Case C-318/09 P: Judgment of the Court (Sixth Chamber) of 21 December 2011 — A2A SpA, formerly ASM Brescia SpA v European Commission (Appeals — State aid — Aid granted to public utilities — Tax exemptions — Decision declaring the aid scheme incompatible with the common market — Action for annulment — Admissibility — Standing — Legal interest — Article 87 EC — Concept of ‘aid’ — Article 88 EC — Concept of ‘new aid’ — Article 10 EC — Duty of loyal cooperation — Regulation (EC) No 659/1999 — Articles 1 and 14 — Lawfulness of a recovery order — Principle of legal certainty — Duty to state reasons)