[bdauvergne]

Without any argument apart "there seem to be rules to follow inside the EU" it seems unsubstantiated.

A better argument would be that digging or laying 3000Km 12GW terrestrial electric line through Spain and France would be expensive and especially difficult to sell to them, even if they could benefit from the energy.

[throwaway894345]

It’s already been clearly substantiated: running the cable through Spain or France would give leverage to those countries regarding (among other things) territorial disputes. This has nothing to do with the EU except in the tangential sense that Spain and France are both member states.