CETO Wave-Powered Desalination Pilot Plant, Garden Island

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Design of the CETO pilot plant. Image courtesy of Carnegie Wave Energy Limited. Schematic diagram of the Australian facility. Image courtesy of Carnegie Wave Energy Limited. Interior of the containerised desalination plant. Image courtesy of MAK Water. The seawater intake bore being drilled at Garden Island. Image courtesy of Carnegie Wave Energy Limited. Carnegie Wave Energy’s CETO Wave-Powered Desalination Pilot Plant is co-located with the Perth Wave Power Project (PWEP) on Garden Island, Western Australia. The plant became operational in April 2014 and is the first commercial-scale wave-powered project in the world to demonstrate both power and fresh water production from the ocean waves. Eastern Treatment Plant (ETP) was upgraded to incorporate an advanced tertiary treatment plant (ATTP). The desalination facility uses a seawater reverse osmosis (SWRO) process, providing water to meet one-third of the water needs of the Royal Australian Navy’s largest naval base HMAS Stirling, which is located 3km offshore from the project site on Garden Island. Construction of the desalination plant started in November 2013 involving a total investment of approximately A$1.27m ($1.17m), which was funded under the Clean Technology Innovation Programme. Carnegie signed a cooperation agreement with the Water Corporation of Western Australia in August 2013 to provide support for the construction of the wave-powered pilot plant. The most important components of the plant are the use of Carnegie’s CETO wave energy technology for the SWRO desalination process. SWRO was chosen as it is the most feasible option technically and economically. Major components of the containerised reverse osmosis filtration facility include onshore plant building, underground storage tanks, seawater intake bore and seawater delivery pipes connecting the plant to the Australian Government Department of Defence water supply system. The project leverages Carnegie’s CETO wave energy hydraulic system infrastructure installed at PWEP. The pilot plant will be powered by hydraulic energy generated from an offshore CETO system. This CETO system operates in deep water, unaffected by storms and away from breaking waves and beach-goers. It operates in a water depth of 20m-50m and comprises a fully submerged buoyant actuator (BA) attached to a pump on the seabed. The BA moves with the currents of ocean waves causing the pump to extend and contract. The pump delivers large volumes of high-pressure water ashore through a subsea pipeline, for desalination using SWRO. CETO wave energy technology thus provides the remote islands and defence bases not only zero-emission power but also desalinated water. SWRO removes dissolved salts and impurities from ocean water. Seawater is forced through a semi-permeable membrane using a pump. Dissolved salts and impurities from the seawater are separated by the external pressure exerted on a semi-permeable membrane. Water molecules pass through the pores while salt and impurities are retained in a concentrated form. This process can be repeated more than once to reduce the percentage of rejected concentrate water. Perth-based MAK Industrial Water Solutions was awarded the manufacturing and construction contract for the pilot plant in December 2013. It provided its expertise in reverse osmosis desalination solutions to the project. Key elements of the plant, including onshore plant and process control systems, were supplied by ABB Australia.

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