A Journey to the Bottom of the Celtic Sea

Onshore and offshore, natural resources have always intertwined with the South West and its coastal communities, with traditional industries like fishing and mining flourishing. But now this region is on the cusp of a fresh frontier, a new decarbonised future that will harness the power of nature through floating offshore windfarms. The sheer scale of the prospect is breathtaking, with plans for phase one of the project in place to generate enough energy to power all the homes in the South West and beyond. This means huge opportunities for the region. 

In the COAST Laboratory at the University of the Plymouth, our researchers are working on new designs and developments, innovating both the floating structure and the mooring and anchoring systems of offshore wind turbines. Professor Deborah Greaves OBE and Dr Emma Edwards are looking at the best ways in which mooring and anchoring systems can be used. Together they are making sure that the floating platforms and turbines remain stable in both regular, calm and extreme sea states, where they will be standing against rough waves and large wind speeds. 

In order to test those things, to make sure that the turbines can survive extreme conditions and operate in the way they should, our experts are using the COAST Lab wave basins to scale down the offshore environment and test the turbine and anchoring system on scale models. The findings from the work taking place are providing key information for not only the Celtic Sea project but also for the UK as a whole, as the UK works to become global leaders in renewable energy, with a keen focus on offshore wind. 

Offshore, just like on land, nature is all around us, with the Celtic Sea spanning a large number of habitats and protected areas which sustain biodiversity and valuable ecosystems, alongside commercial activities like fishing to support local communities. 

But it’s not just about the wind and the water, it’s also about what's underneath the water at the bottom of the sea. To better install the offshore turbines, we need to understand the seabed, what it’s made of and what its properties are if we are to develop this environment in an efficient and sustainable way. Understanding the formation and evolution of the Celtic Seabed is important to the positioning of the offshore wind farms, as it is essentially a giant jigsaw puzzle. So, experts at the University of Plymouth, Dr Martin Stokes and Dr Jenny Gales, are solving the puzzle by working to understand the sea floor and what lays beneath it. 

The Celtic Sea spans from just south of St George’s Channel, to the Bristol Channel, out the Isles of Scilly and finally out to the continental shelf edge. The central part of the Celtic Sea is quite flat and relatively shallow, with depths of 90 – 100 metres water depth. But as you get towards the shelf edge you find water depths of up to 200 metres, with big rocky outcrops such as Haig Fras, just off the Isles of Scilly. You can also find mega ridges and we know that an ice sheet used to span across the shelf edge in past history. The differences in seabed strength of these areas are important to understand and will allow our geologists to advise our engineers not only on where and how to anchor the turbines but also to help decide where best to lay the cabling which will ultimately bring the energy back to shore.

Knowing the geology of the seabed will help us understand environmental sensitivities and ecological impacts, vital knowledge that will be built into the development of these turbines. 

In the South West geology is at the heart of its past, but it's also at the heart of its future and it doesn't stop at the shore. We need to care about the offshore in the same way we care about the land. It’s a journey of understanding that will take us to the bottom of the Celtic Sea. A journey that has been several hundred million years in the making, but one that in the next few decades will be so exciting to be a part of, with researchers at the University of Plymouth leading the way.