Abstract: Understanding critical infrastructures and in particular protecting them in case of natural or man-made threats or disasters is the objective of our research. As use case, the security of the power supply in the year 2030 for the city of Karlsruhe was selected. This scenario contains interdependencies between the electrical power grid and IT components as well as critical infrastructures such as water supply and health care. To simulate the critical infrastructure, their dependencies and potential measures to mitigate effects, agent based simulation models have been developed and applied. The ultimate objective of the research activity is to develop a holistic analysis framework to quantify and evaluate requirements and design decisions of the many players in such complex infrastructures.