Energy storage, and energy systems in general, can give rise to local and global injustices, and thus it is important to develop, deploy and regulate energy systems in a just manner. Energy justice scholarship has two aims, namely to (a) understand and explain claims of injustice (descriptive aim) and (b) evaluate energy systems in terms of justice and propose policy and design recommendations (normative aim). However, existing energy justice frameworks have limited capacities to achieve both aims because they insufficiently acknowledge normative uncertainties. Different stakeholders have different ideas about when something is (un)just, and as such, there is normative uncertainty about what ‘energy justice’ implies for energy systems. This dissertation aims to strengthen the conceptual foundations of energy justice in light of normative uncertainties, which helps achieve both aims. To do so, the dissertation leverages social sciences and political philosophy, more specifically Critical Theory. The conceptual contributions in this dissertation help detect, analyse, and evaluate energy conflicts and claims of injustice and include a revisited energy justice framework, a reconceptualization of recognition justice, and the hidden morality heuristic. This dissertation stresses the importance of acknowledging normative uncertainty in energy decision-making, the need for justification of normative claims, and the importance of a critical dialogue on energy justice in academia and society, to help guide decision-making towards more just energy storage systems.