On the road to 100% renewable energy systems in isolated islands

The integration of renewable energy sources (RES) in islands is crucial to improve their economy allowing them to be energy independent. However, the intermittency of some RES originates grid stability problems and the mismatch between demand and supply. These issues must be carefully addressed according to each island’s peculiarities. The connection between isolated power systems can decrease the RES variability and, thereby, minimize the problems associated with their intermittency. Furthermore, linking all fossil fuel consuming sectors can help to shift demand and supply according to the system’s requirements, following a smart energy system approach. This approach is rarely considered in studies on 100% RES in islands, as most of them only consider the power sector. The scientific contribution of this study is the assessment of the impact of the interconnection of two small islands in the path to 100% RES of the whole energy system. The EnergyPLAN model is used, and the Islands of Pico and Faial, in Azores, are the case studies considered. Although these islands can increase significantly their RES penetration with lower costs, only their interconnection allows for a complete elimination of fossil fuels’ use in both islands. •Paths for 100% renewable energy systems in islands are examined.•The overall energy systems of the Islands of Pico and Faial are considered.•The impact of interconnecting the two islands is assessed.•Both islands can significantly increase their renewable energy sources penetration.•Only their interconnection allows for a 100% renewable energy system in both islands.