Coupling effects of RPS and CET policies on the low-carbon transformation of the Chinese power industry: A combined perspective based on tripartite evolutionary game and system dynamics

The renewable portfolio standard (RPS) and carbon emission trading (CET) policies are effective tools for promoting sustainable development and carbon reduction in the power industry. This paper examines whether the combined implementation of RPS and CET policies creates synergistic effects or leads to policy redundancy in the low-carbon transition of the power sector. Current literature lacks sufficient analysis of the dynamic game relationships and co-evolution paths among stakeholders, including government authorities, thermal power generation companies (TPGCs), and electricity retail companies (ERCs). To address this, we construct a tripartite evolutionary game model involving these entities. We propose propositions for evolutionary equilibrium points of the game system. Through system dynamics simulation analysis, we validate these propositions and identify key factors influencing the system's evolutionary path and stability. The main conclusions are as follows: (1) RPS and CET policies exhibit synergy, enhancing system stability. (2) Dynamic reward-penalty mechanisms are more effective than static ones; moderate rewards and penalties facilitate system evolution better than extreme measures. (3) As carbon prices increase, system volatility decreases, leading to greater stability. (4) When tradable green certificate (TGC) prices are low, government regulation may become ineffective, but high TGC prices can drive TPGCs and ERCs towards low-carbon practices.