By the reason of some renewable energy sources not controlled by human begins but natural environment. Especially, wind power and PV generation controlled by the nature, and therefore PV or wind power is difficult to estimate the output. It is useless for engineering system that the system has lower controllability and cannot estimate the operation. The natural energy sources are not control and difficult of estimation. In this paper represents the P V system output model. P V system output models are two types. One is monthly model, and the other is daily model. These model uses sunlight time and angle of the sun and PV cells. To verify these model, apply the 10 kW P V system and compare estimate output with real generation.