Load aggregators (LAs) aggregating demand response resources to participate in market transactions will reduce the peak power demand and bring huge benefits to the power system. However

the uncertainty factors resulting from electricity users will exert an effect on its economic benefits. To compensate for power shortage

an energy storage capacity optimization model is developed based on grading compensation rules. The bounded unresponsive load caused by customers’ usage habits and subjectivity is represented by a truncated normal distribution model. And according to the percentage of unresponsive load

LAs are classified into four grades facing different compensation standards and market admission rules. Through examples of PJM historical load data

it is proved that the model is capable of solving energy storage capacity optimization problems for LAs to reduce the effects of unresponsive load. Besides

another conclusion can be drawn that rational market rules can spur LAs on to upgrade their resources

which will definitely contribute to stable and reliable market operation.