Published on November 24th, 2008 | by Ariel Schwartz4
"Fish" Machine Turns Ocean Vibrations into Energy
Tidal power is already on its way to becoming a viable energy source, but a University of Michigan engineer believes that slow-moving ocean and river currents could also be renewable energy providers.
The VIVACE (Vortex Induced Vibrations for Aquatic Clean Energy) machine is the first device that can harness water moving slower than 2 knots — a notable ability since most water currents move slower than 3 knots. In contrast, turbines and water mills need 5 to 6 knots to operate.
VIVACE relies on vortex induced vibrations, or undulations that a rounded object makes in a flow of fluid. The kinks in the current’s speed caused by the object’s presence causes eddies (vortices) to form on the opposite side of the object. The vortices then push or pull the object perpendicular to the current.
According to developer Michael Bernitsas, VIVACE copies the natural movements of fish, which curve their bodies to glide between vortices created by the fish in front of them. While the current version of VIVACE is a cylinder attached to springs, future versions will have a fish-like tail and scales.
Bernitsas believes that the machine’s energy will cost about 5.5 cents per KWh—less than both wind and solar power. The VIVACE pilot project will be deployed in the Detroit River within the next 18 months, and hopefully we’ll see a commercialized version of the machine soon after.
Photo Credit: NREL