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Hands-On Experience with Small-Scale Hydropower in Remote Areas: Some Examples of Nepal and Peru
Co p ~- ri ght
©
Buda pest.
Hu ngar~.
IF .-\ C ~h h T rit"nn ittl " ',, rld CO Il ~n:~ s 19~4
HANDS-ON EXPERIENCE WITH SMALL-SCALE HYDROPOWER IN REMOTE AREAS: SOME EXAMPLES OF NEPAL AND PERU J.
Litscher* and N. Kapali**
*E lrrtrvu'a ll E uginl'ering Sen,jff.\ Limilrd , P .O . B ox . CI/ ·IUJ22 ll1 rich. S'I'it:",.laru/ **L"lIi1'nsitaft fUft" Bodfllk"ltu r, A-J J8fJ r inllUl , :\ w l 1";O
AQ§!r2f!. RecentLy, severaL smaLL hydroeLectric power pLants have been constructed in remote areas of NepaL. The unforeseen difficuLties whi ch were encountered during construction are presented here. In Peru, there are more than 100 existing smaLL hydropower pLants which were constructed in the 1950's and 60's. Many of them are out of order or not running properLy. SeveraL representative cases are described and reasons are pointed out. Based on the exampLes given, generaL insights and specific recommendations are discussed regarding the impLementation and operation of smaLL hydropower pLants in the most inaccessibLe regions.
INTRODUCTION SmaLL-scaLe hydro has become very attractive worLdwide since the energy crisis in 1973. Numerous smaLL hydroeLectric power pLants were constructed recentLy in deveLoping countries as weLL as in the more deveLoped countries to reLy on internaL resources as much as possibLe.
NepaL is a LandLocked mountainous country extending aLong the HimaLayas between China and India. Deep vaLLeys are carved out of young mountains by the erosive monsoon fLoods. Though this nation has the biggest specific hydropower potentiaL in the worLd (the theoreticaL potentiaL is impressive with over 80,000 MW), !b~r~_2r~_§~~~r~_QQ§!2fl~§_!Q_Q~
ImpLementing and running smaLL hydro pLants in remote areas of deveLoping countries is compLeteLy different than in deveLoped ones. This statement is proven both by experience with design and construction as weLL as the use and maintenance of smaLL hydroeLectric power pLants.
Q~~rfQm~_ i Q_QriQgiQg_!bi§_QQ~~r_!Q_!b~_~QQ:
fhEI_J_~_Q;~J§~_~~Q_fQ~~IRUCIJQ~_Q£ ~~~hh HY~EQ;h;fIE!f_fQ~;E_fh~~I~ ~;f~h
IN
The SmaLL HydeL DeveLopment Board (SHDB) estabLished in 1976 and responsibLe to the Ministry of Water Resources - experienced some probLems designing and supervising the construction of smaLL hydroeLectric power pLants in NepaL. The design and construction of seven smaLL hydropower pLants was carried out over the period from 1977 to 1982. The size of these projects was in the range of 80 kW to 500 kW. ALL were isoLated schemes in the most out-ofthe-way areas.
The young, unstabLe geoLog y and the difficuLt access, combined with the monsooncLimate hampers the deveLopment of hydr opower to an extreme degree. Present instaLLed capacit y is appr oximateL y 165 MW, which is as Low as 0.2 % of the theoreticaL potentiaL.
fQQ§~m~r§.
The majorit y of the popuLation Lives in the hiLL y regions between the HimaLa ya and the Terai, the Ganges pLain. Most of t he NepaLi peopLe are seLf-reLiant farmers, inhabiting scattered smaLL viLLages on steep terraced sLopes. The peopLe are understanda bLy proud of their devoteLy reLigious, traditi onaL Lifesty Le. The extreme topography of NepaL and the state of transportation faciLities avaiLabLe ma ke the eLectrificati on of the whoLe country fr om a centraLized grid an utopic enterprise. Therefore, and aLso since most of the energ y in the form of firewood is being consumed in the ruraL areas, great emphasis is gi ven t o the impLementation of smaLL hydr oeLectric power pLants.
3343
J. Litscher and N. Kapali
33 44
NEPAL
4
o
"leRO
HyORO
ONGOING
Fig. 1
PLANTS
•
SmaLL hydro projects in Nepal - Location map
3.!._Pr9P _l~!!!?_ ec)fQ!!C)j;~!:~£LQ!!!:iC)g_ the_Q~!!ig!L2c)Q
b) Construct ion
fQC)!!j;!:!!£j;iQc)_Qf_!!m~ll hY9rQ~1~fl!:if_QQ~~!:
Qi2C)!!! a) Design To begin with, the Lack of hydroLogical data or adequate toPo9caphical maps is a common problem in most developing countries and this is no exception in the case of Nepal. The main
Q!:Q~1~!!!_b~!:~L_bQ~~~~!:~_i2_1b~_9££~22L_which-- becomes readily apparent on the first site visit right at the feasibility study stage. Not one of the seven projects was accessible by road. Some 7 - 15 days of walking was required from the nearest road and at least severaL days of trekking from the nearest airport. Air transport is very unreLiabaLe, as was experienced by the engineer for the SalLeri project: After waiting one week in vain for the airplane to arrive, he was compelled to walk all the way back from the site - taking a full six days by foot to accomplish this feat. Actually, he reached Kathmandu before the plane even. Another major prob l em is the large variation of the discharge between the dry and wet seasons. A factor of 1 :1000 is common. This means the~~-i;-~l;o;t-~o-~~t~~-d~~i~g half of the year while floods are commonplace in the rainy season. These floods and the very high bed-loads cause not inconsiderable problems for the design of the intakes. For our purposes, once the initial problems with the feasibility stage were overcome, few problems ~ere encountered during the actuaL design process. However, real probLems with the (unappropriate) design cropped up and became extremely obvious during construction.
For the implementation of a power plant, one must not forget that not only the staff but also construction materials and the sometimes heavy equipment have to reach the site one way or the other. Thus, access is once again the major problem. Anyone not familiar with Local conditions can hardly imagine the meaning of "access" in this country. If you want to build a smaLL hydropLant anywhere in the world and there is no access by road, you might logicaLly conclude the simplest task would be to construct one. In NepaL, you wouLd be sadly mistaken. Consider for a moment the fact that to link two points in Nepal onLy some 50 km apart, the road would have to have a total length of approx. 130 km and the construction time wouLd be more than 10 years, not to mention the cost. As already stated, none of the seven projects were linked by a road. So, the only means of transportation were porters for loads up to 50 kg, and aircraft for the heavy equipment. The first version of the Namche project, for example, was a convential design as commonly found in European countries. It transpired that it would take at least 1~Q_t~2!:2 to transport the cement to the site, and transportation costs would be no less than five times the cost of the cement. Another probLem not to be overLooked was the f12§b_flQQQ§L unfortunateLy very common in NepaL. The rivers and streams are characterized by great fLuctuation in levels and discharges during seasons. In addition to the
Small-scale Hydropower in Remote Areas fLoods, the rivers are subjected to LandsLides, which frequentLy bLock narrow gorges temporariLy. Upon collapse, the retained water is released quickly, causing flash floods. Already three of the seven smaLL hydro pLants have been affected by such flash floods and severe damage has occurred. WhiLe construction was in progress on the Doti project, a first fLash fLood hit the powerhouse site. The whoLe Layout of the project had to be changed and redesigned. To top it aLL off, a second fLash flood then heaviLy damaged the pLant after its compLetion. The majority of the projects have also been hampered and deLayed by the lack of communi ca1iQO_fEfili1i~~ between cent;~l-;ffi~~-~~d-the very remote construction sites. Letters invariably took three wee ks or more to reach the site. Many misunderstandings cropped up because communication facilities were just not availabLe.
Fig. 3
Under the auspices of the Small Hydel DeveLopment Board seven smaLL hydropower pLants were designed and constructed. Five pLants were completed, none of them within less than three years' construction time. Three schemes were affected by flash fLoods and two projects have not yet been completed - and this some seven years after construction started. Needless to say, NepaL has one of the most difficult and challenging topography in the worLd for the construction of hydropower pLants. In brief, access, fLash fLoods and communication are the major problems to be ove rcome. ~ff~~§;
The smalL hydro projects should be designed always keeping in mind the difficuLty of access. This task - easier said than done means basing the design on Local technoLogy and localLy avaiLabLe construction materials.
Typical erosion and inaccessibLe terrain in the hi lly areas of Nepal
3345
J. Lit sc her and N. Kapali
334 6
Large resources do exist however in the form of Local knowhow in water engineering. Trekking through the countryside, it is amazing to see how skiLLfuLly the indigenous population buiLd diversion dams and seasonal intakes in the biggest rivers. As a matter of fact, the existing locaL technoLogy is regrettabLy not nearLy utiLized by consuLtants or engineers as much as it couLd be. The design of canaLs shouLd by aLL means foLLow the contour Lines to the greatest extent possibLe and not a straight aLignment, which wouLd onLy aggravate instabiLity of the soiL and causes severe probLems during the rainy season.
The instaLLation of wireLess set connections between the head office and the construction sites wouLd aLmost soLve the communication probLem during construction and therefore again save time. The Lack of such radio communication was an additionaL hindrance in the impLementation of the seven smaLL hydro pLants.
FLash fLoods: In case of fLash fLoods, the
In Peru, more than 100 existing smaLL hydroeLectric power pLants do not run properLy or are out of order. Most of these are situated in remote areas and operated as isoLated schemes.
f;;~;s-;f - ~ature are so overwheLming that the
most rea s onabLe tactic is not to offer any resistance to them. This means for exampLe to buiLd seasonaL or semi-permanent intakes with LocaL materiaLs onLy, Living with the fact that they wiLL inevitabLy be washed away from time t o time by heavy monsoon fLoods. Labor costs for rebuiLding damaged structures are comparativeLy Low in contrast to imported materiaLs Like cement and steeL bars. This approach wouLd prove more economic even over the Long run than the so-caLLed more "scientific methods" with Large quantities of cement. The significance of "communication" is inescapabLe even when designing a project. The LocaL features of the construction site have to be communicated to the centraL office somehow. Taking into account the inaccuracies of the existing data at hand, it proved to be difficuLt if not impossibLe to produce an accurate design at the desk in the Kathmandu centraL office. Thus, as a ruLe of thumb, design done on the site directLy might be a more accurate and Less time consuming approach.
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Under an aid program for deveLoping countries sponsored by the Swiss government, we were asked in summer 1982 to investigate some of tpese smaLL hydro pLants and to make recommendations for improving the operation and maintenance of the schemes. In a first phase, tweLve smaLL hydropLants in the district Apurimac and Cuzco were seLected for investigation. The size of these schemes was in the range of 15 kW to 1800 kW. To date, the periods of service have varied between 11 and 27 years. ALL of them are of the conventionaL run-of-river type with intake, open canaL, forebay, penstock, powerhouse and taiLrace. The discharge is in the range of 30 LIs to 1250 LIs and the head varies from 14 m to 240 m. Since 1972 most of the schemes have been owned and operated by ELectroperu, the nationaL eLectricity utiLity.
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Fi g. 2
___________________
SmaLL hydro projects in Peru - Location map
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.
.
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Small-scale Hydropower in Remo te Ar eas
The districts of Apurimac and Cuzco lie in the southern part of the Peruvian Andes. Most of the landscape is well above the jungle, of the type alti piano, and covered with pampa grass. The people live in villages which are often situated near a mine. Access, by road, along erosive rivers in deep valleys and over high passes, is difficult and often blocked by landslides. The steep slopes are rarely terraced and the highest peaks are covered with snow and ice all year-round. Since there is no water retention by forests, the discharges are very low in the dry season and large floods are common in the rainy season.
a) Inventory of the technical conditions As a first step, all twelve selected schemes were visited, and discussions with the plant operators were held. Figure 4 shows the summary of the results. Upon travelling to the var i ous sites, we already experienced one big problem in maintaining the schemes: nameLy, ~f~~?S. In the first place, it was difficuLt to get an adequate vehicle. Second, it was not easy to even find a driver who was wiLlingLy to drive on the dangerous roads. And, third, our difficuLties were compounded by deLays due to several breakdowns and detours caused of landslides.
Cuzco is heavily frequented by tourists, while the formerly prosperous mining area of Apurimac is a remote and poor district, bordering the district of Ayacucho, which is the ce nt er of some terrorism.
Scheme
PISAC
District
CUZCO
Capac 1ty
20kW
Heali
01 scha rye Turbi ne
91Jm
35 I /s
--URUBAMBA
CUI CO
2x50k"
60rn
Pel ton
Only the two Matara schemes and the Vilcabamba pLant were in relatively good condition. In general, the main difficulties arise with the machinery, while the civil structures cause less probLems. In most of the scheme s the electrical installations are of poor quality and sometimes quite dangerous.
Inlt i al End of Yea r s Operati o Opera· Opera - of Ope houn tion ticn rat10n 1965
2,100 1/ s
1",Pel ton 19 50 h Franci 5 1955
I nW
71)"
30 l / s
Pe 1ton
1960
TAMBOBAMBA
APURIHAC
17 kW
bOrn
30 l /s
Pe 1ton
1959
APURIHAC
50k W
_.. . _._-- -
SOm
1969 1969
19 14
-
23
APURIHAC
2,650kW
130",
65 I /s
. -. ---- -
Pe l t on
195 7
._1980
APURIHAC
LAMBRAHA
APURI HAC
180kW
2,6,51 / , 2)(F r .:wc l s 1962
IO!lm
15h ni ght
24h
I Sh night
lZk W
--f----- --
20rn
- ---
23
( 7h night)
-
21
l1ght & i ndus try
-
Village connected t o the g ri d
1i9ht
11ght
120'W
1ight & 400kW i ndu s try
24h
..._-
-
pea k. i n9
.. .
.
-
I>e llon
1956
60 l / s
Francls
1960
23
10h night
1/ ,
Frand s
1~59
17
bh night
Generator burned out
"---- - 1 ight & IMustry
---In gOOd ('ondl t ion
-- - - - ----- -----Staru,l - by for' Md lor d Nue vd
- -- t - - - -- - - - - I igll t
_. _ 1~0
1976
ll g tlt
l~ O kW
Gen~ra
tur
tJur n ~ d
ou l
--
~-
Pe 1 ton
1960
23
lh nl ght
1 i ght
150 l / s
Frdn c is
1972
11
10h night
ll'=iht
3)(300 1/ 1
3xTurgO
1936
CU RPAHUAS I
APURIHAC
17kW
3Sm
60 l / s
VILCABAMBA
APURIHAC
I,.W
15111
HANCAHUARA
APURI HAC
3,600.-
23Sm
Fi g. 4
40kW
-- - ---- ... _-._-" - - f - -._- - --.- -15h night 11ght .. _---
CHUQUI BAHB ILLI, APUR I HAC
light
- --
- .--
40"1
Remad,s
bi lIt~d
27
200 l/s
--- l~k W
(.0111 -
----- - - _.- 1---- - I--- --
HATARA VIEJA
Diese 1
24
1-HATARA NUEV A
Con~ u rne r
--
APURIHAC
CURAHUAS I
18
--_ .- -
COTABAHBA
- .--
-
- -
- --_. - -
3347
1951
1,
m ll!l:~
Out ut o pe ration dUr11l9 dry s edSUn
Out u f o J,.: e r.l t 1on SlnCt:: rni ne was c l os ed duwn
Main features of the investigated schemes
The investigated schemes can be divided into three major groups: Rural schemes: p 50 kW T~;bi~e-~ithout governor, supply for lighting only; electricity of ve ry poor quality. Examples: Cotabambas, Curpahuasi, Tambobamba, Vil cabamba ~~mj:jDg~?1rj~!_ ~~ b~m~?~
p 100 kW Turbine with governor, suppLy mainly for lighting electricity of poor to medium qual ity. Examples: Matara Vieja, Urubamba
IDQ~?1ri21_§~b~m~?~ p 1000 kW Turbine with govern or, supply for lighting and machinery; electricity of good quality, tension and frequency maintained within certain set limits. Examples: Matara Nueva, Mancahuara
Out of the twelve schemes, three are out of order for technical reasons. In two cases, ChuquibambiLla, Curahuasi, the generators failed and have to be rewinded. For both schemes, diesels were instalLed with a much Larger capacity. In one event, Mancahuara, the plant has been out of operation since the
3348
J. Litscher and N. Kapali
cLosure of the main consumer, a goLd and siLver mine. The Curpahuasi pLant is out of operation during the summer months due to Lack of water.In some pLants the output was reduced during the summer months because part of the discharge was used for irrigation purposes. In most cases the operators are competent and wiLLing to operate the pLants. However, the standard of maintenance is very Low. This is mainLy because of Lack of adequate tooLs, Lubricants, and, worst of aLL, spare parts. The spare part probLem is common in deveLoping countries. Here, in Peru, the main difficuLty for obtaining spare parts are the foLLowing: fQIDID~Di£§!iQD_:
After a journey of severaL days to the site the technician may discover to his annoyance that he brought aLong the wrong spare part.
-
Qi~!ri~~!iQD_~
An order for spare parts goes to the centraLized administration of ELectroperu. The order goes from the LocaL office to the zonaL office, from there to the regionaL office, and finaLLy to the nationaL office.
- fiD§D£iD9l In times of a severe budget constraints, which is generaLLy the case, the nationaL office has other priorities than spare parts for smaLL hydropLants. The Lack of spare parts resuLts in "improvised" repairs (hand to mouth) and onLy serves to decrease the motivation of the operator. In one case, a Leakage of a turbine casing was fixed with cement and in another, a Leakage in the penstock was fixed with a jute bag. b) Power market and sociaL aspects To obtain some information about the power market and the sociaL aspects, discussions were heLd not onLy with the various operators but aLso with severaL LocaL peopLe. Most of the pLants operate onLy during the night hours and suppLy eLectricity for Lighting onLy. The pLants are often overLoaded and therefore deLiver a poor quaLity of eLectricity. In some viLLages the suppLy is very unreLiabLe. Even moonLight is brighter than the pubLic street Lighting. It must be understood that, in some cases, the number of consumers is decreasing despite the fact that ELectroperu is subsidizing the eLectricity tariff. UnfortunateLy, the smaLLer of the hydropLants especiaLLy have not made much of an impact on the economic situation of the popuLace. Th~refore, one cannot expect much LocaL enthusiasm for maLfunctioning pLants. On the other hand, most of the peopLe wouLd certainLy appreciate a more reLiabLe 24-hour suppLy and the possibiLity of connecting any kind of machine to the pLug. As Long as the eLectricity is mainLy used for Lighting, the probLem of a Low Load factor cannot be soLved. In some cases the situation improved sLightLy by using dieseLs for peaking, but fueL is expensive. For this reason the dieseLs do not operate during daytime. Most of the investigated schemes were not evaLuated by economic criteria. Thus the instaLLed capacity was chosen arbitrariLy. In various cases, there is enough discharge to increase the instaLLed capacity.
In remote areas of Peru, tweLve existing smaLL hydroeLectric power pLants were investigated. After an average Lifetime of twenty-five years, eight pLants are stiLL operating. Four schemes are out of order, two of them because of overheated generators, one because the viLLage concerned was connected to a regionaL grid and one because a mine, the main consumer, was cLosed down. The technicaL condition of the civiL structures in generaL is satisfactory, but the condition of the eLectromechanicaL equipment is usuaLLy poor, except the Matara scheme. This is mainLy due to Lack of adequate tooLs, Lubricants, and spare parts. NearLy aLL of these smaLL power pLants operate onLy a few hours during night and suppLy eLectricity mainLy for Lighting. NormaLLy, the smaLL hydro pLants beLow 100 kW are overLoaded and consequentLy suppLy a poor quaLity of eLectricity. Some of the smaLL schemes are supported by running a dieseL during the peaking hours. OnLy the Matara Nueva scheme, with an instaLLed capacity of 1300 kW, is running properLy. It is weLL maintained and operating round the cLock, suppLying reLiabLe eLectricity both for Lighting and industriaL purposes. The LocaL peopLe wouLd appreciate a reguLar and reLiabLe 24-hour suppLy and to have the possibiLity for connecting any kind of househoLd machine, though a certain psychoLogicaL factor might be invoLved here. The existing smaLL hydro pLants are the first generation of a ruraL eLectrification. UsefuL experiences couLd be gained and they shouLd no doubt heLp to improve the next generation of ruraL eLectrification. For the renewaL of the investigated smaLL hydro pLants, the foLLowing recommendations are given: A smaLL hydroeLectric power pLant in remote areas of Peru shouLd have a certain minimum instaLLed capacity and not be too smaLL, say in the range of 500 kW to 1000 kW (industriaL schemes). Operation and maintenance costs wouLd not be much higher than for a very smaLL scheme. The Load factor, actuaLLy very Low, shouLd be raised by consumers of integrated projects such as pumping for irrigation, cottage industries, saw miLLs, etc. Again, for improving the Load factor, a centraLized industriaL scheme in the range of 500 kW to 1000 kW shouLd suppLy the nearby viL Lages by a so-called "mi cro-grid" and repLace the very smaLL schemes. The industriaL schemes shouLd operate 24 hours and suppLy a reLiabLe quaLity of eLectri city. The eLectromechanicaL equipment to be instaLLed shouLd be uniform to simpLify maintenance and to faciLitate the procurement of spare parts.
©
Buda pest.
Hu ngar~.
IF .-\ C ~h h T rit"nn ittl " ',, rld CO Il ~n:~ s 19~4
HANDS-ON EXPERIENCE WITH SMALL-SCALE HYDROPOWER IN REMOTE AREAS: SOME EXAMPLES OF NEPAL AND PERU J.
Litscher* and N. Kapali**
*E lrrtrvu'a ll E uginl'ering Sen,jff.\ Limilrd , P .O . B ox . CI/ ·IUJ22 ll1 rich. S'I'it:",.laru/ **L"lIi1'nsitaft fUft" Bodfllk"ltu r, A-J J8fJ r inllUl , :\ w l 1";O
AQ§!r2f!. RecentLy, severaL smaLL hydroeLectric power pLants have been constructed in remote areas of NepaL. The unforeseen difficuLties whi ch were encountered during construction are presented here. In Peru, there are more than 100 existing smaLL hydropower pLants which were constructed in the 1950's and 60's. Many of them are out of order or not running properLy. SeveraL representative cases are described and reasons are pointed out. Based on the exampLes given, generaL insights and specific recommendations are discussed regarding the impLementation and operation of smaLL hydropower pLants in the most inaccessibLe regions.
INTRODUCTION SmaLL-scaLe hydro has become very attractive worLdwide since the energy crisis in 1973. Numerous smaLL hydroeLectric power pLants were constructed recentLy in deveLoping countries as weLL as in the more deveLoped countries to reLy on internaL resources as much as possibLe.
NepaL is a LandLocked mountainous country extending aLong the HimaLayas between China and India. Deep vaLLeys are carved out of young mountains by the erosive monsoon fLoods. Though this nation has the biggest specific hydropower potentiaL in the worLd (the theoreticaL potentiaL is impressive with over 80,000 MW), !b~r~_2r~_§~~~r~_QQ§!2fl~§_!Q_Q~
ImpLementing and running smaLL hydro pLants in remote areas of deveLoping countries is compLeteLy different than in deveLoped ones. This statement is proven both by experience with design and construction as weLL as the use and maintenance of smaLL hydroeLectric power pLants.
Q~~rfQm~_ i Q_QriQgiQg_!bi§_QQ~~r_!Q_!b~_~QQ:
fhEI_J_~_Q;~J§~_~~Q_fQ~~IRUCIJQ~_Q£ ~~~hh HY~EQ;h;fIE!f_fQ~;E_fh~~I~ ~;f~h
IN
The SmaLL HydeL DeveLopment Board (SHDB) estabLished in 1976 and responsibLe to the Ministry of Water Resources - experienced some probLems designing and supervising the construction of smaLL hydroeLectric power pLants in NepaL. The design and construction of seven smaLL hydropower pLants was carried out over the period from 1977 to 1982. The size of these projects was in the range of 80 kW to 500 kW. ALL were isoLated schemes in the most out-ofthe-way areas.
The young, unstabLe geoLog y and the difficuLt access, combined with the monsooncLimate hampers the deveLopment of hydr opower to an extreme degree. Present instaLLed capacit y is appr oximateL y 165 MW, which is as Low as 0.2 % of the theoreticaL potentiaL.
fQQ§~m~r§.
The majorit y of the popuLation Lives in the hiLL y regions between the HimaLa ya and the Terai, the Ganges pLain. Most of t he NepaLi peopLe are seLf-reLiant farmers, inhabiting scattered smaLL viLLages on steep terraced sLopes. The peopLe are understanda bLy proud of their devoteLy reLigious, traditi onaL Lifesty Le. The extreme topography of NepaL and the state of transportation faciLities avaiLabLe ma ke the eLectrificati on of the whoLe country fr om a centraLized grid an utopic enterprise. Therefore, and aLso since most of the energ y in the form of firewood is being consumed in the ruraL areas, great emphasis is gi ven t o the impLementation of smaLL hydr oeLectric power pLants.
3343
J. Litscher and N. Kapali
33 44
NEPAL
4
o
"leRO
HyORO
ONGOING
Fig. 1
PLANTS
•
SmaLL hydro projects in Nepal - Location map
3.!._Pr9P _l~!!!?_ ec)fQ!!C)j;~!:~£LQ!!!:iC)g_ the_Q~!!ig!L2c)Q
b) Construct ion
fQC)!!j;!:!!£j;iQc)_Qf_!!m~ll hY9rQ~1~fl!:if_QQ~~!:
Qi2C)!!! a) Design To begin with, the Lack of hydroLogical data or adequate toPo9caphical maps is a common problem in most developing countries and this is no exception in the case of Nepal. The main
Q!:Q~1~!!!_b~!:~L_bQ~~~~!:~_i2_1b~_9££~22L_which-- becomes readily apparent on the first site visit right at the feasibility study stage. Not one of the seven projects was accessible by road. Some 7 - 15 days of walking was required from the nearest road and at least severaL days of trekking from the nearest airport. Air transport is very unreLiabaLe, as was experienced by the engineer for the SalLeri project: After waiting one week in vain for the airplane to arrive, he was compelled to walk all the way back from the site - taking a full six days by foot to accomplish this feat. Actually, he reached Kathmandu before the plane even. Another major prob l em is the large variation of the discharge between the dry and wet seasons. A factor of 1 :1000 is common. This means the~~-i;-~l;o;t-~o-~~t~~-d~~i~g half of the year while floods are commonplace in the rainy season. These floods and the very high bed-loads cause not inconsiderable problems for the design of the intakes. For our purposes, once the initial problems with the feasibility stage were overcome, few problems ~ere encountered during the actuaL design process. However, real probLems with the (unappropriate) design cropped up and became extremely obvious during construction.
For the implementation of a power plant, one must not forget that not only the staff but also construction materials and the sometimes heavy equipment have to reach the site one way or the other. Thus, access is once again the major problem. Anyone not familiar with Local conditions can hardly imagine the meaning of "access" in this country. If you want to build a smaLL hydropLant anywhere in the world and there is no access by road, you might logicaLly conclude the simplest task would be to construct one. In NepaL, you wouLd be sadly mistaken. Consider for a moment the fact that to link two points in Nepal onLy some 50 km apart, the road would have to have a total length of approx. 130 km and the construction time wouLd be more than 10 years, not to mention the cost. As already stated, none of the seven projects were linked by a road. So, the only means of transportation were porters for loads up to 50 kg, and aircraft for the heavy equipment. The first version of the Namche project, for example, was a convential design as commonly found in European countries. It transpired that it would take at least 1~Q_t~2!:2 to transport the cement to the site, and transportation costs would be no less than five times the cost of the cement. Another probLem not to be overLooked was the f12§b_flQQQ§L unfortunateLy very common in NepaL. The rivers and streams are characterized by great fLuctuation in levels and discharges during seasons. In addition to the
Small-scale Hydropower in Remote Areas fLoods, the rivers are subjected to LandsLides, which frequentLy bLock narrow gorges temporariLy. Upon collapse, the retained water is released quickly, causing flash floods. Already three of the seven smaLL hydro pLants have been affected by such flash floods and severe damage has occurred. WhiLe construction was in progress on the Doti project, a first fLash fLood hit the powerhouse site. The whoLe Layout of the project had to be changed and redesigned. To top it aLL off, a second fLash flood then heaviLy damaged the pLant after its compLetion. The majority of the projects have also been hampered and deLayed by the lack of communi ca1iQO_fEfili1i~~ between cent;~l-;ffi~~-~~d-the very remote construction sites. Letters invariably took three wee ks or more to reach the site. Many misunderstandings cropped up because communication facilities were just not availabLe.
Fig. 3
Under the auspices of the Small Hydel DeveLopment Board seven smaLL hydropower pLants were designed and constructed. Five pLants were completed, none of them within less than three years' construction time. Three schemes were affected by flash fLoods and two projects have not yet been completed - and this some seven years after construction started. Needless to say, NepaL has one of the most difficult and challenging topography in the worLd for the construction of hydropower pLants. In brief, access, fLash fLoods and communication are the major problems to be ove rcome. ~ff~~§;
The smalL hydro projects should be designed always keeping in mind the difficuLty of access. This task - easier said than done means basing the design on Local technoLogy and localLy avaiLabLe construction materials.
Typical erosion and inaccessibLe terrain in the hi lly areas of Nepal
3345
J. Lit sc her and N. Kapali
334 6
Large resources do exist however in the form of Local knowhow in water engineering. Trekking through the countryside, it is amazing to see how skiLLfuLly the indigenous population buiLd diversion dams and seasonal intakes in the biggest rivers. As a matter of fact, the existing locaL technoLogy is regrettabLy not nearLy utiLized by consuLtants or engineers as much as it couLd be. The design of canaLs shouLd by aLL means foLLow the contour Lines to the greatest extent possibLe and not a straight aLignment, which wouLd onLy aggravate instabiLity of the soiL and causes severe probLems during the rainy season.
The instaLLation of wireLess set connections between the head office and the construction sites wouLd aLmost soLve the communication probLem during construction and therefore again save time. The Lack of such radio communication was an additionaL hindrance in the impLementation of the seven smaLL hydro pLants.
FLash fLoods: In case of fLash fLoods, the
In Peru, more than 100 existing smaLL hydroeLectric power pLants do not run properLy or are out of order. Most of these are situated in remote areas and operated as isoLated schemes.
f;;~;s-;f - ~ature are so overwheLming that the
most rea s onabLe tactic is not to offer any resistance to them. This means for exampLe to buiLd seasonaL or semi-permanent intakes with LocaL materiaLs onLy, Living with the fact that they wiLL inevitabLy be washed away from time t o time by heavy monsoon fLoods. Labor costs for rebuiLding damaged structures are comparativeLy Low in contrast to imported materiaLs Like cement and steeL bars. This approach wouLd prove more economic even over the Long run than the so-caLLed more "scientific methods" with Large quantities of cement. The significance of "communication" is inescapabLe even when designing a project. The LocaL features of the construction site have to be communicated to the centraL office somehow. Taking into account the inaccuracies of the existing data at hand, it proved to be difficuLt if not impossibLe to produce an accurate design at the desk in the Kathmandu centraL office. Thus, as a ruLe of thumb, design done on the site directLy might be a more accurate and Less time consuming approach.
~Q!!!!!!!'!Dif2!iQD:
!~ ~ -
Under an aid program for deveLoping countries sponsored by the Swiss government, we were asked in summer 1982 to investigate some of tpese smaLL hydro pLants and to make recommendations for improving the operation and maintenance of the schemes. In a first phase, tweLve smaLL hydropLants in the district Apurimac and Cuzco were seLected for investigation. The size of these schemes was in the range of 15 kW to 1800 kW. To date, the periods of service have varied between 11 and 27 years. ALL of them are of the conventionaL run-of-river type with intake, open canaL, forebay, penstock, powerhouse and taiLrace. The discharge is in the range of 30 LIs to 1250 LIs and the head varies from 14 m to 240 m. Since 1972 most of the schemes have been owned and operated by ELectroperu, the nationaL eLectricity utiLity.
---
Fi g. 2
___________________
SmaLL hydro projects in Peru - Location map
~
L
_
_
L
.
.
.
:
.
.
~
.
________
'
_
_
_
_
_
_
~
-+- -'------'-_ _
Small-scale Hydropower in Remo te Ar eas
The districts of Apurimac and Cuzco lie in the southern part of the Peruvian Andes. Most of the landscape is well above the jungle, of the type alti piano, and covered with pampa grass. The people live in villages which are often situated near a mine. Access, by road, along erosive rivers in deep valleys and over high passes, is difficult and often blocked by landslides. The steep slopes are rarely terraced and the highest peaks are covered with snow and ice all year-round. Since there is no water retention by forests, the discharges are very low in the dry season and large floods are common in the rainy season.
a) Inventory of the technical conditions As a first step, all twelve selected schemes were visited, and discussions with the plant operators were held. Figure 4 shows the summary of the results. Upon travelling to the var i ous sites, we already experienced one big problem in maintaining the schemes: nameLy, ~f~~?S. In the first place, it was difficuLt to get an adequate vehicle. Second, it was not easy to even find a driver who was wiLlingLy to drive on the dangerous roads. And, third, our difficuLties were compounded by deLays due to several breakdowns and detours caused of landslides.
Cuzco is heavily frequented by tourists, while the formerly prosperous mining area of Apurimac is a remote and poor district, bordering the district of Ayacucho, which is the ce nt er of some terrorism.
Scheme
PISAC
District
CUZCO
Capac 1ty
20kW
Heali
01 scha rye Turbi ne
91Jm
35 I /s
--URUBAMBA
CUI CO
2x50k"
60rn
Pel ton
Only the two Matara schemes and the Vilcabamba pLant were in relatively good condition. In general, the main difficulties arise with the machinery, while the civil structures cause less probLems. In most of the scheme s the electrical installations are of poor quality and sometimes quite dangerous.
Inlt i al End of Yea r s Operati o Opera· Opera - of Ope houn tion ticn rat10n 1965
2,100 1/ s
1",Pel ton 19 50 h Franci 5 1955
I nW
71)"
30 l / s
Pe 1ton
1960
TAMBOBAMBA
APURIHAC
17 kW
bOrn
30 l /s
Pe 1ton
1959
APURIHAC
50k W
_.. . _._-- -
SOm
1969 1969
19 14
-
23
APURIHAC
2,650kW
130",
65 I /s
. -. ---- -
Pe l t on
195 7
._1980
APURIHAC
LAMBRAHA
APURI HAC
180kW
2,6,51 / , 2)(F r .:wc l s 1962
IO!lm
15h ni ght
24h
I Sh night
lZk W
--f----- --
20rn
- ---
23
( 7h night)
-
21
l1ght & i ndus try
-
Village connected t o the g ri d
1i9ht
11ght
120'W
1ight & 400kW i ndu s try
24h
..._-
-
pea k. i n9
.. .
.
-
I>e llon
1956
60 l / s
Francls
1960
23
10h night
1/ ,
Frand s
1~59
17
bh night
Generator burned out
"---- - 1 ight & IMustry
---In gOOd ('ondl t ion
-- - - - ----- -----Staru,l - by for' Md lor d Nue vd
- -- t - - - -- - - - - I igll t
_. _ 1~0
1976
ll g tlt
l~ O kW
Gen~ra
tur
tJur n ~ d
ou l
--
~-
Pe 1 ton
1960
23
lh nl ght
1 i ght
150 l / s
Frdn c is
1972
11
10h night
ll'=iht
3)(300 1/ 1
3xTurgO
1936
CU RPAHUAS I
APURIHAC
17kW
3Sm
60 l / s
VILCABAMBA
APURIHAC
I,.W
15111
HANCAHUARA
APURI HAC
3,600.-
23Sm
Fi g. 4
40kW
-- - ---- ... _-._-" - - f - -._- - --.- -15h night 11ght .. _---
CHUQUI BAHB ILLI, APUR I HAC
light
- --
- .--
40"1
Remad,s
bi lIt~d
27
200 l/s
--- l~k W
(.0111 -
----- - - _.- 1---- - I--- --
HATARA VIEJA
Diese 1
24
1-HATARA NUEV A
Con~ u rne r
--
APURIHAC
CURAHUAS I
18
--_ .- -
COTABAHBA
- .--
-
- -
- --_. - -
3347
1951
1,
m ll!l:~
Out ut o pe ration dUr11l9 dry s edSUn
Out u f o J,.: e r.l t 1on SlnCt:: rni ne was c l os ed duwn
Main features of the investigated schemes
The investigated schemes can be divided into three major groups: Rural schemes: p 50 kW T~;bi~e-~ithout governor, supply for lighting only; electricity of ve ry poor quality. Examples: Cotabambas, Curpahuasi, Tambobamba, Vil cabamba ~~mj:jDg~?1rj~!_ ~~ b~m~?~
p 100 kW Turbine with governor, suppLy mainly for lighting electricity of poor to medium qual ity. Examples: Matara Vieja, Urubamba
IDQ~?1ri21_§~b~m~?~ p 1000 kW Turbine with govern or, supply for lighting and machinery; electricity of good quality, tension and frequency maintained within certain set limits. Examples: Matara Nueva, Mancahuara
Out of the twelve schemes, three are out of order for technical reasons. In two cases, ChuquibambiLla, Curahuasi, the generators failed and have to be rewinded. For both schemes, diesels were instalLed with a much Larger capacity. In one event, Mancahuara, the plant has been out of operation since the
3348
J. Litscher and N. Kapali
cLosure of the main consumer, a goLd and siLver mine. The Curpahuasi pLant is out of operation during the summer months due to Lack of water.In some pLants the output was reduced during the summer months because part of the discharge was used for irrigation purposes. In most cases the operators are competent and wiLLing to operate the pLants. However, the standard of maintenance is very Low. This is mainLy because of Lack of adequate tooLs, Lubricants, and, worst of aLL, spare parts. The spare part probLem is common in deveLoping countries. Here, in Peru, the main difficuLty for obtaining spare parts are the foLLowing: fQIDID~Di£§!iQD_:
After a journey of severaL days to the site the technician may discover to his annoyance that he brought aLong the wrong spare part.
-
Qi~!ri~~!iQD_~
An order for spare parts goes to the centraLized administration of ELectroperu. The order goes from the LocaL office to the zonaL office, from there to the regionaL office, and finaLLy to the nationaL office.
- fiD§D£iD9l In times of a severe budget constraints, which is generaLLy the case, the nationaL office has other priorities than spare parts for smaLL hydropLants. The Lack of spare parts resuLts in "improvised" repairs (hand to mouth) and onLy serves to decrease the motivation of the operator. In one case, a Leakage of a turbine casing was fixed with cement and in another, a Leakage in the penstock was fixed with a jute bag. b) Power market and sociaL aspects To obtain some information about the power market and the sociaL aspects, discussions were heLd not onLy with the various operators but aLso with severaL LocaL peopLe. Most of the pLants operate onLy during the night hours and suppLy eLectricity for Lighting onLy. The pLants are often overLoaded and therefore deLiver a poor quaLity of eLectricity. In some viLLages the suppLy is very unreLiabLe. Even moonLight is brighter than the pubLic street Lighting. It must be understood that, in some cases, the number of consumers is decreasing despite the fact that ELectroperu is subsidizing the eLectricity tariff. UnfortunateLy, the smaLLer of the hydropLants especiaLLy have not made much of an impact on the economic situation of the popuLace. Th~refore, one cannot expect much LocaL enthusiasm for maLfunctioning pLants. On the other hand, most of the peopLe wouLd certainLy appreciate a more reLiabLe 24-hour suppLy and the possibiLity of connecting any kind of machine to the pLug. As Long as the eLectricity is mainLy used for Lighting, the probLem of a Low Load factor cannot be soLved. In some cases the situation improved sLightLy by using dieseLs for peaking, but fueL is expensive. For this reason the dieseLs do not operate during daytime. Most of the investigated schemes were not evaLuated by economic criteria. Thus the instaLLed capacity was chosen arbitrariLy. In various cases, there is enough discharge to increase the instaLLed capacity.
In remote areas of Peru, tweLve existing smaLL hydroeLectric power pLants were investigated. After an average Lifetime of twenty-five years, eight pLants are stiLL operating. Four schemes are out of order, two of them because of overheated generators, one because the viLLage concerned was connected to a regionaL grid and one because a mine, the main consumer, was cLosed down. The technicaL condition of the civiL structures in generaL is satisfactory, but the condition of the eLectromechanicaL equipment is usuaLLy poor, except the Matara scheme. This is mainLy due to Lack of adequate tooLs, Lubricants, and spare parts. NearLy aLL of these smaLL power pLants operate onLy a few hours during night and suppLy eLectricity mainLy for Lighting. NormaLLy, the smaLL hydro pLants beLow 100 kW are overLoaded and consequentLy suppLy a poor quaLity of eLectricity. Some of the smaLL schemes are supported by running a dieseL during the peaking hours. OnLy the Matara Nueva scheme, with an instaLLed capacity of 1300 kW, is running properLy. It is weLL maintained and operating round the cLock, suppLying reLiabLe eLectricity both for Lighting and industriaL purposes. The LocaL peopLe wouLd appreciate a reguLar and reLiabLe 24-hour suppLy and to have the possibiLity for connecting any kind of househoLd machine, though a certain psychoLogicaL factor might be invoLved here. The existing smaLL hydro pLants are the first generation of a ruraL eLectrification. UsefuL experiences couLd be gained and they shouLd no doubt heLp to improve the next generation of ruraL eLectrification. For the renewaL of the investigated smaLL hydro pLants, the foLLowing recommendations are given: A smaLL hydroeLectric power pLant in remote areas of Peru shouLd have a certain minimum instaLLed capacity and not be too smaLL, say in the range of 500 kW to 1000 kW (industriaL schemes). Operation and maintenance costs wouLd not be much higher than for a very smaLL scheme. The Load factor, actuaLLy very Low, shouLd be raised by consumers of integrated projects such as pumping for irrigation, cottage industries, saw miLLs, etc. Again, for improving the Load factor, a centraLized industriaL scheme in the range of 500 kW to 1000 kW shouLd suppLy the nearby viL Lages by a so-called "mi cro-grid" and repLace the very smaLL schemes. The industriaL schemes shouLd operate 24 hours and suppLy a reLiabLe quaLity of eLectri city. The eLectromechanicaL equipment to be instaLLed shouLd be uniform to simpLify maintenance and to faciLitate the procurement of spare parts.