Sea-bed generator rides renewables wave

THE Australian-designed CETO wave power generator prototype is aimed at leading to the development of a renewable energy system many times more powerful and efficient than wind or solar power.
Sea-bed generator rides renewables wave Sea-bed generator rides renewables wave Sea-bed generator rides renewables wave Sea-bed generator rides renewables wave Sea-bed generator rides renewables wave

The CETO prototype was launched yesterday at the Australian Marine Complex, Henderson, Western Australia. It will be towed to a site about 150m off the shore of North Fremantle and sunk in about seven metres of water.

Unlike previous types of wave power generators, CETO sits on the seabed rather than being floating or semi-submersible. This means it can’t be seen from the shore and makes it safe from storms and ocean forces.

As a wave moves over the top of the CETO unit, it is enhanced. The wave crest depresses a disk and the force is transmitted to reciprocating pumps which deliver water at 7000kpa (1000psi).

The high-pressure seawater comes ashore in a 125mm pipe, which multiplies the pressure, to a turbine to produce electricity. It can also pass through a reverse osmosis filter to produce fresh water.

While other wave energy technologies require undersea grids and costly marine qualified plant, CETO requires only a small diameter pipe to carry high pressure seawater ashore to either a turbine or a reverse osmosis filter, and CETO can be employed in any location that geographical and wave conditions permit, according to the unit’s inventor, Hardman chairman Alan Burns.

“Wave energy may be one of the lowest cost renewable energy sources because of its high power density,” Burns said.

“Today we have significant power and fresh water problems and this system offers a significant solution to those challenges. Western Australia has one of the world’s great wave energy regimes, as local surfers know. Within the next year or so this unit will provide much of the information we need in order to harness this energy.”

Burns and Renewable Energy Holdings, which owns the intellectual property, have a five-year plan to refine and commercialise the system. They envisage arrays of units on the sea floor producing electricity and fresh water inexpensively and with little environmental impact.

Burns, said the first task in the testing phase would be to pump seawater ashore at 7000kpa (1000psi). This would determine the size of the turbine installed on shore to generate electricity, currently expected to be up to 100 kilowatts for this prototype, enough power for 100 homes.

CETO has dual capability to produce power or fresh water and in desalination mode the prototype is expected to produce about 300,000 litres of fresh water per day.

Burns said CETO's efficiency was expected to be the major advantage over other wave energy prototypes that were generating electricity offshore but experiencing substantial energy loss in piping it to land. CETO simply delivers very high pressure seawater ashore in a 125mm pipe to either a turbine or filter.

The prototype will connect to a small onshore plant in the port area of North Fremantle. A small garden around the plant will be watered by the desalinised water and the electricity will be sold into the grid, Burns told EnergyReview.net.

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