A submerged buoy-like device is harnessing the sea’s ‘epic amounts of energy’ in Scottish trial

Sea-based trials of a wave energy converter weighing 50 metric tons have produced “highly encouraging results,” according to the company behind its development.

On Tuesday, Scotland-based AWS Ocean Energy said the average amount of power its device was able to capture “during a period of moderate wave conditions” came to more than 10 kilowatts, while it also recorded peaks of 80 kW.

In addition, AWS said its Waveswing was able to operate in more challenging conditions, including Force 10 gales.

The piece of kit — which has been described as a “submerged wave power buoy” — has a diameter of 4 meters and stands 7 meters tall.

The Waveswing, AWS Ocean Energy says, “reacts to changes in sub-sea water pressure caused by passing waves and converts the resulting motion to electricity via a direct-drive generator.”

Compared to more established renewable technologies, the 16 kilowatt Waveswing is small. Firms like Denmark’s Vestas, for instance, are working on 15 megawatt wind turbines.

This phase of testing is set to wrap up before the end of this year, with more tests set to be carried out in 2023.

In terms of real-world applications, AWS Ocean Energy CEO Simon Grey said the Waveswing had features that made it “ideal for remote power applications such as powering subsea oilfield assets and oceanographic monitoring.”

Grey later added that the firm also expected to “develop platforms hosting up to twenty 500 kW units with a potential capacity of 10 MW per platform.”

The sea trials are taking place at a European Marine Energy Centre testing site in the sheltered waters of Scapa Flow, Orkney.

An archipelago, Orkney is located north of the Scottish mainland. EMEC, which is based there, has become a major hub for the development of wave and tidal power since its inception in 2003.

Neil Kermode, who is EMEC’s managing director, said it had been “great to see the Waveswing deploy, survive and operate at our test site this year.”

“We know there are epic amounts of energy in the seas around the UK and indeed the world,” Kermode went on to add. “It is really rewarding to see a Scottish company make such progress in harvesting this truly sustainable energy.”

While there is excitement about the potential of marine energy, the footprint of wave and tidal stream projects remains very small compared to other renewables.

In data released in March 2022, Ocean Energy Europe said 2.2 megawatts of tidal stream capacity was installed in Europe last year, compared to just 260 kilowatts in 2020.

For wave energy, 681 kW was installed, which OEE said was a threefold increase. Globally, 1.38 MW of wave energy came online in 2021, while 3.12 MW of tidal stream capacity was installed.

By way of comparison, Europe installed 17.4 gigawatts of wind power capacity in 2021, according to figures from industry body WindEurope.