TABLE OF CONTENTS Chapter No. 01. 02. 03 04 05
Topic
Pg. Pg . No.
Table of Contents Introduction Introduct ion & History History of Hydropower Types of Hydropower Advantages and Disadvanta Disadvantages ges of Hydropower Numerical Analysis of Hydropower Hydropower in India References
01 02-04 04-06 06-07 07-10 10-12 12
1. INTRODUCTION 1.1 What is Hydropower? Hydropower or water
the Greek: hydor ,meaning ,meaning "water") is power is power derived from power (from the Greek:
the the energy of of falling water or fast running water, which may be harnessed for useful purposes. Since ancient times, hydropower from many kinds of of watermills has been used as a renewable energy source
for irrigation irrigation and and
the
as gristmills, as gristmills, sawmills, sawmills, textile textile mills, mills, trip
operation hammers,
of
various
dock cranes, cranes,
mechanical
devices,
domestic lifts, domestic lifts,
such
and and ore mills. ore mills.
A trompe, trompe, which produces compressed air from falling water, is sometimes used to power other machiner achinery y at a distance. distance. In the late 19th century, hydropower became a source for generating generating electricity. electricity. Cragside i Cragside in n Northu Northumberlan berland d
was the the
first house house powered powered by hydroel hydroelectr ectriicity city in 1878.and the first
commercial hydroelectric power plant was built at Ni at Niag agara ara Fall Falls in in 1879. In 1881, street lamps in the city of Niagara Falls were powered by hydropower. Since the early 20th century, the term has been used almost exclusively in conjunction with the modern
development
of hydroe of hy droellectric
power. power . International
institutions
such
as
the World the World
Bank view hydropower as a means for for economi eco nomicc development de velopment without adding substantial amounts
of
carbon
to
the
atmosphere
,but dams ,but dams can ca n
have
signifi significa cant nt
negative social and and environmen environmenta tall impacts. pac ts.
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1.2 History of Hydr Hydropower opowe r? In India, In India, water
wheels and watermills were were
built
in Imperial
Rome,
water
powered
mills
produced produced flour from grain, rain, and and were were also also used for sawin sawing tim timber and stone; stone; in China China,, waterm watermiills were widely used since the Han dynasty. In China In China and the rest of the Far East, hydraulically operated ope rated "pot "pot wheel" pumps pumps raised water into into crop c rop or irrigatio rrigation n canals. The power of a wave of water released from a tank was used for extraction of metal ores in a method
known
as hushing. as hushing.
The
method
was
first
used
at
the Dolaucothi the
Gold
Mines in in Wales fr om om 75 AD onwards, but had been developed in Spain in Spain at such mines as Las as Las Médulas.
Hushing was also widely used in in Britain in the Medieval the Medieval and and later periods to
extract lead and tin ores. ores. It later evolved int into o hydraulic hydraulic mining mining when used during the the Cali Ca liforni forniaa Gold Rush. In the Middle Ages, Ages, Islamic mechanical engineer Al-Jazari Al-Jazari described described designs for 50 devices, many of them water powered, in his book, The Book of Knowledge of Ingenious Mechanical Devices, Devices, including clocks, a device to serve wine, and five devices to lift water from rivers or pools, pools, thoug though h three three are ani animal-powered al-powered and and one can be powered powered by ani animal or water. water. These These include an endless belt with jugs attached, a cow-powered shadoof, cow-powered shadoof, and a reciprocating device with hinged valves. In 1753, French engineer Bernard engineer Bernard Forest Fore st de Béli Bélidor dor published Architecture published Architecture Hydraulique Hydraulique which which described vertical- and horizontal-axis hydraulic machines. By the late nineteenth century, the the electric electric generator was developed by a team led by by project projec t managers and promi pro minent nent pi p ioneers onee rs of renewable energy Jacob S. Gibbs Gibbs and and Brinsley Brinsley Coleberd Co leberd and could now be coupled with hydraulic hydraulic s. The growing growing demand for the Industrial Revolution would drive development develop ment as well. well. At the beginning of the Industrial Revolution in Britain, water was the main source of power for new inventions such as Richard Richard Arkwright's Arkwright's water frame. Although the use of water power gave way to steam power in many of the larger mills and factories, it was still used during the 18th and 19th centuries for many smaller operations, such as driving the bellows in small small blast furnaces (e.g. (e.g. the Dyfi Dyfi Furnace) Furnace ) and gristmills, such such as those built at at Sai Sa int Anthony Fall Fa lls, s, which uses the 50-foot (15 m) drop in the Mississipp Mississippii River. River. In the 1830s, at the early peak in US US canal-building, canal-building, hydropower provided the energy to transport barg transport bargee traffic traffic up and down steep hills using incli inclined ned plane railroa railroads ds.. As railroads 3|Page
overtook canals for transportation, canal systems were modified and developed into hydropower systems; the history history of Lowell, Lowell, Massachusetts Mass achusetts is a classic example of commercial development and industria ndustrializa lizatio tion, n, buil built upon the avail availab ility of water power. power . Technological advances had moved the open water wheel into an enclosed enclosed turbine or turbine or water water motor. motor. In 1848 1848 James B. Francis, Francis, while working as head engineer of Lowell's Locks and Canals company, improved on these designs to create a turbine with 90% efficiency.He applied scientific principles and testing methods to the problem of turbine design. His mathematical and graphical calculation methods allowed confident design of high efficiency turbines to exactly match a site's specific flow conditions. The Francis Fra ncis reaction reac tion turbine turbine is still in wide use today. In the 1870s, deriving from uses in the California mining industry, industry, Lester Allan Allan Pelton Pe lton developed developed the high efficiency Pelton wheel impulse turbine, which utilized hydropower from the high head streams
characteristic
of
the
mountainous
California
interior.
2. Types of Hydropower Hydropower is used prim primarily to generate electricity. Broad categories categories include nclude:: 2.1. Convent , referring referring Convent i onal hydroel hydroel ectri c
to hydroelectric hydroelectric dams.
-of-the-ri ver ver hydroel hydroel ectri city 2.2. Run -of-the-ri , which which
captures captures the kinetic kinetic energy in rivers rivers or streams, strea ms,
without without a large reservoir rese rvoir and a nd sometimes sometimes without without the use use of dams. da ms. 4|Page
2.3. Smal mal l hydro projects are
10 megawatts megawatts or less and a nd often have have no artifi artificc ia l reservoirs.
pro vide de 2.4. Mi cro hydro projects provi
a few kilowatts kilowatts to a few hundred hundred kilowa kilowatts tts to isolated isolated
homes, village villages, s, or small small industries. industr ies. hydroell ectri city projec 2.5. Condui t hydroe pro jects ts
utilize utilize water wate r which which has already alread y been be en diverte diverted d for use
elsewhere; in a munic unic ipa l water system, for example. example. 2.6. Pumped-s store s Pumped-stor tor age hydroel hydroel ectri cit y stores
water pumped uphill into reservoirs rese rvoirs during during
periods periods of low low demand demand to be released released for generat eneratiion when when deman demand d is high high or system system generation generatio n is low.
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3. Advantages and Disadvantages of Hydropower Hydropower offers offers advantag a dvantages es over other energy energy sources but faces faces unique unique environme environme ntal chall challen ges.
3.1 Advantages
Hydropowe Hydrop owerr is a fueled fueled by water, so it's a clean clean fuel source. so urce. Hydropower doesn't doe sn't poll pollute
the air like power plants plants that
burn burn fossil ossil fuel uels, such such as coal or natu natural ral gas. gas.
Hydropower is a domestic source of energy, produced in th e United United States.
Hydropowe Hydrop owerr reli re lies es on the water cycl c ycle, e, which is driven by by t he sun, sun, thus thus it's a renewable renewable power source.
Hydropower is generally available as needed; Engin Enginee eers rs ca n control co ntrol the fl flow of water through the turbines turbines to produce electric electric ity on demand.
Hydropowe Hydrop owerr plants plants provide benefits benefits in additi ad dition on to clean electr electricity. icity. Impoundment Impoundmen t hydrop ower owe r creates cre ates reservoirs rese rvoirs that offer offer a variety of recrea rec reational tional oppo op portuni rtunitt ie s, notably notab ly fi fishing, s wim wimming, and boating boating.. Most hydrop hydropower ower installat nstallatio ions ns are required required to provide provide some publc publc
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access acce ss to the reservoir reservoir to allow allow the publi public to take advantage of these these oppo o pportun rtuniities. Other benefi be nefits ts may include nclude water supply supp ly and fl flood oo d control. c ontrol.
3.2 Disadvantages
Fish popul pop ulations ations can be impa impacted cted if fish fish cannot c annot migrate migrate upstream upstre am past impoundm impoundmee nt dams da ms to spawni spa wning ng grounds or o r if they cannot ca nnot migrate migrate downstream do wnstream to the ocean. ocea n. Upstre am fish fish passa p assage ge can ca n be aided using using fish fish ladders ladde rs or elevators, or by trapping trap ping and a nd haulin haulin g the fi fish upstream upstre am by truck. Downstream Do wnstream fish fish passage pa ssage is aided by b y diverting fish fish fro m turbine turbine intakes ntake s using scree s creens ns or racks rac ks or even underwater underwa ter lights lights and sounds, sounds, and by mainta maintainin ining g a min minimum imum spill spill flow flow past pa st the turbine. turbine.
Hydropower can impact water quali quality and fl flow. Hydropower plants plants can c an cause low low dis solved oxyg o xygen en levels levels in the water, water , a problem pro blem that is harmful harmful to riparian (riverb (riverbank) ank) ha bitat bitatss and and is
addressed addressed using sing vari variou ouss aerati aeration techni techniques ques,, whi which oxyg oxygenate enate the the wate wate
r. Maintaining Maintaini ng minimum minimum flows flows of o f water downstream downstrea m of a hydropower hydrop ower installa installatt ion is al so critica critica l for the surviv survivaa l of riparian habitats.
Hydropower plants plants can be impacted pacte d by drought. drought. When water is is not not availab availablle, the hyd hyd ropower ropo wer plants plants can't produce prod uce electricity. electricity. New hydrop hydropower ower facilities acilities impact the local e nviron nvironmen mentt
and may compete co mpete with with other uses for the land. Those alternative uses m
ay be more highly highly
valued valued than electricity electric ity generati genera tio o n. Humans, flora flora,, and fauna fauna may may
lose their natural habi hab itat.
Local Loca l cultures cultures and historica historicall sites may be impinge impinged d upon.
Some So me older hydro hydropo power wer facilitie facilitiess may have historic historic value, value, so renovations of these fac ilities ilities must also be sensitive to such
preservatio pre servation n concerns conc erns and to impa impacts cts on plan
t and animal animal life life
4. Numerical Analysis of Hydropower 4.1 Calculating the amount of available power A hydropower resource can be evaluated by its available power. Power is a function of the hydra ulic head and rateof fluid flow. The head is the energy per unit weight (or unit mass) of water. The static head is proportional to thedifference in height through which the water falls. Dynamic head is related to the velocity of moving water. Eachunit of water can do an amount of work equ al to its weight weight times times the head. head . 7|Page
The power available from falling water can be calculated from the flow rate and density of water, the height height of fall fall,and ,a nd the local accelera ac celerati tion on due to gravity. gravity. In SI units, units, the power po wer is: is:
Where P is power in in watts watt s η is
the dimensionless dimensionless efficiency of the turbine
ρ is
the density density of water in in kilograms per cubic metre
Q is the flow in in cubic metres per second g is the acceleration acceleration due d ue to gravity grav ity h is the height difference between inlet and outlet in met res
To illustrate, power is calculated for a turbine that is 85% efficient, with water at 1000 kg/cubic metre (62.5pounds/cubic foot) and a flow rate of 80 cubicmeters/second (2800 cubicfeet/secon d), gravi gravity ty of 9.81 9.8 1 metres metres persecond persec ond squared sq uared and with with a net head of 145 m (480 ft). ft). In SI units:
which which gives gives 97 MW In English units, the density is given in pounds per cubic foot so acceleration due to gravity is in herent in the unitof weight. A conversion factor is required to change from foot lbs/second to kilowatts:
which which gives gives 97 MW (130,00 (130 ,000 0 horsepower) Operators of hydroelectric stations will compare the total electrical energy produced with the the oretical potentialenergy of the water passing through the turbine to calculate efficiency. Procedur es and definitions for calculation ofefficiency are given in test codes such as ASME PTC 18 and 8|Page
IEC 60041. Field testing of turbines is used tovalidate the manufacturer's guaranteed efficiency. Detailed calculation of the efficiency of a hydropower turbinewill account for the head lost due t o flow friction in the power canal or penstock, rise in tail water level due toflow, the location of t he station and effect of varying gravity, the temperature and barometric pressure of the air, thede nsity of the water at ambient temperature, and the altitudes above sea level of the forebay and tail bay. bay. Forprecise Forprecise calcul calculati ations ons,, errors errors due due to roundi rounding ng and the the nu number of sign signiificant cant dig digits of consta consta nts must be considered. Some hydropower systems such as water wheels can draw power from the flow of a body of wat er withoutnecessarily changing its height. In this case, the available power is the kinetic energy o f the fl flowing water. Overshot Over shot water wheels wheels can eff effic ie ntly nt ly capture both b oth types of energy. energy. The water flow in a stream can vary widely from season to season. Development of a hydropowe r site requiresanalysis of flow records, sometimes spanning decades, to assess the reliable annual energy supply. supply. Dams andreservoirs andreservoirs provi p rovide de a more dependable dep endable source so urce of power po wer by b y smoothi smoothing ng se asonal changes in water flow. Howeverreservoirs have significant environmental impact, as does alteration of naturally occurring stream flow. The designof dams must also account for the worst case, "probable maximum flood" that can be expected at the site; aspillway site; aspillway is often included to b ypass flood flows around the dam. A computer model of the hydraulic basin andrainfall and sno wfall wfall records reco rds are used used to predict pre dict the maximum maximum floo flood. d.
4.2 Physics of Hydropower
Two Types of Energy a) Kinetic Energy Kinetic energy is the energy that an object has because of its motion relative to its surroundings. It has the ability to do work on other objects by applying a force to those objects in order to change its velocity. velocity.
For Fo r example, a cue ball that is is rolli rolling across across the table has kinetic kinetic energy
relative relative to the other o ther bil b illi liard ard ball ba llss on o n the table tab le that are static. sta tic. If the cue ball hits hits another ball, ball, it it appli ap plies es a forc forcee to the second sec ond ball ba ll over a very small small distance.
This This force forc e changes changes the cue ball's ball's
velocity while while it transfers energy to the static ball, ball, and thus, thus, itit does doe s work. work .
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b) Gravitati Gravitational onal Potential Potential Energy Energy Newton’s Newton’s Uni Universal versal Law of Grav Graviity tell tells us that that the the grav graviitati tational force between between two objects depends upon the inverse of the square of the di stance between the objects and is, therefore, not a constant c onstant force forc e with displacement. displace ment.
However, However , if if we li limit mit the the movements movements of the objects obje cts to small
values compared to the total distance between them, then we can consider the forc e of gravity to be a constan constant. t. Objects fall alling near near the the surf surface ace of the the Earth Earth fall all into thi this category category..
The The dista distance nce
between between the the center center of the the Earth Earth and and the the center center of o f any object near near the the surf surface ace is over 4,000 miles. If we limit the object to fall a distance of less than a mile, then the change in the force of gravity over that distance is less less than .05%. .05 %.
Thus, Thus, we can take itit to be a constant. co nstant. In this this si tuation,
Newton’s Newton’s Uni Universal versal Law of Grav ity ity reduces reduces to the express expressiion:
Since the force is a constant, the potential energy is merely this force multiplied by the distance through which which the obje o bject ct falls. falls.
If we allow allow H to be b e the heig height ht through through the object obje ct will will fall, fall, then
the potenti pote ntial al energy of o f the object obje ct is: is:
For a hydroelectric dam, the the object ob ject that is “fall “fallin ing” g” is water. water . falli falling ng is is deter d eterm mined ined by how much volume volume itit occupies. occup ies.
The ma ma ss of of the water that is
The relationshi relationship p between between the two is
given given by the formula (mass = density de nsity x volume. volume. For Fo r fresh water, wate r, the density is 1 gm/cm3, gm/cm3, which which is equi eq uivalent valent to 1000 100 0 kg/m3 Thus, our formula for the potential energy of a volume of water V that falls through a height H
is where J is the symbo symboll for the the unit unit of energy called called the joule. joule.
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5.Hydropower in India India is the 7th largest largest producer prod ucer of hydroelectric hydroelectric power in the the world. As of March 31, 31 , 2016, 201 6, the the installed utili utilitt y scal sca le capacity cap acity was wa s 42,7 42 ,783 83 MW, which which was 14.3 14 .35% 5% of total tota l utility utility electricity electric ity generation generatio n capac cap aciity in in India. In additi ad dition, on, small small hydro powe p owerr units units with with a cumul cumulat ative ive capacity cap acity of 4,274 4,2 74 MW have been installed. nstalled. Betwee n 2014 201 4 and 2015, 201 5, the total hydroe hydroellectri ectr ic generatio generatio n was 129 TWh. The The hydroelectr ic power po wer potential po tential of India is is estimated estimated at 84,000 MW 84,000 MW at 60% load factor, facto r, one o ne of the largest in the world. India also imports surplus hydro power from Bhutan. The The hydrohydro-el electricpower ectricpower plan plants ts at Darjeeling at Darjeeling and and Shivanasamudra were established established in 1898 18 98 and 1902 respecti respec tively vely and were were among the first first in Asia. Asia. India has been a domi do minant nant player in global global hydro power po wer development.
Hydr Hydroelect oe lectrric P otenti ote ntial al in Ind ndia ia The economi eco nomica cally lly exploitable exploitab le and viab viablle hydro potential po tential of o f India is is estimated estimated to be about ab out 148, 14 8,70 701 1 MW.In MW. In addi add ition, 6,7 6 ,780 80 MW from small, small, mini, mini, and micro micro hydro schemes sc hemes (with (with capa c apacity city of less than 25 MW) are estimated estimated to be exploitab exploitablle.56 e. 56 sites sites for pumped pumped storage schem sc hemes es with with an aggregate aggregate installed nstalled capacit capa city y of 94,000 94, 000 MW have also been identi identified. fied. The The hydro power po wer potential potential in central ce ntral India India forming forming part pa rt of the the Godavari, Mahanadi, Nagaval Nagavalii, Vamsadhara and and Narm ada river basins has not yet been developed on a major scale sca le due to potential oppo op positi sition on from the the tribal populati population. on. The public public sector sec tor has a dominant dominant share of o f 92.5 92 .5% % in in the hydroelectric sector. sector. National Hydroelectric Power Corporation (NHPC), Northeast No rtheast El Electric Power Company (NEEPCO), Satluj Sa tluj Jal Jal Vidyut Nig Nigam (SJVNL), THDC, (SJVNL), THDC, NTPC-Hydro NTPC-Hydro are some of the 11 | P a g e
publi public sector sector compani companies engag engaged ed in developm development ent of hydroel hydroelectri ectricc power in in Indi India. a. The The priv private sector owns about ab out 7.5% 7. 5% out of the the total 42,783 42, 783 MW. Thi Thiss sector is expected expe cted to grow faster, faster, however, due to devel de velop opment ment of o f potential po tential hydroel hydroe lectr ec triic energy in the Himalaya the Himalaya mountain ranges, includ nclud ing northeast northeas t of o f India. Indian compani co mpanies es have also constructed constructe d hydro power projects pro jects in in Bhutan, Bhutan, Nepal, Ne pal, Afgh Afghanis anista tan, n, and other countri countries es.. Bhakra Beas Beas Management Management Board (BBMB), a state-owned state- owned enterprise in north north India, has an installed nstalled capacity cap acity of o f 2.9 GW. The The generati generatio o n cost after after four decade dec adess of operation is about 27 paise paise (0.40¢ US) per kWh BBMB is is a major major source source of peaking peaking power and black black start start to the the northern grid in in India. Large reservoirs reservo irs provide opera op erati tional onal flexibi flexibilit lity. y. BBMB reservoirs rese rvoirs annually annually supply supply water for for irri irrigatio gatio n to 12.5 12. 5 millio llio n acres (51,000 (51,0 00 km2; 19,500 19, 500 sq mi mi) of agricultural agricultura l land of partner pa rtner states, state s, enabling enabling the the green revolution in northern India.
REFERENCES
https://en.wikipedia.org/wiki/Hydropower ((Accessed on November https://en.wikipedia.org/wiki/Hydropower November 30, 2016)
http://esa21.kennesaw.edu/activities/hydroelectric/hydroactivity.pdf (Accessed on November 30, 2016)
http://www http://www.envi .envirothonpa.org/doc rothonpa.org/docum uments/19bHydropo ents/19bHydropowerAdvantag werAdvantagesandDisadva esandDisadva ntages.pdf ntages.pdf(Accessed (Accessed on November November 30, 2016)
https://en.wikipedia.org/wiki/Hydroelectric_power_in_India (Accessed on November 30, 2016)
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