The three key concepts of interdependency, resiliency and sustainability of a complex system have appeared in a number of studies and in various contexts. Nevertheless, little has been done to define and analyse them, especially the latter two, in a unified quantitative framework for engineering infrastructures. In this paper, we propose overarching mathematical modelling frameworks to quantify these three key concepts in the context of complex infrastructure systems with multiple interdependent subsystems (i.e., the system of systems). We show how interdependencies between subsystems can affect the resiliency and sustainability of the entire system. We provide a case study in the context of biofuel development and use different dynamical models to demonstrate these concepts.