A Comprehensive Study on Hydropower Potential of Nepal

A Comprehensive Study on Hydropower Potential of Nepal


Er. Khimananda Kandel |  Dec. 16, 2020,

engineersnepal.com

Abstract 

The recent study entitled "A Comprehensive Study on Hydropower Potential of Nepal, has shown the Hydro Potential for 20%, 40%, 60% and 80% probability of flow exceedance as 147535.51 MW, 56277.51 MW, 27127.02 MW and 18471.75 MW respectively.  Similarly, the study on the hydro energy potential of Nepal has shown the potential for 20%, 40%, 60% and 80% probability of flow exceedance as 470089.22 GWh 274790.25 GWh, 173846.76 GWh and 130232.51 GWh respectively. Province-wise hydro potential study of Nepal has also been made except for province No. 2 where there is very low or negligible hydropower potential. It is found that Province No. 1 is rich in hydropower with power potential as 15615.77 MW and energy potential as 76519.78 GWh for 40% probability of flow exceedance. Similarly, other Provinces with hydropower potential in descending order are Province No. 6, Province No. 4, Province No. 3, Province No. 7, Province No. 5 and Province No. 2 respectively.

 

Key words: Hydropower Potential, Run-of-River (R0R), Hydrology Guru Model, River Basins, Provinces, Nepal

 

Background 

 

Till now, the comprehensive study with power and energy generation for multiple scenarios. Dr. Hari Man Shrestha, water resources expert, while conducting an academic research for his Cadastre of Hydropower Resources Ph.D. thesis at the Moscow Power Institute (then USSR), in 1966 AD, came up with an exciting finding, which showed Nepal's theoretical hydropower potential at an 83000 megawatts. This study was made at the time when there were limited gauge stations and rainfall stations and analysis tools.

 

Apart from this study, a study was made by Dr. Raghu Nath Jha which shows the hydropower potential of Nepal for Saptakoshi, Narayani and Karnali River Basins in Run-of-River option for 40% flow exceedance and 80% efficiency as 53,836 MW and 346538 GWh, respectively. This study has also shown that for 50% flow exceedance and 80% efficiency, total hydropower potential and corresponding annual energy capacity of Nepal on run-of-river basis is 36,247 MW and 256, 256 GWh, respectively. Similarly, for 60%, flow exceedance and 80% efficiency, total hydropower potential and corresponding annual energy capacity of Nepal on Run-of-River basis is 27,544 MW and 211,561 GWh, respectively. The recent study is a try to find out the energy potential of Nepal by using the available latest technology so that energy potential can be found out in terms of installed capacity and energy. It is expected that the present document will pave a foundation for the comprehensive planning of hydropower projects and take initiatives for long-term energy planning of Nepal to meet the future energy requirements of Nepal.

Assumptions

Some assumptions have been made in this study. Some of the assumptions are as followings.

•     Discharge of the river is estimated by using Hydest Method, Modified Hydest Method and Hydrology Guru Model. Discharge and power estimation is also made for all the alternatives.

•     Monsoon wetness index of Nepal is estimated by using the Monsoon Wetness Index Contour and the Annual Wetness index is taken as 120% of Monsoon Wetness Index.

•     Overall Efficiency of the proposed project is taken as 87% .

•     Gross head is taken as the head between the consecutive headworks.

•     Hydropower potential study, in general, is made for up to 3000 m and in some exceptional cases, hydropower potential is estimated for up to 3500 m RL.

•     To the possible extent, potential headworks has been adjusted to the licensed boundary of Department of Electricity Development (DOED).

•     In general, the catchment area is estimated at the proposed headworks in case of the Run-off type projects and in case of potential storage project catchment area for up to possible dam axis is considered for hydrological analysis.

•     The gross head of the project is taken as the difference between the RL of headworks and powerhouse and for the analysis of hydropower projects of installed capacity for above 100 MW, gross head is taken as the difference in RL in the license boundary issued by Department of Electricity Development (DOED).

•     Annual Energy is taken as 90% of the maximum energy generation capacity of the project.

 

Hydrological Analysis

Hydrological analysis has been made by DHM/WECS (Hydest) Method, Modified Hydest Method and "Hydrology Guru Model". The results presented in this study are derived from Hydrology Model.

 

Estimation of gross head and Catchment Area

Identification of the potential head is made manually for all the river basins of Nepal. In many cases, the proposed site also lies in the license issued by Department of Electricity Development. The gross head of the project is estimated by using the web based platform for energy development by re-sampled data with 100 m resolution generated from DEM (Digital Elevation Model) of 30 m resolution. In most of the projects, the catchment area (Total, Below 5000 m and Below 3000 m) has been estimated by using the same platform. In some cases, the catchment area (For China Catchment and the catchments in some small river basins) have been generated by using google earth.

 

Limitations

 

Some of the limitations of the study are as followings:

 

 •    In general, the hydropower study potential for above 3500 range has not been made. The study has only focussed on the technically possible potential hydropower sites.

•     In general, a hydropower project sites with an installed capacity below 1 MW at 40% probability of flow exceedance has not been considered in this study.

•     Hydropower Potential of the rivers originating from small catchment of Chure Range of Nepal, has not been considered in this study where there is some potential of hydropower generation in Storage mode.

•     The gross head of the project has been estimated by using the web based platform for energy development by using resampled data with 100 m resolution generated from DEM (Digital Elevation Model) of 30 m resolution.

•     For the rivers bordering the Provinces, hydropower sharing has been made based upon the proportion of geographical coverage between headworks and powerhouse.

•     In case of theoretical storage project, the total head is taken as the difference of elevation between two consecutive intakes.

 

Study Basins

Hydro potential study of Nepal in terms of Power and Energy has also been made for Arun,  Tamor, Mai Khola, Sunkoshi, Likhu, Dudh Koshi, Tamakoshi, Bagmati, Trishuli, Budhigandaki, Marsyangdi, Seti/Madi, Kaligandaki, Rapti, Bheri, Babai, Karnali, Seti Far Western and Mahakali River Basins.

 

 

Figure 1 : River Basins of Nepal

 

 

 

 

 

 

 

 

Basin-wise Findings

 

The summary of the findings of the hydropower potential of Nepal is as followings.

 

Table 1 : Hydropower potential of Nepal (MW)

S.N.

River Basin

Q20 Power (MW)

Q40 Power (MW))

Q60 Power (MW)

Q80 Power (MW)

Storage Annul Average Power (MW)

1

Arun River Basin

15538.04

6699.69

3089.58

2126.80

8182.87

2

Tamor River Basin

8749.17

3367.09

1428.63

907.31

4566.41

3

Mai Khola and Branches

478.99

166.36

70.23

42.94

246.53

4

Sunkoshi River Basin , Bhotekoshi and Indrawati

11320.48

4017.48

1913.04

1360.49

5832.52

5

Likhu Khola River Basin

1752.00

661.11

318.97

231.13

891.15

6

Dudh Koshi River Basin

10641.24

4049.24

1959.93

1429.71

5401.44

7

Tamakoshi River Basin

6543.23

2008.82

920.97

609.74

3433.47

8

Bagmati River Basin

1774.81

583.45

261.10

164.74

1028.83

9

Trishuli River Basin

7781.12

4045.84

1696.75

760.24

4423.92

10

Budhi Gandaki River Basin

5838.37

2347.06

1140.44

723.93

2975.41

11

Marsyangdi River Basin

8412.31

3159.79

1527.64

1091.25

4210.24

12

Seti River Basin

2277.66

745.87

354.72

255.81

1182.63

13

Kaligandaki River Basin

14793.45

4750.57

2180.74

1547.46

7732.03

14

Rapti River Basin

2990.83

966.28

403.93

304.43

3035.28

15

Bheri River Basin

10944.40

4085.94

1931.49

1370.55

5724.82

16

Babai Sharada River Basin

520.08

174.80

88.57

60.92

285.07

17

Karnali River Basin

23989.22

10049.94

5215.52

3511.48

13051.28

18

Seti River (FarWestern) Basin

6103.27

2002.85

1171.63

847.75

3193.16

19

Mahakali Basin

7086.83

2395.33

1453.16

1125.07

4306.76

 

Total

147535.51

56277.51

27127.02

18471.75

79703.81

 

The summary of the findings of the hydro energy potential of Nepal is as followings.

 

Table 2: Hydropower Potential of Nepal (GWh)

S.N.

River Basin

Q20 (GWh)

Q40 (GWh)

Q60 (GWh)

Q80 (GWh)

Storage Annul Average Energy (GWh)

1

Arun River Basin

53197.07

32838.94

20105.28

15424.64

61288.09

2

Tamor River Basin

28254.49

15908.57

9021.35

6529.00

34201.47

3

Mai Khola and Branches

1504.57

788.80

449.87

313.54

1846.48

4

Sunkoshi River Basin , Bhotekoshi and Indrawati

35854.97

19833.66

12567.57

9847.78

43684.38

5

Likhu Khola River Basin

5662.96

3312.48

2124.59

1679.66

6674.54

6

Dudh Koshi River Basin

34696.25

20440.17

13105.38

10402.66

40455.71

7

Tamakoshi River Basin

19974.29

9691.84

5982.80

4448.26

25716.00

8

Bagmati River Basin

5471.47

2812.04

1694.48

1205.52

7705.72

9

Trishuli River Basin

29080.81

21281.29

12391.47

5694.06

33134.28

10

Budhi Gandaki River Basin

19385.97

11595.47

7274.71

5205.12

22285.21

11

Marsyangdi River Basin

27075.13

15739.23

10021.15

7934.01

31533.84

12

Seti River Basin

7088.69

3676.08

2327.44

1856.53

8857.65

13

Kaligandaki River Basin

44755.72

23030.72

14204.82

11196.82

57911.33

14

Rapti River Basin

5433.66

2511.03

1580.62

1183.45

7640.38

15

Bheri River Basin

34665.56

20186.45

12591.01

9902.74

42877.77

16

Babai Sharada River Basin

1631.30

884.05

576.93

441.82

2135.15

17

Karnali River Basin

82353.65

51322.64

33817.98

25377.63

97751.46

18

Seti River (FarWestern) Basin

19119.09

10546.05

7682.99

6194.48

23916.10

19

Mahakali Basin

14883.57

8390.74

6326.33

5394.79

20348.22

 

Total

470089.22

274790.25

173846.76

130232.51

569963.79

 

Basin-wise Findings

The summary of the province wise comparison of hydropower potential in terms of MW for different probability of flow exceedance is presented in the table below.

Table 3: Province-wise Hydropower Potential of Nepal (MW)

S.N.

Province

Q20 Power (MW)

Q40 Power (MW))

Q60 Power (MW)

Q80 Power (MW)

Storage Annual Average Power (MW)

1

Province 1

39567.81

15615.77

7164.16

4951.78

20453.26

2

Province 3

24560.88

9489.08

4318.46

2655.63

13185.11

3

Province 4

30639.43

11133.15

5217.33

3528.00

15890.63

4

Province 5

7197.46

2320.71

1033.62

736.37

5205.40

5

Province 6

26870.39

11140.85

5644.29

3865.58

14564.31

6

Province 7

18699.54

6577.95

3749.16

2734.40

10405.10

 

Total

147535.51

56277.51

27127.02

18471.75

79703.81

 

The summary of the province wise comparison of hydro energy potential in terms of GWh for different probability of flow exceedance is presented in the table below.

Table 4: Province-wise Hydropower Potential of Nepal (GWh)

S.N.

Province

Q20 Energy (GWh)

Q40 Energy (GWh)

Q60 Energy (GWh)

Q80 Energy (GWh)

Storage Annual Average Energy (GWh)

1

Province 1

130293.72

76519.78

46766.75

35888.58

153190.82

2

Province 3

80832.33

47610.52

29176.05

19434.11

98753.81

3

Province 4

97454.42

55062.44

34264.46

25573.31

119017.67

4

Province 5

18224.02

9103.19

5661.58

4318.85

23894.13

5

Province 6

88709.75

55210.82

35845.55

27263.44

106463.68

6

Province 7

54574.99

31283.48

22132.37

17754.22

68643.68

 

Total

470089.22

274790.25

173846.76

130232.51

569963.79

References

•  DOED, "Expression of Interest for Environmental and Social Impact Assessment (ESIA) of Karnali (Chisapani) Multipurpose Project", March 2015

•  DOED, Expression of Interest for Feasibility and Environmental Impact Assessment (EIA) Study of Seti River (SR-6) Storage Project, June 2016

•  Dr. Hari Man Shrestha, "The Case of Upper Karnali Hydroelectric Project" •          Dr. Raghunath Jha, "Total Run of River type hydropower Potential of Nepal".

 •  Field Monitoring Committee/Ministry of Energy, "Field Monitoring Report of NEA Operated Power Plants", Bhadra 2068.

• Globalenergyobservatory.org/geoid/

•  JICA, Electric Power Development Co. Ltd, "Nationwide Master Plan Study on Storage-type Hydroelectric Power Development in Nepal", Final Report, Study Made by NEA, February 2014

•  Keshab Pyakurel, "Project Review: Arun III Hydroelectric Project", July 2015

•  Khimananda Kandel, "A Comprehensive Study on Hydropower Potential of Nepal", March 2018.

•  Ministry of Energy (MoEn), Initiative of Janardan Sharma, Former Minister for Energy, "Nepalko Pani Janatako Lagani",

•  Ministry of Energy (MoEn), Initiative of Mahendra Bahadur Shahi, Former Minister for Energy, "Present Situation of Energy Sector and Immediate Work Plan", Shrawan 2074.

•  Prashant Malla/ Dr. Akhilesh Kumar Karna, GIS/Hydrology Modeling Expert, "Web Based Platform for Hydropower and Energy Development", Aviyaan Engineering Consultancy Pvt. Ltd., January 2018.

•  S.C. Agrawal, CEO, SAPDC(Arun-3), "Presentation on Unlocking Nepal's Large Hydropower Potential and Future Large Storage Hydropower Projects Planning"

• Water and Energy Commission Secretariat (WECS), "Electricity Demand Forecast Report (2014-2040)", January 2017

•  Website of Budhigandaki Hydroelectric Project Development Committee (www. bghep.gov.np)

•  Website of Chilimite Hydropower Company Limited ( www.chilime.com.np)

• Website of Department of Electricity Development (doed.gov.np)

•  Website of Khimti Power Plant (https://hpl.com.np/projects/khimti-power-plant/)

•  Website of Madhya Bhotekoshi Jalabidhyut Company Limited (www.mbjcl.com.np)

•  Website of Ministry of Energy (Moen.gov.np)

• Website of Nepal Electricity Authority (www.nea.org.np)

•  Website of Pancheshwor Multipurpose Project (www.pmp.gov.np)

•  Website of Upper Tamakoshi Hydropower Limited (tamakoshihydro.org.np)

•  West Seti Hydro Limited, "Environmental Assessment Report, Nepal: West Seti Hydroelectric Project" for Asian Development Bank (ADB), August 2007

 


Chairperson,

Water and Energy Consultants' Association Nepal (WECAN).

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