48651 final fact finding report

THE OPTIONS TO DEVELOP MICRO HYDRO POWER PROJECTS

Rural Electrification in Nias Island and Aceh

TABLE OF CONTENTS

1 SUMMARY 5

2 NIAS ISLAND 8

2.1 General 8 2.2 Site Visited 15 2.2.1 Site 1: Gomo, Hili ‘anaa 15 2.2.2 Site 2: Alasa, Fulolo 20 2.2.3 Site 3: Lawu-lawu, Hilisondrekha 25 2.2.4 Site 4: Bawomoawo, Onowaembo 28

3 ACEH UTARA 30

3.1 General 30 3.2 Site Visited 32 3.2.1 Site 5: Alue Salak, Gampong Riseh Tunong 32

Figures Figure 1: Administrative Map of NiasFigure 2: Main Rivers in Nias Island Figure 3: Potential Sites in Nias Island Figure 4: Distribution Lines of PLN in Nias Figure 5: Rain Fall Data 2000-2005

9 10 11

Island 12 13

Figure 6: Estimated Flow Duration Curve Derived from Rainfall Data 14 Figure 7: Basic Setup of MHP Gomo, Hili ‘anaa 16 Figure 8: Catchment Area of Gomo River 17 Figure 9: Basic Setup of MHP Alasa (Uluwi River), Fulolo 21 Figure 10: Basic Setup of MHP Alasa (Alasa River), Fulolo 23 Figure 11: Catchment Area of Uluwi and Alasa River 24 Figure 12: Basic Setup of MHP Lawa-Lawu, Hilisondrekha 26 Figure 13: Basic Setup of MHP Bawomoawo, Onowaembo 29 Figure 14: Rain Fall Data 1991-2000 30 Figure 15: Basic Setup of MHP Alue Salak, Gampong Riseh Tunong 34

Tables Table 1: Potential Sites in Nias and Aceh (status Oct. 2005) 5

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ABBREVIATIONS

Abbreviation English Indonesian

BRR Rehabilitation and Reconstruction Agency

Badan Rehabilitasi dan Rekonstruksi

BMG Meteorology and Geophysics Bureau

Badan Meteorologi dan Geofisika

ILO International Labour Organization

Organisasi Buruh Internasional

Kab. District Kabupaten

Kec. Sub-District Kecamatan

KDP / PPK Kecamatan Development Programme

Program Pengembangan Kecamatan

MHP Micro Hydro Power Pembangkit Listrik Tenaga Air skala kecil

NAD Nanggaroe Aceh Darussalam

Nanggaroe Aceh Darussalam

OCHA UN Office for Coordination Humanitarian Affairs

Badan Koordinasi Bantuan untuk Kemanusiaan.

PEMKAB District Government Pemerintah Kabupaten

PLN State Electricity Company Perusahaan Listrik Negara

PU Public Work Pekerjaan Umum

PMU Project Management Unit Unit Manajemen Proyek

PLTA Hydro Power Plant Pembangkit Listrik Tenaga Air

WB World Bank Bank Dunia

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1 SUMMARY

The objective of fact finding mission in the provinces of Nias and Aceh was to assess the micro hydro power potential as an option for energy generation in the two regions asa means of supporting the long term economic development of these Tsunami and earthquake affected areas.

The main focus of the mission was in Nias where a total of 4 sites were assessed. In Aceh 1 potential site was assessed.

In total 12 locations were identified proposed as potential MHP sites. Three of these were proposed by BRR Nias and eight were proposed by other institutions.

The sites proposed were as follows:

Table 1: Potential Sites in Nias and Aceh (status Oct. 2005)

No Site Recommended by

Status

1 Gomo River- Kec. Gomo, Kab. Nias Selatan

BRR 55-60kW village supply or 300kW grid connected MHP possible (best potential)

2 Alasa River, Kec. Alasa, Kab. Nias

BRR 30kW village supply or 150kW grid connected MHP possible. Other options at Alasa river to be checked

3 Lawu-Lawu River, Kec. Teluk dalam, Kab. Nias Selatan

BRR only small potential 1.5-2kW site battery charging possible

4 Bawomoawo River, Kec. Guide book 80-150kW grid connected site

5

Gunung Sitoli, Kab. Nias possible (further evaluation recommended)

5 Oyo River, Kec. Amandraya Kab. Nias Selatan

Directorate Irrigation and Water Resource

- pending site visit

6 Muzoi River, Kec. Afulu, Kab. Nias



7 Gidozebua River, Kec. Gido, Kab. Nias



8 Mola River, Kec. Bawolato, Kab. Nias



9 Eho River, Kec. Amandraya, Kab. Nias Selatan

Pemkab Nias Selatan and WB


10 Susua River, Kec. Gomo, Kab. Nias Selatan



11 Masio River, Kec. Lahusa, Kab. Nias Selatan



12 Alue Salak River, Kec Sawang, Kab. Aceh Utara

UNIDO Site potential 25-50kW for village supply + 1.5km away 100-200kW (possibly several MW if grid connected)

The mission took place during rainy season therefore accurate measurement of the stream flow and the subsequent preparation of accurate flow duration curves (FDC) was not possible. Nevertheless rough estimates of stream flows was still possible based on rainfall data acquired and was sufficient for the purposes of the mission. Stream flow data from relevant authorities was not available, however rainfall data from the last 5 years was available. This indicates a relatively favourable rainfall conditions ie. relatively high rainfall for most of the year. Of the 5 locations visited, the sites Gomo and Alasa in Nias were assessed up to pre-feasibility level.

1. GOMO: This site fully fulfils the technical criteria required for further development. The high stream flow of the water source ensures that for the required design discharge of a MHP to supply the village, there is no risk of over dimensioning. The stream flow exceeds comfortably the required design flow for the size of scheme required to supply the village. The most critical issue

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to be considered at this site is the risk of flood flow which demands that the civil structures will need to be designed accordingly ie. large and sturdy structures.

2. ALASA: The Alasa river has so far not been harnessed for power production. The waterfall area has been developed for eco tourism and is a place of natural beauty. Local tourists visit the site particularly at weekends and on public holidays. There is also a hotel and jungle trekking tracks close by. The discharge is relatively low and most likely insufficient to support the development of a MHP. It is proposed that alternatives should be explored.

Preliminary Recommendations: The Provinces of both Nias and Aceh possess many hilly and mountainous regions. With high rainfall characteristics the MHP potential in both provinces is very good. Currently energy production relies very much on diesel which results in very high energy production costs. This limits the extent to which PLN is able to expand grid networks and is a major burden to the development expansion of rural electrification in the 2 provinces. Obviously the recent natural disasters has further exacerbated this situation. For a long term sustainable exploitation of the MHP potential in these 2 regions, a more detailed and systematic evaluation of the potential areas during dry season is highly recommended. Based on the findings of this mission it can be assumed that are numerous sites suitable for both grid connected and stand alone schemes. Ideally flow data should be collected during the next dry season (January-April) as a basis for the selection of suitable sites to be further developed.

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2 NIAS ISLAND

2.1 General

The island of Nias is divided into two administrative areas namely Kabupaten Nias and Kabupaten Nias Selatan. Figure 2 shows the main rivers of Nias (Source: Directorate Irrigation and Water Resource). Currently there are no flow measuring stations installed on these rivers. It appears any existing data was lost during the earthquake and Tsunami. The only relevant meteorological data was obtained from BMG Binaka Gunung Sitoli (see figures 5a & 5b). The geographical conditions if Nias wherby they have rain throughout most of the year (no real dry season) combined with the dense vegetation and mountainous terrain represent the ideal natural conditions for small scale hydro power development. Using the ‘Turc” methodology which uses rainfall data and catchment area size to estimate stream flow, a preliminary flow duration curves has been made for selected sites ( see figure 6). Although this may be sufficient for the small schemes where stream flow obviously exceeds design flow throughout the year (ie. large river), for a more conclusive assessment of the available stream flow, on site measurements must be carried out during the driest periods of the year (dry season).

Nias possess a large hydraulic potential suitable for energy generation in the remote rural areas. Additionally the opportunity for grid connection substituting the many diesel gensets operated by PLN is also very high. The PSK Tersebar legislation introduced by the Indonesian Government in 2002 which allows small scale private power producers (<1 MW) utilizing renewable energy sources to generate and sell power to the PLN means that this potential could be exploited on a fully commercial basis through the sale of power to the PLN grid.

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Figure 1: Administrative Map of Nias1)

1) Source: BRR office

9

Figure 2: Main Rivers in Nias Island2)

2) Source: BRR office

10

Figure 3: Potential Sites in Nias Island3)

3) Source: Nias Directorate Irrigation and Water Resource, Arnold Lopulalan (World Bank-KDP) and Hans Martin (Pemkab Nias Selatan)

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Figure 4: Distribution Lines of PLN in Nias Island4)

4) Source: PT. PLN Wilayah Sumut Cabang Sibolga

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Figure 5: Rain Fall Data 2000-20055)

(a)

(b)

5) Source: Summary of annex 3

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Figure 6: Estimated Flow Duration Curve Derived from Rainfall Data6)

6) Turc analysed 254 drainage basins mainly in Malaysia and PNG to provide a generalised calculation method. He investigated the pragmatic use of rainfall and temperature to determine the annual evapotranspiration and provided factors to determine an annual FDC.

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2.2 Site Visited

2.2.1 Site 1: Gomo, Hili ‘anaa

Location: Hili ‘Anaa Site code:

SUM050

Basic Data: Village / Kecamatan / /Kabupaten /Province

Hili ‘anaa / Gomo / Nias Selatan / Sumatra Utara

Owner of Project: Project

Contact person: Mr. Tolonasokhi Telaumbanua

Initiating Agency: UNIDO

River: Gomo

Intake Coordinates: N= 0° 51.866’ E= 97° 46.264’

Year of erection: Study 2005

Contractor nn

Gross Head: 25 m

Net Head: 20 m (due to flood situation)

Measured Flow: 2665l/s (before rain- after rain estimated to 100.000l/s)

Min. Flow: >600l/s

Design Flow: 450l/s Turbine (stand alone)

Catchments area: > 8.00 km2

Power design: 60 kW stand alone (300-500kW grid connected)

Power firm: 60 kW

Consumers: 530 households in two settlements (100W/House m=53kW demand)

Supply situation: 5 km to PLN Grid

Productive Use: Water supply pump, lights, chicken farming mills etc

Distribution 2 Villages and some scattered Houses: Estimated 3 Transformers /4km Line

Estimated Cost USD252000 = USD4200 / kW including distribution – without diesel backup (without tax and other government charges)

Survey team Gerhard Fischer, Bolly Iskandar Z, Hari Wibowo, Aa Saefudin

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Hili ( i / id) is l li l l/ i i ial

suppl i l id ( i i ) iicini

l i assi in ious i ises i

i iviti i i l i ii i ivities i l i l

i i i i i li i i itional

head ( i l ion) i l i ial coul ll i lyi id ( i i i id

l ial a l i l ld i l i l l l lp in i i i ion

ii l l i l i l i

l iti i in (fl l i i isifl i 3/ l i l i i i ificivil l iti is i ipossibl i l i l i l i ifi i

Fi i i

‘anaa 3h car dr ve from Gunung Sitoli 5km to PLN gr ocated c ose to a waterfall of 27m he ght and a measured f ow of 2600 s. Th s s te has potent to

y v a a stand a one village gr 50-60kW nstalled capac ty two villages n the nearby v ty. The two villages are current y be ng sted by the Red Cross var post earthquake recovery efforts. Ass stance compr the rebuild ng of houses and commun ty support act es a med at st mu at ng econom c recovery of the villages. Integrat ng a MHP nto these act s wou d prov de a very worthwhile and re evant contr but on to these on-go ng program and s therefore h gh y recommended. Further downstream from the waterfall, there s the poss bility to acqu re add

drop n e evat of approx mate y 30 meters. Th s potent d be deve oped for a arger s ze scheme supp ng the PLN gr gr d connect on). The s te for a grconnected scheme wou d have an overall potent of between 300-500kW. As` ong term commun ty based MHP, the deve opment of such a scheme woucontr bute great y to the econom c deve opment of the area. It wou d a so hecreat ng awareness and understand ng of the mportance of catchment area protectand preservat on. The r ver has a collects f ow from a arge catchment area. Th s resu ts n extreme y h gh stream f ow cond ons dur ng heavy ra ood f ow). At the t me of the s te v t, the ow was est mated at >100m s f ow. Th s wou d requ re the construct on of s gn cant

structures capab e of handling these arduous cond ons. Whilst th s techn cally e, t wou d result n a re at ve y h gh spec c costs for the s te.

gure 7: Bas c Setup of MHP Gomo, H li ‘anaa

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Figure 8: Catchment Area of Gomo River

Intake: Must be integrated upstream from the waterfall. During flood conditions the water level is rising by 2 - 3m. Under these conditions an extremely high amount of silt, debris and large boulders are swept down the river.

Picture 1 : Proposed Intake area (upstream view). Headrace route will be on the left side of the picture.

Forebay&Headrace: Approximately 130m long positioned on the very steep slope. The construction will require proper erosion protection and support.

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Picture 2 : White arrow indicates where the proposed Forebay tank would be positioned

Penstock: 130m long. Picture 3 : Red dotted line indicates the proposed Penstock route.

Transmission: Approximately 5km of transmission line is required. Two step-up / step-down transformers are required to ensure transmission losses are kept at acceptable levels.

Power House: Must be built 3 - 4m above the normal water level to be safe from flooding. A bridge to the power house and for transport during construction is required

Picture 4 : White arrow indicates the proposed Power House location.

Village: The total number of households in the 2 villages is 530. In addition there are some small clusters of houses scattered in the surrounding area. It would be necessary to extend the distribution lines if these houses are to be connected.

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Picture 5 : Typical houses in Hili ‘anaa village.

Bridge: A bridge willis approx. 55m

need to be built to provide access to the Power House location. Length of the bridge

Picture 6 : Red dotted line indicates the proposed bridge location.

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2.2.2 Site 2: Alasa, Fulolo

Location: Fulolo Site code:

SUM051

Basic Data: Village / Kecamatan/ /Kabupaten /Province

Fulolo / Alasa / Nias / Sumatra Utara


Contact person: Mr. Suardin Hulu


River: Uluwi - side river of Alasa river



Contractor Nn

Gross Head: 25.5 m (water fall)

Net Head: 22 m (to power house)

Measured Flow: 380 l/s (Uluwi river estimated >1000l/s)

Min. Flow: >200l/s (estimated- to be confirmed in dry season)

Design Flow: 200l/s Turbine

Catchments area: 2.69 km2 (see Figure 8)

Power design: 30 kW

Power firm: 30 kW (grid connected 50-70kW possible)

Consumers: 264 households without grid connection (100W/House m=28kW demand)

Supply situation: About 1km to PLN grid. PLN is not covering the remote parts of the village.

Productive Use: lights, mills etc

Distribution Houses are scattered: Estimated 2 Transformers /5km Line

Estimated Cost USD185300 = USD6200 / kW including distribution – without diesel backup (without tax and other government charges)

Survey team Gerhard Fischer, Bolly Iskandar Z, Hari Wibowo, Aa Saefudin

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lolo i i id i ii i j i l i

i i l i l i l/possibl l ion i l i l i ipl l i i l ibl

i l l iisl i i

i l i i l i l ii il i l i i l

i ly i i i ial.

Fi i l l i Ri lolo

Fu s a 3 hour car dr ve from Gunung Sitoli. The PLN gr s 1 km from the s te. An mpress ve waterfall, Air Ter un “LUAHA ‘NDROI” ex sts on the U uwi r ver wh ch feeds nto the arger Alasa r ver. The f ow was est mated at 360 s and the

e head was 22m. The ocat s a popu ar tour st ocat on and s deemed a ace of natura beauty. The s te s a so deemed somewhat suscept e to future

earthquake tremors. Dur ng the recent earthquake arge bou ders of 3m d ameter were d odged and have fallen nto the r ver. Close by s the arger Alasa r ver wh ch has a stream f ow approx mate y 2 t mes that of the Uluw . A deta ed assessment of opt ons a ong th s r ver stil needs to be carr ed out to accurate dent fy ts potent

gure 9: Bas c Setup of MHP A asa (U uw ver), Fu

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Intake: A dam structure and sedimentation must be integrated into the upstream river. Then the penstock must cross a vertical rock wall.

Picture 7 : Proposed Intake area (upstream view). Headrace route will be on the right side of the picture.

Forebay & Headrace chanel: About 150m Headrace channel in partially steep area is required to build forebay and power house at a save location.

Picture 8 : Red dotted line indicates the proposed Headrace route.

Penstock: Approximately 40m from the forebay to Power House. Picture 9 : Red dotted line indicates the proposed Penstock route.

Transmission: All together estimated with 4.8km. Three transformers are required.

Power House: Must be built 3-4m above the water level to be save from flooding.

Village: There are 264 houses in one village which would be supplied.

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el icit i

i ibl lopi i i ii i l l

i i l ii i i i l

( i ) ical i

� : mi� l : � l :

Fi : i l l i lolo

Picture 10 : There is no ectr y anymore n this area.

Although the s te appears feas e for deve ng cons der ng the mportance of the waterfall as a tour st attract on and the fact that the Alasa ocated c ose by has a greater d scharge due to ts arger catchment area. Based on a prelim nary desk study carr ed out on the Alasa r ver, the catchment area s approx mate y 5.90km2.

see F gure 10 & 11Other techn data der ved from the desk study are as follows:

Head gross n. 20m Headrace ength max. 600m Penstock ength max. 100m

gure 10 Bas c Setup of MHP A asa (A asa R ver), Fu

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Figure 11: Catchment Area of Uluwi and Alasa River

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2.2.3 Site 3: Lawu-lawu, Hilisondrekha

Location: Hilisondrekha Site code:

SUM052

Basic Data: Village/Kecamatan/ Kabupaten / Province

Hilisondrekha / Teluk Dalam / Nias Selatan / Sumatra Utara


Contact person: Mr. Serius Ziraluo


River: Lawulawu



Contractor Nn

Gross Head: 56 m

Net Head: 54 m

Measured Flow: Approx. 5l/s

Min. Flow: >4 l/s (seems to be a source)

Design Flow: 3.5 l/s Turbine

Catchments area: 0.13 km2

Power design: 1.1 kW

Power firm: 1.1 kW (Battery charging unit)

Consumers: 165 households.

Supply situation: Not sufficient power for regular connection. Possible for Battery charging station. Hybrid system with Diesel.

Productive Use: lights, mills etc

Distribution Can be possible without Transformers /600m Line

Estimated Cost USD4400 = USD4000 / kW including one set of batteries- without diesel backup (without tax and other government charges)

Survey team Hari Wibowo, Aa Saefudin

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l i is l i li ( ii / id)

i i il i ive

head i i l l/ itii l lyi i i

si l l i i i i il le i l lds wi

ies i l lds i iion i wi ( id) coul

consi

Fi : i i

The Lawu awu r ver ocated n the Hi sondrekha village a 4 hour car dr ve from Gunungs toli 5-10km to PLN grThe s te was proposed by BRR. It was descr bed as a waterfall of 90m head w th permanent water f ow. Based on the s te measurements, however, the effect

s 54m w th a very small f ow of approx 5 s. These cond ons do support the build ng of a stand a one scheme supp ng power v a a gr d network, however, the

te cou d be deve oped as a 1.1kW battery charg ng stat on. W th th s s ze the scheme wou d be ab to support approx mate y 50 househo th charged batter f proper y managed. Although there are 165 househo n the v llage the opt to comb ne the scheme th other energy sources hybr d be

dered.

gure 12 Bas c Setup of MHP Lawa-Lawu, Hil sondrekha

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Intake: A Tyrolean Weir Intake will be the most suitable solution for this site. Picture 11 : The proposed Intake area (downstream view). The Headrace route will be on the right side of the pictures.

Headrace: Total length will be approximately 50m.

Penstock: Total length will be approximately 160m.

Transmission: Total length will be approximately 600m.

Power House: Approx. 2m above the water level. There is no flood in this area.

Village: There will be 165 houses in one village. Picture 12 : The houses are concentrated in one area.

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--

2.2.4 Site 4: Bawomoawo, Onowaembo

Location: Bawomoawo Site code:

SUM053

Basic Data: Village / Kecamatan / /Kabupaten /Province

Onowaembo / Gunungsitoli / Nias / Sumatra Utara


Contact person:


River: Bawomoawo River

Intake Coordinates:


Contractor Nn

Gross Head: 68 m (estimated from Guide book- not checked)

Net Head: 65 m

Measured Flow: >300l/s (estimated –not measured)

Min. Flow: >150l/s

Design Flow: 400l/s Turbine (Grid connected system)

Catchments area:

Power design: 150 kW (Grid connected system)

Power firm: 55 kW

Consumers: grid connection

Supply situation:

Productive Use: Village income due to power sales to PLN

Estimated Cost USD375000 = USD2500/ kW (without tax and other government charges)

Distribution 1 Trafo 200m Power lint to PLN Grid

Survey team Gerhard Fischer, Bolly Iskandar Z

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i i ii / i

i i i ioned in i i i l l i i i

based ( i ) l i l i l/additi l

loi as ri inues i idl l le is i l i l i i i local i i

i l icini

Fi : i

The Bawomoawo r ver I the village of Onowaembo s 7km or 0.5 hour car dr ve from Gunungs toli 500m to PLN Gr d. The 50m h gh Bawomoawo waterfall near the v llage Onowaembo s menttour st gu de books. The s te cou d be deve oped as a gr d connect on commun ty

or pr vate power p ant n the future. The f ow was est mated about 300 s. In on to the 50m head availab e at the waterfall, further downstream head can be

exp ted the ver cont to descend qu te rap y. Tota availab head approx mate y 65m. The waterfall s a popu ar dest nat on w th tour sts espec ally on weekends due to ts c ose v ty to Gunungsitoli.

gure 13 Bas c Setup of MHP Bawomoawo, Onowaembo

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3 ACEH UTARA

3.1 General

The Integrated Farm Area Development Program implemented by North Aceh Government is aimed at to empowering local communities, stimulating the local economy and developing the regions agricultural potential for agro industries including eco-tourism. The program is located in Riseh Tunong, Kecamatan Sawang, Kabupaten Aceh Utara. 66 km from Lhokseumawe and approximately 20km from kecamatan Sawang. The total area covered by the program is 277.000ha. A 1000 temporary homes will be constructed to accommodate 800 poor families and 200 families of ex GAM members. Currently there are 250 families living in an area of 700 ha land. The land was formely utilized by the forestry industry. The program has established a project management unit (PMU) responsible for managing and supervising the program. In the future it is hoped that the residents will be able to produce various kinds of high quality agricultural produce stimulating the local economy. Additionally it is planned to carry out various research and development projects related to agricultural technology. The only meteorological data which could be obtained was from BMG Malikulsaleh which is located ± 23km from development area (see figure 14a & 14b).

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3.2 Site Visited

3.2.1 Site 5: Alue Salak, Gampong Riseh Tunong

Location: Gampong Riseh Tunong

Site code:

SUM054

Basic Data: Village / Kecamatan / Kabupaten / Province

Gampong Riseh Tunong / Sawang / Aceh Utara / NAD


Contact person: Mr. Nurdin


River: Alue Salak

Intake Coordinates:

Year of erection: Study

Contractor Nn

Gross Head: Option 1: 37m Option 2: 67 m Option 3: 90m

Net Head: Option 1: 35m Option 2: 65 m Option 3: 88m

Measured Flow: 150l/s first day and 106l/s one day later without rain

Min. Flow: >70l/s (estimated only) (firm 50l/s)

Design Flow: Option 1: 70l/s Option 2: 90 l/s Option 3: 120 l/s Storage: non 220m3 540m3

Storage (3h peak load):

Option 1: non Option 2: 220m3 Option 3: 540m3

:

Catchments area:

Power design: Option 1: 14kW Option 2: 34kW Option 3: 61kW

Power firm: Option 1: 10kW Option 2: 26kW Option 3: 46kW

Consumers: 250 Households – long term 1000 Households

Supply situation: (up to 400 House holds each 100W ) Option 1: Backup Diesel Genset Option 2: Backup Diesel Genset Option 3: no Backup

Productive Use: Water supply pump (Filter & Desinfection), lights, mills etc

Estimated Cost USD3500 / kW including distribution – without diesel backup

Distribution Houses are scattered: Estimated 3 Transformers /6km Line

Survey team Gerhard Fischer, Bolly Iskandar Z.

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The transmigration area Gampong Riseh Tuong, Sawang, Aceh Utara possess very good hydraulic potential. In this village, there are two small rivers which can be used to produce between 30-50 kW of power. The specific size of the plant will depend on the amount of head ((35-90m) utilized. This will be sufficient to supply the current population of 250 houses, however, insufficient to supply the intended full population of 1000 households in the future. During dry season and during peak hours, a diesel backup system will be required. It is strongly recommended to conduct a detailed hydraulic survey of the rivers during dry season together with a site survey on all options for energy production in the area. In addition to providing domestic electricity, a MHP scheme could also integrate a number of productive “end uses” such as fish farming. The current water supply system has been very badly designed and was not operational at the time of the site visit. It could be considered to combine the building of a MHP plant with the building of a new water supply system utilizing gravity rather than the current diesel powered system. Approximately 1.5km from the village, there is a large river (estimated flow 5000l/s) with a potential to supply energy to the entire settlement in future. This river has the potential for a much larger size power plant which could be developed for supplying power to the PLN grid, however, a more detailed assessment of the viability of such a project would need to be carried out.

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34

Fi : i l lgure 15 Bas c Setup of MHP A ue Sa ak, Gampong Riseh Tunong

Intake: A weir diversion structure must be integrated into the river Picture 13 : The proposed Intake area will be located on the right side of the river (downstream view).

Forebay & Headrace: It is located approximately 500m from proposed Intake. The length of the Headrace channel will be 500m.

Picture 14 : The proposed Forebay area will be close to the existing storage tank used for the water supply.

Penstock: The length of penstock for option 1, option 2 and option 3 will be, respectively: approx. 300m, 720m and 1200 m.

Picture 15 : Upstream view. The proposed Penstock route will be parallel to the river.

Transmission: Three or four transformers are required.

Power House: There are 3 possible locations for the proposed Power House area; option 1, option2 and option 3, which are positioned approx. 250m, 600m and 1000m respectively from the forebay tank.

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Picture 16 : Downstream view (taken from the existing storage). The proposed Power House will be closed to road & houses (option 1).

Village: Eventually there will be a 1000 houses which will require electrification. However it is as a 1st phase it is proposed to build a plant with a capacity capable of supplying up to 400 houses.

Picture 17 : The development area has many houses which are dispersed over a wide area.

4 Preliminary Recommendation

On the basis of the findings of this mission the following is recommended.

1. Of the sites visited the Gomo site is clearly the most attractive option to be developed. Although accurate stream flow measurements was not possible, it is clearly apparent that the required design flow does not exceed the minimum available flow of the river. This site could therefore be developed directly without the need for further detailed stream flow measurements during the dry season. Regarding cost, the specific costs are relatively high compared to other parts of Indonesia due to the nature of the scheme (difficult civil construction) and relatively high costs of materials in Nias.

2. In general Nias possess a significant untapped MHP potential. Besides for rural electrification via stand alone village electrification projects of the type proposed above, this potential can be exploited for grid connected schemes substituting diesel power plants which currently supply the entire existing power supply of Nias. Grid connected schemes could be developed on a fully commercial basis considering the currently very high production costs incurred by PLN (>Rp. 2000 / kWh). Considering this a more detailed assessment of the islands potential should be carried out during the dry season. This would allow for the collection of more accurate flow data which is essential for the accurate design of schemes. Ideally a MHP master plan development would be conducted, however, obviously this requires a long term commitment and energy development plan be initiated.

3. In Aceh if there is a genuine interest and financial commitment to support the Alue Salak, Gampong Riseh Tunong project, a more detailed project preparation should be carried out similar to that conducted in Goma, Nias.

48651 final fact finding report

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