August 15, 2007 4:00 AM PDT
An artist's rendering of the Archimedes Water Swing from AWS Ocean Energy, based in Scotland. Unlike the Finavera devices, these are completely submerged. While the water swing might be more aesthetically appealing, ships still have to watch out for it, and it could pose dangers to marine animals. The device uses air (rather than seawater) to create hydraulic pressure. Prototypes are scheduled to be deployed in U.K. waters over next few years. Each buoy is expected to generate 500 kilowatts of power.
Photo by AWS Ocean Energy
