The U.S. Electric Power Research Institute is currently testing a turbine designed for generating hydroelectricity with significantly reduced fish mortality.
The turbine, designed by Alden Laboratories, aims to provide safer passage for fish migrating downstream. Current methods of protecting fish, such as bypasses and non-generating spills, are estimated to reduce the amount of hydroelectic power produced by as much as 8,500 megawatt hours per annum in the United States alone.
Instead of the six or more blades common in older turbine designs, the Alden turbine has only three blades, reducing the chance that fish will be struck by a blade. The blades also have a semi-round edge, which pushes enough water in front of the spinning blades to move the fish out of their path. The Alden turbine has no gaps between the blades and turns slower than conventional turbines, which means tha it has less impact on fish. Up to 98% of fish survive passing through the Alden turbine compared ith 80 to 85% with a traditional turbine.
The Electric Power Research Institute is deploying the Alden Turbine at the School Street – Brookfield Renewable Power Project in Cohoes, New York for three years of testing.