14 DAY TRIAL // A new source of hydro-energy lies where not many of us expected – in the dangerous grip of the oceanic or river currents. With this in mind, Michael Bernitsas, a professor at the Department of Naval Architecture and Marine Engineering from the University of Michigan, managed to conceive a machine that would take on the fish movement techniques in order to help turn the motion of the currents into electricity.
The device, called a Vortex Induced Vibrations for Aquatic Clean Energy (or VIVACE, for short), is the first of its kind, and it is able to operate at slow current velocity, which makes it best suited for any type of water in any part of the world. It is capable to operate within water environments with currents moving slower than 2 knots (about 2 miles or 3.3 km per hour), a category in which most of Earth's currents fall. By comparison, water mills and turbines require an average speed of 5 or 6 knots for efficient results.
Another positive aspect of VIVACE is that it does not rely on waves, turbines, dams, tides or the likes for functioning purposes. Instead, the one-of-a-kind hydrokinetic energy system rather depends on "vortex induced vibrations," caused by a rounded object in the flow of a fluid like air or water. "For the past 25 years, engineers – myself included – have been trying to suppress vortex induced vibrations. But now at Michigan we're doing the opposite. We enhance the vibrations and harness this powerful and destructive force in nature," explained Bernitsas, cited by Scientific Blogging.
"VIVACE copies aspects of fish technology," added the expert. "Fish curve their bodies to glide between the vortices shed by the bodies of the fish in front of them. Their muscle power alone could not propel them through the water at the speed they go, so they ride in each other's wake."
The cost expected for the energy yielded by VIVACE is supposed to be approximately 5.5 cents per kilowatt hour, while wind-generated energy costs 6.9 cents, nuclear power is set at 4.6, and solar electricity costs 16 to 48 cents per kilowatt hour. "There won't be one solution for the world's energy needs," shared Bernitsas. "But if we could harness 0.1 percent of the energy in the ocean, we could support the energy needs of 15 billion people."