In Greek mythology, Ceto was a sea goddess. Ceto was a daughter of Gaia and Pontus, and she personified the power of the sea.
In a current incarnation, CETO is the name of a wave power technology that uses air-filled buoys that float in the sea. As the waves go up and down, the buoys pull pistons up and down inside underwater pipes, pushing the seawater onshore. The buoys are fully submerged and permanently anchored to the sea floor, so they don't spoil the seascape.
CETO units are manufactured from steel and rubber. The buoys are like bladders, they are made from hypalon. CETO components have a known subsea life of over 30 years. No new technology needs to be developed and all such components are relatively cheap and simple to manufacture, without making countries dependent on imports of scarce resources.
Another advantage of this technology is that it can deliver a relatively steady supply of electricity, at times when there is little or no wind or sunshine.
The electricity thus generated can be sent either to the grid, or used for other purposes such as desalination. Up to 100% of the electricity can go into the grid during periods of peak demand on the grid, while desalination can take place during periods when there's little or no demand for more electricity on the grid.
Australian company Carnegie Corporation plans to build a CETO wave farm on Garden Island, off the coast of Perth, Australia. Managing Director Mike Ottaviano says: "We'll generate electricity at around about the cost of a wind farm." The plans include installation of a Pelton Turbine, supplied by Swiss company Calder AG, and a Desalination Plant, supplied by Australian company Citor Pty Ltd.
Since 60% of the world's population lives within 40 miles (about 60 km) of the sea, the electricity and water can thus be produced where they are consumed. There no need to first build pipelines from dams to cities. Nor is there a need to first build high voltage direct current (HVDC) lines. Electricity from wind farms and solar concentrators often needs to be brought to cities over HVDC lines. There's little or no need to expand the electric grid or to upgrade the water distribution network. This technology can replace coal-fired power plants and secure water supply relatively swiftly, easily and without much extra cost.
While wave power levels may differ from place to place (see image below), the potential for wave power clearly is huge, especially when combined with applications such as water desalination. CETO can operate efficiently in swell in the 1 to 2 meter wave height range, greatly increasing the number of potential base-load sites globally. For example, much of Southern Australia receives significant wave heights in excess of 1 meter 100% of the time.
References:
Hypalon - Dupont
Pelton Turbines - Calder
CETO - Carnegy
Funds put firm on crest of bid to make wave power - the Australian
Average annual wave power levels - World Energy Council
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Comments: 13
I just read your article Four Cycles of a Sustainable Economy, Sam, and this is excellent illustration of what you are saying there.
Col. underlines the fact that technologies like this are not new. I would agree that the economic stimulus bill should specify incentives for development and deployment of renewable energy projects, such as this.
Perhaps you (and others) will write the new administration to that effect.
Thanks, Steve. I just published my Open Letter warning President Obama about a Global Cap-and-Trade Scheme and I did submit a link at the White House contact page.
Further, every transformation "device" employed also requires both a capital investment and ongoing maintenance.
In the case of the hydraulic turbine, very little of the hydraulic head available in the waves could be recovered as work from the process (well under half, overall)
Instead of employing all these exergy consuming steps, why not use the seawater directly in food production techniques described at http://www.seawatergreenhouse.com
If food can be produced economically at the seashore, how much "advertising" could it possibly take to convince people to abandon congested cities for a life near the sea, at least in tropical areas?
There are many different ways to extract energy from the sea, including tidal energy, wave energy and what is sometimes referred to as blue energy - mixing salty water with fresh water. Recently, there was an article in New Scientist on the latter.
Similarly, there are different desalination methods. Most desalination plants use reverse osmosis, pressure or heat to remove salt from seawater. In June 2006, MIT Technology Review discussed a water desalination system using carbon nanotube-based membranes, developed by researchers at Lawrence Livermore National Laboratory, that could reduce the cost of desalination by 75%.
In July 2007, the Singapore Government offered S$4 million worth of research funds to a desalination proposal that consumed 1.5 kilowatt-hour (kWh) energy or less per cubic metre of potable water produced from seawater. Almost one year later, a team of Siemens researchers won the challenge with a proposal to remove salt from seawater by using a novel electricity-based method that includes electrodialysis and ion exchange.
My article Four Cycles of a Sustainable Economy contains a link to that method, explaining how surplus energy could be used for desalination.
When taken in isolation, such methods may at first glance seem expensive, but when seen as complementary and as part of cycles, the cost can drop dramatically. Moreover, when the pollution and environmental harm of other methods is taken into account, those new methods can be more than price-competitive, compared to conventional methods. The above article illustrates this by combining wave power with desalination.