All of Europe's national grids are interconnected, and most of them import or export more than 10% of their power budget (some both, depending on the time of da

All of Europe's national grids are interconnected, and most of them import or export more than 10% of their power budget (some both, depending on the time of day). A large power fluctuation/blackout in one country can easily spread to neighbouring countries, the junctions can't absorb the sudden shift in network load.