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Harnessing the power of the waves

AW-Energy’s WaveRoller technology is set to leapfrog competing systems in terms of performance, cost, and environmental impact in enabling us to harness the power of the sea – thanks to its ability to generate energy in a wider spectrum of conditions than existing wave energy solutions.

The oceans have long been proposed as an environmentally friendly source of energy, alongside wind and solar power. Various commentators have estimated that wave energy has the potential to meet up to 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 the surge phenomena found near the sea bottom at intermediate depths close to shore. This makes it well-suited to locations with long wave periods and strong swells. The annual power levels that can be achieved at these locations are subject to considerably less fluctuation than surface wave devices or wind energy.

Modular wings

The WaveRoller system features hinged plates, or ‘wings’, anchored to the sea bottom, which are moved back and forth by the surge movement of the sea, and hydraulic cylinders, which collect the kinetic energy generated. This energy can then be converted into electricity by a hydraulic motor/generator system. WaveRoller technology can also be used for desalination purposes to produce drinking water.

The concept is a modular one, with each module comprising between three and five wave elements. As there is no upper limit on overall capacity, it will be easy to ramp up capacity by simply adding new modules. Maintenance is also easy, thanks to the fact that each module is mechanically independent, which also means that electrical output can be maintained while one or more modules are being worked on.

Environmental and visual impact is minimal, as WaveRoller elements do not significantly hinder the natural movement of the water, and coastal craft, such as fishing vessels, can pass over them safely.

Success in the field

Following prototype testing, a pilot WaveRoller plant was installed off the Portuguese coast at Peniche in 2008 to test the capture efficiency of the system’s wings. This has proved very successful from a technical standpoint and has won the unanimous support of local residents, marine biologists, fishermen, and politicians.

AW-Energy expects to complete its multiwing design in 2009 and have a scaled-up plant connected to the grid in 2010 or 2011 to demonstrate the potential of the concept for stable, long-term generation and as an alternative to offshore wind energy and more traditional energy sources when the CO2 factor is taken into account.

The WaveRoller is based on ‘wings’ that can exploit the strong back and forth movement of bottom waves found in coastal areas. A pilot unit, seen here prior to installation, is now in operation off the Portuguese coast.

> Tuomo Hyysalo
(Published in HighTech Finland 2009)