Solutions to today energy challenges need to be explored through alternative, renewable and clean energy sources to enable a diverse energy resource plan. An extremely abundant and promising source of energy exists in oceans. Ocean energy exists in many forms. Among these forms, significant opportunities and benefits have been identified in the area of ocean wave energy extraction, i.e., harnessing the wave motions and converting them into electrical energy. Regarding this emerging and promising area of research, this paper presents ocean wave energy fundamentals and then reviews the fundamental concepts and the main projects around the world. It also reports issues regarding electrical generator topologies associated to wave energy converters.