Project Leaflet

Xe Pian & Xe Namnoy Hydropower Scheme
Lao PDR
Client
Dong Ah Construction Industrial
Company Ltd.
Seoul, Korea
Project
Hydropower storage project
Service Provider
Pöyry Energy Ltd.
Services
Feasibility study:
• Photogrammetric and terrestrial
topographic mapping
• Geological investigations
• Environmental impact assessment
• Feasibility design
• Simulation and optimisation of
plant size and operation
• Economic and financial analyses
• Advisory services during PPA
negotiations
Execution Period
Project Description
The Xe Pian & Xe Namnoy hydropower scheme is being implemented
by the client as a BOT venture with
the government of People’s Democratic Republic of Laos for power exports to Thailand.
The headworks of the high-head project are located on the Bolaven plateau some 500 km south-east of the
capital city of Vientiane. The tailworks
discharge into the Sekong river, a
major Mekong tributary, at the foot of
a steep, 800 m deep escarpment.
The headworks consist of a diversion
weir and two fill dams which are 49m
and 78 m high with their appurtenances.
The impounded reservoirs are inter-
connected via water transfer tunnels.
The 17 km long waterways comprise
headrace tunnel, surge tank, vertical
shaft, high pressure tunnel and open
steel penstock
Three Pelton units of 124 MW are
installed in the open-air powerhouse.
Pöyry Energy Ltd.
Hardturmstrasse 161, P.O. Box, CH-8037 Zurich, Switzerland
Phone: +41 44 355 55 54, Internet: www.poyry.com
1994 – 1995
Xe Pian & Xe Namnoy Hydropower
Scheme
Key Data
Xe Pian dam
Type
Height
Fill volume
Length of crest
earth-rockfill
49 m
1.1 million m3
1240 m
Xe Pian reservoir
Catchment area
Total storage
Active storage
212 km2
20 million m3
14 million m3
Xe Namnoy dam
Type
Height
Fill volume
Length of crest
rockfill with core
78 m
4.6 million m3
1560 m
Xe Namnoy reservoir
Catchment area
Total storage
Active storage
533 km2
1001 million m3
907 million m3
Xe Pian river diversion
Phase 1 open
Phase 2 through
concrete section
Xe Namnoy river diversion
One tunnel of
Diameter
Length
Xe Pian spillway
Three radial gates
9.5 m
462 m
10.1 m
×10 m
Xe Namnoy spillway
Ungated chute
Crest length
45 m
Water transfer conduit
Xe Pian to Xe Namnoy
Internal diameter
Length
4.75 m
8,050 m
Power waterways
Pressure tunnel upper
part:
Ø 4.75 m, L 13,700 m
(concrete)
Pressure shaft:
Ø 4.5 m, height 497 m
(concrete)
Pressure tunnel lower
part:
Ø 4.5 m, L 410 m
(concrete)
Ø 3.25/3.00 m, L
1,425 m (steel)
Cut and cover steel
penstock
Ø 3.0 m, L 695 m
Powerhouse
Type
Installed capacity
Pelton units
Design discharge
Gross head
Energy production
at Thai border
open-air
3 ×124 = 372 MW
40 m3/s
656m– 691 m
1927 GWh/year
Xe Namnoy dam
Project layout