The action will set up a joint programming initiative to develop Smart, Integrated, Regional Energy Systems that enable regions and local communities to realize their high ambitions of moving towards decarbonised energy systems and at the same time link them to a secure and resilient European energy system. This shall include solutions that allow for a high proportion of renewables up to and beyond 100% in the local or regional supply. The initiative will coordinate relevant RDD programs in the involved European, associated countries and regions represented in the consortium connecting them with other funding and financing partners. It will accelerate the deployment of latest resource-efficient and decarbonising energy system solutions, thus strengthening the competitiveness in relevant markets and lerveraging sustainable structures already established by ERA-Net Smart Grids Plus . The latter is focussing on the broad involvement of a large number of countries and regions in order to implement European smart electricity grids research agendas, while the ERA-Net SG+ RegSys will build on this with a new approach, developing integrated, regional energy systems, including the full spectrum of energy carriers and infrastructures. A highly ambitious consortium will pilot new formats of collaboration with regional and local stakeholders as well as supply and demand side oriented technology policy.