DNV GL thumbs-up for WaveRoller

International classification conglomerate DNV GL Renewables has given its stamp of approval to the WaveRoller wave-energy device.

A 300kW version of AW-Energy’s near-shore wave-energy converter has been running off northwest Portugal since 2012.

The key hydraulic stage of the part-scale machine’s power take-off, which is fed by three 100kW devices, has shown “excellent performance” in a wide range of wave conditions, churning out around 500kWh a day.

DNV GL reported that the machine, grid-connected via a substation at Peniche, generated “even in very mild conditions” of two-metre swells and “continued to operate as predicted even during more turbulent periods” with waves approaching ten metres in height.

“DNV GL and AW-Energy have been working closely to establish an appropriate framework for the design of the WaveRoller..." says DNV GL head of wave and tidal energy Joao Cruz.

“The results are very encouraging. This positions the WaveRoller... technology at the forefront of the wave-energy industry.”

John Liljelund, chief executive of Finland's AW-Energy, adds: “This proves that wave-surge converters like WaveRoller are clearly becoming the industry standard for near-shore wave energy.”

The WaveRoller is based around a seabed-foundation fitted with a series of hinged panels that sway back and forth in the wave surge, driving piston pumps that propel a working fluid through a hydraulic generator. The device is designed for deployment in waves of three to five metres and water depths of around 12 metres.

Full-scale next-generation WaveRollers are being lined up for operational tests at a facility being built in Finland.