The device has now been recovered to shore for detailed inspection prior to being re-deployed at EMEC’s test site.
This important milestone in the development of the 16 kW Archimedes Waveswing follows successful quayside testing and preparation at Copland’s Dock in Stromness since its arrival in Orkney in late January. Since then several short weather windows have enabled deployment of the anchor and anchor block, umbilical cable and EMEC’s test support buoy, as well as two trial deployments of the Waveswing.
Quayside and marine operations have been carried out by the local Orkney supply chain: installation and recovery operations were completed by Green Marine using the ‘Green Isle’ multicat vessel; test support buoy and umbilical deployments by Leask Marine; and lift operations by Heddle Construction.
When installed, the 50 tons, seven-metre high, four-metre diameter device is moored to a gravity-base anchor on the seabed using a single tension tether and sits around three metres below the surface. The Waveswing generates energy by reacting to changes in pressure caused by passing waves. The subsea location and ability to winch low in the water column allows extreme storm loadings to be avoided so that the device can continue to operate in rough sea conditions. The Waveswing is also designed to react to long ocean swell waves as well as short, wind-driven seas, for high energy capture.
The shakedown testing addressed one of the key scientific uncertainties in relation to the behaviour of the Waveswing: how the device will respond to changing water depth and pressure. The tests demonstrated a 2x ratio between change in depth and movement of the floater thus confirming the power-generation potential for the device.
The £3.4 million prototype development project has been funded by Wave Energy Scotland (WES), as part of the Novel Wave Energy Converter development programme. The demonstration at EMEC is also supported by the Interreg North-West Europe’s Ocean DEMO project.
“Completion of this initial phase of testing is without doubt the most significant step forward yet in the development of Waveswing” said Simon Grey, CEO of AWS Ocean Energy. “These tests could not be carried out at model scale, nor could they be modelled using computers with any degree of certainty. The results confirm what we have hoped for in terms of performance potential. Furthermore, demonstrating the practical deployment, operation and recovery of the Waveswing is also a significant step. Getting to this stage is a tribute to the skills and commitment of the whole team at AWS, our subcontractors and the fantastic support we have received from EMEC, WES and many others. Since arriving in Orkney our team has completed no less than 10 significant lifting, marine or diving operations. The support of the Orkney supply chain in completing these, despite the weather, has been tremendous. Our current single absorber design is suitable for remote power applications such as powering subsea oilfield assets and oceanographic monitoring. However, we are convinced that the future lies in multi-absorber platforms which can achieve the scale necessary for wave power to make a significant contribution to renewable energy supplies. We expect to develop platforms hosting up to twenty 500 kW units with a potential capacity of 10 MW per platform. We are currently seeking development partners to join us on this exciting journey”.
Tim Hurst, Managing Director of WES, added that the company has supported the development of this technology throughout its competitive Novel Wave Energy Converter programme and that the Waveswing offers design features that independent assessors have highly rated for their potential to deliver reliability and cost reduction to wave energy.
“It’s great to see that these features will now be tested in a real sea environment” Mr Hurst said. “The data gathered will be an important output of the WES programme and will support future developments.”
The Waveswing development programme has been supported by a strong, predominantly Scottish team of subcontractors including 4c Engineering and Quoceant on design, Sequentec on supply of the control system, Malin Marine for the main build and assembly work, and JGC Engineering for fabrication of the anchor frame. International subcontractors include Trelleborg for supply of the rolling seal and SRP Subsea for supply of the Rocksteady mooring connector. Quayside and marine operations were carried out by Orkney-based companies Green Marine, Leask Marine, and Heddle Construction, with demonstration activities supported by EMEC’s operational team.
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