Equilibrium Models Of Electricity Markets Considering Demand Response And Renewable Energy Support Policies

Due to the worldwide energy conservation and emission reduction policies and the development of smart grid,demand response and renewable energy gain wide attention and application around the world.Meanwhile,the implementation of various demand response programs and renewable energy support policies will certainly have great effects on the market participants' strategic behaviors and the overall electricity market competition outcomes.Researches on these influence mechanisms will be conducive to improve the design of the electricity market,and be of important theoretical and practical significance to improve the electricity market competition efficiency.Under this background,based on oligopolistic competition equilibrium theory,this dissertation commits to study the electricity market equilibrium models considering demand response programs and renewable energy support policies,and address the problems of what impacts of the introduction of demand response programs and renewable energy support policies will have on the market participants' strategic behaviors and the whole electricity market equilibrium outcomes.The main work and the key contributions of this dissertation are as follows:Firstly,to investigate the impacts of interruptible load(IL)program on the electricity wholesale market competition,a novel demand model is proposed to incorporate the IL program.On this basis,the Cournot and supply function equilibrium models are presented for wholesale markets with IL program,respectively.The introduction of IL program leads to a non-smooth equilibrium problem.To solve this equilibrium problem,a novel solution method is proposed.The simulation examples are proposed to examine the impacts of interruption volune,interruption threshold price and different competition modes on the generation firms' bidding strategies and the equilibrium outcomes of electricity wholesale market.The simulation results show that:(1)With the IL program,the electricity price and its fluctuation can be lowered.This effect becomes more obvious when the uncertainty of market demand is relatively large or the demand elasticity is relatively low.(2)The interruption volume and interruption threshold price have significant influence on the electricity market equilibrium outcomes.The relatively large interruption volume and the relatively low interruption threshold price are more helpful to reduce the electricity price and its fluctuation.(3)Under the Cournot competition mode,implementing IL program is more helpful to reduce the electricity price and its fluctuation,and mitigate the market power of generation firms.This part is one of the key contributions of this dissertation.Secondly,to study the impacts of IL program on alleviating the fluctuation of renewable energy,a Coumot equilibrium model for the wholesale market with IL program and wind power is presented.The conditional value-at-risk is used to measure the market risk of the generation firms,the impacts of the IL program on the equilibrium outcomes of electricity wholesale markets with wind power and generation firms' risk are examined.The simulation results show that:(1)Implementing IL program can reduce the electricity price and its fluctuation caused by the integration of wind power.Especially when the uncertainty of wind power output is relatively large,this effect is more obvious.(2)IL program is an effective way for generation firms to mitigate their risks in the wholesale market with wind power.Thirdly,assume that the flexible consumers are allowed to take part in the wholesale electricity market competition in the form of demand response(DR)aggregators,the Cournot and supply function equilibrium models are build,respectively.Load shifting and curtailing programs can be incorporated at the same time by a special constraint.The nonlinear complementarity approach is used to solve this equilibrium problem.Numerical examples show that:(1)The DR resource joined the market competition can effectively encourage the flexible consumers to shift the load from peak-periods to off-peak-periods,and reduce the difference between peak and valley.(2)For DR aggregators,the DR aggregators with load shifting and curtailing resources are more competitive in the wholesale electricity market.(3)For flattening the system load curve,the model of DR aggregators with Cournot mode is better,and for flattening the electricity price curve,the model of DR aggregators with supply function mode is superior.This part also is one of the key contributions of this dissertation.Finally,a two-stage joint equilibrium model considering the tradable green certificate(TGC)market and wholesale electricity market is proposed.In stage one,the renewable firms behave a la supply function mode in the TGC market,and in stage two,all generation firms behave a la Cournot mode in the wholesale market.This equilibrium model can be formulated as an equilibrium problem with equilibrium constraints(EPEC)and is solved by the nonlinear complementarity approach.It is shown that:(1)Renewable firms will exercise market power in two markets by different ways.When the RPS is relatively low,renewable firms tend to hold back some of TGCs in the TGC market to exercise market power;when the RPS is relatively high,renewable firms turn to cut down their output in the wholesale market to exercise market power.These strategic behaviors can raise both the TGC and electricity prices.(2)Facing increasing TGC price,strategic fossil fuel firms choose to reduce their output in the wholesale market,so as to reduce the demand of TGCs,bring down TGC price and TGCs purchasing cost.(3)The generation cost reduction of renewable firms can lower both TGC and electricity prices,and mitigate the market power of generation firms in two markets,which has positive impacts on the market operation efficiency.This part is one of the main contributions of this dissertation.