Alden Fish-Friendly Turbine: Final Considerations for Development and Application

A new fish-friendly hydro turbine concept known as the Alden turbine has been developed over the past decade. The Alden turbine is designed for smaller, radial flow applications to provide the safe passage of migrating fish during power production. The Alden turbine features an innovative runner geometry that incorporates only three blades with thick entrance edge profiles to reduce fish strike probability and resulting mortality rates. The blade shapes are also designed to maintain minimum pressures, shear levels and pressure change rates within the water passage that will not harm passing fish. During the final stages of development, with funding from the Department of Energy (DOE), the Electric Power Research Institute (EPRI) and industry partners, Alden Research Laboratory collaborated with Voith Hydro in York, Pennsylvania to enhance the turbine performance through modification of the hydraulic passageways, including the spiral case, distributor (stay vanes and wicket gates), runner and draft tube. Each design modification was also evaluated for fish passage in order to ensure that the original fish-friendly characteristics of the machine were maintained. Once the design modifications were defined, Voith Hydro built and tested a physical model of the turbine at their hydraulic laboratory in York, PA. Details of the hydraulic design and corresponding model test results are presented herein. The development effort also includes a mechanical and balance of plant equipment sizing for installation at Brookfield Renewable Power’s School Street Station in upstate New York. The anticipated scope of supply and associated equipment and installation costs are discussed relative to conventional turbine types including Francis, Kaplan, Voith Hydro’s minimum gap (MGR) Kaplan, and propeller turbines for the same application. This technical comparison will focus on sizing, performance, and fish survivability. The current paper also addresses the application of the Alden turbine to additional hydro sites with differing site conditions.