Purpose This paper aims to study dams on transboundary rivers. In this study, the case of the Nu–Salween–Thanlwin River is reviewed. This study is an attempt toward developing a conceptual model to explain the unequal hydropower exchange of hydropower dams on transboundary rivers.Design/methodology/approach This paper reviews big dam project plans on the Salween–Thanlwin River near the Myanmar–Thailand border from the perspective of critical hydropolitics. The evidence is drawn from an extensive review of academic literature, reports, newspapers and websites on this topic. Cascao and Zeitoun’s (2010) four pillars of power, namely, geographical, material, bargaining and ideational power, are reviewed in the case of the Salween–Thanlwin River and its riparian states.Findings On the basis of a realist discourse, power relationships between dams and their socio-environmental effects are discussed from the perspective of critical hydropolitics. Multiple levels of power asymmetry regarding geographical, material, bargaining and ideational power are observed. The powerful states are high electricity consumers and importers. They invest in hydroelectric dams of adjacent developing states and buy back most of the electricity generated to fuel their industrialization and urbanization. Weak states generally do not have high bargaining power. They depend on the investment of high material power states for domestic and economic development and gain from the export of electricity. However, the externalities of hydropower dams are transferred to these weak states. This contributes to an unequal hydropower exchange model.Practical implications The model provides an analytical framework for hydropower dam projects through which comprehensive and multidimensional views are extracted. Academia, policymakers, private developers, international development agencies and nongovernment organizations will have a better understanding of hydropower dam projects and the interactions among riparian states.Originality/value This conceptual model stems from Cascao and Zeitoun’s (2010) four pillars of power – geographical, material, bargaining and ideational power. The author limits the framework to hydroelectric dams in transboundary rivers. The powerful states are high electricity consumers and importers that dominate the dam development projects and exchange process. [ABSTRACT FROM AUTHOR]