Operation of wind-battery hybrid power stations in autonomous Greek islands

Greek territory includes a large number of islands that are not interconnected with the main Greek power system. These autonomous islands are powered by oil-fired power stations and they present significant wind potential. However, in such systems wind penetration has to be limited due to technical constraints. This situation can be drastically improved with the operation of hybrid power stations, which combine renewable with conventional generation and storage facilities. This paper studies the operation of hybrid power stations that contain advanced sodium sulfur (NaS) batteries as storage medium in the autonomous power system of Samos Island. The analysis ensures the proper power system operation with respect to technical constraints by implementing optimal power flow analysis. Moreover, the paper proposes a proper battery size in order to optimize the cost savings of the system.