Case C-454/18: Judgment of the Court (Third Chamber) of 11 March 2020 (request for a preliminary ruling from the Förvaltningsrätten i Linköping — Sweden) — Baltic Cable AB v Energimarknadsinspektionen (Reference for a preliminary ruling — Internal market for electricity — Directive 2009/72/EC — Transmission of electricity — Concept of ‘transmission system operator’ — Regulation (EC) No 714/2009 — Interconnector — Transmission line connecting the national transmission systems of the Member States — Article 16(6) — Scope — Use of revenues resulting from the allocation of interconnection capacity — Undertaking which merely operates a cross-border high-voltage power line connecting two national transmission networks)