»EU Member State Obligations to Expand the Electricity Grids Based on EU Primary Law« The aim of an internal market for energy, the so-called Energy Union and the de facto changes in electricity production structures require a suitable electricity transmission and distribution grid within the EU Member States. The study demonstrates that the EU provisions on the free movement of goods contain not only an economic and political but a legal obligation for the EU Member States to create and maintain a minimum level of existing electricity infrastructure for the internal market.