To represent energy gathered in energy harvester, it is necessary to simulate movement of the energy harvester parts. The aim of this article is to present a new way to simulate movement of energy harvester in point of view of robotic approach. The power buoy is one of the best examples to show potentiality of modelling such mechanism as robotic chain. In the article two ways of buoy’s motion are presented. As a result it occurs that it is possible to use robots kinematic chain theory to present kinematic chain of energy harvesting system.