Abstract Satisfying the growing energy demand, power systems are required to increase their capacity and be able to distribute energy over wider geographical area. To maintain the reliability of such power systems, more dependence is placed on automating the process controlling the physical system. Such power systems are known as smart grids, where data is transmitted in real-time across the power grid facilitating automated actions. These smart systems have intrinsic vulnerabilities. A smarter power grid is more reliant on an ICT backbone. Such reliance renders the physical power system subjected to an ICT realm whose security depends on a set of metrics, and standards alien to those of classical power systems. The sustainability of a power system will depend on the secure and reliable operation of the new smart system. This paper proposes a comprehensive approach to solve the challenges enumerated above. The proposed approach sets the ground for new metrics of overall system sustainability, by dissecting the overall smart grid into three layers: the physical system, the SCADA system, and the ICT infrastructure. The proposed methodology is tested on the case of electric vehicles, where cyber intrusion scenarios are studied in light of their effect on the physical layer.