It sits along the bottom of a river, ocean, waterway and as currents pass over it it forces the rods to move thus producing Hydro-kinetic power. Below are a couple websites I found describing the system and the research going into it. This systems would easily be installed in the bottom of the river without having to to do any demolition other than digging a line for the cable to get back to the building. And if this system works it could be something implemented all along the river system helping to offset electric costs to the area.
http://www.engin.umich.edu/dept/name/facilities/mhl/facilities/renewable_energy.html
http://www.vortexhydroenergy.com/