Water currents cause vibrations in stationary cylinders. Dr. Andrei Metrikine wants to use this phenomenon to harvest energy from slow water currents.
At a lunch lecture of the Ocean Energy steering group, Professor Andrei Metrikine from the Faculty of Civil Engineering and Geo Sciences, introduced a new and fairly unknown form of wet energy called Vortex Induced Vibration or VIV. A stationary cylinder is placed in a current and the cylinder will then start to vibrate at a stable frequency. When the vibrating horizontal cylinders move magnet rings along coils they generate electricity.
The Vivace system designed by the University of Michigan has used this principle in a pilot to harvest energy from river streams. The system, they said, would be especially suited for low-speed streams at walking velocities.
In the Netherlands, Tauw consultancy organised a test of the Vivace system in the summer of 2012. The prototype was in the water for about a month before the test was aborted. There was too much debris in the water which caused the system to get stuck. Also, the efficiency (the share of the kinetic energy harvested as electric energy) was lower than promised according to spokesman Barry Meddeler at Tauw. "It was not a success", he said.
Metrikine wants to develop a more advanced version of the system. Without wanting to reveal too much detail, he did say the new vortex energy system would have no moving parts underwater and it would work with cantilevers rather than bobbing cylinders and possibly from a floating platform.
Peter Scheijgrond, an independent consultant on ocean energy, commented that Metrikine would have to prove that his system would be more efficient and less expensive than rotary systems such as the Bluetec platform that is currently in a field test. Otherwise, vortex energy doesn't stand a chance.