some food for thought...
http://www.physorg.com/news156596965.html
excerpt:
In the proposal, physicist Roberto De Luca from the University of Salerno in Italy has suggested that flowing salt water could generate an electromotive force, which in turn could generate an electric power output. In his theoretical analysis, he considers letting salt water (containing sodium and chlorine ions) run through a rectangular pipe that has two metal electrodes on the sides, under the influence of a perpendicular magnetic field. In this set-up, the Lorentz force acts on the sodium and chlorine ions in the salt water, creating a Faraday voltage across the two electrodes, and producing an electromotive force.