The shifting of the European countries, including the Netherlands, towards an electricity production dominated by renewable energy sources to be (nearly 70%) by mid-century will have a significant impact on the frequency performance of electric networks. This would cause the level of grid inertia to be considerably reduced. From this perspective, I have been working with DNVGL for a period of 9 months on developing a dynamic power system model that provides the possibility of assessing the frequency performance of the Dutch electric network as part of the Synchronous Grid of Continental Europe. The main aim of this model is to consider the anticipated decrease in system inertia caused by the high penetration of renewables in a future situation.