This paper describes the installation, technical characteristics, operation and economic evaluation of one of the largest grid-connected photovoltaic (PV) systems installed in Greece, and in particular in the island of Paros in the Aegean Sea. Attention is drawn on the impact of PV utilization on the ecological tourism, which is growing very fast in Greece. Also, several issues are considered when assessing the value of PV electricity. The value of PV has been examined from various perspective consumer, utility and environmental and for central and decentralized PV systems in conjunction with the benefits for all the involved parties, i.e. the owners, operators, users, tourists, investors, renewable system industry and local authorities.