Asian Development Bank (ADB) sees the only possibility of solving this problem to build further hydropower plants, in particular with a storage lake, to be able to cover peak loads and to be able to export electricity to India.
Construction stages
The project was divided into the following construction phases (lots):
- C1: Construction of the 44 m high gravity dam with flood relief as well as the adjacent basin for desanding
- C2: Construction of the 5.9 km long, concrete-lined tunnel
- C3: Construction of the moated castle and the machine house
The construction work for lots C1 to C3 was carried out by the Italian company Impregilo . The cost of this was $ 121 million.
- 4: Gates for the weir, lining of the tunnel, other steel components
- 5: Electrical systems
- 6: Francis turbines , generators, 3 transformers plus 1 replacement transformer and the switchgear
- 7: Construction of the 132 kV lines to Pokhara and Butwal
Lots C1 and C3 were funded by ADB, lots C2 and 4 to 7 by the Overseas Economic Cooperation Fund (OECF), a Japanese development aid organization.
Delays
There were several main factors behind the delays that resulted in the project being delayed by 21 months. The delays had both technical and organizational reasons:
- Due to the geological structure, unexpected problems arose during the work to divert the Kali Gandaki , the construction of the sedimentation basin, the tunnel construction and the construction of the moated castle .
- Necessary changes that were determined by the commissioned companies were only answered very slowly by NEA.
- There was little or no assistance from NEA for the necessary import of material from India.
- The construction company planned some work incorrectly, whereby in particular the seasonal fluctuations in the water flow of the Kali Gandaki were not sufficiently taken into account. For example, a second, not actually planned, diversion of the river was necessary.
- The construction of the 132 kV line to Pokhara met resistance from the local population, so the route had to be changed.
costs
Total costs were $ 354.8 million, of which 241.3 million were in foreign currency and 113.5 million in NRs . Originally, the project was set at $ 452.8 million, with a foreign currency component of $ 320 million that was to be raised through loans. A $ 160 million loan was made available by the Asian Development Bank (ADB). Another $ 160 million came as a loan from the OECF. With these 320 million dollars, the foreign currency requirements of the project should be covered. The portion in local currency should be covered by the government of Nepal or by the Nepal Electricity Authority (NEA). The actual expenses were thus well below the originally estimated costs.
In order to be able to service the loans, the ADB was asked when the contract was signed that the electricity prices be increased by the NEA. The electricity price should rise to 9 NRs per kWh between 1996 and 2004 , which corresponds to an increase of 90%. However, this was not implemented by NEA, so that the electricity price in 2011 was only 7.16 NRs / kWh.
Problems during operation
Vibrations in the power plant
Due to strong vibrations in the power plant, the machines usually run with less than 35 MW each, as the vibrations increase sharply with higher output. According to the power plant staff, the vibrations appear to be coming from the suction pipes of the turbines. Perhaps cavitation responsible for the vibrations and the noise. In any case, machine 3 had cavitation holes with a diameter of up to 3.5 cm and a depth of up to 2 cm. Another explanation would be the incorrect calculation of the suction hose, which may be a meter too low. If so, it would be a serious design flaw.
Settling basin
The Kali Gandaki carries a lot of sediments with it, which makes it necessary to remove sand using a sedimentation basin before the water can be directed to the turbines. The inlet devices to the settling basins do not work as originally planned, so that the sediments cannot settle properly. This leads to increased wear on the turbines.
See also
Web links
swell
- Project Performance Evaluation Report (Eng.) In December 2011 the Asian Development Bank carried out a study on the Kali Gandaki A hydropower plant in order to examine whether the originally planned goals were actually achieved.
Remarks
- ↑ The rainy season, caused by the monsoon, lasts from June to October, the dry season from November to May.
- ↑ At an exchange rate of 100 NRs = 0.74924 EUR, 9 NRs per kWh correspond to a price of 0.0674 EUR or 6.7 ct per kWh.
Individual evidence
- ↑ a b Performance Evaluation Report December 2012 Nepal: Kali Gandaki “A” Hydroelectric Project. (PDF 1.7 MB p. 11 Executive Summary) Asian Development Bank (ADB), December 2012, accessed on March 1, 2015 (English).
- ↑ a b c d e Kali Gandaki Hydroelectric Power Plant Nepal. Global Energy Observatory, accessed March 1, 2015 .
- ↑ a b c d ADB, Chapter 2, pp. 6-8.
- ^ Hydroelectric Power Plants in Nepal. Power Plants Around the World, accessed March 1, 2015 .
- ↑ a b ADB, Chapter 2, pp. 4-5.
- ↑ ADB, p. 57 Table A9
- ↑ ADB, Chapter 4, p. 21.
- ↑ ADB, Chapter 5, p. 29.
- ↑ ADB, Appendix 2, pp. 39-40.
- ↑ ADB, Appendix 6, p. 49.
- ↑ ADB, Chapter 2, p. 10.
- ↑ ADB, Appendix 7, p. 54.
- ↑ ADB, Chapter 2, pp. 11-12.
- ↑ ADB, Appendix 6, p. 50.
- ↑ ADB, Appendix 14, pp. 75-76.
- ↑ a b ADB, Basic Data
- ↑ ADB, Chapter 2, p. 16.
- ↑ ADB, Appendix 5, p. 45.
- ↑ a b ADB, Appendix 6, pp. 52-53.