NOVELTY - A power receiving apparatus e.g. power conditioner (20) has a right power meter (26) measures a power amount of power received by power receiving unit in specified period. A determining unit compares information on power amount received by power receiving unit and information on power amount measured by right power meter and determines whether two power amounts match. A power reception control unit e.g. conditioner microprocessor (23) stops power receiving unit from receiving power and from receiving information, when determining unit has determined that two power amounts do not match.    USE - Power system with power transmitting apparatus such as solar cell module, and power receiving apparatus such as power conditioner for nuclear and hydroelectric power generation to generate electricity with low environmental impact.    ADVANTAGE - The power system is capable of preventing illegal tampering with a generated amount of green power. The security of the data communication carried out between the solar cell module and the power conditioner is ensured by the transport layer security (TLS) session. By controlling the transmission and reception of power based on the comparison between the generated power amount and the received power amount, illegal overstating of green power by connecting an external power source to the power line is prevented. Thus the illegal activity that overstates green power in an attempt to have bonds issued can be prevented. Since the self-consumed power amount that decides the monetary value of the green power bonds is calculated by taking into account the losses that occur when the battery is discharged, the green power bonds that reflect the additional environmental value is issued more precisely.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for power transmission control method.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic block diagram of the power system.    Solar cell module (10)    Power meter of solar cell module (12)    Power conditioner (20)    Microprocessor of power conditioner (23)    Power meter of power conditioner (26)