On the small island of Graciosa in the Azores the world's first electric system based on 100% renewable electricity generation is being built. The system uses electricity from solar and wind power, electricity storage in batteries and advanced control to stabilize the grid for short-term fluctuations. As backup for extended periods of low renewable generation, a third of the existing capacity from diesel generators will be kept, which means that the electrical system in the end will not be "100% renewable" at all times.
The new grid on Graciosa is built by the German-US company Younicos. Previously, the company integrated the first ever megawatt-scale battery into the European power grid in Berlin in cooperation with Vattenfall. The Danish financial investor Recharge A/S has bought 50.1% of the electricity network on Graciosa and are investigating the possibility of building a similar renewable power system on other islands in the Azores.
Graciosa belongs to the central island group in the Azores and has an area of 61 km². The island has approximately 5,000 permanent residents.