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Vivace (energy created by vortex induced vibrations) development.
Energy from vibrations can be destructive and are engineered out of designs, structures etc. Failure to do so resulted in the collapse of the 1800 m long Tacoma Narrows Road Bridge in Nov 1940 where the whole bridge was set into torsional vibrations. The energy to set up these destructive forces was induced from wind blowing across the bridge which produced vortices setting the bridge into a twisting motion. Another example of wind induced vibrations was the collapse of the Ferrybridge UK cooling towers in 1965.
Prof. Michael Bernitsas at the university of Michigan is developing a Hydro Kinetic Energy System which uses vortices in the water current (moving at 1 to 3 mph) flowing across cylindrical tubes to cause them to vibrate vertically on springs creating energy harnessed to generate electrical power. The system would be located on the river or sea bed.
The prototype for the Detroit River field test has 8 cylinders, 25 cm dia and 2 m long (ref 202.)
The future projected cost of 5 cents/kw hr is competitive with nuclear or wind power. The electrical power density could however be higher than for wave, tidal or wind turbine farms and of course it would have a high load factor or be continuous, not requiring so much diversity and energy storage capacity systems attached to the transmission grid.