Induction mechanism and optimization of tradable green certificates and carbon emission trading acting on electricity market in China

China has promised that CO2 emissions per GDP in 2030 would decrease by 60% to 65% than that in 2005, and proposed the goal of achieving carbon neutral by 2060. In order to fulfill these goals, Carbon Emissions Trading (CET) and Tradable Green Certificates (TGC) have been implemented in the power industry during the ‘13th five-year’ period. We firstly simulate the combined effects of TGC and CET on the electricity market from 2020 to 2026. Further, we build a policy synergy model to explore the optimization relationship between TGC and CET systems. The results show that, the power supply structure can be optimized under TGC and CET systems. The growth rate of CO2 emissions from the power industry will slow down, accelerating peaking CO2 emissions of the power industry. The national CO2 emissions reduction goal (1.185–1.037 tons /RMB 10,000 yuan by 2030) is expected to be achieved. There may be policy redundancy between TGC and CET systems. It is determined by how to set renewable energy objective and CET quota objective. Under multiple policy objectives, the key is to obtain the policy synergy intervals for staged optimization. Finally, we propose some suggestions on the improvement of TGC and CET mechanisms, and combined implementation and optimization of multiple emission reduction policies.