As a market-based support policy of renewable energy

the renewable portfolio standard(RPS)and tradable green certificate(TGC)scheme is receiving ever-increasing attention. The integration of the RPS and TGC scheme is expected to exert significant influences on the electricity wholesale market competition

especially the interplay between the TGC market and the electricity wholesale market. To quantitatively investigate these influences

based on the oligopolistic competition equilibrium theory

a two-stage joint equilibrium model considering the TGC market and wholesale market is proposed. In stage one

the renewable firms behave à la supply function mode in the TGC market

and in stage two

all generation firms behave à la Cournot mode in the electricity wholesale market. The equilibrium model is formulated as an equilibrium problem with equilibrium constraints(EPEC)and is solved by the nonlinear complementarity approach. Finally

simulation examples focus on studying the strategic behaviors of generation firms in two markets under various RPS requirements and the interaction of these strategic behaviors. Simulation results show that

with various RPS values

the renewable firms exercise market power in different markets and drive up the electricity price and TGC price.