An aggregation system, comprising: a control apparatus which is provided for each consumer and is adapted to control charging and discharging of each of one or more subordinate power apparatuses and power I/O to/from a system respectively; and a server apparatus which is adapted to send a demand response-related control instruction to the control apparatus of each of the consumers respectively, wherein the server apparatus is adapted to calculate, for each of the consumers and as an allocation amount of the consumer, an upper limit value for the power which the consumer inputs from the system or a lower limit value for the power which the consumer is to output to the system, according to a requested task and power provision amount, and is adapted to send the respective control instructions designating the calculated allocation amount of each consumer to the control apparatus of the consumer, wherein the control apparatuses each are adapted to control the charging and discharging of the corresponding power apparatus so that the power input from the system is equal to or smaller than the allocation amount designated in the control instruction or so that power equal to or larger than the allocation amount is output to the system, wherein the control apparatus is a power conversion apparatus which is adapted to convert the power that is input from the system from AC to DC and is adapted to charge the required power apparatus and which is adapted to convert the power that has been discharged from the power apparatus from DC to AC and is adapted to output the power to the system, wherein the server apparatus is adapted to designate, in the control instruction and in addition to the allocation amount, a control mode which prescribes a power discharging source and a discharging destination of the power, or an operation mode comprising a combination of a plurality of the control mode, and wherein the control apparatus is adapted to exercise control to input and output power of the allocation amount designated in the control instruction to/from the system and charge and discharge the corresponding power apparatus by means of the operation mode or control mode designated in the control instruction, characterized in that a plurality of types of the operation mode are predefined, wherein the consumer is able to configure the desired operation mode for its own control apparatus, and wherein the server apparatus is adapted to allocate the allocation amount to the consumer of the control apparatus for which an operation mode prioritizing the control instruction from the server apparatus has been configured as the operation mode. a control apparatus which is provided for each consumer and is adapted to control charging and discharging of each of one or more subordinate power apparatuses and power I/O to/from a system respectively; and a server apparatus which is adapted to send a demand response-related control instruction to the control apparatus of each of the consumers respectively, wherein the server apparatus is adapted to calculate, for each of the consumers and as an allocation amount of the consumer, an upper limit value for the power which the consumer inputs from the system or a lower limit value for the power which the consumer is to output to the system, according to a requested task and power provision amount, and is adapted to send the respective control instructions designating the calculated allocation amount of each consumer to the control apparatus of the consumer, wherein the control apparatuses each are adapted to control the charging and discharging of the corresponding power apparatus so that the power input from the system is equal to or smaller than the allocation amount designated in the control instruction or so that power equal to or larger than the allocation amount is output to the system, wherein the control apparatus is a power conversion apparatus which is adapted to convert the power that is input from the system from AC to DC and is adapted to charge the required power apparatus and which is adapted to convert the power that has been discharged from the power apparatus from DC to AC and is adapted to output the power to the system, wherein the server apparatus is adapted to designate, in the control instruction and in addition to the allocation amount, a control mode which prescribes a power discharging source and a discharging destination of the power, or an operation mode comprising a combination of a plurality of the control mode, and wherein the control apparatus is adapted to exercise control to input and output power of the allocation amount designated in the control instruction to/from the system and charge and discharge the corresponding power apparatus by means of the operation mode or control mode designated in the control instruction, characterized in that a plurality of types of the operation mode are predefined, wherein the consumer is able to configure the desired operation mode for its own control apparatus, and wherein the server apparatus is adapted to allocate the allocation amount to the consumer of the control apparatus for which an operation mode prioritizing the control instruction from the server apparatus has been configured as the operation mode.