Don Sahong Hydropower Project
The Mekong River Commission (MRC) carried out prior consultation for the Don Sahong Hydropower project to discuss and evaluate benefits and associated risks of the project which may have significant impacts on the environment and people in the Lower Mekong Basin. The Don Sahong Hydropower Project will produce 260 megawatts of electricity and will be situated in one of the braided channels in the Mekong River’s Siphandone area of Southern Lao PDR.
The prior consultation started on 25 July 2014. The process was undertaken in response to an official notice submitted by Lao PDR, one of the four MRC Member Countries, on 30 June 2014, informing the other Member Countries, Cambodia, Thailand and Viet Nam, through the MRC Secretariat, of its intent to have the project undergo prior consultation.
The prior consultation was conducted by the MRC Joint Committee (JC), a governing body comprising one high-level government official at no less than Head of Department level from each Member Country, with technical and administrative support by the MRC Secretariat and the a working group.
The prior consultation is one of three procedures required for the development of different types of water-use projects in the Lower Mekong Basin as specified in the Procedures for Notification, Prior Consultation and Agreement (PNPCA) established under the 1995 Mekong Agreement.
What Will Happen During the Prior Consultation Process?
Once the Member Countries receive the prior consultation submission, the MRC Secretariat coordinates a technical review of the project’s submitted documents. The review will determine compliance with the MRC’s Preliminary Design Guidance for Proposed Mainstream Dams in the Lower Mekong Basin. During this time, the PNPCA Joint Committee Working Group (PNPCA JCWG)holds meetings to discuss related activities such as a road map of the project and a technical review of the project. The Joint Committee may hold a meeting to discuss the process. Field visits to the project may also take place if needed.
The technical review report, which may include findings from the national public participation meetings, will be presented to the MRC Joint Committee. After that, the notified countries will submit their official reply forms to the MRC Secretariat to have their comments on record.
The final stage is for the Joint Committee to hold a meeting to discuss the project prior consultation with an aim to reach an agreement to achieve an optimum use and prevention of waste of water, and to issue a decision that contains agreed-upon conditions for the project.
Public Participation
Even though public involvement is not a requirement of the process, the Member Countries have agreed to the importance of public participation, and national public consultations or information sharing meetings were held appropriately and according to national mechanisms and practices in the respective countries.
The MRC Secretariat held a regional public consultation, aiming to inform, involve and consult regional and international organisations, civil society, the media, research institutes and the MRC's Development Partners on the proposed Don Sahong Hydropower Project as well as the prior consultation process. It was an additional avenue for those who may not have the opportunity to participate in the national consultations or information sharing meetings held by each respective MRC Member Country. Members of the public, including civil society, could also submit their views, petitions and comments on the project during the process to the MRC via its website at: http://www.mrcmekong.org/stakeholder-consultations and the MRC ensured that these would be presented to the Joint Committee.
Views and comments reflected in previous and ongoing stakeholder participation mechanisms were also considered during the evaluation. The aim was for the Joint Committee members to be informed of public opinion and concerns raised both in their own country and in other neighbouring countries on a proposed project and then use this information as part of their consideration.
Extension of the Project
Lao PDR on 2 June 2022 sent an official letter to the MRC Secretariat, notifying on an extension of the Don Sahong Hydropower Project for under the PNPCA. The extension under this “Notification” comprised the inclusion of an additional turbine that sees an increase of the generating capacity from four to five turbine-generator units. The additional turbine is to be used to provide additional power during the wet season (from June to November), while also providing for spare capacity during routine maintenance of the turbines. Based on the notified document, the additional power to be generated will be for export to Cambodia.
The Secretariat shared this notification, together with the submitted “Brief Description of the Design for Don Sahong Modification Hydropower Project”, with the three notified Member Countries: Cambodia, Thailand and Viet Nam on 10 June 2022. It also conducted a review of the extension of the project, shared the report with the four Member Countries, and presented it at the 54th Meeting of the JC on 30 September 2022. The JC requested additional documents on this extension from the notifying country.
Lao PDR provided additional documents namely: 1) Feasibility Report of the DSHPP Extension; 2) Executive Summary Amendment of the Environmental and Social Management and Monitoring Plan; 3) Amendment to the Environmental and Social Impact Assessment; and 4) Amendment to the Environmental and Social Management and Monitoring Plan. These documents were then forwarded to Member Countries in December 2022. With these additional documents, the MRC Secretariat has updated its review and is made available on this page.
What the extension looks like
The information from the submitted documents for Notification (Brief Description of the Design for Don Sahong Modification Hydropower Project) and additional documents indicated that the intention is to add one more turbine-generator unit to the existing four units (each unit is capable of producing 65MW of energy). The total installed capacity of the project will be 325 MW (5 x 65 MW) and the average annual energy generation will increase by 234 GWh. This will be used to provide additional power during the wet season (from June to November) and for spare capacity during routine turbines maintenance.
The construction phase is planned for approximately 30 months, originally planned from 1 December 2021 to 30 June 2024. The operation phase is due to commence on 1 October 2024.
The additional turbine will be located on the right bank of the Don Sahong Project, at the dam site. The powerhouse for the new turbine is about 70 m away from the first phase powerhouse. The project consists of the left-bank non-overflow embankment, the right-bank non-overflow embankment, headrace, the powerhouse annex, the auxiliary powerhouse annex, the erection bay, and the switchyard annex.
The installed capacity of the additional turbine will be 65MW. The design discharge is 400m3/s. The total design flow after modifications would be 5 x 400 m3/s = 2000 m3/s. The modified project will utilize the existing 230-kV transmission line to dispatch the energy. The additional unit has no sluicing mode requirement.
Two new concrete gravity embankments connected to the existing embankment will be constructed forming a headrace channel. The embankment on the left side will be 94 m long and the embankment on the right side will be 65 m long. The maximum height of the embankments is 25.9 m.
More information can be found on the right corner, marked “Extension Documents”.
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