Inverse magneto hydrodynamics is employed to exploit natural movement of ocean water at coastal facilities using arrays of tubes to channel the water through orthogonal magnetic fields to generate DC voltage. Each such tube houses a plurality of serially arranged hydro-voltaic cells to produce electrical energy without mechanical movement. The tubes are preferably arranged to produce improved land use efficiency as compared to other known renewable energy generating systems such as photo-voltaic and wind turbines. A pumped salt water version is also disclosed.