This chapter provocatively argues that there is no such thing as sustainable energy. The black and white dichotomy of unsustainable versus sustainable leaves out important "colors" that reflect the complexity of the energy discussion. By reviewing the rapid developments in biofuel – which is supposedly sustainable – and the ensuing food crisis in the beginning of the century, it shows that sustainability is about much more than renewability. Sustainability is presented as a moral framework that comprises several underlying values, including safety, security, environmental benevolence, resource durability, and economic affordability. These values are presented in relation to different production methods for nuclear energy, creating an ethically nuanced picture of this energy technology. The chapter further addresses energy ethics. While sustainability and energy ethics have a great deal in common, energy ethics can provide us with a more fine-grained analysis of the broader ethical issues associated with energy, including questions of human rights, risk acceptability, and justice.