New technology could transform slow-moving ocean and river currents into a reliable and affordable alternative energy source by harnessing natural vibrations.

A University of Michigan engineer invented a machine that and turns potentially destructive vibrations into clean, renewable power.

The machine is called VIVACE, which stands for Vortex Induced Vibrations Aquatic Clean Energy. The design is based on the extensively studied phenomenon of vortex induced vibrations -- first observed over 500 years ago by Leonardo DaVinci.

DaVinci referred to the vibrations as "Aeolian Tones," and the phenomenon has a rather dark history. For decades, engineers have tried to prevent these vibrations from damaging offshore equipment and structures.

These types of vibrations in the wind toppled the Tacoma Narrows Bridge in 1940, and caused the Ferrybridge power station cooling towers in England to fall in 1965.

"For the past 25 years, engineers -- myself included -- have been trying to suppress vortex induced vibrations," said VIVACE developer Michael Bernitsas, a professor in the university's Department of Naval Architecture and Marine Engineering.

Now, Bernitsas said they are doing just the opposite.

"We enhance the vibrations and harness this powerful and destructive force in nature," he said.

The device was developed after studying fish, which have used the vibrations to their benefit for years.

"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 each other's wake," Bernitsas said.

Although the current model looks nothing like a fish, Bernitsas said future versions will have the equivalent of a tail -- even the surface texture of scales.

This generation of the machine has a cylinder that hangs horizontally across the flow of water. The presence of the cylinder causes alternating vortices to form above and below it, and they push the passive cylinder up and down and create mechanical energy which is then converted into electricity.

Just a few cylinders might be enough to power an anchored ship or a lighthouse, Bernitsas said. They can be stacked like a ladder, rest on a river bed, or be suspended under the surface of the water.

Bernitsas estimated that a running-track array of VIVACE converters about two stories high could power about 100,000 homes.

Perhaps best of all, because the machine moves slowly, developers do not think the system would harm marine life like dams or water turbines.

VIVACE is the first device of its kind because it can works in flows moving slower than 2 knots, or about 2 mph. Most of the Earth's currents are slower than 3 knots, allowing it to harness energy from most water currents around the globe. Wind turbines and water mills require an average of 5 or 6 knots to be efficient.

In terms of cost, Bernitsas said VIVACE energy would run at about 5.5 cents per kilowatt hour -- almost as efficient as nuclear energy, which costs 4.6. Wind power costs 6.9 cents per kilowatt hour and solar costs anywhere between 16 and 48 cents, depending on location.

"There won't be one solution for the world's energy needs, but if we could harness 0.1 percent of the energy in the ocean, we could support the energy needs of 15 billion people," Bernitsas said.

Researchers recently completed a feasibility study that found the device could draw power from the Detroit River, and are working to deploy a pilot project there within the next 18 months.

A handful of institutions and government organizations have supported the development of this technology, including The U.S. Department of Energy, the Office of Naval Research, the National Science Foundation and the Michigan Universities Commercialization Initiative. The technology is being commercialized through Bernitsas' company, Vortex Hydro Energy.

More information and video of the machine in action can be found on the company's Web site at VortexHydroEnergy.com