Oh buoy: wave energy converters are producing electricity from the seas

4 min

The ocean has always been regarded as an unimaginably vast, almost untameable energy source, one that is respected and revered in equal measure. Humans have been sailing and harvesting the seas for millennia but now there is a new type of exploration taking place as scientists and renewable energy innovators understand more about the awesome energy source that the oceans, and waves in particular, can provide.

Wave energy is generated by converting the energy within ocean waves (swells) into electricity. According to ARENA, tidal energy comes in two forms, both of which generate electricity:

  • Tidal range technologies harvest the potential energy created by the height difference between high and low tides. Barrages (dams) harvest tidal energy from different ranges
  • Tidal stream (or current) technologies capture the kinetic energy of currents flowing in and out of tidal areas (such as seashores)

In Northern Europe, where the seas can be especially rough and powerful, wave energy converters (WEC) are being developed and deployed to harness the energy from those formidable waves. A WEC is defined as a device that converts the kinetic and potential energy associated with a moving wave into useful mechanical or electrical energy.

In Scotland, a marine services company, Malin Renewables, was recently awarded a £1M contract to develop and deliver a 50 tonne WEC to harness the powerful movement of the sea into electricity.  Malin stated in a media release that they were appointed by AWS Ocean Energy Ltd to build the half scale Archimedes Waveswing power generation device, designed for offshore wave energy production. The development of the Archimedes Waveswing is funded by Wave Energy Scotland and will be fabricated and assembled at Malin’s Westway Park site in Renfrew, 5 miles west of Glasgow. Scotland is home to a number of organisations and projects exploiting the powerful waves off their rugged coastline.

The Waveswing itself is a submerged power buoy that reacts to changes in sub-sea water pressure caused by passing waves and converts the resulting motion to electricity via a direct-drive generator.  According to AWS, the system is suitable for deployment in water depths in excess of 25m and can be configured for ratings between 25kW and 250kW by selecting the appropriate scale.

Closer to home, ARENA has provided funding support for 14 ocean projects in recent years. They also work closely with the ocean energy industry, sharing lessons from their wave energy projects and supporting activity to advance the sector through research and development projects.

CSIRO has stated that wave energy is an emerging technology that has been generating interest as an alternative renewable energy source in Australia. There are in excess of 200 wave energy devices in various stages of testing and demonstration on our coastlines, however there is limited published data on its viability as an alternate energy source.

Preliminary estimates by CSIRO also suggest that Australia has an abundant and attractive wave energy resource (given our island nation status) and could potentially contribute 11% of Australia's energy needs by 2050.

As more is learned and the technology continues to advance, the potential for ocean energy to contribute to Australia’s energy mix could one day be as vast and abundant as the oceans themselves.

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