Impounding of the tallest roller-compacted concrete gravity dam starts at Nam Ngiep 1 Hydropower Project
Nam Ngiep 1 Hydropower Project (NNP1) commenced impounding water in its main reservoir on 15th May 2018 and full supply level in the reservoir is expected to be reached in December 2018.
The impounding of the tallest roller-compacted concrete gravity dam in Laos and the region will take place in two distinct phases as the spillway gates are constructed. During the initial phase from May to July 2018, the water level is expected to reach an approximate elevation 312 metres above sea level from the original river level of approximately 190 metres. By then the first of four spillway gates will be installed and any surplus water can be released by using this spillway gate. The remaining spillway gates will be completed by January 2019.
Depending on rainfall and natural inflow into the reservoir, the water level during the second phase of impounding from October to December 2018 is expected to reach full supply level of 320 metres above sea level in December 2018.
Communities both upstream and downstream of the NNP1 Project in both Bolikhamxay and Xaysomboun Provinces have been advised to take all necessary precautions as the rise in reservoir level gradually takes place over an approximate 75 km distance upstream from the main dam located in Bolikhan District of Bolikhamsay Province during this period.
“I would like thank everyone who has worked towards this milestone. The impounding is another great achievement and one step closer to the commissioning of both Units by the end of 2018,” Mr. Yoshihiro Yamabayashi, the Managing Director of Nam Ngiep 1 Power Company Limited, said at the Ceremony for the Start of Impounding of Water in the Main Reservoir that was held on 25th May 2018 at Phouhomxay Resettlement Village Hall in Bolikhan District, Bolikhamxay Province in Lao PDR.
The ceremony was attended by Bolikhamxay and Xaysomboun Provincial Governors, dignitaries of the Embassies of Japan, Thailand and Vietnam, government officials from the central, provincial and district government, village authorities, shareholders, contractors, subcontractors, and senior management and staff of NNP1.
The ceremony was jointly organized by Nam Ngiep 1 Power Company and Obayashi Corporation, the Civil Works Contractors for the Project.
“The Nam Ngiep 1 Project is one of the high priority projects of the Government of Laos and will make significant contribution to the development of the Lao PDR,’ said H.E. Bounma Bouchaleune, Vice Governor of Bolikhamxay Province at the impounding ceremony on 25th May 2018.
“I would like to express my heartfelt and highest respect to Nam Ngiep 1 Power Company and all those who have been working for this significant project. I am convinced that it would help strengthen the foundation for the sustainable development of the Lao PDR and for its graduation from the Least Developed Country status,” said H.E Mr.Takeshi Hikihara, Ambassador of Japan to the Lao PDR, who joined the ceremony.
The Nam Ngiep 1 Hydropower Project has an installed capacity of 290 megawatt. The Project consists of two dams and two powerhouses along the Ngiep River in Bolikhamxay Province, in Lao PDR.
Since the construction formally started after financial closure in August 2014, by the end of April 2018 approximately 95% by value of work was completed with many notable achievements along the way.
The construction of the roller-compacted concrete placement of approximately 2.3 million cubic metres for the main dam commenced in 2016 was completed by 29 April 2018 in order for the impounding of water in the main reservoir to begin on 15 May 2018.
The main dam of the Nam Ngiep 1 Hydropower Project is 167 metres in height, its crest length is 530 metres in length and it is the tallest roller-compacted concrete gravity dam of its type in Lao PDR and the region. The construction of the 230 kV transmission line from the main powerhouse to the Nabong Substation in Vientiane Capital was completed in May 2018.
The construction of the re-regulation dam and impounding of water in the re-regulation reservoir was completed in 2017. The construction of 115 kV transmission line from the re-regulation powerhouse to the nearby Pakxan Substation is expected to be completed, by the Electricite du Laos, in June 2018.
The resettlement of approximately 520 households from the single village in Bolikhan District, Bolikhamxay Province and four villages in Hom District, Xaysomboun Province was completed on 11 April 2018. Among them currently about 75 Project affected households from both Bolikhamxay and Xaysomboun Provinces reside in the Phouhomxay Resettlement Village where all associated infrastructure and agricultural lands has been developed and completed by the Nam Ngiep 1 Power Company in April 2018.
The Nam Ngiep 1 Project is being constructed and will be operated by the Nam Ngiep 1 Power Company whose shareholders are the Kansai Electric Power Company of Japan, EGAT International of Thailand, and Lao Holding State Enterprise.
The Project expects to begin to generate electricity in late 2018 or early 2019 and approximately 95% of this power will be exported to Thailand, the remainder being used for domestic consumption.
The Project expects to generate more than USD 600 million in direct revenue and other indirect benefits to the Lao Government during its 27-year concession period, after which ownership will be transferred to the Lao Government.
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