**Marine Hydrokinetic Turbines and Fish Behavior: A Delicate Balance**
Researchers from the Pacific Northwest National Laboratory and the University of Washington have been studying the interaction between fish and marine hydrokinetic (MHK) turbines, aiming to understand the ecological impact of these renewable energy devices. Their work, published in the journal *Renewable and Sustainable Energy Reviews*, combines experimental observations and computational simulations to shed light on how fish behave around these turbines.
The study focuses on vertical axis turbines, which are used in tidal and riverine environments for renewable energy generation. The researchers conducted laboratory experiments with rainbow trout, observing their behavior around a turbine. They found that the fish consistently avoided areas with high turbulence and shear, preferring low turbulence zones like the downstream sidewalls of the turbine.
To complement these observations, the team used high-fidelity large eddy simulations to capture essential flow features around the turbine. These simulations revealed details such as wake asymmetry, vortex shedding, and spatial variations in turbulence intensity under different flow and rotational regimes. The researchers then characterized the hydrodynamic stressors and energetic demands on the fish using various turbulence metrics, including turbulence kinetic energy, Reynolds stress, and integral length scale. They also estimated the thrust force generated by the fish.
The findings demonstrate that turbine-induced turbulence significantly influences fish movement and habitat selection. This highlights the need to consider behavioral responses in conventional fish injury assessment frameworks. The researchers suggest that their results could inform the design and operation of hydrokinetic turbines in ecologically sensitive waters, ensuring a balance between renewable energy extraction and aquatic ecosystem protection.
For the energy sector, this research underscores the importance of understanding and mitigating the ecological impact of MHK turbines. By designing turbines that minimize turbulence and shear, or by strategically placing them in areas with lower fish activity, the industry can work towards more sustainable and eco-friendly renewable energy solutions.
Source: The research was published in the journal *Renewable and Sustainable Energy Reviews*.
This article is based on research available at arXiv.