Ærø is a Danish island, located in the Baltic Sea near the southern entrance to the Little Belt to the south of Fyn. Ærø is 88 km2 and has approx. 7.000 inhabitants. Most of them living in the 3 largest cities: Ærøskøbing, Marstal, and Søby or in one of the 14 villages on the island.
Ærø is known for being advanced in the field of Renewable energy, having one of the largest solar energy installations in the world, as well as a large park of windmills. Taken together, Ærø has reached a level, where 50% of its energy consumption comes from renewable energy.