Independent Natural Resources Inc's. ( INRITM) SEADOGTM wave pump is a form of wave power that has been around for a while that I hadn't heard of. It seems to me to have several advantages over other forms of wave power, being simpler than most, consuming no external power and having no electrical cables connecting it to the shore.
The SEADOGTM pump captures ocean-wave energy to pump large volumes of seawater, consuming no fuel or electricity. The pump uses buoyancy to convert wave energy to mechanical energy. The main components of the pump include a buoyancy chamber (the lower cage in the picture, buoyancy block (yellow object), piston assembly (center of upper chamber), 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.
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 (into the air in the picture). Each cycle of the buoyancy block rising and falling, drawing in and expelling water, is called a stroke. Each stroke of the piston causes the water to be pumped from the piston cylinder in a regular manner.
A prototype SEADOG unit has been successfully tested in the Gulf of Mexico off the coast of Freeport, TX for the past year, where INRI says it exceeded expectations for performance and durability. The pump stands 35 feet high and weighs 17,200 pounds. During the gulf trial the pump encountered modest waves ranging in height from 6” to 6 feet and consistently pumped 12 – 18 gallons of seawater per minute with a head pressure of approximately 110 to 125 feet.
From a Feb. 2007 press release:
To create hydroelectricity, the SEADOG ocean-wave pump captures energy from ocean swells or waves to pump seawater to a land-based holding area or water tower, where the water can be returned to the ocean through hydroelectric turbines, thereby producing inexpensive, renewable electricity.
According to INRI's calculations, the company's wave-pump technology is capable of generating an average of 755 megawatts of hydroelectric energy for every 1 square mile pump field, assuming ocean swells averaging at least 9 feet. With swells of at least 5 feet, a 1 square mile pump field could generate approximately 242 megawatts.
According to AnalogZONE
INRI is currently constructing a scaled-up version which will be tested in the more challenging environment off the rugged coast of Northern California; in the Table Bluff area of Humboldt County. If the prototype SEADOG survives its one-year ordeal intact, plans call for a small-scale 16-pump pilot wave farm which will be used to fill a 50,000 gallon storage tank attached to a hydroelectric generator. If the $3 million phase-I trial is able to reliably deliver the 500+ kW (enough to light around 600 homes) INRI hopes to expand the project to a 200-pump 6.7 MW system that would produce power at a cost of around 3.5 cents/kW-hr, a price that approaches typical wholesale rates for fossil-generated power.
SEADOGTM Pump Benefits
- Pump operation requires no fuel or electricity and introduces zero carbon dioxide into the atmosphere.
- The pump is an adaptable device that can be scaled and configured for most of the world’s shorelines.
- Pump design and construction is simple and utilizes materials that are readily available almost anywhere. Pump manufacturing is well suited for job creation in the region of deployment.
- The pump device contains no electrical or hydraulic components which can be damaged by seawater and possibly introduce pollutants to the water or air.
- An installed and operating pump system (array of pumps) will continue to function if one or more pumps are shut down for maintenance.
Benefits in Hydroelectricity Generation
- Unlike most other renewable energy sources SEADOGTM pumps used in hydroelectricity generation can be a base-load (primary) source of power, drawing from the water holding area when it is needed to match demand.
- Once appropriate approvals are secured a system (array) of SEADOGTM pumps can be deployed very rapidly, with power generation coming on-line in stages.
- Preliminary data from SEADOGTM pump lab and field studies suggests that SEADOGTM pump system has the potential to be cost competitive with any other form of base-load power generation.
Thanks to the Mendo Coast Current for the tip.