Renewable energy based power generation system holds the most promising solution for remote area power supply. In this study, the long term operation performance of a 19.8kWp standalone solar photovoltaic (SAPV) system in a remote island is investigated. The methodology for evaluating system performance is introduced, and then the detailed assessment results are presented, accompanying with analysis and discussion. Results show that the photovoltaic (PV) array operated well with AC power generation efficiency of about 10% and overall system efficiency is about 7.7%. The reference yield, array yield and final yield are 4.08, 3.05, and 2.45kWh/kWp/day, respectively, therefore the resultant performance ratio is 60%, demonstrating that the performance of SAPV plant is satisfactory during the reporting period. However, after long term performance monitoring and analysis, the limitation of SAPV system begins to arise due to lack of grid management and compensations from other energy sources, suggesting that it would be better to develop or integrate it into a microgrid system with hybrid sources if possible.