Case C-648/18: Judgment of the Court (Fourth Chamber) of 17 September 2020 (request for a preliminary ruling from the Tribunalul București — Romania) — Autoritatea națională de reglementare în domeniul energiei (ANRE) v Societatea de Producere a Energiei Electrice în Hidrocentrale Hidroelectrica SA (Reference for a preliminary ruling — Internal market in electricity — Free movement of goods — Article 35 TFEU — Quantitative restrictions on exports — Measures having equivalent effect — National measure requiring electricity producers to offer for sale all the electricity available to them exclusively on a centralised competitive market of the Member State concerned)