WaveRoller underwater device gets ready to rock

Finland’s AW-Energy confirmed a place among the front runners to get an industrial-size wave-power device flowing commercially onto a national grid when a consortium it leads inked a €3m ($4.4m) deal with the EU to deploy a ‘semi-scale’ version of its WaveRoller off Portugal.

The largest by far of three prototypes to be installed in the waters near the town of Peniche, the 300-kilowatt (kW) machine will be built and run by a group that includes industrial European heavyweights Bosch Rexroth and ABB, Portuguese renewable energy operator Eneólica, and compatriot technical and strategic support body the Wave Energy Centre.

EU funding for the further development of the WaveRoller — a seabed-anchored ‘moving wing’ that transforms the back-and-forth surge motion rolling beneath incoming waves into electricity — came as part of the first contract out of the blocks under the so-called Call FP7 demonstration of innovative full-size-systems scheme.

“We have been generating electricity already in the real marine environment via our earlier prototypes, and now this funding will allow us to build and deploy our first grid-connected unit off Portugal,” says WaveRoller chief executive John Liljelund.

“The economics of connecting a 300-kilowatt (kW) unit to the grid are not supportable, but we have to prove the technology before building a larger version.”

Two small 10kW WaveRoller prototypes have been running off Peniche for several years, with data collected during testing used for verification of the computation fluid dynamic (CFD) simulations and design of the new, semi-scale unit, as well as for monitoring of sediment movements and fouling phenomenon in its surrounds.

WaveRoller’s Finnish inventor, a professional diver named Rauno Koivusaari, had his eureka moment in 1993.

As he was exploring a shipwreck in the Baltic Sea, he was nearly knocked unconscious by a bulkhead door swinging open and shut in the underwater current. The 300kW device that has grown out of that near-miss will weigh around 30 tonnes and feature a 50–100 sq metre hinged wing that rocks to and fro in the waves, with a piston-like pump capturing the created energy and a hydraulic generator converting it into electricity.

“To see the device work, it reminds one of one those old Jacques Cousteau movies where the seaweed is dancing in the flow under water,” says Liljelund, “although of course, the WaveRoller moves a little more slowly.”

Ultimately, multiple WaveRollers, each with their own power take-off system, are envisaged as mounted on one ‘floatable’, 500-tonne concrete base in water depths of between 10–50 metres. The units would feed power into a shared junction box, with electricity transmitted to shore via a single power cable.

Liljelund says that early environmental impact work with the WaveRollers showed the technology, which moves with the natural motion of the water and makes no noise, to be a friendly fit with the marine milieu.

Within the project consortium, Bosch Rexroth will be responsible for supplying the power take-off system and ABB for supplying the electrics, including the site-to-shore power cable.

AW-Energy will handle project management and oversee construction of the 300kW prototype’s platform at a Finnish fabrication yard, with the wings and concrete base being delivered by a manufacturing facility in Portugal.

Once floated out and installed offshore in two years’ time, the WaveRoller will be run by operator Eneólica, with the Wave Energy Centre providing third-party verification of the sea trials and carrying out a thorough environmental impact assessment.

“We built the consortium similar to what we expect to be the future potential value chain of WaveRoller [with major components suppliers, an operator and an industry body].

“We are making use of a lot of well-known components based on mature technologies that have already been used in other different industrial concepts, but are going to be used for the first time in wave-energy conversion,” states Liljelund.

“Assuming the system works as it should, we will be ready to ramp up development of a larger unit,” he adds.

AW-Energy has a groundwork agreement with Eneólica to build several full-scale WaveRollers once the technology is proven.The holy grail is a one-megawatt (MW) device, according to Liljelund, that could be wired into multiple-unit platforms and ultimately integrated into 30MW–50MW wave-energy farms.

“In the next five to 10 years, if we can build a 5MW–10MW farm, that would be very good,” he says. “But we are a long a way off from gigawatt developments — we are some way behind the wind industry.”

Liljelund reckons the wave-power industry as a whole will benefit from the findings gained during the next phase of WaveRoller testing.

“This latest money comes from the EU, so we hope there will be a lot of things that other wave-energy companies can learn from our experience,” says Liljelund.

“We feel this is good because we as an industry have to co-operate to make the market [for wave energy] emerge. We are not looking at this project in terms of our competitors, we are looking at it in terms of colleagues and co-inspirers.”