The objective of this paper is to give an introduction into ocean wave energy converters and their impact on power systems. The potential of wave energy is very large. There are a lot of different methods and systems for converting this power into electrical power, such as oscillating water columns, hinged contour devices as the Pelamis, overtopping devices as the wave dragon and the Archimedes wave swing. The main characteristics of these wave energy converters are discussed. A lot of research, development and engineering work is necessary to develop the experimental systems into reliable and cost-effective power stations. The wide variety of systems makes it difficult to say general things about power quality. However, the large variations of output power are a common problem. Whether this can be solved by using wave farms has to be investigated further.