ch 1. introduction final 1

8/10/2019 Ch 1. Introduction Final 1

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Chapter 1 1

1

1.1

1.1.1

Power is the rate of energy supply/consumption/demand. It is represented by P and Standard unit

of measurements in SI Unit is Watt.

( )sNmSJW

STime

mntDisplacemeNForce

Time

doneWork

STime

JEnergywattPower /1/11

)(

)(

)(

)()( ===

===

Energy can be in any form like Heat, Light, and Electricity

Energy in the form of Electricity is commonly termed as power and used widely all over the

world as it is easily transportable at high speed and convertible in to different form of energy

efficiently as per requirement. Electricity is taken as basic commodity as it is essential for running

communications and electronics equipments.

Energy is essential for anybody to perform work- day to day work (cooking, transportation,heating, cooling, lighting etc); Commercial activities (shopping complex, theatres, and cinema

halls) and Industrial use (production of goods, commodities, processing and refining etc)

Common units of Energy and Power measurements used in hydropower Engineering

Energy Power

Value Name Symbol Value Name Symbol

10 j Deca joule Daj 10 w Deca watt d w

10 j Hecta joule Hj 10 w Hecta watt h w

10 j Killo joule Kj 10 w Killo watt k w

10 j Mega joule MJ 10 w Mega watt Mw10 j Giga joule GJ 10 w Giga watt Gw

10 j Tera joule TJ 10 w Tera watt Tw

10 j Penta joule PJ 10 w Penta watt Pw

10 j Exa joule EJ 10 w Exa watt Ew

10 j Zetta joule ZJ 10 w Zetta watt Zw

1 HP = 735.5 W in Metric (MKS) system mostly used in Hydropower Engineering academic

courses but 1 HP = 746 W in FPS system not more used in academic exercise.

Hydropower engineering deals with the Electricity energy generated from the electro-mechanical

equipment (turbine-generator) and the unit of electricity energy measurement is KWh or Unit.

1 KWh or 1 Unit of electricity is the energy obtained from a heater (or other electrical appliances)

of 1 KW capacity in 1 hour.

JssJhrWhourKWKWh 510363600/100011000111 ====

Common Energy Conversion factorsUnit MJ KWh Ton of oil

Equivalent (TOE)Standardm

3gas

Raw OilBarel

Fuel wood(1 bhary)

1 MJ 1 0.278 0.0000236 0.025 0.000176 7.8E-051 KWh 3.6 1 0.000085 0.09 0.000635 0.000281 Ton of oil Equivalent (TOE) 42300 11750 1 1190 7.49 3.31

1 Standard m3 gas 40 11.11 0.00084 1 0.00629 0.002791 Raw Oil Barel 5650 1569 0.134 159 1 0.441 Fuel wood (1 bhary = 2.4m

3)

12800 3556 0.302 359 2.25 1

Source: 10 Yr 10000 MW Task force report 2009 (BS 2065)


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Chapter 1 2

1.1.2

Sun is the main source of Energy in the form of solar radiation. Some of thatenergy has been preserved as fossil energy, some is directly or indirectly usable;

for example, via wind, hydro- or wave power.

The term solar constant is the amount of incoming solar electromagnetic radiationper unit area, measured on the outer surface of Earth's atmosphere, in a planeperpendicular to the rays.

The solar constant includes all types of solar radiation, not just visible light. It is measured by satellite to be roughly 1366 watts per square meter, though it

fluctuates by about 6.9% during a yearfrom 1412 W m2

in early January to1321

W m2

in early July, due to the Earth's varying distance from the sun by a few parts

per thousand from day to day.

For the whole Earth, with a area of 127,400,000 km2, the total energy rate is 174petawatts (1.74010

17W), plus or minus 3.5%. This value is the total rate of solar

energy received by the planet; about half, 89 PW, reaches the Earth's surface.

Primary Sources of Energy

Fossil fuels oil, natural gas and coal

Non Fossil fuels- namely nuclear power and renewable sources

Renewable sources- hydro, solar, wind, Geo-thermal, Tidal

Consumption of Energy and Power Situation in World

In 2008, total worldwide energy consumption was 474 exajoules (4741018J) with 80 to90 percent derived from the combustion of fossil fuels This is equivalent to an average

power consumption rate of 15 terawatts (1.5041013

W)

Economic Crisis from 2006-2009 the energy consumption has not been increased butslightly decreased

Rise of Energy consumption between 2005 and 2030 is approximately 41 percent.

This demand increase will take place in developing countries, where the present demand

of energy is low due to less or small economic activities which are expected to grow mostrapidly during its development process.


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Chapter 1 3

Global economic output, as measured by Gross Domestic Product (GDP), (Nepal = 65 KWh/capita in2005 and targeted to reach 100 KWh/capita by 2012)

*OECD (Organization for Economic Cooperation and Development) Member Countries

(30)

Australia, Austria, Belgium, Canada, Czech Republic, Denmark, Finland, France, Germany,

Greece, Hungary, Iceland, Ireland, Italy, Japan, Korea, Luxembourg, Mexico, Netherlands, New

Zealand, Norway, Poland, Portugal, Slovak Republic, Spain, Sweden, Switzerland, Turkey,

United Kingdom, United StatesThe linkage between electricity demand and economic progress is evident when considering

electricity use (kilowatt-hours, kWh) on a per-capita basis relative to GDP per capita in countries


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Chapter 1 4

around the world. China, South Korea and the United States are specifically highlighted in the

chart above, which displays OECD*countries in red and non-OECD nations in blue.

Source: The Outlook for Energy A View to 2030 http://exxonmobil.com/corporate/images/enlarged_eoworld.jpg

Modern energy supplies (Nuclear Energy) are still a precious commodity for millions of

people due to complex technology and higher risk posed to human and environmental

health due to leakage of radioactive radiation.

1.1.3 /

Yearly Energy Supply (Production) by type in MGJ

Type 51/52 52/53 53/54 54/55 55/56 56/57 57/58 58/59 59/60 60/61 61/62 62/63 63/64 64/65 65/66

Year 1994/95 1995/96 1996/97 1997/98 1998/99 1999/00 2000/01 2001/02 2002/03 2003/04 2004/05 2005/06 2006/07 2007/08 2008/09

Traditional 258.11 263.48 267.02 272.77 278.60 284.61 290.86 302.08 308.61 315.27 322.10 328.09 334.78 341.62 348.87

Fuel wood 230.55 235.37 237.45 242.56 247.76 253.09 258.64 269.16 274.96 280.89 286.96 292.46 298.33 304.72 311.17

Agri. Residue 10.35 10.56 11.63 11.89 12.14 12.44 12.73 13.03 13.33 13.63 13.96 14.01 14.37 14.36 14.68

Animal dung 17.21 17.55 17.93 18.32 18.70 19.08 19.49 19.90 20.32 20.75 21.18 21.63 22.08 22.54 23.02

Commercial 24.79 27.69 29.48 35.10 34.85 44.90 43.34 43.85 43.27 44.86 43.20 46.60 43.96 44.26 48.90

Petroleum 19.13 21.56 23.64 28.97 28.16 30.20 31.29 32.31 32.12 31.60 30.06 29.26 30.14 27.91 33.01

LPG 0.64 0.89 1.07 1.15 1.24 1.49 1.97 2.40 2.76 3.26 3.82 3.99 4.61 4.77 5.70

Motor sprit

(Gasoline)1.15 1.36 1.49 1.58 1.66 1.87 1.98 2.12 2.26 2.28 2.53 2.71 3.41 3.38 4.16

Air turbine

fuel1.36 1.45 1.75 1.87 2.00 2.04 2.28 1.72 1.91 2.32 2.42 2.33 2.31 2.49 2.49

Kerosene 6.56 7.58 8.82 12.52 10.69 12.01 11.47 14.02 12.64 11.27 8.66 8.22 7.17 5.63 2.54

High speed

Disel8.61 9.50 9.80 11.42 11.97 11.76 12.37 10.86 11.38 11.37 11.91 11.16 11.63 11.48 17.69

Light Disel oil 0.13 0.17 0.09 0.04 0.04 0.17 0.13 0.09 0.02 0.02 0.00 0.01 0.01 0.01 0.01

Fuel oil 0.43 0.34 0.34 0.04 0.17 0.43 0.59 0.58 0.55 0.42 -0.03 0.00 0.05 0.03 0.00

Others 0.26 0.26 0.30 0.34 0.38 0.43 0.48 0.52 0.59 0.66 0.75 0.84 0.95 0.12 0.41

Coal 2.85 3.07 2.56 2.60 2.90 10.48 7.45 6.48 5.72 7.29 6.46 10.36 6.16 8.24 7.75

Electricity 2.81 3.07 3.28 3.54 3.79 4.22 4.61 5.07 5.43 5.97 6.67 6.97 7.66 8.10 8.14

Renewable

(others)0.32 0.45 0.58 0.71 0.84 1.01 1.22 1.39 1.58 1.71 1.91 2.10 2.32 2.50 2.73

Biogas 0.30 0.43 0.55 0.68 0.81 0.98 1.18 1.35 1.53 1.65 1.85 2.03 2.22 2.38 2.59

Micro-hydro 0.02 0.02 0.02 0.03 0.03 0.03 0.04 0.04 0.05 0.05 0.06 0.07 0.09 0.11 0.14

Solar 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.002 0.002 0.003 0.003 0.003 0.004 0.006

Total 283.23 291.62 297.07 308.58 314.29 330.52 335.42 347.33 353.45 361.84 367.21 376.79 381.05 388.38 400.51


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Chapter 1 5

Source: WECS Energy synopsis Report

Electricity is clean energyas it does not produce any type of pollution on its use, convertible to any form

of energy easily. Transportation and handling management is easy.

Sectorial Energy Consumption in Nepal

Historical trend of Sectorial Energy Consumption in Nepal (MGJ)

Year 51/52 52/53 53/54 54/55 55/56 56/57 57/58 58/59 59/60 60/61 61/62 62/63 63/64 64/65 65/66

Sector 1994/951995/961996/971997/981998/991999/00 2000/01 2001/02 2002/03 2003/04 2004/05 2005/06 2006/07 2007/08 2008/09

Residential 260.86 267.34 274.24 283.74 287.67 295.00 301.13 314.61 320.18 326.22 331.55 339.77 345.384 351.192 356.752

Industrial 11.08 11.76 6.43 6.90 7.54 15.72 12.99 12.52 11.97 13.72 12.74 12.99 12.7914 13.9887 13.3698

Commercial 2.56 2.85 3.20 2.94 3.20 3.71 4.13 4.94 4.09 5.33 5.33 5.71 4.6738 4.8857 5.1222

Transport 7.84 8.73 11.93 13.55 14.82 12.78 13.59 12.01 13.85 13.12 13.89 14.40 14.5095 15.0366 20.876

Agricultural 0.64 0.68 0.98 1.11 0.72 2.98 3.15 2.77 2.90 2.90 3.07 3.28 3.0106 2.5208 3.6464

Other 0.26 0.26 0.30 0.34 0.34 0.34 0.43 0.47 0.47 0.55 0.64 0.64 0.6803 0.7584 0.7399

Grand Total283.23 291.62 297.07 308.58 314.29 330.52 335.42 347.33 353.45 361.84 367.21 376.79 381.05 388.382 400.506


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Most of the Energy is used for residential use, The industrial use is comaparatively low and will

be very high in development of economic activities under the process of making new

industrialized Nepal

The amount of Per capita

electricity consumption reflects

the living standard of people and

their economic conditions.

The per capita electricity

consumption in Nepal is only 69

KWh and aimed to reach up to

100 KWh by 2012 (II nd Interim

Plan 2010-2012)

The per capita electricity

consumption of Nepalese people

is about 37 times less than the

world average and 27 times lessthan the average Asian people.

48% of the total population in

Nepal has access to the

Electricity. Only 8% of people

of rural areas enjoy it (MOF

2007, Energy Synopsis of Nepal

WECS-2010)

1.1.4

Side Effect of fossils fuels is emission of GHG gas (CO2, CH4 and N2O) causing the Globalwarming and climate change. Climate change rise of temperature, disturbance in rainfall

(monsoon rain, high intensity, unpredictable rain, landslide, flood and draught affecting


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Chapter 1 7

agriculture, ecosystem, biodiversity causing large numbers of endangered species of flora and

fauna)

GHG Emissions from Fossil Fuel Combustion in Nepal in 1994/95 (Gg)

Sectors Diesel Kerosene Coal Gasoline LPG Fuel Oil Total

Residential - 291 2 - 24 - 317

Industrial 73 6 233 - - 8 320

Transport 360 19 2 75 - - 456

Agricultural 135 - - - - - 135

Commercial 4 113 26 - 15 8 166

Energy

Conversion

- - - - - 71 71

Total 572 429 263 75 39 87 1,465Sources: WECS 1996 in Nepal's Initial National Communication, 2004

Note: These exclude emissions from the burning of aviation fuel

GHG emission from Combustion of Fossils Fuel (1994/1995)

Residential21.6%

Industrial

21.8%

Transport

31.1%

Agricultural

9.2%

Commercial

11.3% Energy Conversion

4.8%

Sources: WECS 1996 in Nepal's Initial National Communication, 2004

Sectorial GHG Emission from Combustion of Fossils Fuel (1994/95)

Electricity Energy do not produce any emissions in its use so it is termed as clean energy and the

efficiency of the energy use also has been improved significantly due to invention of modern

electrical appliances.

1.1.5

The first hydropower development or installation in the world was in 1882 and it is in Wisconsin

of USA. The capacity of the first hydropower plant was only 200 kW. Similarly the first

hydropower development or installation in India was in 1987 in Darjeling. The capacity of the

Indian Hydropower project was of 130 kW. Pharping Hydel Powerhouse of 500 kW capacities is

the first powerhouse installed in Nepal in 1911.


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The Pharping hydropower station was developed with the technical and financial aid of British

Government at the cost of NRs 713373.07 within 17 months in 1911 (BS 1968 Jestha 9 completed

date) . The power house with the installed capacity of 500 kW was running successfully till 1981

but after then, the water used for the plant was diverted for drinking purpose and the plant was

shut down. Even now, this plant can be restarted if the supply of water is made possible (NEA,

2003a).

Nepals first hydropower plant was installed not so long time after the first hydropower plants

were installed in USA or in India

First Hydropower Plants

The Government of Nepal decided to open its doors to the private sector involving both local and

foreign investors to promote Public Private Partnership under the BOOT system in 1992 in order

to fulfill the growing electricity demand using Nepals abundant hydro potential.

Commissioning dates of hydropower Projects in Nepal

S.N. Name of Power project InstalledCapacity(MW)

AverageannualEnergy(GWh)

CommissionandoperationYear

Investor Cost perKW

A Hydro Electricity

1 Pharping 0.5 3.3 1911 Nepal/British RS 1426.75

2 Sundarijal 0.6 4.8 1936 Nepal

3 Panauti 2.4 7.0 1965 Russia

4 Pokhara Phewa 1.0 8.5 1967 India

5 Trishuli 21.0 114.5 1968 India US$1296.30

6 Sunkosi 10.0 70.0 1973 China US$1093.70

7 Tinau 1.0 10.2 1974 BPC

8 Gandak 15.0 48.0 1979 India US$1300.00

9 Kulekhani-1 60.0 201.0 1982

WB and

others US$1950.0010 Devighat 14.1 114.0 1983 India US$2781.69

11 Seti 1.5 1.8 1985 China

12 Kulekhani-II 32.0 95.0 1986 Japan US$1937.50

13 Marshyangdi 69.0 462.0 1989 German/WB US$3333.33

14 Andhikhola 5.1 38.0 1991 BPC

15 Jhimruk 12.3 81.0 1994 BPC

16 Chatara 3.2 3.8 1996 Nepal/WB

17 Puwa khola 6.2 48.0 1999 Nepal US$2887.10

18 Khimti 60.0 353.0 2000HPC/IPP-norway US$2250.00

19 Modi 14.0 87.0 2000 Nepal/Korea US$1864.86

20 Bhotekoshi 36.0 250.0 2000 IPP (USA) US$2666.67

21 Kaligandaki 144.0 625.0 2001 Nepal/ADB US$2638.89


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Chapter 1 9

22 Indrawati 7.5 49.7 2002 IPP-Nepal US$2666.67

23 Chilime 22.1 137.0 2003 IPP-Nepal

24 Tatopani (Myagdi) 2.0 10.2 2004 Nepal

25 Sunkosi 2.6 14.4 2005 Nepal

26 Piluwa khola 3.0 19.4 2006 IPP-Nepal

27 Khudi 4.0 24.3 2006 IPP-Nepal

28 Middle Mrshyangdi 70.0 398.0 2009Nepal/German NRs 312000

29Small hydropwer-32 nos(Government) 8.1 37.0 different time Nepal

30Small hydropwer-12 nos(Ipp-Nepal) 7.64 40.0 different time Nepal-IPP

Total Hydro electricity 635.84 3355.9

B Thermal

1 Hetauda- Disel 14.4 43.0 1963 Nepal

2 Duhabi multifuel 39.0 165.0 1991Nepal-Finland

Total ThermalElectricity 53.4 208.0

Grand Total 689.24 3563.9Source: NEA annual report 2009, and 10 Yr 10000MW Task force Report 2009 (BS 2065)

Project under Construction

S.N. Name of Project InstalledCapacity(MW)

Investor Status

1 Lower Indrawati Khola SHP 4.50 IPP-Nepal

2 Mardi Khola SHP 3.10 IPP-Nepal completed

3 Ridhi Khola 2.40 IPP-Nepal completed

4 Upper Hadikhola 0.991 IPP-Nepal completed

5 Lower pilluwa 0.990 IPP-Nepal testing

6 Kulekhani III 14 Japan

7 Chamelia 30 Nepal/Korea

8 Mai khola (Himal Dolakha Hydro) 4.455 IPP-Nepal completed

9 Lower Modi (United hydro) 9.9 IPP-Nepal

10 Siprin khola (synergy HPP) 9.658 IPP Nepal

11Ankhu-1 Hpp (ankhu khola Jal bidhutcompany) 6.930 IPP Nepal

12Phawa khola HPP (Shivani Hpp Pvtltd) 4.950 IPP Nepal

Source: NEA annual report 2010/11

S.N. Description InstalledCapacity(MW)

Productionin Wetseason(maximumMW)

Productionin Dryseason(minimumMW)

Remarks

A Production of Electricity

1 Non Reservoir Project

NEA power projects 385.66 350 141.9Independent PowerProducers (IPP) 158.315 150 58.1

Sub Total 543.975 500 200

2 Reservoir Project

NEA power projects 92 0 92Independent PowerProducers (IPP) 0 0 0


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Chapter 1 13

1.1.

The worlds total technical feasible hydro potential is estimated at 14 370 TWh/year, of

which about 8082 TWh/year is currently considered economically feasible for

development.

About 700 GW (or about 2600 TWh/year) is already in operation, with a further 108 GW

under construction [Hydropower & Dams, World Atlas and Industry Guide, 2000].

Most of the remaining potential is in Africa, Asia and Latin America:

Remaining hydropower potential is in Africa, Asia and Latin AmericaTechnically feasible Economically feasible

potential: potential:

Africa 1750 TWh/year 1000 TWh/year

Asia 6800 TWh/year 3600 TWh/year

North + Central America 1660 TWh/year 1000 TWh/year

South America 2665 TWh/year 1600 TWh/year

Total 12835 TWh/year 7200 TWh/year

At present hydropower supplies about 20 per cent of the world's electricity. Hydro

supplies more than 50 per cent of national electricity in about 65 countries, more than 80

per cent in 32 countries and almost all of the electricity in 13 countries.(Source: IAEA Report on Hydropower and the World's Energy Future)

1.1.

Nepals theoretical hydropower potential of 83 GW is about 1.5% of worlds total

hydropower potential of 5610 GW in comparison with the Nepals land (147181 km2) of

only 0.11% of the world total (Shrestha, 1985, p.34).

This shows that hydropower potential per unit land area in Nepal is about 13 times higher

than that of the world average.

As the aforementioned value of hydro potential does not include that from the small river

basins (i.e. catchment areas < 300 sq. km, river length < 10 km.) and there are significant

numbers of such rivers in Nepal, the real hydropower potential of Nepal might be much

higher than this. To date, there are no comprehensive and detailed studies defining the

total micro hydro potential of Nepal from such small rivers.


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Chapter 1 14

Theoretical hydropower potential of rivers of Nepal

1.1.

Although Nepal has developed its first hydropower project about a century ago, the

development pace of its hydropower development is not as it was expected and needed.

Due to this, severe load shedding is unavoidable and becomes a part of Nepalese people.Only about 1.5% of the economically feasible potential or 1% of theoretical potential has

been installed. Only about 48% of the total population has access to the electricity.

Challenges

The following are the challenges that were faced in hydropower development in Nepal

Lack of political stabilityPolitical situation in Nepal is not favorable and stable since from 1990. Any one

of elected government has completed its full phase tenure since from the great

peoples movement in 1990 (Jan Andolan of 2046). Political parties and leaders

do not have clear vision for development of hydropower and its water resourcesfor well being of the Nepalese people. Political leaders focused only on benefits

of their own people and parties rather than the overall development of Nepal.

During Panchyat period also, the development pace in hydropower is not

encouraging as the development activities were based on grant and aid of

developed countries and developing partners. There was no vision of technologytransfer and independency. During Ranas regimes, the hydropower development

was carried out only for limited use of their own benefits.

Present political instability has brought disorder in laws and regulations enhanceviolence and insecurity at local and central level. This resulted retardation of

investment and development activities in hydropower.

Lack of Technology and Skilled man powerAlthough Nepal has large potential of hydropower development, it does not have

its own technology and sufficient skilled man power. The Nepalese engineer has


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Chapter 1 16

frequent in recent years posing serious uncertainties and threads to the hydro-

power projects. The GLOF events has been increased and caused serious floodswith debris flow which may damage the structures of hydropower projects. The

natural risks and threads have been taken as the one of the most difficultchallenges in hydropower development.

Opportunities

Nepal is in between the two giant countries China and India. Both of the countries are

developing very rapidly in recent years. They need lot of power/energy for their

development activities. Nepal has more than six thousands of rivers and rivulets and has

favorable topographical and geological conditions for hydropower developments. Thefollowing points can be taken as opportunities for hydropower development in Nepal.

Clean Energy

Hydropower is taken as clean energy as it does not produce any pollution during

its use and production. It is renewable and hence more attractive sources of

energy. The technology of its production and uses has been already developed and

affordable. The hydropower is easy to handle and transport from its production to

the load center.

The water of Nepalese rivers can be taken as white coal and policies has been

introduced to exploit the white coal in worldwide for supply of necessary energy(IAEA energy for future world).

Market availableThe market for Hydropower is easily available for Nepal since its neighbors are

being in developing phase and the economic activities are being taken at rapidly.

The electricity energy produced in Nepal can be exported to India and China thus

helps to reduce trade gap of the nations with these country.

Electricity produced can also be used for domestic use in promotion of industrial

activities and replacement of the petroleum fuels that has to be imported paying

hard currency. Thus market for hydropower development is abundant and can betaken as opportunities.

Favorable geological and topographical conditionsThe steep topography (High river gradient) with good geological conditions (hardrock in river bed) are the favorable and essentials for development of hydropower

projects at low cost of investment. The perennial rivers with considerable low

flow are good for hydropower productions. Although sediment flow rate in the

middle mountains and chure range are high, the sediment flow and production

rate in high Himalayas are less and can be taken as the opportunity.

Cheap labor force availability


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Chapter 1 17

Nepal has developed lot of engineering institutes and technical centers after the

restoration of Democracy in 1989 (BS 2046). The institutions have produced lotof skilled and semi skilled man powers. Although the human resources do not

have experience of the mega projects, they have equipped with theoretical andpractical knowledge at the institutions. These human resources are available at

cheap rate compared to that of the man power from developed countries. The

availability of the man powers both skilled and unskilled labors can be taken as

good opportunities to develop hydropower schemes for harnessing nations water

resources.

1.2 ()

Power System comprised of three components; a) Production/generation b)

Transmission/ evacuation and c) Distribution.

1.2.1 /

Power production in the form of electricity needs rotation of the electric coil inside strong

magnetic fields. Generator is the electromechanical parts which converts the mechanicalenergy in to the electrical energy based on Faradys Principle. The coil is rotated in stron

magnetic field at high velocity to induce electricity in the coil. The range of voltage of

the generated current is 6.6KV to 11 KV. The shaft of the generator can be rotated

providing energy from various sources like from coal, Diesel and water. Based on the useof energy to drive the shaft of generator, power system can be grouped in to two systems.

Thermal Power system

Electricity is produced from running of generator directly from shaft energy obtained

from diesel engines. Steam engines can also be used for to drive the shaft of generator.Coals/Gasoline is used as main fuel for steam engines. The efficiency of the thermal

power system is relatively lower than the hydropower generation and it is expensive than

hydropower regarding the operation and maintenance cost. The total installed capacity of

thermal power is 53.4 MW but about 20 MW is in operational use.

Hydropower system

In this system, Electricity power is generated by the use potential or kinetic energy of

water. As, water is being renewable in nature, high importance has been provided for thissystem. Besides it, hydropower system is pollution free and so, it is taken as the

environmental friendly system for power production. Although the investment cost ishigh, the operation and maintenance cost is low and it is attractive being the clean energy

having no pollution during production and consumption. The total installed capacity is

about 634.3 MW out of which 92 MW is reservoir type and rest 542.3 MW is runoff river

types which produce about 500 MW only in wet season and 200 MW in dry season.

Advantages Disadvantages

i) Renewable (white coal) High gestation periodii) Running cost is low high investment costiii)Quick response (1 to 2 min) to power system (peaking) dependent in nature


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Chapter 1 18

Solar power system

Solar or photovoltaic cells are used to trap solar energy and to produce electricity. InNepal solar system is used only for lighting the in the rural areas as the power production

is in small scale and expensive.In developed countries the other sources of power supply are Nuclear, Tidal, Wind and

Geothermal.

1.2.2 /

Generally the load centre is far from the generation or production system and the power

produced from the plants are evacuated or transmitted to the distribution centre through

transmission line. Transmission Lines do not supply the power to the customer it suppliesthe power to the distribution centre (Sub stations) only. The electricity generated from the

generators are in 11 to 25 KV range and stepped up to the transmission voltage33/66/132/230 KV. Transmission line may be single circuit or double circuit depending

upon the numbers of wires in the transmission line. In developed country high

transmission voltage 765 KV and 1200 KV as power capacity is directly

proportional to the square of transmission voltage.For transmission line greater than

600 km, DC transmission is economical at 400 KV and the line is connected to AC

system at the two ends through a transformer connecting through converter and inverter

(silicon control rectifier)

1.2.3

Based on supply system, power system can be divided into isolated and grid system. Inisolated system the power is supplied from a definite power plant while in grid system the

supply of power is made available from multi power plants. Failure of a particular power

plant will not disturb the power supply in grid system. The grid system might be regional,

national or international also.

Advantage

Use of remote energy source Improve reliability Utilization of the time difference between various time zones where peak demand

are not coincident, require low installed capacity

Maintenance of power plant possible without disturbing the supplyDisadvantage

High power loss in transmission lines in the grid connected system due to long

transmission lines

1.3 ,

Less than 100 KW: Micro

100 KW to 500 KW: Mini

500 KW to 10 MW: Small hydro

10 MW to 300 MW: Medium Hydro

Bigger than 300 MW: Big Hydro


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Chapter 1 19

1.3.2

Low, medium and high head are terms used to indicate the most suitable type of turbine

for the project. Various types of turbines are used depending upon the head of the powerplant.

Low Head up to 10 m Use: Cross-flow, axial-flow or propeller turbine (Kaplan)

Medium Head 10 m to 200 m Use: Cross-flow, Francis, Pelton or Turgo turbine

High Head 200 m to 1000 m Use: Pelton, Turgo-impulse or Francis turbine

Francis Turbine

Pelton Turbine

Kaplan Turbine (Propeller)

Pelton Turbine Runner Close view


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1.3.3

Runoff the river, Pondage Runoff River (PROR), storage, pump storage plants and Tidal

Run-of-River (RoR) type

A run-of-river project is built to use some or most of the flow in a stream depending upon

the flow throughout the year. No attempt is made to store water for the dry periods. A

run-of-river project would not normally have a dam, other than an intake weir, which is a

very low head structure at the intake. The intake weir keeps the water in the stream high

enough to fill the pipe at all times.

Suitable where the fluctuation of flow in dry season and wet season flow are small like in

rivers coming from Tibet at border such schemes do not alter the flow regime at the

downstream. Khimti, Khudi, Trishuli etc

Pondage Run-off River Type (PROR)

Run off river plants are provided with pondage to regulate flow to the plant which

enables them to take care of our to hour fluctuation in load on the plant throughout the

day or week. The water in river are stored at the head pond during non peak load or off

peak load hours of a day to with draw or use the stored water for power production

during the peak hours of load. The PROR power plants may operates at full capacity forall hours during high flow or rainy season but it produces power at full capacity at peak

load hours. The power plant may shut down or operate at lower capacity during the peak

off hours in dry season. At the same location, the installed capacity of the PROR plants

are higher than the ROR type plants and operate at full capacity only at peak load hours.

Marshyangdi 69 MW, Middle Marshyangdi 70 MW and Kaligandaki A 144 MW are

PROR project in Nepal.

Reservoir Storage Plants

Hydropower plants which draw water from large storage reservoirs developed byconstructing dam across the river are called reservoir or storage project. Depending upon

the storage volume, these plants can hold surplus water from periods when the stream

flow exceeds demands for utilization during the period when demand exceeds the stream

flow. Better utilization of hydropower potential is thus achieved with such plants. The

water flow stores in wet season to supply in dry season. Kulekhani reservoir project is

only one storage project in Nepal Kulekhani-I 60 MW and Kulekhani-II 32 MW.

Pump storage


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Plants in which all or portion of the water used by these plants is pumped back to the

head water pond to be made available again for the power generation during peak hours

of demand. This type of the power plant essentially consists of a tail water pond and headwater pond. During peak load water is drawn from the head water ponds through the

penstock to operate hydro electric generating units. The water is collected in to tail water

pond and during the off peak hours, pumps are operated to pump the water back from the

tail water pond to the head water pond. Power for operating the pumps is provided by

some of peak thermal or hydropower plant.

For head up to 120 m special Francis turbine has been developed for the pump storage

plants. The runners of the turbines are so shaped that they can be used both as turbine as

well as pumps. Such turbines are known as reversible turbines.

For high head, multistage centrifugal pumps are used for pumping water and high head

Francis Turbines are installed in power production.

Tidal Plants

Sea water rises or falls twice a day, each full cycle occupying about 12 hours 25 minutes.

The tidal range or the difference between the high tide and low tide level is utilized to

generate power.

This is accomplished constructing a basin separated from the sea by a wall and installing

a turbine in opening through this wall.

During high tide water passes from the sea to the basin thus running the turbine and

generating power. During low tide, water from the basin flows back to the sea which can

also be utilized to generate power by providing another set of turbine operating in

opposite flow direction.

ExampleFrance: Rance power plant, tidal range 11 m, 9 units of 38 MW each with total

capacity of 342 MW.

12 hr 25 min 12 hr 25 min

Tidal Ran e


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ch 1. introduction final 1

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