Assistant Professor Ecole Polytechnique Fédérale de Lausanne, United States
Abstract Submission: Hydropower tailrace channels offer promising sites for hydrokinetic energy harvesting due to their fast currents, scheduled flow releases, proximity to existing infrastructure, and low environmental impacts. However, deploying energy-extracting devices introduces flow resistance, leading to a slight increase in water levels that may decrease the available hydraulic head and, consequently, reduce upstream hydropower generation. This study proposes a one-dimensional momentum balance approach to estimate this water level increase, which is validated against three previous laboratory and field measurements at different scales. Combining with the backwater equation to assess the water surface recovery upstream from the turbine, we can thus identify the optimal turbine siting distance that maximizes net power production by balancing hydropower loss and hydrokinetic gain. The analysis is based on the hydraulic conditions of the channel and the characteristics of the hydrokinetic turbines. Additionally, we estimate the hydrokinetic potential in U.S. hydropower tailraces and present two case studies. The findings support the integration of hydrokinetic turbines downstream of dams to enhance energy production at existing facilities and Non-Powered Dams (NPDs) with minimal structural modifications while also serving as potential sites for large-scale field testing of hydrokinetic devices.
