Hydropower dams

With its vast, complex network of tributaries, the Mekong river system has been identified as a valuable source of hydroelectricity generation from as early as the 1960s. Today, the Lower Mekong Basin is a key site for large-scale hydropower dam development,1 and it is estimated that it has the potential to generate 30,000 megawatts (MW) of electricity for the region.2

Regional governments are considering the construction of 88 more dams in the Lower Mekong River basin3 by the year 2030. Over 120 dams are planned for the tributaries and 11 large-scale hydropower dams are slated for the Lower Mekong mainstream, which has the potential to produce over 13,000 MW of hydropower4. While Thailand and Vietnam have already developed most of their tributary sites Cambodia, Laos and Myanmar currently possess the greatest potential for hydropower resource development, and by the year 2030, they’re expected to reach a combined percentage of hydroelectric generation of 96 percent5.

Meeting Demand

Faced with increasing global energy prices, along with inflated forecasts in energy demand, Thailand and Vietnam view hydropower as an attractive, renewable resource that will not only help meet their exploding energy demands, but also diversify their energy mix. Thailand’s total energy consumption is 80 percent fossil fuel reliant, raising serious questions about the country’s future energy security. For the less-developed host countries of hydropower dams such as Myanmar, Cambodia and Laos, hydropower represents huge foreign direct investment opportunities and the potential for immediate GDP growth fueled by a rise in electricity export revenues6. The Laos government is billing itself as the “battery of Southeast Asia7” with 60 generation projects planned for its tributaries and nine on the Mekong mainstream8, which forms a major component of its projected GDP growth of 7% per year9.

Large vs. Small Hydropower Dams

There are several types of hydroelectric power plants and they vary in size. The Clean Development Mechanism10, under Article 12 of the Kyoto Protocol, promotes “small” hydropower as a viable alternative to large scale hydropower dams because they are more environmentally sustainable and directly displace greenhouse gas emissions11. The smallest CDM project12, located in Bhutan, has a generation capacity of 0.1MW while the largest is a 1200MW capacity facility in Brazil13. The CDM defines a hydropower project with an output capacity of 15MW or more as “large”, while the European Union defines a large hydropower project as one with an installed capacity greater than 20MW. Unlike large scale projects, small hydropower projects are subjected to fewer regulations and assessments. They often receive less scrutiny and tend to be viewed as individual projects rather than as part of a series or “cascade” of dams in the region. Thus the cumulative impacts of small dams are often neglected.

Regional Investment

Economic and energy related development and security factors across the Mekong region have resulted in a trend of “regional bilateralism”14, where key decisions and investment deals regarding trans-boundary water resource developments are largely made outside of international frameworks, and instead remain cross-border between the strongest economies in the region (Thailand and Vietnam) and the less industrialized, but resource-rich countries (Cambodia, Laos and Myanmar).

Lower Mekong Basin hydropower projects

Take a tour of the planned hydropower projects on the Lower Mekong's mainstream.

A range of private investors, like national banks and multinational companies from China, Malaysia, Thailand and Vietnam, have formed hybrid private-public partnerships with host governments to build hydroelectric dams in the Lower Mekong Basin with the intent to purchase the bulk of that electricity. Only about 10 percent of the hydroelectricity generated in Cambodia and Laos will remain in-country, the rest intended for export15. China has surpassed the World Bank as the biggest financier of large dams globally, with about 25,000 dam projects worldwide, or half the world’s total16. In Cambodia, Laos and Myanmar, China has invested more than US$6.1 billion between 2005 and 201117. To date, much of Cambodia’s hydroelectric power expansion has been financed by Chinese corporations, such as the state-owned Sinhydro – the world’s largest hydropower developer18.

All the Lower Mekong Basin countries are members of the Mekong River Commission, the only inter-governmental body tasked with facilitating dialogue between all private and public stakeholders in the region related to water governance, which grew out of the 1995 Mekong Agreement19.

Despite these regional processes, no consensus among MRC members needs to be reached for a dam to be planned, approved, or constructed. This fact has led to several trans-boundary disputes between the public-private dam builders and the people and governments who are downstream from the hydropower dams and most likely to be affected by their construction.

Dam Diplomacy: Laos

The controversial Don Sahong Hydropower Project is located on southern Laos on the Cambodian border and is projected to generate 260 MW of electricity. The dam was the subject of an MRC Special Session on Prior Consultation held on 28 January 2015, and illustrates how the regional inter-governmental process works in practice. The result of the six-month prior consultation process included the MRC’s technical review and a series of recommendations including those of the remaining member countries, Cambodia, Thailand and Vietnam. In general, it was agreed that information about the environmental and social trans-boundary impacts was inadequate and an additional 6 month consultation time was required to study the region properly. For its part, Laos issued the following concluding statement: “Laos will continue to exercise its sovereign right to develop its natural resources within its territory subject to the guiding principles of reasonable, transparency and good faith.”

This is the second prior consultation process the MRC has undertaken. The first was in September 2010, when significant concerns by member countries were raised about the 1285 MW Xayaburi Hydropower project, which is also located on the Mekong mainstream in mountainous Northern Laos. At a cost of US$3.8 billion, the public-private partnership between Thailand’s largest construction company CH-Karnchang, six Thai commercial banks and the state-owned Krung Thai Bank, along with the government of Laos, construction of Xayaburi was delayed in 2012 due to fierce protests in Cambodia and Vietnam. Locally, the lack of early consultation and information regarding the project’s impacts on the 202,000 people living and working near the dam site was in question, as was the Laos government’s resettlement of 2,100 people. Both MRC processes have concluded with Laos making a unilateral decision to proceed with dam construction.

Environmental Impacts

Many of the concerns raised by those opposed to the 11 mainstream hydropower projects are contained in the MRC’s Strategic Environmental Assessment (SEA)20. A critical appraisal of the planned 11 large-scale dams on the Mekong mainstream, the 2010 report outlined key concerns echoed by local and international civil society groups, as well as down-stream governments.

In weighing the economic benefits against the environmental costs and the impacts on communities, the key recommendation of the SEA was to defer all mainstream dams for a period of up to ten years, until further studies can be conducted to ensure all stakeholders are informed of the risks. The MRC also warned that the likely costs and benefits of hydropower dams on the Mekong mainstream are likely to be distributed inequitably.

Some of the risks highlighted in the assessment include the livelihoods and food security of more than 70% of inhabitants who rely on the fisheries, riverbank gardens, ecotourism ventures, and fertile agricultural lands of the Mekong Basin for survival.


The Council Study

The Council Study is a five-year examination of the sustainable management of the Mekong River system, including impacts from hydropower development.1 When researchers modelled the development of all the proposed hydropower schemes they found the impact could be a reduction in lake and floodplain fisheries production of up to 70 percent across the Mekong basin.2 The result of this would be billions of dollars of losses in annual GDP for downstream countries such as Cambodia.3

Associated Risks

Shifts in weather patterns, have increased irregularities of weather patters resulting in unseasonal floods and drought periods throughout the region. Recently on September 11th the Nam Ao Dam along the Nam Ao River in Thathom District of Xaysomboun Province, burst as a result of heavy rains. The dam, which was at 85% completion, was expected to generate between 12 MW to 15 MW of power. Below is harrowing footage of the dam bursting along with Sentinel 2 images of before and after the event. The incident raises significant questions regarding the extenuating risks associated with hydropower construction after the devastating effects of such a small dam bursting. 



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