Wave Power

In the 1970s, two countries began to realise the potential of wave power. Japan and England began to develop methods for using waves to generate power. Wave energy generation devices fall into two general classifications, fixed and floating.

Fixed generating devices

Fixed generating devices, which are mounted either on the sea bed or shore, have some significant advantages over floating systems, particularly in maintenance. However, the number of suitable sites available for fixed devices is limited.

Floating devices

Floating wave energy devices generate electricity through the rise and fall of the floating part of the device. This is different to fixed systems that use a fixed turbine which is powered by the motion of the wave.

One such device, the Salter Duck, is able to produce energy extremely efficiently, however its development was stalled during the 1980s due to a miscalculation in the cost of energy production by a factor of 10 and it has only been in recent years when the technology was reassessed and the error identified.

Wave power in Australia

Energetech Australia Pty Ltd has produced a prototype model of a new type of oscillating water column. This wave energy system which allows more power to be tapped from the ceaseless motion of the ocean waves.

Initial testing of the 1/25 model have been encouraging and Energetech received a $750 000 grant through the Australian Greenhouse Office's Renewable Energy Commercialisation Program to construct a 300kWp wave power generator on the breakwater at Newcastle or Port Kembla.

Energetech’s Wave Energy System is the only system in the world that uses a parabolic wall to focus the power of incoming waves. The wave energy is converted to electricity using a revolutionary turbine developed in Australia that is four to five times more efficient than competing technology, the Wells Turbine.

The Energetech wave generator is designed to be anchored on shore in areas where there is fairly deep water right up to the coast such as on harbour breakwaters or rocky cliffs. The parabolic shield focuses waves into the bottom of a chamber filled with air, the shield increasing the amplitude of the waves at the focal point by about a factor of three. The rising and falling column of water in the chamber pushes air back and forth through an aperture in which a turbine is placed.

This back and forth motion - the oscillatory motion - of the air has been the ongoing source of design problems for this style of wave generator. The Wells Turbine is relatively inefficient in converting this oscillatory motion into electricity and often stalls completely. Wave power projects in some parts of the world have ground to a halt because of the limitations on the performance of turbines in oscillating flows of air.

Energetech's technology - Tom's Turbine - continues to spin at high speed in one direction despite the oscillating flow of air, the blades on the turbine being constantly adjusted by mechanical actuators linked to microprocessor controls and pressure sensors in the air flow.

Did you know?

The Energetech wave generator is designed to be anchored on shore in areas where there is fairly deep water right up to the coast such as on harbour breakwaters or rocky cliffs.

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