CETO

The name is inspired by the Greek ocean goddess, Ceto. As of January 2016, the system distinguishes itself from other wave-energy devices in being fully submerged. Submerged buoys are moved by the ocean swell and driving pumps that pressurize seawater delivered ashore by a subsea pipeline. Once onshore, the high-pressure seawater is used to drive hydro-electric turbines, generating electricity. The high-pressure seawater can also be used to supply a reverse osmosis desalination plant, producing freshwater. Some historic conventional seawater desalination plants are large emitters of greenhouse gases; this is due to the amount of energy required to drive the grid-connected pumps that deliver the high-pressure seawater to reverse osmosis membranes for the removal of the salt.[3]

As of January 2016, CETO 6 is in development, and differs from CETO 5 in having a larger buoy, with the electrical generation onboard and the power being transferred to shore by an electrical cable. The buoy is designed for deeper water and further offshore than CETO 5.[4]

Stage 1, already been completed, involved the manufacture, deployment and testing of a single commercial-scale autonomous CETO unit off Garden Island. For this stage, the CETO unit was not connected to shore but was stand-alone and autonomous, providing telemetric data back to shore for confirmation and independent verification of the unit's performance.

Stage 2 involved the design, construction, deployment and operational performance evaluation of a grid-connected commercial-scale wave-energy demonstration project, also at Garden Island. The facility consisted of multiple submerged CETO units in an array, subsea pipeline(s) to shore, hydraulic conditioning equipment, and an onshore power generation facility.

In early 2015 a multi megawatt system was connected to the grid, with all the electricity being bought to power HMAS Stirling naval base. Two fully submerged buoys which are anchored to the seabed, transmit the energy from the ocean swell through hydraulic pressure onshore; to drive a generator for electricity, and also to produce fresh water. As of 2015 a third buoy is planned for installation.[5][6]

The Réunion Island project is a joint venture between Carnegie and EDF Energies Nouvelles. The project will initially consist of the deployment of a single, autonomous commercial scale unit (stage 1) which will be followed by a 2MW plant (stage 2) and a further expansion of the project to a nominal 15MW installed capacity (stage 3). As of April 2011 stage 1 has been awarded $5M of French government funding.[7]

A cable between a buoy and the seabed anchored hydraulic pump snapped in a CETO 4 prototype installation in January 2014. The buoy was swept away during Cyclone Bejisa, which also led to a fatality and widespread damage on Réunion Island. The design was an earlier iteration than the Perth CETO 5 installation and lacked the quick release mechanism which was included in CETO 5.[8]

Carnegie has signed a formal funding and collaboration agreement with the Irish Government's Sustainable Energy Association (SEAI) for a €150,000 project to evaluate potential CETO wave sites in Ireland and develop a site-specific conceptual design. The project is 50% funded by the SEAI and 50% by Carnegie, and forms the first phase of detailed design for a potential 5 MW commercial demonstration project in Irish waters. The project was under way in 2011 and is being managed through Carnegie's Irish subsidiary, CETO Wave Energy Ireland Limited.[2]