Dammed if They Do, Dammed if They Don’t: Southeast Asia’s Hydropower Rush

Southeast Asian nations are “damming” the Mekong basin—constructing dams to propel hydropower across the region. Yet hydropower is increasingly damaging the Mekong ecosystem, jeopardizing local communities’ agricultural harvests and economies. States like Thailand and Vietnam utilize hydropower to improve domestic energy security. Laos and Cambodia take it a step further, using hydropower as a significant driver for economic growth. When forced to confront these issues, the blame game ensues, with southern basin nations pointing to China as the largest culprit of hydropower-ed ecological degradation. But as the Mekong ecosystem continues to degrade, and as El Niño-induced water shortages strain regional energy security, Southeast Asian nations should reconsider how much hydropower is worth pursuing. 

Hydropower is the cornerstone of Laos’s economic development. The country’s hydropower is in demand across the region, but primarily backed by Thailand, which signed a deal to import 10,500 megawatts (MW) of electricity from Laos in 2022. Laos currently has two dams on the lower Mekong mainstream, with at least seven more in the works. Laos’s latest Thai-backed hydropower project, the 1,460-MW Luang Prabang hydro dam, is currently being constructed on the lower Mekong and will contribute to the degradation of freshwater fisheries, a staple for the local food supply. The dam’s construction also detracts tourists from Luang Prabang, harming local economies.  

In Cambodia, hydropower plays an important role in managing high energy costs. In 2023, electricity cost around $0.25 per kilowatt-hour per Cambodian household, over triple the cost of electricity in neighboring Vietnam. Hydropower projects, however, do not operate with transparency, leaving local communities in the dark. Construction on Cambodia’s newest dam, the Lower Srepok 3, will reportedly displace over 4,000 families. The dam may also significantly flood indigenous land, forests, and farmland, devastating local communities.  

Hydropower dams across the Mekong basin have hit Vietnam’s communities the hardest. Vietnam’s access to the river is limited to the Mekong Delta, with the area accounting for one third of the country’s total GDP. Currently, China’s upstream dams have trapped 30 percent of the sediment that would normally flow downstream to the delta, with Laos and Cambodia’s dams blocking an additional 5 percent. The decreased sediment flow  degrades the agricultural productivity of the Mekong states, especially Vietnam. And if all the planned hydropower projects in the Mekong are carried through, the sediment reaching the delta will be 97 percent lower than in natural conditions. Vietnam’s fisheries are also in jeopardy, with the country projected to lose 30 percent of its fish catch by 2040. 

Most hydropower plants over 45 years old need to be refurbished to maintain performance.  This need for modernization may be an opportunity to upgrade dams to mitigate environmental ramifications. Technicians are currently developing hydropower systems with fish-safe turbines that can maintain fish migration patterns. Modern sustainable hydropower infrastructure can also improve drought management and flood control, alleviating the delta during dry seasons. But while better suited to manage droughts, sustainable hydropower still faces an inevitable pitfall—overcoming the dry seasons. Hydropower, sustainable or not, is susceptible to unreliable power during the dry seasons, and is jeopardizing regional energy security through potential weather-induced outages. Additionally, the majority of hydropower plants in the region are less than 45 years old. Only five of the plants are over 45, with four of those located in Thailand and one in Laos. As a result, countries would have to refurbish hydropower plants earlier than necessary, making the technology much less attractive to implement.  

Floating solar voltaic (FPV) provides a potential solution. Traditional solar power already has the opportunity to be effective in the Mekong nations, which all have exhibit significant untapped solar potential. FPV is a particularly compelling avenue—it addresses traditional solar power’s need for large areas of land to provide sufficient power by placing solar infrastructure on the water. Better, FPV can utilize existing hydropower infrastructure to operate, which allows China, Cambodia, and Laos to keep their existing infrastructure without having to build more dams. This technology is already being explored in Thailand, with its first project consistently producing more electricity than expected.  

 Southeast Asian nations do not need to “dam” themselves to economically prosper.  Investing in different renewable energy technologies will not only help improve domestic energy security, but also protect local ecosystems and safeguard local economies.  

Lauren Mai is a program coordinator and research assistant for the Southeast Asia Program at the Center for Strategic and International Studies in Washington, D.C.