Hydropower in the Mekong River Basin

The estimated hydropower potential of Mekong River Basin about 58,930 Megawatts (MW).^[1][2][3] As of February 2024, there are an estimated 167 Hydropower Plants (HPPs) in the Mekong, with a combined installed capacity of some 36,376.3 MW. An additional 20 HPPs are currently under construction and at various stages of completion. These have a combined installed capacity of an additional 4,535.5 MW.

The single most significant impact on the use of water and its management in the Mekong Region is hydropower.^[4] These developments in the Mekong River Basin have resulted in substantial environmental and social impacts, which are summarised below. These have fuelled controversy ^[5] and hydropower is a prominent part of the discussion around the river, its basin, and its management. This debate occurs in both the academic literature, as well as the media, and is a focus for many activist groups.^[6][7]

The countries that share the Mekong River Basin have all sought the large-scale infrastructural development of its waters. As part of China's Great Western Development program, large-scale hydropower development in China's Yunnan Province has been substantial,^[8][9][10] on the Mekong, the Jinsha, and the Red rivers. Large amounts of Yunnan's hydropower is exported eastwards to energy intensive load centres, such as Guangxi and Guangdong.^[11] Yunnan, however, has large electricity over-supply problems, which has led to significant hydropower curtailment.^[11][12]

The Lao government has also prioritized hydropower development, primarily as an export commodity. In 2021, almost 82% of Lao electricity was exported, mostly to Thailand.^[13] Power production (from all sources, including hydropower) contributed 12.8% to national GDP in 2022, while electricity exports comprised almost 29% of total export values in the same year,^[14] and investments in electricity production represented 79% of total foreign direct investment in 2021.^[15]

Most of Cambodia's hydropower has been developed in the southwest of the country, outside of the Mekong River Basin.^[16][17] Its largest HPP, the Lower Sesan 2 is, however, within the Mekong River Basin, and generates some 20% of the country's electricity.^[18] Cambodia has ruled out developing hydropower on the Mekong mainstream,^[19] but multiple dams are planned for construction in Mekong tributary catchments. Cambodia also exports electricity directly from the Don Sahong HPP, a southern Lao dam located on the Mekong mainstream.^[20]

In Thailand, little technically exploitable hydropower potential remains in its parts of the Mekong River Basin. Most of its HPPs were developed in the 1980s and 1990s, and accompanied by large-scale irrigation infrastructure development as part of the massive Kong-Chi-Mun Project,^[21] more recently rearticulated as the Khong-Loei-Chi-Mun Project ^[22][23] Large-scale energy infrastructure in Thailand has been met with strong resistance - for example, the Assembly of the Poor's opposition to the Pak Mun HPP, the last dam to be commissioned in Thailand. This has forced Thailand to export the social and environmental externalities of hydropower construction and operation to neighbouring states.^[24][25]

While there are multiple HPPs planned for Myanmar parts of the Mekong River Basin,^[26] years of political instability have generally impended hydropower development.

Vietnam's Mekong hydropower development is concentrated in its Central Highlands. It does not appear as if any technically-exploitable hydropower potential remains. Here, hydropower has also been accompanied by significant irrigation development. Vietnam's hydropower investments in this area includes sizeable dams on two key Mekong tributaries, the Sesan and the Srepok rivers.