The aim of this paper is to present an analysis of long term outdoor exposure of two thin film photovoltaic (1PPV) module technologies deployed in semi-arid climate in Saida" city located in Algeria. The TFPV modules are: a-Si:H/mu c-Si:H (micromorph) and copper indium selenide (as). The ITPV modules were characterised by measuring their I-V curves during three years under the same outdoor climate conditions, where the measurement of weather parameters were also performed. The goal of the analysis is to evaluate the degradation rates of the FAT modules in semi-arid climate. The analysis is based on two techniques, the effective peak power of PV module and power irradiance technique. It was found that TFPV modules CIS and micromorph exhibit a degradation rate of -2.34%/year and -1.73%/year respectively. The calculated degradation rate for CIS technology is higher than those reported in the literature for locations in Europe and lower than those for locations with hot and humid conditions. In the opposite the degradation rate of the micromorph was lower than those given in the literature.