Tidal Turbine’s Fish, Seabird Impact Put To Test

We’ve been learning that offshore wind turbines don’t appear to have significant adverse impacts on fish and bird populations – but what about wave and tidal devices?

These marine power technologies are only now beginning to be deployed, and not at a big scale, but a consortium of U.K. scientists is trying to get some early sense of their potential impact. As part of a three-year, $1.9 million project, they combined cutting-edge sonar systems on a seabed frame and placed it within 25 meters of an underwater turbine that’s being tested in Scottish waters.

marine impact, tidal power devices

OpenHydro tidal turbine, before being lowered to the seabed. (image via OpenHydro)

The big advance here is having the sonars right down on the seabed, virtually alongside the turbine. Typically, the researchers say, sonars are deployed on a ship as separate units looking down at the seabed.

The underwater sonars operate autonomously but in a coordinated way, facing upwards and allowing “a full ‘acoustic curtain’ along the tidal flow and around the turbine in a highly challenging environment,” the researchers say. But that’s just one aspect of the monitoring system rigged up at the European Marine Energy Centre.

A National Oceanography Centre marine radar is also scanning activity on and above the sea surface, “mapping the extreme currents and waves at the site and tracking the behaviour of birds and marine mammals in the immediate area,” the researchers say.

And there’s even a human involved: “Along with all the high tech instrumentation, a skilled birder, University of Aberdeen Ph.D. James Waggitt, made observations on high ground nearby which identified the times and types of seabirds diving for food within the site.”

This move to assess the impact of marine energy devices, called Flowbec, comes at a time of considerable debate about how land-based renewable energy development might be affecting ecosystems.

Pete Danko is a writer and editor based in Portland, Oregon. His work has appeared in Breaking Energy, National Geographic's Energy Blog, The New York Times, San Francisco Chronicle and elsewhere.