This topic came up in another forum where the original subject was the forthcoming ban on domestic coal.
I reckon that EdF would not have invested in IFA2 (local to me) with the aim of importing leccy, but the publicity materials mention the benefits of flow either way.
In my mind's eye I can visualize a bunch of generators being connected by the national grid such that their power flows down a voltage gradient to millions of consumers: the average voltage in the power stations must be higher than that at the consumers' intakes.
With me so far?
So how is the direction of flow in the interconnectors managed?