Giant Rubber Snake 'Anaconda' Could Bring Cost of Wave Power Down
Wave Power TechnologyMost wave power devices so far, like those from Ocean Power Delivery, are made of metal and contain many hydraulic rams, hinges and articulated joints. This makes them expensive, and the more things there are to break, the higher maintenance costs will be.
Introducing the AnacondaFrancis Farley, an experimental physicist, and Rod Rainey of Atkins Oil and Gas, have invented a new device that could help bring the cost of wave power down. They call it the 'Anaconda' after the species of aquatic boas (and a cheesy movie). It's basically "a large distensible rubber tube that is closed at both ends and filled completely with water [...] designed to be anchored just below the sea’s surface, with one end facing the oncoming waves." It is meant to be cheap to produce and maintain.
Inside the tube, the bulge waves are accompanied by a periodically reversing flow. One way of extracting power from the Anaconda is to use a pair of duck-bill valves to convert this into a rectified flow past a turbine between high and low pressure reservoirs.
R&D, Prototype, FutureThe University of Southampton (UK) is starting a program of "large-scale laboratory experiments and mathematical studies" to make full-size Anacondas a reality. They are getting funding from the Engineering and Physical Sciences Research Council (EPSRC) and are collaborating with the inventors.
So far the device has only been proven at very small scale in the laboratory (hence the bathtub look of the picture above), so the next step will be to use rubber tubes that are bigger: 0.25 meters and 0.5 meters in diameter. You can see a video of it in action in a pool on the official Anaconda website.
A full-scale Anaconda would be huge. 200 meters long (656 feet), 7 meters in diameter (23 feet), and it would be deployed in the ocean at water depths of 40 to 100 meters (130 to 330 feet). Electricity production for one unit is estimated at 1 megawatt, enough to power 2,000 UK houses. The cost of that electricity is estimated at US$0.12 per kWh or less. That's still more than coal, but much better than other wave-power projects so far (though they are also improving). The first full-scale Anaconda could be tested in about 5 years.
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Anaconda Official Site