The increasing power generation out of intermittent renewable energy sources will result in a reduction of the grid stability if no compensatory actions are taken. This issue may lead to future obligations for energy providers. This paper studies the implication of the future obligations for generators in Europe according to the recommendations of ENTSO-E, in particular the obligation for some generators to have a synthetic (or virtual) inertia and a frequency sensitive control. These obligations will be described in details in the paper, in particular their effect on the grid management and stability. The impact of this new actions on the energy production will be discussed. The continental European grid frequency is used as an example.