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Published on October 16th, 2009 | by Tina Casey


Renew Blue Uses Ocean to Desalinate Itself

October 16th, 2009 by  

Ocean waves will power a new desalination plant in Texas.In an elegant piece of sustainable engineering, the company Renew Blue, Inc. will use wave power to run a desalination plant in Freeport, Texas, then bottle the results in corn-based biodegradable plastic for sale under the Renew Blue brand.  The wave power system, called SEADOG, will employ a buoy-and-piston mechanism combined with a water wheel to generate electricity at an offshore platform, enough to power operations at the plant.


Though disposable bottled water is a thorn in the side of sustainability, the reality is that disposable bottles will be with us, at least for some limited uses, far into the foreseeable future.  The Renew Blue solution offers a way to provide the convenience with a lower carbon footprint.

Renew Blue and the SEADOG Pump

Renew Blue is a subsidiary of Independent Natural Resources, Inc. (INRI), a Minnesota company that owns the rights to SEADOG.  Unlike conventional pumps that require a fuel source, SEADOG is a proprietary wave-powered technology based on an air-filled buoyancy block within a cylindrical chamber.  The chamber stays relatively stationary while the block rises and falls with the waves.  In turn, the motion of the block moves a piston within a cylinder, drawing in and expelling water with every stroke.  According to INRI, the system has been performance-tested at the Texas A&M University Offshore Technology Research Center, the same facility used by the energy industry.  At a trial in the Gulf of Mexico, modest waves ranging from only six inches to six feet created enough movement to allow the SEADOG pump to lift water approximately 110 to 125 feet.

SEADOG and Desalination

According to Houston Chronicle writer Tom Fowler, 18 of the SEADOG pumps will be deployed at a platform off the coast of Freeport, Texas.  The system will deliver up to 60 kilowatts of electricity and the desalination equipment only requires about 4 kilowatts for its 3,000 gallon-per-day operation, so even allowing for electricity to light the platform there will be a more than adequate supply. Considering the system’s zero-emission technology, scalability, and minimalist construction and design specifications, INRI is optimistic about the potential for SEADOG to be adapted to a variety of sites worldwide.

Wave Power and the Modular Advantage

Given the upredictibility of the ocean environment, one attractive aspect of the SEADOG is its reliance on relatively small, separate modules instead of a single integrated system.  When one module breaks down or requires maintenance, the others continue to operate.  In this regard SEADOG is similar in concept to another modestly scaled wave power system developed by Swell Fuel, which generates electricity directly from a buoy-based wave power module and can put itself into a “safety” position when conditions are extreme.

Drinking Our Way Out of Rising Sea Levels

Desalination is rapidly emerging as one solution to the globe’s impending (and in some areas, omnipresent) water shortage.  Up to now, the high energy demands of conventional desalination equipment have mitigated against mass-scale desalination, but SEADOG and other new wave power systems are pointing a way around that problem, and more wave power development funding is starting to flow  In addition, new desalination technology that uses significantly less energy is starting to enter mainstream usage, the U.S. Navy being one example.

Image: mrhayata on flickr.com. 

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About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.

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