The use of renewable energy is growing significantly around the world. In front of the growing demand for electricity essentially for the remote and deserted locations needs. Photovoltaic systems, especially water pumping systems, begin to find great applications. Unfortunately these systems have encountered a number of problems even nowadays: a problem of maintenance. Various modeling techniques are developed by researchers to model components of renewable energy systems. Performance of individual component is either modeled by deterministic or probabilistic approaches; in this book we propose the graphical methods (bond graph) for modeling, fault detection and isolation of energy production systems. This book can be interesting to readers looking for a deeper knowledge in MPPT tracking or those looking for an introduction to PV power generation, because it includes a review of the general concepts related to PV power generation.