The extraordinary increase of renewable generation units in Europe connected to the transmission and distribution grid via inverter systems highly impacts the dynamic behaviour of the energy system. In contrast to conventional synchronous machines, which dampen frequency deviations due to their inherent inertia, such inverter-connected
generation units, like wind and photovoltaics, act inertia-free and therefore do not support frequency stability. Hence, the future need for system services providing highly dynamic reactions to compensate these effects needs to be assessed. This includes a detailed analysis
of the expected system parameters, possible implementation requirements and specific limitations of the analysed technologies and system services. As the current regulatory framework foresees those types of system services only partially this aspect has to be investigated,
as well.
