Piezoelectric electrical generators comprise cantilevered beams of piezoelectric material, cross sections of the beams preferably being triangular and of increasing area from free end to fixed end. Arrays of spaced apart beams are disposed in overlapping, interdigitated relationships with arrays of cams, and the cam arrays are moved relative to the beam arrays for causing engagement and deflection of the beams by the cams for the generation of electrical energy. One system comprises a raft floating on the surface of an ocean. Cam arrays are suspended from the raft for interaction with vertically extending beam arrays mounted on the ocean floor beneath the raft. Relative vertical movements are caused by passing surface waves. In another system, beam arrays are suspended from an above surface structure, e.g., an oil drilling ocean platform, and the beam arrays extend towards and interact with cam arrays mounted on the upper surface of a floating raft.