Abstract: Due to the differences in the scales of the installed capacity of the renewable energy power (REP), the load power consumption, and the power regulation capabilities in different regions, setting reasonable utilization rate targets of REP by region is the key to leading the high-quality development of REP in the future. Aiming at the optimization calculation of the reasonable utilization rate of REP, which comprehensively considers the environmental benefits of REP, the flexibility retrofits and the peak load regulation of thermal power, a method for calculating the environmental cost of the power system during the operation phase considering the accommodation of REP is proposed. Firstly, the relationship between the simultaneous rate and the production of REP is established, and the distribution characteristics of simultaneous rate and utilization rate of REP are obtained. Secondly, the profit and loss utilization hours of the REP plants are analyzed. A REP accommodation optimization calculation model is established with the goal of optimal environmental cost in the operation stage. Finally, case calculations are carried out based on the actual data of the provincial power grid in the operation area of the State Grid Corporation of China (SGCC), and the newly installed capacity and reasonable utilization rate of REP under the scenario of the minimum environmental cost during the operation stage are obtained.