Agios Efstratios, a volcanic island with 250 residents in the northeastern Aegean Sea, has shifted from complete dependence on fossil fuels to generating 91% of its electricity from renewable sources. The EU-backed Ai Stratis – Green Island project prevents approximately 1,000 tons of carbon dioxide emissions annually. Its hybrid system combines a 900-kilowatt wind turbine, a 225-kilowatt solar farm, battery storage, and automated energy management that responds in real time. Renewable electricity is distributed through the island’s existing grid.
When generation exceeds demand, surplus electricity is stored in batteries, which release power when renewable production falls short. During winter, excess energy is also converted into heat and stored in four hot-water tanks with a combined capacity of 500 cubic meters. For resident Charalambos Makris, who manages two guesthouses, the heating system removes the need to operate an indoor boiler while providing quiet, economical heating. Deputy Mayor Zoi Vlastou regards the pilot project as a model for other Greek islands and the country more broadly.
The project’s budget totals 7.23 million euros, with 85% financed through the European Union’s Cohesion Policy and 15% through Greek national funds. Installation posed substantial logistical challenges: the wind turbine, standing 77 meters tall and weighing nearly 30 tons, had to be transported and assembled at the island’s highest point. According to CRES project manager Panagiotis Zorlos, however, the greatest challenge was adapting Greek energy standards, whose general regulatory framework did not specifically address this distinctive system. Other Greek islands, including Tilos, Ikaria, and Astypalea, are following its example.
