  The recent attention towards research and development in cyber-physical
energy systems has introduced the necessity of emerging multi-domain
co-simulation tools. Different educational, research and industrial efforts
have been set to tackle the co-simulation topic from several perspectives. The
majority of previous works has addressed the standardization of models and
interfaces for data exchange, automation of simulation, as well as improving
performance and accuracy of co-simulation setups. Furthermore, the domains of
interest so far have involved communication, control, markets and the
environment in addition to physical energy systems. However, the current
characteristics and state of co-simulation testbeds need to be re-evaluated for
future research demands. These demands vary from new domains of interest, such
as human and social behavior models, to new applications of co-simulation, such
as holistic prognosis and system planning. This paper aims to formulate these
research demands that can then be used as a road map and guideline for future
development of co-simulation in cyber-physical energy systems.
