Fraunhofer Institute for Energy Economics and Energy System TechnologyWithin the scope of research projects, the various installations and devices in energy systems are considered: e.g. Photovoltaic and wind turbines, hybrid systems with storage, converters, electric machines, electric vehicles, etc. A characteristic common feature of all devices and installations is that their function is not considered isolated from the energy system. Interactions of the devices with each other and with the system are always taken into account in order to add value to the energy system as a whole.