Environmental effects of hydrokinetic turbines: opportunities and limitations for large-scale laboratory testing

The recent surge in interest in hydrokinetic turbines has created an urgent need to identify the scope and scale of likely environmental impacts.  Carefully constructed studies performed in large-scale hydraulics laboratories can provide data and analyses that will help identify likely consequences of deployment of these structures.  The ability to test under a range of conditions, with multiple species and turbine designs means that these facilities will play a key role in framing the discussion about whether, where, and in what densities hydrokinetic turbines can be installed.  Comprehensive experiments should look not only at immediate impacts of turbines, such as blade strike, but will also identify broader effects of multiple structures.  It will be necessary to evaluate effects on multiple life stages, as well as likely indirect effects like predation and avoidance behaviors.  In some cases, turbines may make it more difficult for fish to access valuable habitat, creating sub-lethal, but chronic habitat degradation.  Thoughtful development of laboratory experiments can help to identify and characterize these various risks.  Ultimately, though, this work will have to be coupled with field evaluations to both verify effects and to identify and prioritize which questions are most important for laboratory testing.