This paper presents a systematic techno-economic analysis of autonomous PV-Diesel energy system with battery storage. This hybrid type power system was developed and installed on the roof of the Electrical Engineering Laboratory building in the city of Xanthi, Greece, where a weather station is also installed providing necessary meteorological data since 2002. Such system can be generally used to supply electrical loads of isolated remote areas. The actual design of such a system is based on: a pre-defined load pattern to be supplied; the pertinent weather data; the relevant market prices; and the applicable recent economic rates (