From the first phases of considering plant design and layout or a refurbishment program, important parameters are set that have a major influence on both energetic and environmental performance. In particular, the hydraulic as well as the mechanical design of the turbines offers many opportunities to significantly and positively influence fish survival rates. In order to accurately assess different designs in terms of their fish mortality-related performance, comprehensive knowledge of injury mechanisms and their corresponding mitigation measures is necessary.
Since the 1990s, ANDRITZ has followed a combined design strategy to ensure high rates of fish survival. Different design features are possible, associated with the various injury mechanisms caused by the different stressors (measurable, physical qualities that can be linked to each injury mechanism). It is worth noting that the optimal choice of design parameters for fish survival might be slightly different from those design considerations in which maximizing energy production or minimizing costs are the only targets. Nonetheless, efficient operations and good fish survival rates are possible if the appropriate design considerations are made.
ANDRITZ uses a biological assessment tool supported by CFD to record the various stressors on a fish along its trajectory through an operating turbine. Based on in-depth knowledge of the stressor limits for injuries to various fish species, survival rates can be calculated with this assessment tool.