Method of controlling a battery, computer readable recording medium, electric power generation system and device controlling a battery

A computer-readable recording medium which records a control programs for causing one or more computers to perform the steps comprising:

• detecting an amount of electric power generated by the power generator at a first time and a second time prior to the first time;
• computing a rate of increase or decrease of the amount of electric power between the first time and the second time;
• computing a target output value for the electric power to be supplied to an electric power transmission system based on the rate;
• and
• supplying to the electric power transmission system electric power corresponding to the target output value from at least one of the power generator and the battery.

An electric power generation system, comprising:

• a power generator configured to generate electric power using renewable energy;
• a battery configured to store electric power generated by the power generator;
• a detector configured to detect the amount of electric power generated by the power generator at a first time and a second time prior to the first time;
• a controller configured to compute a rate of increase or decrease of the amount of electric power between the first time and the second time, to compute a target output value for the electric power to be supplied to an electric power transmission system based on the rate, to supply to the electric power transmission system electric power corresponding to the target output value from at least one of the power generator and the battery.