Lao Mekong Sanakham Hydropower ProjectFeasibility Study Report

Lao Mekong Sanakham Hydropower ProjectFeasibility Study Report

Contents

1.Overview2.Hydology & Sediment3.FSL select4.Installed capacit5.Reservoir inundation 6.Project layout

1.Overview2.Hydology & Sediment3.FSL select4.Installed capacit5.Reservoir inundation 6.Project layout

1

OverviewOverview

OverviewOverview

The Sanakham Hydropower

Project is the 5th cascade project

planned on the main stream of the

Mekong River in Laos. The proposed

dam site is approximately 1737km

away from the Mekong River estuary

in river channel distance, around

155km from Vientiane, the capital of

the country .

The Sanakham Hydropower

Project is the 5th cascade project

planned on the main stream of the

Mekong River in Laos. The proposed

dam site is approximately 1737km

away from the Mekong River estuary

in river channel distance, around

155km from Vientiane, the capital of

the country .

VientianeVientiane

SANAKHAM

155km

Pak LayPak Lay

81km

1772

250

230

192

SANAKHAM

Longitudinal section for cascade development of the Lower Mekong River Longitudinal section for cascade development of the Lower Mekong River

Luang Prabang

Pa Mong

Pak Beng

Sayaburi Pak Lay

Sambor

Don Sahong

Stung Treng

Ban KoumSANAKHAM

For 10 cascade hydroelectric

stations on the main stream, Pak

Beng, Luang Prabang, Sayaburi,

Pak Lay and Sanakham are

located in Laos, Pa Mong and

Ban Koum are situated in the

reach on Laos-Thailand border,

Don Sahong on the border

between Laos and Cambodia,

and Stung Treng and Sambor in

Cambodia.

In July 2009, CNR completed Optimization Study of

Mekong Mainstream Hydropower

the location of Sanakham dam site is moved downstream

from 1772km to 1737km, 2km away from the Thailand-Laos

border.

In August 2009, GOL made it clear that “the maximumoperating level of Sanakham Hydropower Project on theMekong River in Laos is 220m MSL. ”

In July 2009, CNR completed Optimization Study of

Mekong Mainstream Hydropower

the location of Sanakham dam site is moved downstream

from 1772km to 1737km, 2km away from the Thailand-Laos

border.

In August 2009, GOL made it clear that “the maximumoperating level of Sanakham Hydropower Project on theMekong River in Laos is 220m MSL. ”

On December 27, 2010, Overseas Investment Company of DTP

signed the Project Development Agreement (PDA) with GOL.

On December 27, 2010, Overseas Investment Company of DTP

signed the Project Development Agreement (PDA) with GOL.

In June, 2010, Hydrochina Xibei Engineering Corporation completed the

feasibility study in accordance with GOL’s requirement. In July 2010, GOL

reviewed the feasibility study report in line with the WB’s criteria. On August

9, 2010, Electricity Department under Ministry of Energy and Mines, Laos

issued their review comments on the feasibility study.

u

In June, 2010, Hydrochina Xibei Engineering Corporation completed the

feasibility study in accordance with GOL’s requirement. In July 2010, GOL

reviewed the feasibility study report in line with the WB’s criteria. On August

9, 2010, Electricity Department under Ministry of Energy and Mines, Laos

issued their review comments on the feasibility study.

u

Hydrology & Sediment Hydrology & Sediment

Luang Prabang station and Vientiane station are selected

as the design basis for hydrology design of Sanakham Project.

Methodology is the same as that in last version of FS report

Annual mean flow is 4550 m3/s at Sanakham dam site

(CLOSE TO the data of last version)

Item Jun. Jul. Aug. Sep. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May year

Average annual flow (m3 / s) 3,519 7,132 12,131 11,222 6,771 3,970 2,428 1,740 1,380 1,180 1,190 1,690 4,550

Percentage in annual water flow (%)

6.36 13.3 22.6 20.3 12.6 7.17 4.53 3.25 2.33 2.2 2.15 3.16 100%

Hydrology & SedimentHydrology & Sediment

Flood Standard and Characteristic DischargeFlood Standard and Characteristic Discharge

Dam type Work condition

Return

period

(year)

Flood discharge

(m3/s)

Gravity

dam

Design flood 500 31700

Check flood 2000 34400

Energy dissipation and

scour prevention facilities 50 25000

Check flood Standard CHANGED TO 10000 year at last version

The design flood result for Sanakham Hydropower Project

The design flood result for Sanakham Hydropower Project

Design stage ItemDesign values of various frequencies Xp(%)

0.01 0.02 0.05 0.1 0.2 0.333 0.5

Feasibility study Qm 37300 36100 34400 33100 31700 30800 29900

Pre-feasibility study Qm 37300 36100 34400 33100 31700 30800 29900

Planning (MRC1994) Qm 33900

Optimization report

Qm

38800 37000 34700 3300029000

(MRC-CNR2009 )

(36150～41400)

(34550～39450)

(32500～36800)

(30900～34900)

Design stage ItemDesign values of various frequencies Xp(%)

1 2 3.33 5 10 20 33.3 50

Feasibility study Qm 28400 25000 23900 22900 21300 19400 17800 16300

Pre-feasibility study Qm 28400 25000 23900 22900 21300 19400 17800 16300

Planning (MRC1994) Qm 28800 23600

Optimization report Qm 27200 25500 23000 21100 19000 16200

The design value result of average flow in December, January and February during river closure period

The design value result of average flow in December, January and February during river closure period

MonthDesign values of various frequencies Xp(%)

p=10% p=20%

December

First ten-day period 3890 3400

Middle ten-day period 3040 2840

Last ten-day period 2610 2440

January

First ten-day period 2380 2150

Middle ten-day period 2100 1940

Last ten-day period 1890 1790

February

First ten-day period 1720 1610

Middle ten-day period 1620 1520

Last ten-day period 1560 1480

The staged design flood result The staged design flood result

Stage Period (month.day)Design values of various frequencies Xp(%)

5 10 20

Jan. January 1 - January 31 2900 2620 2380

Feb.～Apr. February 1 - April 30 2060 1980 1840

May May 1 - May 31 5260 4200 3360

Jun. June 1 - June 25 9200 8240 6770

Jul. ～Sep. June 26 - October 5 23000 21000 19500

Oct. October 6 - November 5 15100 13500 12200

Nov. November 6 - November 30 9750 8410 6830

Dec. December 1 - December 31 5120 4650 3870

the average sediment concentration in main flood season is

0.686kg/m3, and annual average sediment concentration is

0.495kg/m3.

In the design at this stage, the bed load discharge at the

dam site is estimated by 2% of bed-suspension ratio, and the

average annual bed load discharge is 1.31 million tons.

the average sediment concentration in main flood season is

0.686kg/m3, and annual average sediment concentration is

0.495kg/m3.

In the design at this stage, the bed load discharge at the

dam site is estimated by 2% of bed-suspension ratio, and the

average annual bed load discharge is 1.31 million tons.

FSL SelectFSL Select

It is defined in Optimization Study of Cascade Hydropower

Projects on the Mekong Mainstream in Laos completed by CNR

in July 1, 2009 and file (No. 807 / DOE) “Maximum operating

water level of 5 cascade hydropower project on mainstream of

the Mekong in Laos” issued by Ministry of Energy and Mining

of Laos that the maximum operating level of the Sanakham

hydropower project shall be 220m.

It is defined in Optimization Study of Cascade Hydropower

Projects on the Mekong Mainstream in Laos completed by CNR

in July 1, 2009 and file (No. 807 / DOE) “Maximum operating

water level of 5 cascade hydropower project on mainstream of

the Mekong in Laos” issued by Ministry of Energy and Mining

of Laos that the maximum operating level of the Sanakham

hydropower project shall be 220m.

FSL SelectFSL Select

Installed capacitInstalled capacit

Installed capacitInstalled capacit

Four schemes with installed capacity of 540MW, 600MW,

660MW and 720MW are compared, and 660MW scheme is

considered as optimal.

Four schemes with installed capacity of 540MW, 600MW,

660MW and 720MW are compared, and 660MW scheme is

considered as optimal.

List of Hydro-Energy Parameter for Each Installed Capacity SchemeList of Hydro-Energy Parameter for Each Installed Capacity SchemeItem Unit Scheme 1 Scheme 2 Scheme 3 Scheme 4

Installed capacity MW 540 600 660 720

Normal storage level m 220 220 220 220

Max. head m 20 20 20 20

Min. head m 4.0 4.0 4.0 4.0

Mean head m 15.80 15.80 15.80 15.80

Weighted mean head m 14.51 14.51 14.51 14.51

Mean head in flood season m 12.35 12.35 12.35 12.35

Weighted mean head in flood season m 11.85 11.85 11.85 11.85

Rated head m 13.5 13.5 13.5 13.5

Available discharge m3/s 4500 5000 5500 6000

Annual energy output 108 kWꞏh 34.136 35.666 36.967 38.055

Of which: flood season (June ~ Nov.) 108 kWꞏh 20.001 21.499 22.785 23.865

Dry season (Dec. ~ May ) 108 kWꞏh 14.135 14.167 14.182 14.190

Utilization hours h 6321 5944 5601 5285

Water flow utilization ratio ％ 71.66 75.20 78.37 81.23

Reservoir Inundation Reservoir Inundation

THE SKETCH MAP OF RESSETTLEMENT PROCESS FOR SANAKHAM HPPTHE SKETCH MAP OF RESSETTLEMENT PROCESS FOR SANAKHAM HPP

The resettlement progress will be compatible with the project construction. The best time for moving people will be in the dry season in year 4 and 5.

Project Layout Project Layout

Comparison of dam siteComparison of dam site

upper and lower

dam are selected for

comparison. the

distance between the

two dam sites is about

3.1km. Lower dam site

is better

upper and lower

dam are selected for

comparison. the

distance between the

two dam sites is about

3.1km. Lower dam site

is better

Technical economy comparison of upper and lower dam sitesTechnical economy comparison of upper and lower dam sites

Item Upper dam site Lower dam site Conclusion

Geology and topography

Rock at right bank is highly weathered with strong load relief, river valley is narrow, riverbed is

covered with shallow silty sand

River valley has open and vast terrain, riverbed is covered with deep silty sand

Two sites can satisfy dam construction requirement

Project layout

River course is smooth and straight, favorable to sand sluicing, it is narrower compared with the lower dam site, left bank will be further excavated to create slope, pre-excavation of ship lock will be difficult

River course turns, measures shall be taken to intercept and sluice sand, left bank has wide terrace, favorable to pre-excavation of ship lock, project layout will be flexible

Lower dam site has smaller risk, and higher safety margin

Reservoir inundation B. Pak La village will not be inundated B. Pak La village will be affected during construction Upper dam site is better

Construction condition

River diversion works will be greater compared with the lower dam site, the existing riverbed is narrow where flow velocity will be high, silty sand at 1st stage whole year cofferdam footprint and its foundation will be severely eroded, cofferdam protection works will be huge

Topography is relative gentle, construction layout is relative simple, river course at the lower dam site is wider, during 1st stage river diversion, the existing riverbed is wider, river flow velocity is relatively low, silty sand at 1st stage whole year cofferdam footprint and its foundation will be less eroded, cofferdam protection works will be small

Lower dam site has better construction condition as artificial aggregate site is close, 1st stage cofferdam can be constructed during dry season

Installed capacity 648MW 660MW

Hydro energy Utilized water head will be 0.28 m lower than the lower dam site, electricity output will be 3.6271 billion kw.h

Electricity output will be 3.6967 billion kw.h

Lower dam site will produce 70 million kw.h more electricity output

Conclusion Lower dam site is better

Selection of dam axisSelection of dam axis

upper and lower dam

sites axis are selected for

comparison. distance

between the two axis is

280m. And Upper dam

axis is suitable .

upper and lower dam

sites axis are selected for

comparison. distance

between the two axis is

280m. And Upper dam

axis is suitable .

Technical economy comparison of upper and lower dam axisTechnical economy comparison of upper and lower dam axis

Item Upper dam axis Low dam axis Conclusion

Topography and geology

Riverbed overburden is 15m in maximum depth, lowest

elevation of bedrock top is 170m

Riverbed overburden is 31m in maximum depth,

lowest elevation of bedrock top is 165m

Upper dam axis is better

Project layout Small overburden quantity, small concrete quantity

High overburden quantity, high concrete quantity Upper dam axis is better

Construction condition

Caisson works of river diversion will be small

Quantity and height of caisson of river diversion

is larger

Construction of upper dam axis is less difficult

Upper dam axis is suitable

1#~13# flood sluice gate section

1#~12# powerhouse section

14#~18#Flood sluice gate

section

Fish pass

500kVswitchyard

230kVSwitchyard

Project structuresarranged from leftbank to right bankare: left bankconcrete wing dam,ship lock, 13 floodsluice gate section,powerhouse section(including 12 units), 5right bank floodsluice gate section,fish pass, right bankconcrete wing dam,etc. The total lengthof water retainingstructure is 886.2 m,maximum concretedam height is 57.2m;230kV and 500kVswitchyards arearranged atdownstream terracesof the left bank andright bank damabutmentsrespectively.

Project structuresarranged from leftbank to right bankare: left bankconcrete wing dam,ship lock, 13 floodsluice gate section,powerhouse section(including 12 units), 5right bank floodsluice gate section,fish pass, right bankconcrete wing dam,etc. The total lengthof water retainingstructure is 886.2 m,maximum concretedam height is 57.2m;230kV and 500kVswitchyards arearranged atdownstream terracesof the left bank andright bank damabutmentsrespectively.

Selected project layout Selected project layout

Navigation

Flood sluice gate section 1~13#250m

Ship lock36m

Left bank wing dam70m

Powerhouse section (1~12# unit blocks and erection bay)352.2m Flood sluice gate section 14~18#

98m Right bank wing dam 80m

886.2m

Upstream and downstream views of selected scheme Upstream and downstream views of selected scheme

230.5▼

230.5▼

▼168.3

▼232.70

56m 43.7m 43.7m 43.7m 43.7m 43.7m 43.7m

Main erection bay

Auxiliary erection bay

▼187.4

Sluice outlet

Powerhouse system consists ofmachine hall, main and auxiliaryerection bays, service building,approach channel, tailrace,switchyard, etc. Unit block length(following river direction) is 80.7m,unit installation elevation is 187.4m,foundation elevation is 168.3m; onesluice outlet will be arranged atmiddle pier between two units ( atotal of 6 sluice outlets) in order toprevent silt deposition before powerintake.

Powerhouse system consists ofmachine hall, main and auxiliaryerection bays, service building,approach channel, tailrace,switchyard, etc. Unit block length(following river direction) is 80.7m,unit installation elevation is 187.4m,foundation elevation is 168.3m; onesluice outlet will be arranged atmiddle pier between two units ( atotal of 6 sluice outlets) in order toprevent silt deposition before powerintake.

Fish pass

Fish pass inlet is set ondownstream floodplain atright bank of the project,outlet is set upstream of wdam at right dam abutment. Fpass is of diaphragm paconsisting of inlets (lower ininvert elevation 198m，uppinlet invert elevation 201.3mfish pass pond, rest pool, out(invert elevation 217m), floretaining gate, bulkhead gate, eWidth of fish pass pond is 5design water depth is 3longitudinal slope ratio i＝1/design stage difference 0.0857m

Fish pass inlet is set ondownstream floodplain atright bank of the project,outlet is set upstream of wdam at right dam abutment. Fpass is of diaphragm paconsisting of inlets (lower ininvert elevation 198m，uppinlet invert elevation 201.3mfish pass pond, rest pool, out(invert elevation 217m), floretaining gate, bulkhead gate, eWidth of fish pass pond is 5design water depth is 3longitudinal slope ratio i＝1/design stage difference 0.0857m

Fish PassFish Pass

Navigation

U/S cofferdam

U/S longitudinal guide wall D/S longitudinal guide

wall

D/S cofferdam

1st stage rainy-season river diversion1st stage rainy-season river diversionThe 1st stage

river diversion

structure involves the

1st stage starter

cofferdam, 1st stage

upstream and downstream

all-year-round

cofferdams,

longitudinal concrete

guide wall (including

open caisson). The

upstream and downstream

all-year-round

cofferdams are

constructed to retain

water; river flows

through narrowed

riverbed and original

riverbed is used for

navigation.

The 1st stage

river diversion

structure involves the

1st stage starter

cofferdam, 1st stage

upstream and downstream

all-year-round

cofferdams,

longitudinal concrete

guide wall (including

open caisson). The

upstream and downstream

all-year-round

cofferdams are

constructed to retain

water; river flows

through narrowed

riverbed and original

riverbed is used for

navigation.

2ns stage D/S cofferdam

2nd stage U/S

cofferdam

2nd stage river diversion plan layout2nd stage river diversion plan layout

The 2nd

stage river

diversion

involves the 2nd

stage upstream

and downstream

all-year-round

cofferdams and

longitudinal

guide wall,

left-bank 13

sluice gates for

water releasing

as well as

permanent

shiplock for

navigation.

The 2nd

stage river

diversion

involves the 2nd

stage upstream

and downstream

all-year-round

cofferdams and

longitudinal

guide wall,

left-bank 13

sluice gates for

water releasing

as well as

permanent

shiplock for

navigation.

THANKS! THANKS!