From: By Paul Schaefer, ENN
Published August 7, 2007 03:44 PM

Wave-powered Electricity and Desalination

Aug 6, 2007 14:54

MINNEAPOLIS, Aug. 6 -- A new technology may make it much easier to make freshwater from ocean water and generate electricity in the process.

The technology, called SEADOG is about to begin three months of tests in the Gulf of Mexico, off the Texas coast. The project is being done in cooperation with Texas A&M University Marine Engineering Technology Department.

The SEADOG Pump system can provide both abundant fresh water when combined with desalination and produce clean renewable energy when combined with a variety of turbine-driven systems.

Here's how it works. SEADOG captures ocean-wave energy from swells or waves to pump large volumes of seawater to shore-based storage or sea-based platform systems while consuming no fuel. In February 2007 the technology was ocean tested validating the results of several years of concepts and planning, demonstrating the company's wave-pump technology is a way of harvesting -- without pollution -- power from ocean waves.


"As a wave energy collector, its simplicity, apparent efficiency and effectiveness is commendable and can be placed among the best available wave energy collectors to date," said Frank Warnakulasuriya, Ph.D., assistant head of the department, Marine Engineering Technology, Texas A&M University at Galveston.

The size, configuration and pumping capacity of the pump depends on the wave regime, height and frequency. During ocean testing, a single wave-pump experienced waves between 6 inches to 8 feet and from 2,000 to 50,000 gallons of seawater per day.

Mark A. Thomas, CEO, of INRI(TM) says "Going forward, we're seeking actual ocean environments where we can place a demonstration wave-farm test field involving 9 to 200 wave pumps. If the wave pump continues to perform as well as our sea trials have shown, we believe it has the potential to be a breakthrough for global energy production." Wave farms may range from 50 to 80,000 pumps and exist in sea states from 6 inches to 80 foot seas.

How a SEADOG(TM) Pump Works:

Most wave-energy technologies involve off-shore electrical generation requiring the transmission of power to shore-based electricity grids. These technologies involve costly, complex equipment that is sensitive to corrosive seawater and has the intermittency issues similar to wind and solar. SEADOG(TM) uses a different approach with a simple pump design with few moving parts and no electronics.

To generate electricity, the SEADOG(TM) Pump ocean-wave pump captures energy from ocean swells or waves to pump seawater to a land-based holding area, where the water can be returned to the ocean through turbines, thereby producing inexpensive, renewable electricity. Preliminary estimates based on SEADOG(TM) sea trial results suggest that a 1-square-mile field of SEADOG(TM) Pumps could generate anywhere from 50 megawatts to more than 1,500 megawatts of electricity on average, depending on the wave regime, enough power to run 67,000 to more than 2,000,000 homes.

The device pumps water to shore-based storage or sea-based platform systems, and it can store salt water or desalinated fresh water in the form of potential energy to generate power on demand, even if the current wave regime during a particular period is too low to generate power.

The pump system boasts:

-- No Fuel Required: Pump operation requires no fuel or electricity and

emits zero carbon dioxide or pollution into the atmosphere.

-- No Energy Cost: SEADOG(TM) can significantly reduce desalination cost

as energy consumption represents as much as one-third of the operating cost of producing desalinated water.

-- Adaptable and Scalable: The pump is an adaptable and scalable device

that can be configured for most of the world's coastlines. A system of SEADOG(TM) Pumps can be designed to deliver the water/air volume and

head pressure needs of many applications, including meeting the

particular needs of different stages of the desalination process.

-- No Electronics or Hydraulics: The pump device contains no electrical

or hydraulic components which can be damaged by seawater and possibly

introduce pollutants to the water or air.

The lack of sufficient fresh water is a growing concern in many regions of the world and seawater desalination is increasingly essential. The state of Texas alone has more than 100 desalination plants. The world's desalination capacity is expected to double in size during the next 20 years resulting in an installed capacity of more than 10.5 billion gallons of fresh water per day. Energy consumption is significant in desalination, sometimes accounting for as much as one-third of the operating cost of desalinated water. The SEADOG(TM) Pump has the potential to make desalination less expensive and more accessible without the large-scale use of electricity, and in some cases no electricity usage at all.

According to company calculations, wave-pump technology is capable of generating an average of 755 megawatts of electrical power 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 field could generate approximately 242 megawatts. When comparing the SEADOG(TM) Pump trial off the coast of Freeport, Texas, to other energy sources, SEADOG(TM) showed 25 times more output per square mile of land used than an off-shore wind farm in South Padre, Texas; 14 times more efficient output per square mile of land used than the Pelamis wave converters in Scotland; and 6 times more efficient land use than the Itaipu Dam in Brazil.

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