Price elasticity of demand (PED) influences configuration of reserve capacity of generation side (RCGS) by influencing interruptible load (IL) cost. Quantitative analysis of PED on RCGS configuration from risk viewpoint has been ignored till now. Mathematic model of configuring RCGS in the market environment is proposed from the viewpoint of risk management and coordination optimization based on building IL cost and its interruption compensation risk by customer surplus theory in microeconomics. Influence of PED on RCGS configuration is analyzed quantitatively by simulation. Simulation results show that increasing PED is beneficial to decrease optimal configuration for RCGS and its cost.