The favorable climate conditions of the island of Crete and the recent legislation for utilization of renewable energy sources provide a substantial incentive for installation of photovoltaic power plants. in this paper, the grid connected photovoltaic park of C. Rokas SA in Sitia, Crete, is presented, and its performance is evaluated. The photovoltaic park has a peak power of 171.36 kW p and has been in operation since 2002. The park is suitably monitored during I year, and the performance ratio and the various power losses (temperature, soiling, internal, network. power electronics, grid availability and interconnection) are calculated. The PV park supplied 229 MW h to the grid during 2007, ranging from 335.48 to 869.68 kW h. The final yield (Y-F) ranged from 1.96 to 5.07 h/d, and the performance ratio (PR) ranged from 58 to 73%, giving an annual PR of 67.36%. (c) 2008 Elsevier Ltd. All rights reserved.