Modelling the power of the sea as a low-carbon energy source

Modelling the power of the sea as a low-carbon energy source

Using the power of the sea is nothing new: people have been using tidal range – the rise and fall of sea levels – since medieval times to drive mills and grind grain. New technologies now allow us convert tidal and wave power into electricity, and research from the School of Ocean Sciences at Bangor University aims to understand the available resources and how they can best be harnessed.

“The good thing about tides is they’re predictable, so you can see what contribution they can make for a hundred years into the future. There’s the tidal range, and there’s tidal stream, where you harness the kinetic energy of the tide using a horizontal axis turbine, like an underwater windmill,” says Simon Neill, Professor in Physical Oceanography.

“And then we have wave energy. It’s less advanced than tidal energy because waves by their very nature are quite destructive, and of course you want to put your devices somewhere where the waves are energetic – so at present the devices have to be really overengineered to withstand those forces,” says Neill.

Neill’s research focuses on understanding the resource itself, and identifying the optimal locations for energy devices.

“Waves, for example vary over a long timescale, and you can’t really say anything meaningful about the resource until you have at least a ten-year record. So you could go and put a wave measuring device in place and wait ten years… or you can use modelling. We use measurements to build a model and see how things will vary over 10, 20 or even 50 years. You can look at things like climate change: no one really knows what the wave climate will look like in 2050, so the only thing you can do is run a model,” he says.

The team also looks at the interaction between energy extraction and the resource.

“If I put a 100 megawatt array in place, I wouldn’t really know what the impact on the environment would be until post construction. By modelling you can see what the impacts would be, and change the shape or the spacing between devices to minimise impacts on the environment,” Neill says.

Tidal, and especially wave models, are “extremely computationally expensive” and can take up to three months to complete, even on a facility as extensive as Supercomputing Wales, but the facility and team make it easy for Neill.

“Before this we had to spend a lot of our time setting up and optimising our models – and that was just taking away from the science. Having this dedicated team who deal with all the technical issues is great. After some discussions about a new model application, they’ll take care of all the technical set up and optimisation, and provide me with some scripts to run the model, so I can focus getting outputs,” he says.