Feasibility study of ultra-low-head hydro turbines for energy extraction from shallow waterways

Ultra-low-head turbines can harness energy from previously deemed unsuitable sites, including natural and man-made locations like shallow estuaries, marine canals, and industrial waterways. Various hydro-turbine concepts were evaluated for their potential to extract power from these areas. These turbines can generate renewable energy for utilization in remotely located areas. A horizontal-axis screw turbine concept, horizontal and vertical Savonius turbine concepts, axial turbine concepts, and a gate turbine concept were investigated in the present study using computational fluid dynamic tools. Reynolds Averaged Navier Stokes equations with a shear stress transport model are used to calculate the flow field. The numerical methodology is then verified with previously published data. The turbine performances were compared and the design feasibility was analyzed to find the most effective turbine design which can extract the maximum energy. The gate turbine concept exhibited a significant power output with high efficiency while the screw turbine showed the lowest performance among the tested designs. The horizontal Savonius turbine displayed enhanced performance with an increment of 23.25 % compared to the screw turbine. An additional parametric study is conducted on the gate turbine namely, the number of runner blades, and the gate installation angle. The 3-bladed gate turbine installed at a 14° gate angle showed superior power output and efficiency than other hydrokinetic turbines.