Assessing the Changes in Hydropower Production under Climate Change in the Mekong River Basin

Population growth, urbanization, and economic development in the Mekong River Basin (MRB) have led to an increase in energy consumption in all the member countries. In the last decades, electricity demand has grown faster by 10% per annum. To maintain energy security while also reducing carbon emissions, interest in renewable energy sources such as hydroelectric dams has increased significantly in the Mekong region. Hydropower could provide clean energy, additional water for irrigation during the dry season, and navigation, which could largely contribute to the national economic growth of the riparian countries. The future hydropower generation not only relies on the current river flow variation but also on the future water availability induced by climate change. This study aims to assess the impact of climate change on hydropower production using the most recent climate projections from the Coupled Model Intercomparison Project Phase 6 (CMIP6). Results suggest an increase in annual discharge as well as total inflow under climate change. In general, hydropower production showed an increasing trend under climate change. However, restricted by the current turbine flow capacity, future hydropower production could increase by only 5% given a 22% increase in total inflow. Hydropower dams along the Mekong mainstream are mainly type-C (small turbine flow capacity) dams. These dams can potentially increase hydropower production if the total inflow increase, but it was found that the increase in high-flow (i.e. discharge ≥ Q25) was more dominant. As a result, even for the type-A (large turbine flow capacity) dams, the increase in hydropower production is limited. They also cannot increase the hydropower production as much as the total inflow increase, mainly because of the limited turbine flow capacity. For future hydropower development, stakeholders should prioritize hydropower dams along the mainstream and might consider increasing their turbine flow capacity as it could significantly increase energy production. In other words, if we increase turbine flow capacity within the MRB by the same amount, these dams are more effective since they can utilize the increased flow as much as the turbine flow capacity increases.