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Power from the waves

AW-Energy is pioneering technology to enable us to harness the power of the sea to produce clean and safe energy – and its innovative ‘WaveRoller’ is set to leapfrog competing systems in terms of performance, cost, and environmental impact.

In the search for environmentally friendly energy sources, the power of the oceans has long been proposed as an alternative, along with wind and solar power; and various commentators have estimated that wave energy has the potential to meet 10% of the world’s electricity needs.

A number of concepts have been developed based on phenomena such as tidal currents, with varying success, but AW-Energy’s patented WaveRoller is the first solution to harness waves near the sea bottom in shallow water close to shore.

The WaveRoller concept is economic, scaleable, and has a low level of environmental impact – and is based on taking advantage of the kinetic energy of water movement near the sea bottom.

The system features hinged plates or ‘wings’, anchored to the ocean floor, which are moved back and forth by this movement, and a hydraulic cylinder, which collects the energy generated. This energy can then be converted into electricity by a hydraulic motor/generator system, located either underwater or onshore.

The idea is to assemble WaveRoller plates in modules, making it easy to implement larger generation schemes.

As a WaveRoller installation is located below the surface, the only visual sign of its presence are its onshore control buildings. The system on the sea floor has a minimal impact on marine life; and virtually no noise is generated. As a typical WaveRoller installation is located between 7 and 15 meters below the surface, most vessels can pass above freely. The shallow water used also means that a plant can be installed relatively easily and will have good storm survivability.

Prototype very successful

Following prototype testing in various locations, a pilot WaveRoller plant has been built off the Portuguese coast at Peniche to test the capture efficiency of the system’s wings in particular, and has proved very successful from a technical standpoint so far. It has also won the unanimous support of local residents, marine biologists, fishermen, and politicians.

AW-Energy will complete its multiwing design in 2008 and expects to have a scaled-up plant connected to the grid by around 2010 to demonstrate the capability of the concept for stable, long-term generation.

As the technology approaches full-scale commercialisation, the WaveRoller is expected to be capable of generating electricity at a cost of below €50/MWh, which is on a par with wind power and is competitive with more traditional energy sources when the CO2 factor is taken into account.

AW-Energy’s WaveRoller is based on plates or ‘wings’ anchored to the sea floor, exploiting the strong back and forth movement of bottom waves found in areas close to the coast. A number of prototypes have been tested, and a pilot plant is now in operation off the Portuguese coast.
> Tuomo Hyysalo
(Published in HighTech Finland 2008)