4. pre-feasibility studies on small-hydro · final report (main) chapter 4 pre-feasibility studies...

Final Report (Main) Chapter 4 Pre-Feasibility Studies on Small-hydro

4. PRE-FEASIBILITY STUDIES ON SMALL-HYDRO

4.1 INTRODUCTION

A Pre-F/S has been conducted for the most promising small-hydro potential sites, which were selected through studies of grid extension plans, demand forecasts, and site reconnaissance.

Of the eleven (11) selected sites for the Pre-F/S, topographic surveys, longitudinal profile surveys, and cross-section surveys were conducted for the intake, powerhouse and waterway of the seven (7), mainly MW-class scheme, sites. Furthermore, discharge measurement was conducted for the selected sites during site reconnaissance using equipment purchased by JICA.

The Pre-F/S was conducted keeping in mind the differences between the 100kW-class schemes and the MW-class schemes, such as the difference in scale, cost of development, electricity tariff and financial viability, as well as the differences in the institutional structure for their operation and maintenance.

The Pre-F/S design for the sites where topographic surveys were not conducted was based on 1/50,000 or 1/100,000 topographic maps.

The contents of the ongoing STEP study was considered for the design and cost estimate of the equipment. Further, in the economic/financial analyses, the life-cycle cost, including operation and maintenance, account for the unique characteristics of the northern provinces of Laos.

Flowchart for the Pre-F/S

The study items of the Pre-F/S are as follows:

JICA M/P Study on Small-Hydro in Northern Laos 4 - 1 December 2005


Pre-F/S Study Items

(i) Meteo-hydrological analysis

(ii) Optimum power development plan (Optimization of installed capacity in the case of a grid-connection plan)

(iii) Power development planning and design (civil works, electrical/mechanical equipment, transmission and distribution line, etc.)

(iv) Economic/financial analysis

(v) Initial Environmental Evaluation

4.2 SMALL-HYDRO INVENTORY STUDY

4.2.1 INTRODUCTION

In this Master Plan Study, a Pre-F/S was carried out for each of the eleven (11) small-hydro sites, which were selected from candidates sites (100kW~5MW) in the eight (8) provinces of northern Laos. The procedure leading to the Pre-F/S was as follows.

(i) Preparation of a small-hydro inventory (62 sites)

(ii) Selection of the 24 potential sites for the map study

(iii) Selection of the 24 potential sites for the site reconnaissance (18 sites was scheduled and 6 sites was added during site investigation)

(iv) Selection of the 11 potential sites for the Pre-F/S (10 sites was scheduled originally)

A small-hydro inventory was prepared as the first step of the procedure mentioned above. It may be noted that the approach taken for the selection of the off-grid schemes was not based primarily on hydropower potential (supply) as in the conventional studies, but by first identifying the location and size of electricity demand at the load centers. Therefore, for example, in Bokeo Province where hydropower potential was not yet identified, an extensive map study was conducted for the areas near the load center to identify sites with hydropower potential that could satisfy the electricity demand of the load centers. Further, by referring to the existing report for small-hydro planning prepared previously, the potential sites for small-hydro aiming at the replacement of import electricity and the strengthening of the EDL grid were selected. The total number of these projects is 62 sites.

It may also be noted that for load centers in northern Laos with a small load where expanding the mini-grid for the sake of attaining over 100 kW proved to be costly, installed capacities less than 100 kW were considered despite the original scope stating the target installed capacity of the Study to be greater than 100 kW.



Similarly, despite the upper limit of development set at 5 MW in the scope of the Study, MW schemes greater than 5 MW were also considered in order to take full advantage of the economies of scale of the development for replacement of imported power and strengthening of the EDL grid, where sufficient head and discharge are available.

1 1 Nam Pe 185.8 700 201 Phongsaly MOU Exist2 2 Nam Nga 86 100 202 Mai - Diesel Off-Grid3 3 Nam Kai 220 260 203 Khoua - Diesel Off-Grid4 4 Nam Pok 401 150 204 Samphan - Un-electrified Area O

5 5 Nam Boun 2 311.2 2,500 205 Bouanneau EDL TL in 20076 6 Nam Ou Neau 579 380 206 Gnod Ou - Un-electrified Area O

7 7 Nam May - 100 206 Gnod Ou Access difficulties8 1 Nam Sing 72 500 302 Sing No necesity of new power9 2 Nam Long 156 2,000 303 Long - Diesel Off-Grid (O)

10 3 Nam Pha 217 250 303 Vienhphoukha - Diesel Off-Grid11 4 Nam Heng 265 100 305 Nalae - Additonal HP12 5 Houay Phean 305 Nalae Site is not clear13 1 Houay Lap 67.9 100 403 Namo JICA Visit in Sept.2003

14 2 Nam Phak 595 5,100 403 Namo - Strengthen EDL Grid15 3 Nam Ngao 299 840 405 Beng - Strengthen EDL Grid O

16 4 Nam Tale 89 80 Pakbeng Additonal HP17 5 Nam Beng - 1,500 405 Beng F/S MOU signed in 200218 1 Nam Gnone 121 500 501 Houasay - Import Off-Grid O

19 2 Nam Khanoy 82 80 503 Meung - Un-electrified Area20 3 Nam Hat 501 170 Pha Oudom - Un-electrified Area21 4 Nam Khieo - 100 505 Paktha Site is not clear22 1 Houay Houn 104 100 606 Ngoy EDL TL 22kV Exist23 2 Nam Pa 2 - 70 608 Phnxay Head is too samll24 3 Houay Kouang 37 200 610 Vieng Kam - Un-electrified Area25 4 Houay Hop - 150 610 Vieng Kam Location not clear26 5 Nam Xeng 429 170 610 Vieng Kam - Un-electrified Area(Sub-Dis.) O

27 6 Nam Um - 100 610 Vieng Kam C.A. too small28 1 Nam Peun 211 70 705 Houamouang - Strengthen EDL Grid29 2 Nam Hang 89 70 703 Viengthong Small Hydro Exist Additonal HP30 3 Nam Xam - 2,500 703 Viengthong Small Hydro Exist31 4 Nam Hao 453 5,000 704 Viengxay NK Visit in May 2003 Import Off-Grid O

32 5 Nam Sim 183 9,300 704 Viengxay Out of capacity range33 6 Nam Nua 86.6 2,100 704 Viengxay F/S MOU signed in 200334 7 Nam Sam 97.54 650 705 Houamouang Far from discridt center35 8 Nam Yen 73.954 500 705 Houamouang Far from discridt center36 9 Nam Khoum 131.77 600 705 Houamouang Far from discridt center37 10 Nam Khouan - 200 706 Xamtai Location not clear38 11 Houay Thong - 100 706 Xamtai Far from discridt center39 1 Nam Houng 733.99 650 801 Xayabury EDL TL Exist40 2 Nam Met 474.18 1,800 801 Xayabury EDL TL Exist41 3 Nam Khop 802 Khorb Head is too samll42 4 Nam Ken 415 380 803 Hongsa - Import Off-Grid43 5 Nam Ngeun 1 174.74 - 803 Hongsa EDL TL from Thailand Exist44 6 Nam Ngeun 2 1159 600 803 Hongsa - Import Off-Grid45 7 Nam Yang - 100 803 Hongsa EDL TL from Thailand Exist46 8 Nam Pouy 1 322.3 300 806 Phiang EDL TL Exist47 9 Nam Pouy 2 1,412.51 650 806 Phiang EDL TL Exist48 10 Nam Lay 245 220 807 Paklay NEF Visit in Oct. 2003 Strengthen EDL Grid49 11 Nam Fhoun 1,122.53 650 807 Paklay EDL TL Exist50 12 Nam Gnam 478.15 650 807 Paklay EDL TL Exist51 13 Nam Gnang 311.76 650 807 Paklay EDL TL Exist52 14 Nam Ham 2 97 3,000 809 Boten NK Visit in May 2000. NEF Visit in Oct.2003 Import Off-Grid53 1 Nam Ma 139.3 800 902 Kham Small Hydro Exist54 2 Nam Phot 23.95 600 902 Kham Small Hydro Exist55 3 Nam Houay 108.19 450 903 Nong Het Head is too samll56 4 Nam Xan 134 110 904 Khouan - Un-electrified Area (Sub-Dis.)

57 5 Nam Pen 904 Khouan Head is too samll58 6 Nam Chao 129 100 Makmay - Un-electrified Area59 7 Nam Kuang - 700 903 Nong Het C.A. too small60 8 Nam Ngan 33.06 600 904 Khouan EDL TL Exist61 9 Nam Sen 158 400 907 Phasay Small Hydro Exist62 10 Nam Pot 134.86 2,000 907 Phasay Small Hydro Exist

No.800Xayabury

(JICA)

No.900Xiengkhouang(MIH/PDIH)

Screening of 62 Candidate Sites of Small Hydropower in Northern Laos

No.400Oudomxay

(JICA)

No. 500Bokeo

(MIH/PDIH)

No.600Luangphrabang

(JICA)

No.700Houaphan

(MIH/PDIH)

Water Level GaugeInstallation

(6 Sites)

No.200Phongsaly

(MIH/PDIH)

No.300Louangnamtha

(JICA)

Categories ofTarget Load CenterReferenceCapacity

(kW) District ProvinceSeq No.

No. Project Name C/A(km2)



The small-hydro inventory prepared based on existing reports on small-hydro and information possessed by the counterparts is as shown below.

The load centers to be electrified by small-hydro were selected according to studies of the EDL grid extension plan (PTD2, PTD3), power supply/demand balance and other conditions such as substitution of imported power. The existing 115 kV and 22 kV EDL transmission lines and their plan for 2010 are shown in the figure below.

Districts which are not included in the EDL extension plan for 2010 are classified as load centers, which have been further categorized into three categories as shown in the table and figure below.

It may be noted that Phongsaly District and Bon Neua Districts of Phongsaly Province are not classified as load centers despite the fact EDL has no plans for transmission line extension by 2010, because the existing Nam Ngai Hydropower has sufficient capacity to supply these districts.

Category Situation of the District in 2010 Province District Phongsaly Nhot Ou, Samphan Bokeo Meung, Pha Oudom Luangphrabang Viengkhoune

1 No major power source.

Xiengkhuang Morkmay Luangnamtha Nalae Oudomxay Nga, Pakbeng 2 Existing small-hydro only, and lacking

potential. Huaphanh Viengthong, Huameuang, XamtayPhongsaly May, Khua 3 Existing diesel power only, and lacking

potential. Luangnamtha Viengphoukha

Discussions were held with the PDIH staff during the lectures held in Vientiane for the selection of the above load centers, and their comments and requests were reflected accordingly considering existing spread situation of Pico-hydro and SHS.

2

3

1

Categories of the Load Centers

In addition to load centers mentioned above, the small-hydro potential sites for replacement of import power and strengthening of the EDL grid were selected on the basis of location of the existing transmission line and its extension plan.



4.2.2 RESULTS OF INVENTORY STUDY

SeqNo. Project Name C/A

(km2)

Spec.Dis.

(l/s/kw2)

Dis. inDrySea.

(m3/s)

Effec.Head(m)

Capacityin DrySeason(kW)

InstalledCapa.(kW)

District Province

1 Nam Nga 90 3.1 0.28 16 26 100 202 Mai2 Nam Kai 216 2.7 0.58 24 81 250 203 Khoua3 Nam Pok 407 3.2 1.30 80 613 150 204 Samphan4 Nam Likna 30 204 Samphan5 Nam Ou Neau 610.4 3.7 2.26 40 531 260 206 Gnod Ou6 Nam Boune 2 4,000 207 Bountai7 Nam Long 143.35 3.6 0.52 215 652 2,500 303 Long8 Nam Pha 208 3.0 0.62 25 92 250 303 Vienhphoukha9 Houay Song - 304 Viengphoukha

10 Nam Chouk - 304 Viengphoukha11 Nam Heng 280 1.9 0.53 30 94 225 305 Nalae12 Nam Phak 594 2.7 1.60 100 943 5,100 403 Namo13 Nam Ngao 245 2.0 0.49 80 230 840 405 Beng14 Nam Tale 88 1 0.09 80 41 80 407 Pakbeng15 Nam Gnone 126 2.7 0.34 30 60 600 501 Houasay16 Nam Khanoy 80 3.6 0.29 20 34 80 503 Meung17 Nam Chong - 3.6 0.05 100 25 50 503 Meung18 Nam Polao - 503 Meung19 Nam Hat 560 1.0 0.56 15 49 170 504 Pha Oudom20 Nam Hat 2 112 1.0 0.11 50 30 120 504 Pha Oudom21 Houay Kouang 40 2.4 0.10 34 19 200 610 Vieng Kam22 Nam Mi - 610 Vieng Kam23 Nam Xeng 420 2.5 1.05 20 123 170 610 Vieng Kam24 Nam Peun 216 3.0 0.65 40 152 70 705 Houamouang25 Nam Hang 88 2.5 0.22 80 103 70 703 Viengthong26 Nam Hao 419 3.0 1.26 129 951 5,000 704 Viengxay27 Nam Sim 8,000 704 Viengxay28 Nam Ngen 2 1100 1.0 1.10 20 129 610 802 Khorb29 Nam Ken 312 1.5 0.47 30 83 380 803 Hongsa30 Nam Lay 256.38 1.3 0.33 30 59 220 807 Paklay31 Nam Ham 2 100 1.0 0.10 176 103 1,000 809 Boten32 Nam Xan 3 136 4.0 0.54 60 192 120 904 Khoune33 Nam Chao 128 4.0 0.51 25 75 100 905 Morkmay

No.200Phongsaly

No.300Louangnamtha

No.400Oudomxay

No. 500Bokeo

No.600Luangphrabang

No.700Houaphan

No.800Xayabury

900Xiengkhuang

Project List for Map Study From the small-hydro inventory of 62 potential sites, 24 sites for map study were selected which has hatching in following table. For this selection, the load centers consist of 3 categories mentioned above, as well as the hydropower potential sites suitable for the replacement of import power or the reinforcement of the EDL grid power. The projects without hatching in the table below mean the projects which were added during site reconnaissance.

4.3 SMALL-HYDRO MAP STUDY

4.3.1 INTRODUCTION

The map study of the 24 potential sites was conducted by categorizing them into 2 groups as explained hereunder.

Grouping for the Map Study Group Characteristics of Small-hydro Planning Number of Sites

Group 1 These are off-grid hydropower schemes for supplying to the load centers where EDL transmission lines are not planned. 15 sites

Group 2 These are grid hydropower schemes where sites with high hydropower potential are selected for the reinforcement of the EDL supply or the replacement of imported power from neighboring countries.

9 sites

For the load centers categorized as Group 1, small-hydro potential sites were selected which best satisfied the demand in the respective load centers. Basic data such as discharge and head were roughly calculated in order to make a sketch of a hydropower development plan. The promising sites were selected through analysis of difficulty of construction and economic viability based on these



rough data, and by the use of the selection criteria. Three new sites were identified in Bokeo Province through the map study, where no potential sites were identified before.

As for the sites categorized as Group 2, the hydropower potential was the governing factor for the selection, as they aim to supply power to the EDL grid or to replace expensive imported power.

The basic information used in the map study is as shown below.

Basic Information Used in the Map Study No. Item Method 1 Catchment Area Calculated on GIS map.

2 Dry-Season Discharge at the Intake Site

A dry-season specific discharge map was produced based on results of the JICA Water Resources Guide Book of Lao P.D.R, 2002.(Ref. Supporting Data Files Part-C)

3 Head Calculated on GIS map and/or referred to existing studies.

4 Load at Load Center

In case of off-grid type, the area of electricity distribution, the electrified household number and electricity demand per household (190W) were assumed to estimate the total electricity demand. In case of grid-connection type, the electricity demand of villages was not considered.

5 Installed Capacity and Design Discharge

In case of off-grid type, the installed capacity is decided based on the load mentioned above. In case of grid-connection, the installed capacity was decided by referring of previous study results. Design discharge was calculated from the installed capacity considering its effective head.

Intake Weir The weir high is assumed to be 6 m in all cases, while the crest length is measured from the GIS map.

Headrace Channel, Penstock

The cross-sectional areas of the headrace tunnel and the penstock are calculated from the design discharge, while their lengths were measured on the GIS map.

Powerhouse, Turbine/Generator

Costs of powerhouse and turbine/generator based on costs of previous projects in Laos possessed by DOE.

Transmission Line 22kV

The length of transmission lines measures on the GIS map, while the unit cost per km is based on previous projects in Laos provided by DOE.

Transformer The number of transformers assumed to be 1/village, while its cost is based on cost provided by DOE.

6 Construction Cost

Access Road The length of the access road measured on the GIS map, while existing reports were referred for the unit cost.

The basic information of each of the sites are collected as above, and based on these information, the 18 sites to conduct a site reconnaissance were selected. The selection was conducted by allocating points for the following criteria, while also giving consideration so that the selected sites were not concentrated in a particular province.

(i) Unit construction cost (US$/kW)

(ii) Necessity for electrification (un-electrified area, addition to existing small-hydro, replacement of diesel generator, reinforcement of EDL grid, replacement of imported power)

(iii) Balance between hydropower potential during dry-season and demand

(iv) Accessibility

(v) Possibility to divert water for irrigation



4.3.2 RESULTS OF MAP STUDY

Conclusions from the results of the map study are recorded in Supporting Data Files Part-C and summarized in the table below. The 18 hatched sites, of which 11 sites are of Group 1 and 7 sites are of Group 2, were selected for site reconnaissance.

Group 1 (11 sites selected out of 15 site) Unit Construction

Cost Category Dry-Season Hydro Potential Accessibility Water Use for

Irrigation Seq No.

Project Name Province

US$/kW Points Type Points

Load/ Pot. Points Walking

Distance Points Possibility Points

Total Points

(Max 55)

1 Nam Nga Phongsaly 13,431 12.9 D 6 4.37 0 2 9 x 0 27.9 2 Nam Kai Phongsaly 8,605 17.7 D 6 3.15 2 5 7 o 5 37.7 3 Nam Pok Phongsaly 14,056 12.2 U-DC 10 0.24 10 10 6 x 0 38.2 4 Nam Ou Neau Phongsaly 6,296 20.0 U-DC 10 0.76 10 Dry season 5 x 0 45.0 6 Nam Pha Louangnamtha 8,732 17.6 D 6 2.61 4 0.5 9 o 5 41.6 7 Nam Heng Louangnamtha 19,781 6.5 HY 4 1.06 8 Dry season 5 o 5 28.5 10 Nam Tale Oudomxay 21,145 5.2 HY 4 1.90 6 10 6 x 0 21.2 12 Nam Khanoy Bokeo 21,352 4.9 U-DC 10 2.30 4 5 7 o 5 30.9 13 Nam Hat Bokeo 11.194 15.1 U-DC 10 3.88 2 0 10 o 5 42.1 14 Houay Kouan Luangphrabang 7,730 18.6 U-DC 10 11.56 0 0 10 x 0 38.6 15 Nam Xeng Luangphrabang 7,925 18.4 U-SDC 8 1.35 8 2 9 o 5 48.4 16 Nam Peun Houaphan 21,550 4.7 HY 4 0.44 10 2 9 x 0 27.7 17 Nam Hang Houaphan 35,538 -9.1 HY 4 0.62 10 0 10 x 0 14.9 23 Nam Xan Xiengkhuang 12,679 13.6 U-SDC 8 0.56 10 3 8 x 0 39.6 24 Nam Chao Xiengkhuang 18,692 7.6 U-DC 10 1.24 8 3 8 o 5 38.6

* Category U-DC : Un-electrified District Center U-SDC : Un-electrified Sub-District Center D : District Center electrified by diesel genset HY : District Center electrified by small hydro

Group 2 (7 sites selected out of 9 sites) Unit Construction

Cost Category Dry-Season Hydro Potential Accessibility Water Use for

IrrigationSeq No.

Project Name Province

US$/kW Points Type Points Load/Pot. Points Walking

Distance Points Possibi lity Points

Total Points

(Max 45)

5 Nam Long Louangnamtha 1,853 20 S 6 2.82 4 5 10 x 0 40.0 8 Nam Phak Oudomxay 3,638 18.2 S 6 5.40 0 10 7 x 0 31.2 9 Nam Ngao Oudomxay 7,550 14.3 S 6 3.41 2 10 7 x 0 29.3

11 Nam Gnone Bokeo 3,979 17.9 I 6 8.68 0 3 10 x 0 33.9 18 Nam Hao Houaphan 2,028 19.8 I 6 4.86 0 1 10 x 0 35.8 19 Nam Ngen 2 Xayabury 5,935 15.9 I 6 3.00 2 2 10 o 5 38.9 20 Nam Ken Xayabury 11,228 10.6 I 6 3.00 2 4 9 x 0 27.6 21 Nam Lay Xayabury 14,630 7.2 S 6 3.00 2 1 10 x 0 25.2 22 Nam Ham 2 Xayabury 4,139 17.7 I 6 29.98 0 1 10 o 5 38.7

* Category S : EDL Grid Reinforcement I : Replacement of Imported Power

The above map study is based on various assumptions such as river discharge, head, demand forecast and construction cost. Therefore, through site reconnaissance of the selected 18 sites, these assumptions were to be made more accurate. As a result of the site reconnaissance and screening based on the actual site conditions, eleven (11) sites were selected to conduct a Pre-F/S.

It may be noted that the Study Team has conducted site reconnaissance with DOE for the 18 selected sites, whilst reconnaissance for the remaining 6 sites are to be conducted by DOE/PDIH after the termination of this Study. Therefore, the selected 18 sites were of diverse characteristics, intended for the OJT-style capacity building of the DOE/PDIH engineers, so that they could familiarize with site reconnaissance of various types and would be able to conduct reconnaissance by themselves.



4.4 SMALL-HYDRO SITE RECONNAISSANCE

4.4.1 INTRODUCTION

As a result of the map study, 18 potential sites were selected for site reconnaissance. However, 24 sites were surveyed in total, because an additional 6 sites were identified at site.

From November to December 2004, two teams, each composed jointly of members of the Study Team and DOE, conducted site reconnaissance separately for a total of 19 sites. Later DOE conducted site reconnaissance for the 4 sites in Houaphan and Xiengkhuang Provinces where the JICA Study Team members were not allowed to enter for security reasons.

The route maps of the site reconnaissance held by joint teams of JICA Study Team and DOE are shown below:

Site Reconnaissance Route Map: Team-A Site Reconnaissance Route Map : Team-B

4.4.2 RESULTS OF SITE RECONNAISSANCE

Several formats were prepared for the site reconnaissance in order to secure uniformity in the content, the precision and the method of the site reconnaissance of the two teams as well as to serve as a guideline for the DOE engineers to better understand the items that need to be investigated during the reconnaissance. The formats prepared by the Study Team members include those for civil work,



transmission line route, socio-economic surveys, and environmental impact. The Study Team also prepared an explanation sheet introducing small-hydro projects to be used when visiting district offices and village leaders.

The results of the site reconnaissance are recorded in the site reconnaissance memo and attached in Supporting Data Files Part-C and summarized below:

No. Project Name Topography & Hydrology Access way Socio-environmental Notes

3 N. Pok (Phongsaly, Samphan)

At the weir axis, right bank is flat and crest length become long. Length of open channel is 1.6km and effective head is as small as 78m.

Between power house site and B.Nasai, distance is 6km, steep slope and no access road. Construction of access road to intake site also in necessary.

Hydropowre potential is too big to electrify the district center of Samphan. Connection with EDL grid is mandatory.

Balance of power suppluand demand is not good. (WL measurement site)

4 N. Likna (Phongsaly, Samphan)

River width is 4m. Dry season discharge is about 0.3m3/s. Channel length is 300m and effective head is 14m.

Access to B. Nasai is boat on Nam Ou River. Road was constructed up to confluence of Nam Pok and Nam Ou.

Existing electricity source are piko-hydro and small diesel power.

Alternative site for Nam Pok found at site reconnaissance.

5 N. Ou Neau (Phongsaly, Gnot Ou)

At original weir axis, as paddy field spreadon left bank, it was shifted to narraw section. Channel length is 5km and effective head 20m. Dry season discharge is as big as 2~3m3/s.

Access to intake weir and powerhouse is good. Openchanel locates on right bank and bridge is required to access to right bank.

Due to construction of weir, paddy field on right bank will be inundated. Demand of electrification of district is strong and priority of electrification is high.

Plan of electrification of the villages surrounding district center. Cost for distribution line is high. (WL measurement site, profile survey)

6 N. Boune 2 (Phongsaly, Boun Nua)

River diversion from N. Boun to N. Hoy through 2km tunnel. Effective head is 125m and dry season discharge is 1.0m3/s.

Access from existing paved road to intake is 1km and to power house is 6~8km.

Boun Nuawas electrified by N. Boun 1. However, installed capacity is 110kW and still in short

Installed capacity is 4MW. Implementation after grid connection at 2010 is effective. (topo survey)

7

N. Long (Louangnamtha, Long)

Intake site is V shape gorge with foundation rock exposure and there are water falls at downstream of intake site. Channel length is 4km and effective head is 227m. Dry season discharge is 2.0m3/s.

From district center to entrance of intake weir site through unpaved road, it takes 2 hours. Available only dry season. To dam and power house sites, 300m height down to bottom of V shape gorge by walking.

Provincial tourism office has opinion to keep existing condition without any development for future tourism. Coordination is necessary.

Implementation after grid connection at 2008 is effective. (WL measurement site, topo survey)

8

N. Pha (Louangnamtha, Vieng Phokha)

Head of 30m expected from topo map was not correct and it was 15m at site measurement. Further water depth at flood is 5m. Therefore, effective head is too small.

Access from intake site to powerhouse site is good, and takes 20 minutes by car.

District center had been electrified by diesel(120kW), and stopped at 3 years ago due to machine trouble. Presently diesel of 39kW is available now. Distribution line for 200 HH is available.

At upstream site, irrigation water was taken. Due to less effective head, development of small-hydro is difficult.

9 H. Song (LNT,Vieng Phokha)

Sufficient head was not confirmed by measurement at H. song which is tributary of N. Pha.

Access to intake weir and powerhouse sites are easy. As above

Alternative site for Nam Pha. However, head is not enough.

10 N. Chouk (LNT,Vieng Phokha)

Expected head based on topo map was not found at site by river walking from main road to upstream side of N. Chouk.

As above As above As above

11 N. Heng (Louangnamtha, Nale)

Head of 30m expected from topo map was not correct and it was 10m at site measurement. Therefore, effective head is too small.

From district center to power house site (V. Ban), it takes 2 hours. From V. Ban to intake site, it takes 2.5 hours.

B. Nale was electrified by small-hydro (30kW) and surrounding villages were electrified by SHS or has plan of SHS.

Due to less effective head, development of small-hydro is difficult.

13 N. Ngao (Oudomxay, Beng)

Small-hydro by short cut of winding river. \Dam height is 30m and effective head is 69m only.

From district center to B. Nahom, it takes 45 minutes. From B. Nahom to intake site and power house site, it takes 5hours walking on one way. Access is too bad.

B. Nahomwas electrified by Piko-hydro.

As a alternative plan of N,Ngao project, river diversion plan from N. Ngao to N.Beng should be studied in detail.

15 N. Gnone (Bokeo, Houaysay)

Small-hydro of rapid river with small water fall. Length of open channel is 2km and effective head is 46m. This is not so efficient.

From Houausay to power house site, it takes 45 minutes through paved road and 20 minutes through un-paved road. To intake site by walking, it takes 1 hour

Power house site locates near B. Phouxai which was electrified by Piko-hydro. Powrehouse site is one of tourism zone.

River water is being used for irrigation. And this is considered for planning. (WL measurement site, topo survey)

16 N. Khanoy (Bokeo, Meung)

Head of 20m expected from topo map was not correct and it was 15m at site measurement.

From district center to power house sit, it takes 1.5 hours. To intake site, further walking of 2 hours to upstream side is necessary.

Back water due to construction of intake weir effects to the are of villages.

Due to less head and far distance from demand center, development of small-hydro is difficult.

17 N. Chong (Bokeo, Meung)

River width is 18m and river flow is rapidity. This is small-hydro by use of existing irrigation intake weir. Discharge is small, Length of open channel is 2 km and effective head is 62m.

From district center to B. Tole, intakes 20 minutes by car and 1hour by walking. Access to power house site also almost same. In rainy season, access from Houausay to district center is impossible.

River water is used for irrigation in rainy season and is not used in dry season. District center is electrified huge number of Piko-hydro.

Alternative plan of Nam Khanoy small-hydro. Basic information was obtained at hearing survey of district center.




18 N. Polao (Bokeo, Meung)

Small-hydro planned in the Polao river which is rapid river Along the road. Space for intake weir, water way and power house is limited due to narrow space.

Rom district center to power house site, it takes 1 hour. Access in rainy season is difficult.

Surrounding villages were electrified by Piko-hydro. Main transportation is by boat in the Mekon River.

During hearing survey at district office, information of small-hydro planned by Chinese developer was obtained.

19

N. Hat (Bokeo, Pha Oudom)

Head of 15m expected from topo map was not correct and it was 8m at site measurement. Length of open channel is as long as 2km.

There is intake site and power house site between Pak Hat and district center. Access is easy.

District center had been electrified by diesel generator and stopped due to high fuel cost. Relatively rich households are using personal diesel.


20

N. Hat 2 (Bokeo, Pha Oudom)

Rapid river was found at upstream of Nam Hat. Weir site was decided at site with rock outcrop. Length of open channel is 3km and effective head is 48m.

From district center toward upstream of N. Hat, it takes 30 minutes. Further walking along the river to intake site, it takes 2 hours. There is no village near intake site and condition of footpath is not good.

As above Alternative plan of Nam Hat, the sufficient head was found.

21

H. Kouang (LPB, Vieng Kham)

Dry season discharge is very small and potential is smaller than electricity demandat district center.

From district center to Pak Mong,it takes 2 hours by car. Access to intake weir and power house is not clear.

Diesel generator (150kW) is working at only night time. There area some piko-hydro also.

Due to less river water, development of small-hydro is difficult.

22

N. Mi (LPB, Vieng Kham)

River width at intake weir site is as wide as 150m and crest length of weir become too long. Length of open channel is 1.5km and effective head is 26m.

From B. Donkoun to intake weir site, it takes 20 minutes by boat and 30 minute by walking. To power house site, 10 minutes walking from B. Donkoun.

As above

During hearing survey at

District center, it was recommended as candidate site.

23

N. Xeng (LPB, Vieng Kham)

As the results of comparison of topography, intake site was decided to be narrow portion of the river which was original layout. Length ogf open channel is 2km and effective head is 13m. River gradient is not so steep. Dry season discharge is more than 1.0 m3/s.

From Pak Mong to junction to B. Vanxiang, it takes 1.5 hours by car. To B.Vanxiang, it takes further 2.5 hours by car through paved road. After that, to intake site by 1.5 hours walking.

Due to construction of intake weir, river water level is raised and affects the area of villages in upstream area.

Small-hydro for sub-district center and urgent electrification is required for future development. (WL measurement site, topo survey)

26 N. Hao (Hoaphan, Sopbao)

At the intake site, foundation rock is exposed with steep slope in right bank and paddy field spread in left bank. Length of tunnel is 3km and effective head is 46m.

In take site is far from Xam-Nua by 51 km. From main road to power house site, it takes 1 minute by walking.

At intake weir site, both sides of river are steep and no influence of rising of river water to villages.

Hao River is tributary of Ma river which flow into Vietnam. The head is not so big and project is inefficient. (WL measurement site)

27 N. Sim (Hoaphan, Viengxay)

River diversion from N. Vong to H. Kon through tunnel of 2km in length. Total discharge of both river is 1.1m3/s. Effective head is about 180ｍ.

From Xam-Nua to B. Kang Muang, its distance is 50 km. Further to intake weir site, it is 2 km. It is difficult to go to power house site along N. Vong and access road is required on left bank.

In order to reduce the inundation area of paddy field, river water level raised by construction of intake weir should be controlled as low as possible.

Developer of foreign country has MOU of development. Implementation after EDL grid connection at 2015 is effective. (Topo survey)

29

N. Ken (Xayabury, Hongsa)


From district center to B. Namaignom, it takes 30 minutes by car. To intake site, it takes 40 minutes by walking, and to power house, it takes further 1 hour by walking.

Project site is same as reservoir site of Hongsa Lignite Project. Small-hydro for replacement of import power from Thailand seems not to be necessary for the time being.


31 N. Ham 2 (Xayabury, Boten)

This area has less annual rainfall and less dry season river flow. Dry season discharge at intake site is 0.2m3/s and average discharge is 1.4m3/s. Length of open channel is 2.84km and effective head is 173ｍ . River bed slope is very steep.

From Xayabury to Ban Koum, intakes 6 hours by car. To power house, it takes 30minutes by walking. Further to intake site, it takes 1hour by walking.

One part of rive, which has very steep river bed slope is water fall, and environmental consideration is necessary.

NEF in Japan installed hydrological measurement equipment (rainfall, river flow), and DOE is collecting data. There is developer who has MOU. (Topo survey)

32

N. Xan 3 (Xiengkhuang, Khoune)

Length of open channel is 750m and effective head is 31m. Nam Xan has continuous steep river bed slope and only head of upstream side is effective for small-hydro.

From district center to sub-district center, it takes 2.5 hours by car. To dam site, it takes 1.8 hours by walking. Further to power house site, the footpath is available.

Since there is not wide irrigation area at downstream of river, the water usage seems not to be problem.

If length of open channels extended to 15km, total head is 1,000m. There is possibility of development of MW class for strengthening of EDL grid.

Source : JICA Study Team Note; ＊In table above, the hatching in column of project name mean that the Pre-F/S was carried out.

It may be noted that surveyors for the topographic survey accompanied the site reconnaissance where they were given instructions on the location and range of survey to be conducted.



4.4.3 TOPOGRAPHIC SURVEY

(1) Introduction

Of the twenty-four (24) sites evaluated through the map study, the eighteen (18) sites were selected for the reconnaissance, while the six (6) more sites were identified during the course of the reconnaissance. For the preparation of the Pre-F/S of the eleven (11) sites selected as a result of the site reconnaissance, the seven (7) sites were selected for the topographic survey.

The following task was entrusted to NGD in order to prepare a topographic map with a precision of 1:1,000 scale (1m intervals) required for the planning and design at the Pre-F/S level.

a) Field reconnaissance along with the study team

b) Benchmark setting

c) Traverse survey

d) GPS survey

e) Leveling

f) Detailed survey

g) Profile and cross-section leveling

h) Output of survey results Survey at Site

The sub-contracted work was contracted with NGD through tendering procedure by confirmation of the capability of survey, experience, possessed equipment and tender price. The detail information of survey works which was sub-contracted are shown in following table.

Details of Survey Work Sub-Contacted Project Name Province District Control

Points Area (ha)

Cross Section (km)

Longitudinal Section (km)

Nam Boune 2 Phongsaly Bountai 6 14.31 1.32 3.94 Nam Ou Neua Phongsaly Gnod Ou 3 0.00 0.00 7.73 Nam Long Louangnamtha Long 6 18.11 2.60 4.33 Nam Gnone Bokeo Houasay 6 12.10 1.39 2.32 Nam Xeng Louangprabang Vieng Kham 6 10.02 1.41 2.4 Nam Ham 2 Xayabouly Boten 6 13.84 2.45 2.81 Nam Sim Houaphan Viengxai 6 12.10 0.75 0.68



(2) Instruments

The following instruments were utilized in the survey.

Equipment Model Total Station (Photo: LEICA TC600)

LEICA TC1700 LEICA TC600 LEICA TC307 LEICA TC400 SOKKIA Set500 SOKKIA Set2010

Auto Level (Photo: LEICA NA2)

LEICA NA2 LEICA NA820

GPS (Photo: TRIMBLE 5700)

TRIMBLE 4000SSI TRIMBLE 5700

(3) Survey results

The results of the surveys were processed by CAD software for analysis and converted into drawing data. The newly-set reference points and benchmarks were linked to the grid of national reference points. The UTM (Universal Transverse Mercator) coordinate system and Lao National Datum 1997, the reference level of Laos, were used as the final data. The final outputs of the sub-contracted survey work are listed below:

1 Survey note and computation sheets 1 set 2 Description of new cross section and BMs points 1 set 3 Cross section sheet Original 2 sets 4 Topographic map Copy 6 sets 5 Survey report Original 2 sets 6 Digital data of survey result Copy 6 sets



4.4 SMALL-HYDRO SITE RECONNAISSANCE

4.4.1 INTRODUCTION

As a result of the map study, 18 potential sites were selected for site reconnaissance. However, 24 sites were surveyed in total, because an additional 6 sites were identified at site.

From November to December 2004, two teams, each composed jointly of members of the Study Team and DOE, conducted site reconnaissance separately for a total of 19 sites. Later DOE conducted site reconnaissance for the 4 sites in Houaphan and Xiengkhuang Provinces where the JICA Study Team members were not allowed to enter for security reasons.

The route maps of the site reconnaissance held by joint teams of JICA Study Team and DOE are shown below:

Site Reconnaissance Route Map: Team-A Site Reconnaissance Route Map : Team-B

4.4.2 RESULTS OF SITE RECONNAISSANCE

Several formats were prepared for the site reconnaissance in order to secure uniformity in the content, the precision and the method of the site reconnaissance of the two teams as well as to serve as a guideline for the DOE engineers to better understand the items that need to be investigated during the reconnaissance. The formats prepared by the Study Team members include those for civil work,



transmission line route, socio-economic surveys, and environmental impact. The Study Team also prepared an explanation sheet introducing small-hydro projects to be used when visiting district offices and village leaders.

The results of the site reconnaissance are recorded in the site reconnaissance memo and attached in Supporting Data Files Part-C and summarized below:


3 N. Pok (Phongsaly, Samphan)

At the weir axis, right bank is flat and crest length become long. Length of open channel is 1.6km and effective head is as small as 78m.

Between power house site and B.Nasai, distance is 6km, steep slope and no access road. Construction of access road to intake site also in necessary.

Hydropowre potential is too big to electrify the district center of Samphan. Connection with EDL grid is mandatory.

Balance of power suppluand demand is not good. (WL measurement site)

4 N. Likna (Phongsaly, Samphan)

River width is 4m. Dry season discharge is about 0.3m3/s. Channel length is 300m and effective head is 14m.

Access to B. Nasai is boat on Nam Ou River. Road was constructed up to confluence of Nam Pok and Nam Ou.

Existing electricity source are piko-hydro and small diesel power.

Alternative site for Nam Pok found at site reconnaissance.

5 N. Ou Neau (Phongsaly, Gnot Ou)

At original weir axis, as paddy field spreadon left bank, it was shifted to narraw section. Channel length is 5km and effective head 20m. Dry season discharge is as big as 2~3m3/s.

Access to intake weir and powerhouse is good. Openchanel locates on right bank and bridge is required to access to right bank.

Due to construction of weir, paddy field on right bank will be inundated. Demand of electrification of district is strong and priority of electrification is high.

Plan of electrification of the villages surrounding district center. Cost for distribution line is high. (WL measurement site, profile survey)

6 N. Boune 2 (Phongsaly, Boun Nua)

River diversion from N. Boun to N. Hoy through 2km tunnel. Effective head is 125m and dry season discharge is 1.0m3/s.

Access from existing paved road to intake is 1km and to power house is 6~8km.

Boun Nuawas electrified by N. Boun 1. However, installed capacity is 110kW and still in short

Installed capacity is 4MW. Implementation after grid connection at 2010 is effective. (topo survey)

7

N. Long (Louangnamtha, Long)

Intake site is V shape gorge with foundation rock exposure and there are water falls at downstream of intake site. Channel length is 4km and effective head is 227m. Dry season discharge is 2.0m3/s.

From district center to entrance of intake weir site through unpaved road, it takes 2 hours. Available only dry season. To dam and power house sites, 300m height down to bottom of V shape gorge by walking.

Provincial tourism office has opinion to keep existing condition without any development for future tourism. Coordination is necessary.

Implementation after grid connection at 2008 is effective. (WL measurement site, topo survey)

8

N. Pha (Louangnamtha, Vieng Phokha)

Head of 30m expected from topo map was not correct and it was 15m at site measurement. Further water depth at flood is 5m. Therefore, effective head is too small.

Access from intake site to powerhouse site is good, and takes 20 minutes by car.

District center had been electrified by diesel(120kW), and stopped at 3 years ago due to machine trouble. Presently diesel of 39kW is available now. Distribution line for 200 HH is available.

At upstream site, irrigation water was taken. Due to less effective head, development of small-hydro is difficult.

9 H. Song (LNT,Vieng Phokha)

Sufficient head was not confirmed by measurement at H. song which is tributary of N. Pha.

Access to intake weir and powerhouse sites are easy. As above

Alternative site for Nam Pha. However, head is not enough.

10 N. Chouk (LNT,Vieng Phokha)

Expected head based on topo map was not found at site by river walking from main road to upstream side of N. Chouk.

As above As above As above

11 N. Heng (Louangnamtha, Nale)

Head of 30m expected from topo map was not correct and it was 10m at site measurement. Therefore, effective head is too small.

From district center to power house site (V. Ban), it takes 2 hours. From V. Ban to intake site, it takes 2.5 hours.

B. Nale was electrified by small-hydro (30kW) and surrounding villages were electrified by SHS or has plan of SHS.


13 N. Ngao (Oudomxay, Beng)

Small-hydro by short cut of winding river. \Dam height is 30m and effective head is 69m only.

From district center to B. Nahom, it takes 45 minutes. From B. Nahom to intake site and power house site, it takes 5hours walking on one way. Access is too bad.

B. Nahomwas electrified by Piko-hydro.

As a alternative plan of N,Ngao project, river diversion plan from N. Ngao to N.Beng should be studied in detail.

15 N. Gnone (Bokeo, Houaysay)

Small-hydro of rapid river with small water fall. Length of open channel is 2km and effective head is 46m. This is not so efficient.

From Houausay to power house site, it takes 45 minutes through paved road and 20 minutes through un-paved road. To intake site by walking, it takes 1 hour

Power house site locates near B. Phouxai which was electrified by Piko-hydro. Powrehouse site is one of tourism zone.

River water is being used for irrigation. And this is considered for planning. (WL measurement site, topo survey)

16 N. Khanoy (Bokeo, Meung)

Head of 20m expected from topo map was not correct and it was 15m at site measurement.

From district center to power house sit, it takes 1.5 hours. To intake site, further walking of 2 hours to upstream side is necessary.

Back water due to construction of intake weir effects to the are of villages.

Due to less head and far distance from demand center, development of small-hydro is difficult.

17 N. Chong (Bokeo, Meung)

River width is 18m and river flow is rapidity. This is small-hydro by use of existing irrigation intake weir. Discharge is small, Length of open channel is 2 km and effective head is 62m.

From district center to B. Tole, intakes 20 minutes by car and 1hour by walking. Access to power house site also almost same. In rainy season, access from Houausay to district center is impossible.

River water is used for irrigation in rainy season and is not used in dry season. District center is electrified huge number of Piko-hydro.

Alternative plan of Nam Khanoy small-hydro. Basic information was obtained at hearing survey of district center.




18 N. Polao (Bokeo, Meung)

Small-hydro planned in the Polao river which is rapid river Along the road. Space for intake weir, water way and power house is limited due to narrow space.

Rom district center to power house site, it takes 1 hour. Access in rainy season is difficult.

Surrounding villages were electrified by Piko-hydro. Main transportation is by boat in the Mekon River.

During hearing survey at district office, information of small-hydro planned by Chinese developer was obtained.

19

N. Hat (Bokeo, Pha Oudom)


There is intake site and power house site between Pak Hat and district center. Access is easy.

District center had been electrified by diesel generator and stopped due to high fuel cost. Relatively rich households are using personal diesel.


20

N. Hat 2 (Bokeo, Pha Oudom)

Rapid river was found at upstream of Nam Hat. Weir site was decided at site with rock outcrop. Length of open channel is 3km and effective head is 48m.

From district center toward upstream of N. Hat, it takes 30 minutes. Further walking along the river to intake site, it takes 2 hours. There is no village near intake site and condition of footpath is not good.

As above Alternative plan of Nam Hat, the sufficient head was found.

21

H. Kouang (LPB, Vieng Kham)

Dry season discharge is very small and potential is smaller than electricity demandat district center.

From district center to Pak Mong,it takes 2 hours by car. Access to intake weir and power house is not clear.

Diesel generator (150kW) is working at only night time. There area some piko-hydro also.

Due to less river water, development of small-hydro is difficult.

22

N. Mi (LPB, Vieng Kham)

River width at intake weir site is as wide as 150m and crest length of weir become too long. Length of open channel is 1.5km and effective head is 26m.

From B. Donkoun to intake weir site, it takes 20 minutes by boat and 30 minute by walking. To power house site, 10 minutes walking from B. Donkoun.

As above

During hearing survey at

District center, it was recommended as candidate site.

23

N. Xeng (LPB, Vieng Kham)

As the results of comparison of topography, intake site was decided to be narrow portion of the river which was original layout. Length ogf open channel is 2km and effective head is 13m. River gradient is not so steep. Dry season discharge is more than 1.0 m3/s.

From Pak Mong to junction to B. Vanxiang, it takes 1.5 hours by car. To B.Vanxiang, it takes further 2.5 hours by car through paved road. After that, to intake site by 1.5 hours walking.

Due to construction of intake weir, river water level is raised and affects the area of villages in upstream area.

Small-hydro for sub-district center and urgent electrification is required for future development. (WL measurement site, topo survey)

26 N. Hao (Hoaphan, Sopbao)

At the intake site, foundation rock is exposed with steep slope in right bank and paddy field spread in left bank. Length of tunnel is 3km and effective head is 46m.

In take site is far from Xam-Nua by 51 km. From main road to power house site, it takes 1 minute by walking.

At intake weir site, both sides of river are steep and no influence of rising of river water to villages.

Hao River is tributary of Ma river which flow into Vietnam. The head is not so big and project is inefficient. (WL measurement site)

27 N. Sim (Hoaphan, Viengxay)

River diversion from N. Vong to H. Kon through tunnel of 2km in length. Total discharge of both river is 1.1m3/s. Effective head is about 180ｍ.

From Xam-Nua to B. Kang Muang, its distance is 50 km. Further to intake weir site, it is 2 km. It is difficult to go to power house site along N. Vong and access road is required on left bank.

In order to reduce the inundation area of paddy field, river water level raised by construction of intake weir should be controlled as low as possible.

Developer of foreign country has MOU of development. Implementation after EDL grid connection at 2015 is effective. (Topo survey)

29

N. Ken (Xayabury, Hongsa)


From district center to B. Namaignom, it takes 30 minutes by car. To intake site, it takes 40 minutes by walking, and to power house, it takes further 1 hour by walking.

Project site is same as reservoir site of Hongsa Lignite Project. Small-hydro for replacement of import power from Thailand seems not to be necessary for the time being.


31 N. Ham 2 (Xayabury, Boten)

This area has less annual rainfall and less dry season river flow. Dry season discharge at intake site is 0.2m3/s and average discharge is 1.4m3/s. Length of open channel is 2.84km and effective head is 173ｍ . River bed slope is very steep.

From Xayabury to Ban Koum, intakes 6 hours by car. To power house, it takes 30minutes by walking. Further to intake site, it takes 1hour by walking.

One part of rive, which has very steep river bed slope is water fall, and environmental consideration is necessary.

NEF in Japan installed hydrological measurement equipment (rainfall, river flow), and DOE is collecting data. There is developer who has MOU. (Topo survey)

32

N. Xan 3 (Xiengkhuang, Khoune)

Length of open channel is 750m and effective head is 31m. Nam Xan has continuous steep river bed slope and only head of upstream side is effective for small-hydro.

From district center to sub-district center, it takes 2.5 hours by car. To dam site, it takes 1.8 hours by walking. Further to power house site, the footpath is available.

Since there is not wide irrigation area at downstream of river, the water usage seems not to be problem.

If length of open channels extended to 15km, total head is 1,000m. There is possibility of development of MW class for strengthening of EDL grid.

Source : JICA Study Team Note; ＊In table above, the hatching in column of project name mean that the Pre-F/S was carried out.

It may be noted that surveyors for the topographic survey accompanied the site reconnaissance where they were given instructions on the location and range of survey to be conducted.



4.4.3 TOPOGRAPHIC SURVEY

(1) Introduction

Of the twenty-four (24) sites evaluated through the map study, the eighteen (18) sites were selected for the reconnaissance, while the six (6) more sites were identified during the course of the reconnaissance. For the preparation of the Pre-F/S of the eleven (11) sites selected as a result of the site reconnaissance, the seven (7) sites were selected for the topographic survey.

The following task was entrusted to NGD in order to prepare a topographic map with a precision of 1:1,000 scale (1m intervals) required for the planning and design at the Pre-F/S level.

a) Field reconnaissance along with the study team

b) Benchmark setting

c) Traverse survey

d) GPS survey

e) Leveling

f) Detailed survey

g) Profile and cross-section leveling

h) Output of survey results Survey at Site

The sub-contracted work was contracted with NGD through tendering procedure by confirmation of the capability of survey, experience, possessed equipment and tender price. The detail information of survey works which was sub-contracted are shown in following table.

Details of Survey Work Sub-Contacted Project Name Province District Control

Points Area (ha)

Cross Section (km)

Longitudinal Section (km)

Nam Boune 2 Phongsaly Bountai 6 14.31 1.32 3.94 Nam Ou Neua Phongsaly Gnod Ou 3 0.00 0.00 7.73 Nam Long Louangnamtha Long 6 18.11 2.60 4.33 Nam Gnone Bokeo Houasay 6 12.10 1.39 2.32 Nam Xeng Louangprabang Vieng Kham 6 10.02 1.41 2.4 Nam Ham 2 Xayabouly Boten 6 13.84 2.45 2.81 Nam Sim Houaphan Viengxai 6 12.10 0.75 0.68



(2) Instruments

The following instruments were utilized in the survey.

Equipment Model Total Station (Photo: LEICA TC600)

LEICA TC1700 LEICA TC600 LEICA TC307 LEICA TC400 SOKKIA Set500 SOKKIA Set2010

Auto Level (Photo: LEICA NA2)

LEICA NA2 LEICA NA820

GPS (Photo: TRIMBLE 5700)

TRIMBLE 4000SSI TRIMBLE 5700

(3) Survey results

The results of the surveys were processed by CAD software for analysis and converted into drawing data. The newly-set reference points and benchmarks were linked to the grid of national reference points. The UTM (Universal Transverse Mercator) coordinate system and Lao National Datum 1997, the reference level of Laos, were used as the final data. The final outputs of the sub-contracted survey work are listed below:

1 Survey note and computation sheets 1 set 2 Description of new cross section and BMs points 1 set 3 Cross section sheet Original 2 sets 4 Topographic map Copy 6 sets 5 Survey report Original 2 sets 6 Digital data of survey result Copy 6 sets



4.5 SMALL-HYDRO PRE-F/S

4.5.1 INTRODUCTION

A Pre-F/S was carried out on each of the 11 sites selected through the evaluation of the results of the EDL grid extension plan, demand forecast and the site reconnaissance from the use of the development priority criteria. It may be noted that although the quantity of the sites subject to the Pre-F/S was initially 10 sites, 11 sites were selected through discussion with DOE.

List of Sites Subject to the Pre-F/S Cate- gory

Project Name District Province Demand

Area Map

StudyTopo

SurveySocio

Survey Gauge

Installation Pre-F/S

U N. Likna Samphan D.C. - - O - S/TeamU N. Ou Neau Gnod Ou D.C. O EL only O O S/TeamU N. Boun 2 Bountai

Phongsaly Grid - O - - S/Team

S N. Long Long Louangnamtha Grid O O - O S/TeamI N. Gnone Houasay Grid O O - O S/TeamU N. Chong Meung D.C. - - O - S/TeamU N. Hat 2 Pha Oudom

Bokeo D.C. - - O - DOE

U N. Xeng Vieng Kam Luangphrabang Pak Um O O O O DOE I N. Sim Viengxay Houaphan Grid - O - - DOE I N. Ham 2 Boten Xayabury Grid O O - - DOE U N. Xan 3 Khoune Xiengkhuang Ngan O - O - DOE

Note: I: Import, D: Diesel, U: Unelectrified, AH: Hydro, S: Extension

(1) Site Reconnaissance

As described in the foregoing Section 4.4, two teams (Team-A and -B) consisting of both the Study Team and DOE conducted site reconnaissance through November and December, 2004, while DOE conducted site reconnaissance by themselves in January, 2005 for the sites located in Huaphan and Xienkhuang Provinces where the Study Team is not allowed to enter due to security concerns. Furthermore, a joint team between the Study Team and DOE conducted an additional site reconnaissance in Hongsa District, Xayabury Province in February, 2005.

(2) Topographic Survey

As described in Section 4.7, topographic survey, longitudinal profile survey and cross-section survey were conducted for the 6 sites including the MW-class schemes, while only longitudinal profile survey was conducted for one site. The survey work commenced in December, 2004, and the outputs were submitted in March, 2004.



4.5.2 PRE-F/S PLANNING AND DESIGN METHODOLOGY

The planning and design at the Pre-F/S level was conducted dividing the task evenly between the Study Team and DOE. The Study Team has prepared several tools and programs in order to secure uniformity between the level of output of the Pre-F/S between the two parties. As these tools play an important role in the capacity building of the DOE engineers, detailed explanation were given prior to their use. The contents of these tools were compiled into the Small-hydro Design Manual.

(1) Small-hydro Planning Flowchart

The sites selected for the Pre-F/S can be classified into two categories: (i) off-grid type where the power produced is supplied to the district center and the surrounding villages, and (ii) grid type where the power produced is intended for the reinforcement of the EDL grid. As the planning processes of the two types are not identical, separate flowcharts were prepared.

(i) Flowchart for the Off-Grid Scheme

The aim of the off-grid type hydropower system is to supply the power generated by the hydropower to the district center and the villages in the vicinity by constructing a mini-grid. Since the demand is limited in such a system, the optimum scale of development is governed by the balance between the peak load and the hydropower potential.

For the planning of such a system, the benchmark for the hydropower potential is set at river discharge of 95% dependability, whilst the peak load per household is assumed at 190W/HH (peak hour = 4 hours) based on the load curve of the existing Nam Mong project (refer to Supporting Data Files Part - C). In



addition, the ratio of base load to peak load is assumed at 40%, and the connection ratio is assumed at 80% of the total number of households, so that the scale of development does not become redundant.

(ii) Flowchart for the Grid Scheme

The grid type scheme is a relatively larger scale of development with the aim to reinforce the EDL grid. In this case, as all power generated by hydropower is consumed within the grid system, the optimum scale of development is not governed by demand. It was therefore necessary to plan and design several alternatives and to evaluate their unit generating costs, and the alternative with the lowest generating cost is obviously the optimum scale of development. This is to say that power generation simulation as well as design and cost estimate of all the alternatives considered are necessary at the Pre-F/S level in order to select the optimum installed capacity.

Furthermore, as these grid type projects are intended to feed power to the EDL grid, EDL’s opinion and strategy are important factors when selecting the optimum scale of development.

(2) Hydrological Analysis and the Small-hydro Planning Program

The Study Team prepared two small-hydro planning programs in accordance to the abovementioned flowcharts for the planning at the Pre-F/S level.

The hydrological analysis portion, which is identical in the two programs, generates hydrological data based on other basins with sufficient data. Since hydrological data are not available for any of the Pre-F/S sites, the discharge data at these locations needed to be established. The method of generating discharge data at the targeted location is by catchment area ratio and annual rainfall ratio between the targeted basin and the basins with data, which in this case are Nam Ou and Nam Souang. Prior to the calculation, annual duration curves were prepared for the two basins, and a duration curve that was judged to be standard was selected. In the case of Nam Sim small-hydro only, since the FS was conducted previously, the DOE’s set of daily discharge data gathered from another water level gauging station near to the project site was adopted. The discharge data generated in such manner serves as input for the annual power generation simulation.

(i) Small-hydro Planning Program for Off-Grid Schemes

The input items for the planning program for an off-grid scheme are as follows, since the scale of development is governed by the balance between the peak load and the hydropower potential, as mentioned above.

Supply of Power (Meteo-Hydrology): Catchment area (km2), average annual rainfall (mm), effective head (m), design discharge (m3/s), the need for daily regulation

Demand for Power (Load): Total number of households, connection ratio (standard = 80%), peak load (standard = 190 W/HH), peak hours (standard=4 hrs), base load/peak load (standard=4 hrs), transmission loss (standard = 10%)



Input Example of a Planning Program for an Off-Grid Scheme

A power generation simulation was conducted based on these inputs.

It is noted however that in the case where hydropower potential was insufficient with regard to the peak load, it was necessary to consider daily regulation, and trial-and-error according to the flowchart was necessary.

(ii) Small-hydro Planning Program for Grid Schemes

Since all power produced is consumed in the grid system, most input data for demand is unnecessary.

Supply of Power (Meteo-Hydrology): Catchment area (km2), average annual rainfall (mm), effective head (m), design discharge (m3/s), the need for daily regulation

Demand for Power (Load): Operation rule (peak or base), peak hours

Input Example of a Planning Program for Grid Scheme

Trial-and-error at the planning stage is not required for the grid scheme, but it is necessary to calculate the unit generation costs for the various alternatives in order to select the optimum scale of development.

It is also important to select an operation rule with consideration to the objective of the grid scheme: substitution of an existing diesel genset, replacing the expensive imported power during peak hours, etc.

(3) Deign at the Pre-F/S Level

The design of the eleven (11) selected sites was conducted based on the results of the aforementioned planning process, of which 6 sites were designed by the Study Team and five (5) sites by DOE. The design follows the criteria mentioned in the Small-hydro Development Manual that has been prepared by the Study Team, while a program that calculated the basic dimensions of the civil structures was also prepared by the Study Team. As the use of the program is an important part of the capacity building of the DOE engineers, extensive explanation was given prior to its use.



The design flood for the intake weir was decided to be a 100 year probability flood, basically on the basis of the Lao Electric Power Technical Standard prepared by JICA in 2004. However, in the case of the off-grid small-hydro, the installed capacity is as small as 30~260kW and the river width is relatively small at the location of the intake weir. Therefore, if the spillway for a 100 year probable food is designed for the intake weir in such conditions, un-necessary excavation and concrete structures are required and the spillway structure does not match the existing river width. In order to avoid such design, a 50 year probability flood was adopted for off-grid small-hydro in this Pre-F/S.

The design concept of electrical and mechanical equipment was mentioned in the Small-hydro Manual, which was prepared in this Master Plan Study. The concept for selection of the turbine was considered for 100kW class and MW class respectively and summarized as follows:

Class Off-grid Type (100kW class) On-grid Type (MW class)

Type of turbine

Crossflow Reason of selection 1) Due to independent power

generation and difference of load between day time and night time, the generation with partial load will be continued.

2) Gross head will be 30~100m and small discharge.

3) Maintenance and repair are available by local technique.

Fransis (in case of small discharge and high head : Perton) Reason of selection 1) The generated power will be sent to EDL grid and the

power generation with water level control is expected. In dry season only, the generation with partial load will be carried out.

2) The turbine efficiency is most important. If the difference of river discharge between dry season and rainy season is big, the 2 units of generator should be considered to reduce partial load generation.

Design & Manufacture Ready-made Order made

(4) Cost Estimate at the Pre-F/S Level

Quantity calculations and cost estimates were conducted for the projects for which basic design was completed. The quantity was basically calculated based on the drawings, but a simple program was also prepared which calculates the quantities by use of formulae. Detailed explanation was given to the DOE engineers as this also serves as an important tool for capacity building.

The unit costs used in the cost estimate were derived based on those from previous projects implemented in Lao PDR and unit rates established in the Irrigation Department Office and the PDIH offices of the northern 8 provinces. The unit rate for the civil construction adopted for the Pre-F/S is shown in the table below. The cost of electrical and mechanical equipment was estimated on the basis of the cost of previous projects obtained from EDL.

Unit Costs Work Item Unit Price Table Work Item Unit Price Table

Excavation-common US$/m3 1.50 Wet Masonry US$/m3 70.00 Excavation-rock US$/m3 4.50 Gabion US$/m3 70.00 Excavation-channel US$/m3 2.00 Gate & Trashracks US$/ton 1,500.00 Excavation-tunnel US$/m3 50.00 Penstock US$/ton 3,000.00

Concrete incl. re-bar US$/m3 220.00 Turbine & Generator Based on cost of previous projects with Chinese equipments



4.5.3 RESULTS OF PLANNING AND DESIGN AT PRE-F/S LEVEL

The results of Pre-F/S from planning and design at the Pre-F/S level of the eleven (11) sites are summarized in the table below.

Salient Features and Results of the Pre-F/S

Seq. No. Project Name

Total No. of

HH

Design Discharge

(m3/s)

Effec. Head (m)

Inst. Cap.(kW)

Effec.Ann. Energy (MWh)

Const. Cost (US$)

Gener. Cost

(c/kWh) Pre-F/S

4 N. Likna 154 0.37 12 30 106 198,273 24.70 S/T 5 N. Ou Neau 1,549 1.90 20 260 1,026 1,587,867 20.20 S/T 6 N. Boun 2 Grid 3.90 129 4,000 25,500 5,823,581 2.44 S/T 7 N. Long Grid 1.35 238 2,500 15,269 3,515,003 2.48 S/T 15 N. Gnone Grid 1.55 42 600 2,669 1,275,232 5.18 S/T 17 N. Chong 270 0.12 62 50 119 229,360 25.80 S/T 20 N. Hat 2 693 0.37 48 120 457 1,018,823 29.20 DOE 23 N. Xeng 629 1.64 10 110 416 859,392 29.80 S/T 27 N. Sim Grid 6.71 148 8,000 31,673 6,502,610 2.20 DOE 31 N. Ham 2 Grid 0.78 170 1,000 5,794 1,888,824 3.53 DOE 32 N. Xan 3 431 0.41 29 80 293 462,633 20.80 DOE

The salient features of the Pre-F/S were attached at the end of this Chapter. The planning sheets and drawings are attached in Supporting Data Files Part-C.

As part of the results of Pre-F/S, the generated cost per kWh of each project can be one index for the evaluation of the project. In addition to this evaluation, the projects were compared with the other power source, which consisted of a diesel power generation project and the grid extension project considering the distance from the existing EDL grid line. The results were mentioned in following Chapter 4.9.

4.5.4 NOTES ON PLANNING, DESIGN & COST ESTIMATE AT PRE-F/S LEVEL

Since the planning, design and cost estimate conducted at the Pre-F/S level are preliminary level, the following points need to be noted.

(i) Hydrological Data

Since hydrological data are not available for any of the target basin, it was necessary to generate data using data from other basins. However, the basins with sufficient data are those with extremely large catchment areas relative to the target basin. Therefore, the generated hydrological data are not precise, and water level readings and discharge measurements should be conducted where staff gauges were installed in this Study, so to revise the Pre-F/S in the future.

(ii) Topography and Geology

Topographic survey was conducted only at 6 sites, and the design of the remaining sites are being conducted based on 1:100,000 map which lacks accuracy. In addition, due to limitation in time and budget, the topographic survey was conducted only for a small area, which at times are insufficient to



select the optimum locations of the structures.

Furthermore, since there are no geological information other than the outcrop which were visually confirmed, all rock lines are assumed. Special attention is necessary especially for the schemes with a tunnel, because there is a possibility for a drastic change in the plan when geological information around the tunnel portal and the tunnel route become available.

(iii) Design, Quantity Calculation and Cost Estimate

Since there are many uncertainties as explained in the paragraph above, the design and quantity calculation cannot be accurate. However, it is believed that in most cases, the results are sufficient in order to evaluate whether the scheme is viable or not.

As for the unit cost utilized for the cost estimate, the values are derived based on projects previously implemented in Lao PDR. It should be noted that the cost of the turbine/generator are based on those of the Chinese equipments, and that their unit costs are much lower than prices of turbine/generators quoted in Japan.

(iv) Daily Regulation of Small-hydro

In the off-grid small-hydro planning at the un-electrified district center, the installed capacity of Nam Likna (30kW) and Nam Chong (50kW) became lower than 100kW due to their less demand. Further, since the catchment areas of these projects are small, the potential of power generation in dry season does not meet their demand. Therefore, it is necessary to have daily regulation capacity at intake weir sites. However, as the gate structure installed on the ogee crest of spillway makes the construction cost to be high enough to abandon the project. As the solution of this matter, it was judged that the sandbags would be set on the ogee crest with height of 50 cm during dry season only to maintain daily regulation capacity. This design concept was shown in drawings.


4. pre-feasibility studies on small-hydro · final report (main) chapter 4 pre-feasibility studies...

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