River current turbines are electromechanical energy converters that harness kinetic energy of a stream of flowing river water to generate electricity. Research in this domain is limited and various concepts are emerging only recently. In this paper, an extensive technology survey and comparison of various system options are discussed in order to formulate a basis for further analysis. Simplified mathematical modeling of an augmentation device and Darrieus type rotor has been carried out. Simulations are done in Matlab and results are given with graphical interpretations. In conclusion, directions for further investigation are given and the potential of this technology is re-stressed.