Degradation rates (DR) of various PV modules after 4 years in Thailand are shown.

DR of thin film modules is more widely dispersed than that of Si wafer based type.

Average DRs of individual modules of each PV type range from 1.2 to 6.1%/year.

Impacts of DR on levelized cost of electricity (LCOE) in Thailand were discussed.

Without further cost reduction grid parity in Thailand will occur if DR <0.2%/year.