Harnessing the current: An artist's rendition of how a commercial VIVACE system might look. Passive bars, positioned horizontally, are boxed together in a single unit that could be placed at the bottom of a river or in the path of an ocean current. Dozens of 500-kilowatt units could be grouped together in different configurations to create multimegawatt systems.
Credit: Vortex Hydro Energy
The world's river and ocean currents carry an enormous amount of kinetic energy, but most of this water flows slower than four miles per hour. Existing turbine and water-mill technologies can't generate enough electricity at such speeds to make their deployment economically viable.
Researchers at the University of Michigan say that they have overcome this limitation by taking advantage of energy-packed vortices that are formed when water flows past a cylindrical object, even at low speeds. Salmon and trout are known to leverage the force created by these naturally occurring water swirls so that they can swim upstream. A new mechanical device designed to economically harvest that energy and convert it into electricity could turn waterpower into a much larger part of the world's renewable-energy mix.
"Anywhere we have currents, we can use it," says Michael Bernitsas, a professor in the department of marine engineering at the University of Michigan. He says that the first test of the device will be in the Detroit River, likely in 2010. "If we make it work, and I believe it will, it's going to be a major development," he says. READ MORE »