Abstract
Among the Greek islands, 61 are based—currently—on autonomous electrical systems for covering the electrical energy demand and are characterized as Non-Interconnected Islands (NII). The average electricity production cost in the NII is 2.5 times higher than in areas with access to the main, interconnected electricity grid (IEG) of Greece. In this paper, an analytic overview of the autonomous electricity systems of Greek islands is provided, focusing on electricity consumption and production, as well as on the relative costs. For investigating possibilities for improving the situation, especially in small, remote islands, simulations for the energy system of Astypalea are conducted. It is proved that further use of renewables in combination with energy storage can lower the current, high energy costs. Expansion of the IEG is not economically viable for islands which are far away from the mainland and their peak loads are less than 10 ΜW.