NOVELTY - The apparatus (5) has a measurement part (11) measuring wind speed in an electric power generation part (3). A probability storage part (17) stores probability of wind speed that exceeds range of the electric power generation part when the wind speed is measured by the measurement part. An electric power generation control part (19) stops electric power generation by the electric power generation part when electric power generation amount is less. Measurement data is stored in a history memory part (13). A simulation data storage part (25) stores airflow property.    USE - Control apparatus for a electric power generation system for controlling an electric power generating apparatus while producing electric power by utilizing natural energy i.e. wind force, in a windmill manufacturer, a wind power generation company, an electric power company, a windmill apparatus manufacturer and a power producer company. Can also be used for producing electric power by tidal power and photovoltaic power.    ADVANTAGE - The electric power generation control part stops electric power generation by the electric power generation part when electric power generation amount is less, so that characteristic corresponding to fixed probability can be observed, safe operation can be performed, specific control can be implemented according to an installation place by stopping the electric power generation amount of the electric power generation part and prediction result can be computed.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a method for controlling an electric power generation part    (2) a program comprising a set of instructions to operate a control apparatus.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of an electric power generation system.'(Drawing includes non-English language text)'    Electric power generation part (3)    Control apparatus (5)    Measurement part (11)    History memory part (13)    Probability storage part (17)    Electric power generation control part (19)    Simulation data storage part (25)