This chapter strives toward a conceptual understanding of exnovation processes for energy transitions. Exnovation, the opposite of innovation, describes a process of divestment from fossil-fuel energy technologies and production structures. As an exemplifying case study, it discusses the exnovation of specific, unsustainable electricity production technologies in the face of the German energy transition. By looking at the interplay of politics, scientific modeling, and public involvement, it shows that exnovation is a necessary means for energy transitions but is hard to achieve. The chapter finds that more attention should be given to groups that bring exnovation to the energy transition agenda.