Scottish Association for Marine Science

It goes by the unusual name of SAMS Drifting Ears and soon this device – the first of its kind anywhere in the world – could be playing a vital role in the development of sea power around Scotland’s coastline.

The Drifting Ears are the brainwave of a team of scientists at the Scottish Association for Marine Science (SAMS), the internationally respected marine research establishment on the outskirts of Oban.

Over the past few months Dr Ben Wilson and his team have been looking at the possible environmental impact of wave and tidal devices. Their aim is to help developers ensure the technology that could generate huge quantities of green power does not, paradoxically, have a negative impact on the marine environment from which it comes.

“Developers are racing to come up with machines that are efficient, hardy to the marine environment and economically viable,” says Dr Wilson.

“But there’s a substantial caveat to this contest and one that is in real danger of being swept aside in the race for renewable power.  Can we harness this energy without causing significant harm to the environment? And more specifically, are some device designs inherently more hazardous than others?

“These technologies are new and their environmental impacts unknown, but lessons from other marine activities like naval manoeuvres, shipping and oil extraction give us ample warning that care should be taken.”

The team is currently working in partnership with EMEC looking at the potential polluting effects of underwater sound to develop technology the marine renewables industry can use to measure how noisy marine devices.

“Measuring sound levels in the punishingly energetic marine environment is not a simple task,” reflects Dr Wilson.

“Normally underwater sound is measured by lowering an underwater microphone over the side of a boat and making a recording. This can often be complicated because the boat can generate unwanted sound of its own.

“This problem can be overcome but add to that a strong current – and there are plenty of those around Orkney’s waters – and it can get very tricky indeed.”

And that’s where SAMS Drifting Ears come in. This ingenious boat-free, mobile marine recording system comes with its own sound recorder, GPS and power supply all neatly packed into a small floating case attached to an underwater microphone.

After rigorous testing at the Falls of Lora tidal narrows in Argyll, trials with the ‘ears’ began in earnest earlier this year at the Falls of Warness where EMEC has set up hook-up points on the seabed to which developers can attach prototype devices.

Dr Wilson and his team had the worst kind of Scottish winter weather thrown at them when they set loose a line of drifting ears but the trials went well and, back in the warmer environment of the SAMS labs, the team is now working its way through 20 gigabytes of captured sound data to produce a map.

Dr Wilson is optimistic about the drifting ears’ future role in Scotland’s push for marine power.

“As the EMEC site becomes populated with devices, we’re looking forward to deploying the drifting ears again.

“By comparing the sound levels when there are operating devices from those we’ve recorded at the undeveloped site we’ll get an indication of what sort of noise tidal-stream machines emit in coastal waters.

“This will help us comprehend what a marine mammal or fish will hear as it approaches the device and what acoustic environmental impact this new energy source will have in our coastal waters.

“We will then be one step closer to knowing how green marine renewable energy can be.”