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Monitoring tripod  (Source: University of Washington)
Two new tidal turbines will be placed on the U.S. west coast for the first time

Researchers at the University of Washington will be measuring the environmental effects of tidal turbines through the first tidal energy project on the west coast of the United States. 

The researchers involved in the project are Brian Polagye, a research assistant professor of mechanical engineering at the University of Washington; Chris Bassett, a University of Washington doctoral student in mechanical engineering; Jim Thomson, assistant professor of civil and environmental engineering and oceanographer at the University of Washington's Applied Physics Laboratory, and an extended team of researchers. Together, they will assess tidal turbines' environmental effects through a demonstration project that will consist of large-scale tidal turbines being used on the west coast for the first time. 

Tidal power is a viable alternative energy option that is used in Europe more than the United States at this point. Despite this head start, Polagye says Europe is not that far ahead of the U.S. because they lack the environmental monitoring that this particular project will have. Little is known about tidal power today, and the University of Washington team plan on changing that.

"There really isn't that much information, anywhere, about the environmental effects of tidal turbines," said Polagye. "The results of this pilot project will help decide if this is an industry that has potential for going forward at the commercial scale, or if it stops at the pilot stage."

The tidal demonstration project will consist of two 30-foot-wide turbines located in Admiralty Inlet, which is a gateway to Puget Sound. The U.S. Department of Energy gave the Snohomish County Public Utility District a $10 million grant for this tidal project. They are now in the process of obtaining permits.

The turbines are expected to generate 100 kilowatts of electricity, which has the ability to power 50-100 homes in Washington "during the pilot phase." University of Washington researchers have been in a pilot site approximately 200 feet below the Admiralty Inlet's surface measuring the speed of these waters in order to get an idea of what they will be dealing with. So far, they have measured currents that are up to 8 knots, which is equivalent to 9 miles per hour.

Researchers have been measuring the currents for approximately two years through the use of a monitoring tripod. It is 850 pounds in the water, and is capable of tracking ambient noise, water quality, temperature, salinity and currents. It also records communication between marine creatures. The monitoring tripod has helped researchers learn more about the environment in which the turbines will be placed.

"There's surprisingly little known about the oceanography of these very fast waters," said Thomson. "These kinds of tidal channels where water is going very fast only happen in a few areas, and have not been well studied. The currents are so fast that it's hard to operate vehicles and maintain equipment. And it's too deep for conventional scuba diving."

One of the major concerns regarding this project is the amount of noise the turbines will make, since this could affect marine life, which use sound to communicate. To further investigate the processes and effects of this new technology, researchers used the sound of a Washington state ferry to test how sound travels and spreads through the waters. 

"When currents were more than about 2 knots the instruments are hearing considerable self-noise," said Polagye. "It's similar to when you're bicycling downhill and the air rushes past your ears."

As it turns out, the Admiralty Inlet lessens sound, making it so that the animals' hearing cannot be harmed. On the other hand, not hearing the sounds make it so they cannot avoid the turbines.

Despite this current concern, researchers feel that the Admiralty Inlet is a great spot for tidal power "from an engineering perspective." The turbines should be installed by 2013, and the environmental effects will be closely monitored.

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RE: I guarantee you...
By Solandri on 12/15/2010 3:03:55 AM , Rating: 2
Agreed that there's no sense making fun of studying this stuff. However:
There is a ton of energy in flowing water,just look at hydro electric. Dams built 60 years ago are still giving us tons of juice and guess how long ago their construction costs were paid for.

The energy from hydroelectric comes almost entirely from water dropping in altitude - i.e. gravitational potential energy - not from it flowing.

A cubic meter of water moving 10 km/hr, which is a really strong current, nearly twice as fast as the Gulf Stream, only has a kinetic energy of 3858 Joules. That is, if your tidal turbine managed to extract all the energy in the moving water and stopped it cold, it would extract 3858 J.

For comparison lowering a cubic meter of water just 1 meter in altitude yields 9800 J.

Or to put it another way, the hydraulic head of Hoover Dam (vertical distance from the top of the water to the turbines) is 180m. So each cubic meter of water going through its turbines carries with it 1.764 MJ. To match that energy output from a cubic meter of flowing water, the water would have to be flowing at 214 km/hr, or 133 mph.

The limited vertical displacement of tides in most locales (tides average about 2 meters) puts a rather low cap on how much energy you can extract from them. True, you do get a much larger volume of water than a typical dam gets. But that also means you have to run that much larger volume through a turbine in order to extract the energy. Extracting tidal energy is nowhere near as effective as using hydroelectric dams.

RE: I guarantee you...
By Paj on 12/15/2010 5:50:18 AM , Rating: 2
What about wave power?

Theres a pilot project running of the coast of Western Australia called CETO that, in essence, uses a series of flotation devices attached to generators that are mechanically quite simple and work on the vertical motion of waves. Results so far have been very promising and a commercial scale plant is up and running at the moment.

As I understand, waves are generally more dependable, regular and energetic than tides are. If this is viable at much larger scales then it could be the perfect power solution for Australia, with soo many living by the coast. It could be applied to much of the US too I imagine, as well as the Middle East.

Another advantage of this approach is that the process can also be used to desalinate water (very important in Western Australia - Perth currently has 2 desal plants in operation that consume a ferocious amount of energy).

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