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Engineers on the Wavepod project, which is developing a standardised device able to convert kinetic energy from wave machines into electricity, have produced power from their first prototype.
The development of a commercially viable “power offtake” device able to convert linear motion into electrical energy efficiently and reliably at sea has proved a massive challenge for the many developers of wave power machines.
The Wavepod solves this problem by using a hydraulic system housed in a sealed nacelle to generate electrical power. The electricity is then cabled back to shore. A tenth-scale prototype of the device, comprising a drive train, cylinder frame and power take off, was switched on this week in a laboratory at the Institute for Fluid Power Drives and Controls at Aachen University, Germany.
It is hoped that the development of a common, standardised power offtake system will speed up the deployment of marine renewables projects. The EU estimates that the total resource for wave energy in Europe is around 320 GW.
The prototype was developed by drives and control company Bosch Rexroth and Scottish firm Aquamarine Power, as part of a collaboration between European wave energy developers, utilities and academic institutions. The project started in August this year.
John Malcolm, chief executive of Aquamarine Power, said: “We aim to finish lab testing by March next year and install a further prototype in real sea conditions on our Oyster 800 machine in Orkney in 2016.”
“We have already learned a tremendous amount through the design, build and commissioning of this Wavepod prototype. We are now generating electrical power, and the drive train is using real-life hydrodynamic data from Oyster 800 to ensure the power take off is experiencing exactly the same loads it would encounter at sea.
Aquamarine is developing its own wave power prototype called the Oyster, which takes a different approach to power transmission from Wavepod. The 800kW Oyster wave power generator has been installed at the European Marine Energy Centre in the Orkney Isles since 2012. The Oyster is tethered to the sea bed near shore. It consists mainly of a hinged flap which moves with the waves to drive hydraulic pistons. These pistons pump high-pressured water onshore to a hydro-electric generator, which produces electricity. Aquamarine is currently developing the third version of the Oyster.
Other partners in the Wavepod project include wave generator developers Albatern, Carnegie Wave Energy UK and M4 WavePower, as well as Irish utility ESB, the Offshore Renewable Energy Catapult, IFAS and University College Dublin’s Energy Research Centre.