Increase in global energy demand, depletion of fossil fuels and environmental issues related to current major power generation patterns have proven to be highly effective drivers for a substantial shift towards renewable energy applications. Renewable energy sources (RES) such as wind, solar and biomass can provide reliable energy services and direct benefits at both national and local levels. Nowadays, in most non-interconnected islands the electricity generation cost is extremely high due to the utilization of outdated autonomous power stations (APSs) based on oil-fuel imports and diesel-electric generators. The objective of the present work is to investigate the possibility of achieving energy autonomy in very small (tiny) islands based exclusively on the use of RES. For that reason, a small Aegean Sea island (i.e. Agathonisi) which faces serious energy and water shortage problems is investigated. The proposed system configuration includes commercial wind turbines, photovoltaic panels, batteries and an internal combustion-electrical generator consuming biogas. The excess electricity is used for fresh water production via sea water desalination. Emphasis is given on a detailed energy analysis being the basis for sustainable development The results obtained highlight the feasibility and competitiveness of the proposed system configuration in comparison to the current situation. (c) 2012 International Energy Initiative. Published by Elsevier Inc. All rights reserved.