"If we could harness 0.1 percent of the energy in the ocean," says Professor Michael Bernitsas of the University of Michigan, "we could support the energy needs of 15 billion people."
With that goal in mind, Bernitsas has developed a novel approach to water-based power that takes its inspiration from the movements of fish to generate electricity.
Most water-based power sources (like turbines) require fast-moving water to accomplish electricity generation. But while a turbine requires water currents of 5-6 knots, most of the world's water moves at a much slower pace: 2-3 knots.
Bernitsas felt those slower currents could still do the job, so he designed the Vortex Induced Vibrations for Aquatic Clean Energy (VIVACE) machine to tap into minor fluctuations and vibrations in the water to generate power. The technology behind VIVACE copies aspects of fish movement, says Bernitsas. "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 others' wake."
If it works on a large scale, Bernitsas says VIVACE energy would cost about 5.5 cents per kilowatt hour -- well below the cost of even wind power -- without having an impact on marine life.
Bernitsas details his work and his prototype in the current issue of the Journal of Offshore Mechanics and Arctic Engineering.