ABSTRACT – The principle of energy solidarity, enshrined in Article 194 TFEU, has become an inescapable cornerstone of the European Union’s legal order. No longer confined to a merely programmatic declaration, it has evolved into a binding legal norm, shaping both the interpretation and implementation of European energy policies. This article critically examines the legal foundations of energy solidarity, analyzing its articulation in the case law of the Court of Justice of the European Union (CJEU), which has contributed to defining its scope and enforceability. The paper further explores the normative developments in the European Green Deal context and the REPowerEU plan. Particular attention is devoted to the solidarity principle implications’ for the transposition and implementation of Directive (EU) 2024/1275 on the energy performance of buildings (“Green Homes Directive”), with a focus on the challenges and opportunities it presents for Italy, and the prospects for a just and resilient energy transition within the European Union.
