Abstract: Taking the 20-kW grid-connected photovoltaic system(PV) with quasi-monocrystalline silicon modules for example, the social economic and environmental benefits of photovoltaic applications are calculated based on a benefit analysis model. The results show that the investment and energy recovery periods are 14 years and 2.9 years with one employment position provided on condition that the daily standard radiation hours are 4.14 h, the PV module costs 5.5 Yuan/W, the electricity price is 0.6 Yuan /kWh at the user side and there is no taxation. Compared with coal-fired generation, the emission reduction volume of the PV generation is 496.39 equivalent per year; the environmental cost of the PV power is 0.18 Fen/ kW·h; and the annual return on investment is 2%. The PV instantaneous power is proportional to the solar radiation volume and the environmental temperature. The weak correlation between the system power and the temperature is observed with the correlation coefficient equal to 0.46, while the correlation between the power and humidity turns out to be weak negative with the coefficient correlation of -0.38.

Key words: investment recovery period, quasi monocrystalline silicon, energy return period, grid-connected photovoltaic system