Funded by Horizon 2020, REACT will demonstrate the potential of the large-scale deployment of renewable energy systems (RES) and storage assets on geographical islands to bring economic benefits, contribute to the decarbonisation of local energy systems, reduce greenhouse gas emissions (GHG) and improve air quality. To do so, REACT will deliver a scalable and adaptable cloud-based ICT platform for RES and storage enabled infrastructures, supporting a holistic cooperative energy management strategy at the community level. REACT will combine an optimal control of community owned energy assets, both conventional and renewable, with cooperative demand response (DR) actions, both explicit and implicit, to maximally exploit the flexibility of energy demand. To achieve this, REACT will leverage on energy production and consumption modelling, grid operation fault detection and diagnostics, multicarrier supply optimization and optimal energy dispatching, while enabling synergies between different energy networks and micro-grids of island. REACT will target to enhance the overall energy security of geographical islands with an inherent possibility for scale-up.