The generation system comprises 10 kW of PV, a nominal 53kWh battery bank, and a 5kW diesel genset. The aim of the system is to be supplied by 100% from the solar energy produced by the PVs or stored in the batteries, i.e. the diesel genset is intended only as a back-up unit, in case of prolonged clouds or in emergenecy. A second PV array of about 2kW, mounted on the roof of the control system building (System House). This is a house of about 30 m2 surface area built in the middle of the settlement in order to house the battery inverters, the battery banks, the diesel genset and its tank, the computer equipment for monitoring and the communication hardware, called “System Hut or house”. The 2 kW PV is connected to an SMA inverter and along with a 32-kWh battery bank they provide power for monitoring and communication. Residential service is powered by three Sunny-island battery inverters, connected in a parallel master-slave configuration, forming one strong single-phase circuit. This allows the use of more than one battery inverter only when more power is demanded by the consumers. Each battery inverter has a maximum power output of 3.6kW. The battery inverters in the Kythnos system have the capability to operate in both isochronous or droop mode. The operation in frequency droop mode gives the possibility to pass information on to switching load controllers in case the battery state of charge is low and also to limit the power output of the PV inverters when the battery bank is full.