Energy poverty has been conceptualized as an environmental injustice by Walker and Day (2012). Our paper is an extension of this approach and situated it in a critical way inside Amartya Sen’ work on capabilities (1999, 2009). We show on the one hand how Sen’s idea of justice, which is based on the notion of capability, is relevant to think energy justice and environmental justice, but, on the other hand, that this approach is unsufficient to think the ecological transition. We propose a conceptual framework outlying a democratic way to transition. We suggest turning to non liberal conceptions of freedom and social imagination with C. Castoriadis’ concept of autonomy.