Electric power control method, electric power control device, and electric power control system

1. An electric power control method comprising:

determining a control threshold value at a start of a demand time period based on a demand target value;

measuring an amount of demand electric power of a customer which has received an electric power supply from an external power source and consumed electric power from the start of the demand time period to a time point of update during the demand time period;

updating the control threshold value based on the measured amount of demand electric power and the demand target value; and

supplying electric power to the customer from a distributed power source when an instantaneous value of an electric power consumption of the customer exceeds the control threshold value during the demand time period,

wherein, in the updating,

the measured amount of demand electric power is compared with a total amount which is observed when consumption of electric power with a fixed demand target value is continued from the start of the demand time period to the time point of update,

when the amount of demand electric power is smaller than the total amount, the update is performed by increasing the control threshold value, and

when the amount of demand electric power is greater than the total amount, the update is performed by reducing the control threshold value,

wherein, when the amount of demand electric power is smaller than the total amount, the update is performed by dividing a value obtained by subtracting the amount of demand electric power from the total amount by a time from the time point of update to an end of the demand time period and adding the value obtained by division to the control threshold value.

2. The electric power control method according to claim 1 , wherein

the update of the control threshold value is repeated at predetermined intervals during the demand time period.

3. The electric power control method according to claim 1 , wherein

an amount of electric power consumption of the customer from the time point of update to an end of the demand time period is predicted, and

when a total value of the predicted amount of electric power consumption and the amount of demand electric power is smaller than a total amount which is observed when consumption of electric power with a fixed demand target value is continued from the start of the demand time period to the end of the demand time period, the control threshold value at a time of the update is increased, and,

when the total value of the predicted amount of electric power consumption and the amount of demand electric power is greater than the total amount which is observed when consumption of electric power with a fixed demand target value is continued from the start of the demand time period to the end of the demand time period, the control threshold value at the time of the update is reduced.

4. The electric power control method according to claim 1 , wherein

the distributed power source is an electricity storage system provided with at least one storage battery, and

when the instantaneous value of the electric power consumption of the customer exceeds the control threshold value during the demand time period, the storage battery is discharged and electric power is supplied to the customer.

5. The electric power control method according to claim 4 , further comprising:

charging the electricity storage system in a period in which an amount of electric power consumption of the customer is smaller than the control threshold value when determining that average demand electric power during the demand time period becomes smaller than or equal to the demand target value during the demand time period.

6. The electric power control method according to claim 5 , wherein

when the distributed power source is discharged, the distributed power source is not charged even in a period in which the amount of demand electric power is smaller than the control threshold value in a same demand time period as the demand time period in which the discharge of the distributed power source is performed.

7. The electric power control method according to claim 1 , wherein

the control threshold value is a threshold value for making an average value of the amount of demand electric power smaller than or equal to the demand target value.

8. The electric power control method according to claim 4 , wherein

when the amount of demand electric power exceeds the control threshold value, the storage battery is discharged by an amount corresponding to an excess of electric power, and,

when the amount of demand electric power does not exceed the control threshold value, electric power supplied from the external power source is supplied to the customer without the storage battery being charged and discharged.

9. The electric power control method according to claim 1 , wherein

the customer is collective housing, a commercial facility, a communal facility, or a disaster prevention base.

10. The electric power control method according to claim 1 , wherein

the external power source is a commercial power source.

11. An electric power control device comprising:

at least one memory; and circuitry operative to:

determine a control threshold value at a start of a demand time period based on a demand target value;

measure an amount of demand electric power of a customer which has received an electric power supply from an external power source and consumed electric power from the start of the demand time period to a time point of update during the demand time period;

compare the measured amount of demand electric power with a total amount which is observed when consumption of electric power with a fixed demand target value is continued from the start of the demand time period to the time point of update,

update the control threshold value based on the measured amount of demand electric power and the demand target value; and

supply electric power to the customer from a distributed power source when an instantaneous value of an electric power consumption of the customer exceeds the control threshold value during the demand time period, wherein

when the amount of demand electric power is smaller than the total amount, the update is performed by increasing the control threshold value, and

when the amount of demand electric power is greater than the total amount, the update is performed by reducing the control threshold value,

wherein, when the amount of demand electric power is smaller than the total amount, the update is performed by dividing a value obtained by subtracting the amount of demand electric power from the total amount by a time from the time point of update to an end of the demand time period and adding the value obtained by division to the control threshold value.

12. An electric power control system comprising an electric power control device and a storage battery that is connected to the electric power control device via a communication network, wherein

the electric power control device includes

at least one memory; and circuitry operative to:

determine a control threshold value at a start of a demand time period based on a demand target value;

measure an amount of demand electric power of a customer which has received an electric power supply from an external power source and consumed electric power from the start of the demand time period to a time point of update during the demand time period;

compare the measured amount of demand electric power with a total amount which is observed when consumption of electric power with a fixed demand target value is continued from the start of the demand time period to the time point of update;

update the control threshold value based on the measured amount of demand electric power and the demand target value; and

supply electric power to the customer from a distributed power source when an instantaneous value of an electric power consumption of the customer exceeds the control threshold value during the demand time period, wherein

when the amount of demand electric power is smaller than the total amount, the update is performed by increasing the control threshold value, and

when the amount of demand electric power is greater than the total amount, the update is performed by reducing the control threshold value,

wherein, when the amount of demand electric power is smaller than the total amount, the update is performed by dividing a value obtained by subtracting the amount of demand electric power from the total amount by a time from the time point of update to an end of the demand time period and adding the value obtained by division to the control threshold value.