For Swedish waters, which have relatively small waves, powers of 10 kW per unit are suitable. For bigger waves, like the ones off the coast of Norway

http://www.el.angstrom.uu.se/forskningsprojekt/WavePower/Lysekilsprojektet_E.html

Calculations show that for a unit, like the one above, to give 10 kW power, one needs a linear generator with a stroke length of about 2m. The unit's total weight will be about 20 ton, the bulk of that being the foundation. For Swedish waters, which have relatively small waves, powers of 10 kW per unit are suitable. For bigger waves, like the ones off the coast of Norway or Scotland , bigger units with powers of 100 kW or higher are more advantageous.