h+ Magazine

A generator designed to mimic the motion of fish has the potential to transform energy production in both the developed and developing worlds.

"VIVACE" (Vortex Induced Vibrations for Aquatic Clean Energy), developed by engineers at the University of Michigan, turns potentially destructive vibrations caused by vortices in water — as well as the flow of water itself — into usable electricity. Professor Michael Bernitsas, the lead developer, claims that a fully developed VIVACE system should be able to generate power at about 5.5 cents per kilowatt-hour, a price comparable to wind and coal.

The transformative aspect of VIVACE is that it works in currents moving at under 2 knots. Existing hydrokinetic systems, capturing the energy of waves, currents, and tides, require flow speeds of 5 or 6 knots to operate efficiently, but the majority of available currents run at 3 knots or slower.

VIVACE works by oscillating a cylinder on springs between alternating vortices caused by the shape of the system in the water — the back-and-forth motion of the cylinder generates power. Although the system doesn't look much like a fish, the underlying concept comes from observations of how fish move in turbulent water.

The VIVACE system is compact, and scales well. A few cylinders would be enough to power a small village, while an array of VIVACE devices the area of a running track and about two stories high would produce enough electricity to power 100,000 homes. And because the system works slowly, VIVACE shouldn't threaten marine life.