Michele Kearney's Nuclear Wire: TCASE 9: Ocean power II

Sunday, July 24, 2011

TCASE 9: Ocean power II – CETO

Posted on 11 April 2010 by Barry Brook

In TCASE (thinking critically about sustainable energy) #5, I analysed a currently deployed technology for harnessing wave energy – the Pelamis device. If you haven’t read TCASE 5 then please do so now, since it explains some of the basic physical properties of wave energy, the extend of the global resource, etc. In writing the following post, I’ll consider this to be assumed knowledge.
CETO, named after a Greek sea goddess, has been developed by Carnegie Wave Energy (an Australian company), and is described in detail on their website. It is based on a submerged, underwater buoy-like device, anchored to the sea floor, which pumps water to shore at high pressure (6,400 kPa). Read more about the technology here.
The list of advantages of CETO on the website are worth citing here, as they provide a useful target for analysis. Main ones are:

60% of the world live within 60km (40 miles) of a coast, removing transmission issues.

Waves are predictable days in advance making it easy to match supply and demand. (Wind is predictable hours in advance at best.)

CETO units are designed to operate in harmony with the waves rather than attempting to resist them. This means there is no need for massive steel and concrete structures to be built.

CETO wave farms will have no impact on popular surfing sites as breaking waves equate to areas of energy loss. CETO wave farms will operate in water deeper than 15 metres in areas where there are no breaking waves.

CETO is the only wave energy technology that produces fresh water directly from seawater by magnifying the pressure variations in ocean waves.

CETO contains no oils, lubricants, or offshore electrical components. CETO is built from components with a known subsea life of over 30 years.

Wave energy can be harnessed for permanent base load power and for fresh water desalination. The ratio of electrical generation to fresh water production can be quickly varied from 100% to 0% allowing for rapid variations in power demand.

CETO uses a great multiplicity of identical units each of which can be mass produced and containerised for shipping to anywhere in the world.