Joined Cases C-80/18 to C-83/18: Judgment of the Court (Fifth Chamber) of 7 November 2019 (requests for a preliminary ruling from the Tribunal Supremo — Spain) — Asociación Española de la Industria Eléctrica (UNESA) (C-80/18), Endesa Generación SA (C-82/18) v Administración General del Estado, Iberdrola Generación Nuclear SAU (C-80/18 and C-82/18) and Endesa Generación SA (C-81/18), Iberdrola Generación Nuclear SAU (C-83/18) v Administración General del Estado (C-81/18 and C-83/18) (Reference for a preliminary ruling — Polluter-pays principle — Common rules for the internal market in electricity — Directive 2009/72/EC — Article 3(1) and (2) — Principle of non-discrimination — Financing the tariff deficit — Taxes applying only to undertakings which use nuclear energy to produce electricity)