Impacts of snow changes on hydropower potential under a changing climate

Hydropower is a crucial and the most widely used renewable energy source. In cold regions, snow is critical for sustaining river flows, but its dynamics have been considerably altered by climate change, with consequent impacts on hydropower potential (HP). Despite the importance of these changes, a quantitative understanding of the effects of snow changes on HP, particularly at the global scale, remains limited. Here we address this important knowledge gap by using runoff simulations from four global hydrological models, coupled with a state-of-the-art river routing model, to estimate global gross (GHP) and technical (THP) hydropower potentials. We examine the contribution of snowmelt to HP, analyze their temporal trends, quantify the elasticities of HP to peak snow water equivalent (SWE), and assess future hydropower risks and untapped potential in selected countries. Our results show that the global average GHP during 1971–2010 is 59.39 PWh, with THP ranging from 3.92 to 24.90 PWh across different flow dependability levels. The contribution of snowmelt to HP averages between 11 % and 20 % globally, with a declining trend observed in most regions. Furthermore, elasticity analysis indicates that, as snow decreases, GHP generally declines across most regions, while THP increases in several areas, primarily due to increased cold-season rainfall. Finally, our analysis suggests that some countries may face hydropower risks in the future, whereas most other countries still have over 40 % of their hydropower potential untapped. These findings provide critical insights into the impacts of snow changes on HP under climate change and offer valuable guidance for sustainable water resource management and energy planning in snow-affected regions.