This chapter critically analyses the new challenges and opportunities that prosumers, as new energy actors, bring to achieving energy security goals in the context of the European Union (EU). Following trends in the EU towards new levels of cooperation in energy governance, decentralisation, and the emergence of a ‘gig’ economy, the energy sector is currently undergoing a large-scale transition. One of its core aspects is the progressive top-down diffusion of potential, competences, and leverage across the energy value chain from states and corporate actors towards prosumers. While this trend creates ample potential for facilitating and improving the EU’s security of supply, as well as fulfilling its climate change targets, several caveats exist. These caveats are not confined within energy security prerogatives; they also extend to the critical management of digital security, which the digitalisation of energy services brings to the fore. Private and public finance should be effectively attracted and directed to infrastructure schemes that will enable a transition from the traditional centralised power network to the decentralised nexus of smart grids. Technology will play a crucial role in facilitating the role of prosumers in the new market in the making.