The smart grid is a complex system consisting of interdependent power grid and information and communication (ICT) components. Complex systems have different properties than simple networks and give raise to new risks and failure types. In this paper, we study the dependencies in smart grid and the influence ICT may have on the dependability. We start with giving a categorization of the smart grid components and define state machines for these categories and for smart grid services. Then we investigate their interactions and interdependencies from a dependability perspective. Further, we investigate the positive and negative effects ICT can have on the dependability of the system. Finally, we introduce a meta-model which incorporates the information about the states of the components and services to create a state estimator for the smart grid considering ICT and power components.