Case C-68/18: Judgment of the Court (Fifth Chamber) of 7 November 2019 (Request for a preliminary ruling from the Curtea de Apel București — Romania) — SC Petrotel-Lukoil SA v Agenția Națională de Administrare Fiscală — Direcția Generală de Administrare a Marilor Contribuabili, Agenția Națională de Administrare Fiscală — Direcția Generală de Soluționare a Contestațiilor (Reference for a preliminary ruling — Taxation of energy products and electricity — Directive 2003/96/EC — Article 21(3) — No chargeable event giving rise to taxation — Consumption of energy products on a site that produces such products — Article 2(3) — Obligation to obtain a classification for energy products in order to determine the level of excise duty — Tax rate applicable to those products — Principle of proportionality)