In the past decade real-time embedded systems became more and more complex and pervasive. From the user perspective, these systems have stringent requirements regarding size, performance and energy consumption, and due to business competition, their time-to-market is a crucial factor. Therefore, much work has been done in developing design methodologies for embedded systems to cope with these tight requirements. In this paper, we introduce the concept of application scenarios that group operation modes of an application that are similar from the resource usage perspective, and we describe how to incorporate them in the overall real-time embedded system design process. A case study shows the use of application scenarios for low energy design, under both soft and hard real-time constraints.