Survey of Energy Resources 2007
Wave Country Notes
Australia has had little investment in wave energy but developments led by three companies in recent years are stimulating intense interest, especially in using wave energy for desalination of seawater by pumping seawater into reverse osmosis (RO) plant.
Energetech (Australia) Pty Ltd.
Energetech has deployed a prototype tethered 500 kW nearshore OWC device at Port Kembla, New South Wales. It incorporates a parabolic wave collector to focus waves over a wide area onto a central OWC (to compensate for the lower wave power levels near shore) and a novel variable-pitch turbine that has higher efficiencies than turbines normally used in OWCs (www.energetech.com.au). The project has been carried out with support from the Australian Greenhouse Office, under its Renewable Energy Commercialisation Programme. The company has improved on the prototype design by developing a larger floating device rated at up to 2 MW, intended for deeper waters, and a scheme for 10 floating devices, each rated at 1.5 MW, is currently under development for deployment in Portland (Australia) in the near future; some of these will supply an RO unit on the OWC device itself and deliver low-pressure potable water to shore.
Seapower Pacific Pty
Seapower has developed an underwater, sea bed mounted wave energy device (CETO) for delivering pressurised water to an RO plant on-shore (www.seapowerpacific.com). As waves move over the top of the CETO unit, the wave crest depresses a horizontal disk to actuate reciprocating pumps to pressurise water to 7 000 kPa, which is delivered to shore by a small-bore pipe to an RO plant. A prototype device was successfully tested in Western Australia and the company has developed a follow-on design for deployment in 2008/9.
BioPower Systems is developing both tidal current and wave energy conversion technologies (www.biopowersystems.com). Their bioWAVE™ wave energy conversion system is based on the swaying motion of sea plants in the presence of ocean waves. Their vertically mounted, waving fronds capture a wide range of incident wave energy without using a large rigid structure and can orientate themselves to the prevailing wave direction. The motion is turned into electricity by their O-DRIVE™ generator, which uses a simple single-stage reciprocating gear mechanism, a direct-drive synchronous permanent magnet generator and high-inertia flywheel to produce smooth AC power. The key innovation is the ability of the system to avoid large loadings in extreme waves by lying flat on the sea bed.