Transition towards a hybrid energy system: Combined effects of renewable portfolio standards and carbon emission trading

A hybrid energy system (HES) utilizing complementary energy sources allows for high-quality development of renewables. It is a viable pathway in achieving the low-carbon transition of the power sector. Both Renewable Portfolio Standards (RPS) and Carbon Emission Trading (CET) regulate the low-carbon behavior of conventional power enterprises. This highlights the importance of investigating how the policy mix can drive the transition towards hybrid power generation. This paper develops an evolutionary game between local governments and power enterprises to explore the influence of policy-related parameters on the transition to a hybrid energy system. We find that implementing the policy mix is imperative to the transition when the technology cost of a hybrid energy system is not competitive. Power enterprises can control investment costs through the structure of multi-energy power generation, but are also limited by the lack of renewable absorption capacity. We also find an additive effect between RPS and CET, albeit with differences. Raising the price of tradeable green power certificates (TGC) can effectively facilitate the transition under either a single RPS policy or the policy mix. Reducing initial carbon permits makes sense only under the policy mix. Moreover, the coordinated implementation of multiple policies can contribute to the transition more efficiently, but it deserves attention to avoiding policy redundancy.