There are five synchronous areas in Europe, the largest one being the synchronous grid of continental Europe [1].
Each national grids has interconnections with other grids and you can measure the flow of power through these interconnections to know who is sending electricity or getting electricity from neighbours.
Each national grids has interconnections with other grids and you can measure the flow of power through these interconnections to know who is sending electricity or getting electricity from neighbours.
[1] https://en.wikipedia.org/wiki/Synchronous_grid_of_Continenta...