The use of renewable energy sources is a fundamental factor for a responsible energy policy in the future. Taking into account the sustainable character of the majority of renewable energy technologies, they are able to preserve resources and to provide security, diversity of energy supply and services, virtually without environmental impact. The present paper deals with the description of several applications of renewable energy sources in the area of the South Aegean Sea islands. The potential of the most important forms of renewable energy such as solar and wind energy, biomass, photovoltaics and geothermal energy, is investigated and analysed for the majority of the South Aegean Sea islands, while alternative scenarios are assessed and discussed.