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Wave Power to Run Desal Plant

Houston Chronicle. A small Texas company, Renew Blue, will use 18 ocean Seadog pumps from parent Independent Natural Resources Inc. (INRI) to generate electricity to run a 3,000 gallon per day desalination plant. The Seadog is a point absorber wave energy device that uses pressurized hydraulics for power takeoff; the pressurized water drives a turbine.

Early sketch of the Renew Blue project, with the turbine and desalination plant onshore. Source: INRI. Click to enlarge.

The 18 Seadog pumps in the project off Freeport will be able to generate up to 60 kilowatts of electricity, depending on wave size. The desalination equipment only requires about 4 kilowatts, leaving power to run lighting on the platform, said Sandberg.

Renew Blue has a lease from the state of Texas to place the facility in 25 feet of water about a mile off the coast from Freeport.

The desalinated water will be stored in a 30,000-gallon tank on the platform and then transported to shore, where it will be put in bottles made from corn-based plastic and marketed under the Renew Blue brand.

The Seadog pump. The Seadog Pump, which is seated on the ocean floor, uses buoyancy to convert wave energy to mechanical energy. The main components of the pump include a buoyancy chamber, buoyancy block, piston assembly, piston shaft, piston cylinder, and intake and exhaust valves. When positioned in the water the buoyancy block (filled with air) floats within the buoyancy chamber, moving up and down in relation to the ocean waves and swells. The buoyancy block is connected to the piston shaft which in-turn moves the piston assembly through the piston cylinder.

Loading the Seadog pump for trials in the Gulf of Mexico. Source: INRI. Click to enlarge.

As the buoyancy block moves down in the trough of a wave it draws the piston downward through the piston cylinder. The downward movement draws water into the piston cylinder through the intake valve filling the piston cylinder chamber. As the next wave lifts the buoyancy block the water within the piston cylinder is under pressure and is expelled through the exhaust valve. Each stroke of the piston causes the water to be pumped from the piston cylinder in a regular manner.

INRI has performed prototype performance testing in its internal development lab, in the Texas A&M Offshore Technology Research Center’s wave tank, and most recently, in actual ocean trials conducted off the coast of Freeport, TX.




This could work as long as everyone is okay with the discharge of "brine", the environmental impacts of which are ignored in the article. Tampa Bay Water has a significant desal operation discharging "concentrated seawater" into Tampa Bay at such diluted concentrations that they aren't getting any readings above natural background salinity levels. If they can do the same here, I'd say go for it.


Running electric desalinization off of wave generated electricity is like running electric AC off of PV. You can cool your house using solar thermal powered absorption cooling and you could desalinate sea water using concentrated solar thermal. That way, you get electricity and clean water.

You can pump the water up to elevation using sea wave pumps and generate pumped hydro on the way down. What water you retain can go into the solar thermal distiller and the generated electricity can run the plant and the surrounding communities.


Wow, fantastic, there is more energy avail than needed.
South Australia and the west coast are investigating the wave energy options.

We have a delicate salinity issue in S.A. Spencer gulf relating to very sensitive cuttlefish spawning grounds. This is the one place in the world any cuttlefish aggregations occours.
Also clean green southern ocean tuna farmers are not happy.
The desal water is for Roxby uranium mines.


Due to the short lifecycle other factors etc we know the xtra saline will prevent breeding. We know the specie will be extinct after one lost spawning year.

We also can confidently say it wont happen. The biggest Uranium mine in the world with a GDP the size of S.A.
(and a slightly larger carbon footprint) should stop wasting their money on this one.


Removing desal water @ 3 000 gal/day from the Gulf will certainly not affect the natural ocean salt level. Even 1000+ times that much would not be significant. Natural evaporation does 1 000 000 + times as much.

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