Shetland scientists investigate complex challenges facing world’s most powerful tidal turbine
Marine scientists carried out studies on the world’s most powerful tidal turbine to investigate its interaction with wildlife and the environment.
Experts from UHI Shetland, alongside other academics, used drones and boats to map out the complex tidal flows encountered by Orbital Marine Power’s O2, which is located off Orkney.
Their aim was to find ways to overcome the challenges posed by extremely turbulent currents and support the delivery of the technology’s sustainable development.
Researchers believe tidal could one day supply up to 11 per cent of the UK’s energy needs – but challenging marine conditions are holding the sector back.
Nova Innovation launched the world’s first tidal array in Bluemull Sound in 2016 – and there are likely to be more projects around the islands in the future.
Unlike conventional tidal stream turbines, the O2 floats on the sea surface, anchored by mooring lines to the seabed, and is expected to produce enough power for 2,000 homes a year.
The study highlighted how changing tidal flows, above eight knots, could impact the device and its performance.
It also looked at how the O2’s downstream wake could impact the placing of other turbines as well as marine habitats.
UHI Shetland senior scientist and fisheries lead Shaun Fraser said: “This study showcases the benefits of combining scientific expertise and deploying new technologies so that significant progress can be made in understanding dynamic tidal environments.
“With further development of marine renewable energy infrastructure in the Highlands and Islands region likely in the near future, this work is more relevant than ever to local industries and communities.”
The scientists hope to have arrived at new insights around the optimal placement of tidal turbines.
They also hope their approach can be used to address uncertainties surrounding interactions with the natural environment and marine habitats.
A previous study found that a turbine wake generated a foraging hotspot for nearby breeding seabirds, however if the turbine arrays are too tightly packed it could restrict the movement of some marine fauna.
The authors also encountered orcas travelling past the turbine during one of their drone survey.
The study, published in Nature Communications, was conducted by researchers from the Marine Biological Association (MBA), the University of Plymouth, as well as UHI Shetland.
Lead author, Lilian Liber, who is a fellow at the MBA and the University of Plymouth, said: “Conducting oceanographic surveys in one of the world’s most powerful tidal streams, where currents can exceed eight knots, is both exhilarating and challenging.
“Yet collecting data in these turbulent environments is crucial for addressing some of the complexities the tidal energy industry faces today.
“The optimal placement of these turbines in narrow channels fringed by islands is a complex endeavour, but our novel methods provided robust insights into these turbulent flows and wake signatures.”
Tidal power is seen as one of the more reliable sources of clean energy, with the tides – unlike wind and waves – being both regular and predictable.
The turbines are designed to harness tidal power near the sea surface and are able to generate more energy than wind turbines of the same size.
Alex Nimmo-Smith, professor of marine science and technology at the University of Plymouth and the study’s senior author, said: “Whether it is floating offshore wind farms in the Celtic Sea or tidal turbines off the coast of Scotland, we are going to see more offshore renewable energy platforms being installed all around the UK coastline over the coming decades.
“However, the natural conditions in the waters around the UK are incredibly varied and complex, something that it is impossible to fully replicate in controlled laboratory experiments or computer simulations.
“This study demonstrates a cost-effective means of countering that, and if we are to get the greatest benefits from the clean energy revolution, assessments that factor in real-world environmental conditions will be of critical importance.”
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