Energy markets have undergone fundamental changes at the conceptual level over the last years. The necessity for sustainability has transformed the traditional power production scheme to a distributed energy resource one, while the future points towards a great number of decentralized, small-scale production sites based on renewable energy sources, also. The Smart Grid paradigm is here to stay, while the deregulation of energy markets has defined new rules and new procedures.These changes offer substantial opportunities for all energy market stakeholders, which remain mostly unexploited due to two main reasons: a) the small-scale consumers comprising the vast majority of stakeholders are individually insignificant, and their market power is practically non-existent. Nevertheless, if they were somehow aggregated, their market power would dramatically increase, so as to affect market related policies and, b) there is currently a lack of tools for modeling this aspect of the energy market, i.e. the modeling of all involved entities with respect to their consumption behavior in an aggregate fashion, and the evaluation of trends formulated, policies applied and decisions made against specific socio-economic and environmental performance indicators.Project CASSANDRA aims to build a platform for the realistic modeling of the energy market stakeholders, also involving small-scale consumers. CASSANDRA will not provide another tool for visualization. Rather, it will provide users with the ability to test and benchmark working scenarios that can affect system operation and company/environmental policies at different levels of abstraction, starting from a basic level (single consumer) and shifting up to large consumer areas (i.e. a city). The project main outcomes will be the aggregation methodology and the framework of key performance indicators for scenario assessment, as well as an expandable software platform that providing different energy stakeholders with the ability to model the energy market, in order to assess scenarios for their own purposes.