Local energy storage as a decoupling mechanism for interdependent infrastructures

This paper discusses the role of local energy storage in decoupling interdependent infrastructures within a system-of-systems. In order to quantify the effect that interdependencies have on a given infrastructure supporting a system that belongs to the system-of-systems, its availability is analyzed by dividing failure modes in those originated by system component failures and those caused by external influences to the system, i.e., from interdependencies. The effect that added energy storage has on availability is used in order to evaluate the degree of interdependencies among infrastructures. The analysis focuses on conventional communication sites infrastructure because it present an interesting case of interdependencies with two other infrastructures: roads and a power grid. In this system-of-systems, locally stored energy in the form of diesel for a generator set plays an important role in decoupling interdependencies among these three infrastructures. Influence of operational modes are also considered because different operational modes—e.g., continuous operation after a disaster or standby operation in normal conditions—affects the effect of interdependencies on system availability.