Judgment of the Court (Fifth Chamber) of 19 December 2019.#Engie Cartagena S.L. v Ministerio para la Transición Ecológica.#Request for a preliminary ruling from the Audiencia Nacional.#Reference for a preliminary ruling — Internal market in electricity — Common rules — Directive 2003/54/EC — Article 3(2) — Directive 2009/72/EC — Article 3(2) — Public service obligations — Meaning — National rules — Financing of energy efficiency plans — Designation of electricity generating undertakings — Mandatory contribution.#Case C-523/18.