Technical challenges in modernizing distribution electric power systems with large number of distributed generators

In this paper we consider possible technical challenges which may arise while attempting to modernize today´s electric power systems by connecting many distributed generators (DG) of diverse technologies closer to the end-users within the distribution networks. We report that connecting larger (~1 MW) DGs at the network locations, which result in minimal delivery losses, may lead to frequency instabilities not currently experienced in distribution grids supplied from single power generators. The paper further points out that there is a tradeoff between efficiency and the robustness of future energy systems. For example, adding storage can help, but this adds cost. The paper closes with a discussion of designing advanced enhancing robustness methods to ensure both safety and efficiency.