Optimal Operation Strategy Of Integrated Energy Service Providers With Green Certificate Transactions

In order to ensure the goal of renewable energy utilization and the development of energy structure transformation,the renewable portfolio standard has become an important guarantee for the development of renewable energy.The green certificate mechanism will facilitate the long-term development of renewable energy through market-oriented transactions of the quota indicators.Furthermore,with the rise of the integrated energy systems(IES)and the reform of energy market,the integrated energy service providers(IESPs)have become an emerging entity.Therefore,based on the development mode of IESPs and the promising prospect of renewable energy,IESPs will become indispensable participants in the green certificate trading market.In addition,it is urgent to study the application of green certificate mechanisms in integrated energy market transactions and analyze the impact of green certificate transactions on energy procurement strategies and energy supply schemes of IESP.Considering the competition relationship among multiple IESPs in the market,an energy trading strategy is proposed in this paper based on non-cooperative game theory.Under the background of the energy trading market,a two-tier optimization model with green certificate transactions is proposed,which takes IESP as the main participants.In this optimization model,the upper layer is the optimization model for maximizing the benefits of IESPs,whereas the lower layer is the energy market clearing models,which include the electricity market,natural gas market,and green certificate trading market.Specifically,the IESPs can obtain electricity and natural gas energy by market clearing and satisfy the energy demand while meeting the renewable portfolio standard by purchasing corresponding green certificates.In addition,the non-cooperative game theory is employed to study the optimal bidding strategies in view of the competitive relationship between multiple IESPs.Then,the two-layer optimization model is transformed based on Karush-Kuhn-Tucker(KKT)conditions,and the diagonalization algorithm is adopted to solve the transformed model.Finally,the feasibility of the proposed trading mechanism and optimization model is demonstrated through an illustrative case study.For the energy supply strategy of the IESP from the users perspective,a comprehensive model integrating combined heating and power generating unit(CHP),wind power,photovoltaics,and energy storage equipment has been established for IESP,and a game-based optimization model is proposed to describe the relationship among the IESP and the terminal energy users.First,the users’ electricity,heat demand response models,and the corresponding utility function models are established,respectively.Then,the green certificate transaction model and the profit model based on the Cournot game are built for IESP.Finally,a master-slave game model is proposed,where the IESP serves as the leader while the energy users work as the followers.Besides,the uniqueness of the master-slave game equilibrium is proved and the effectiveness of the proposed optimization approach is verified through simulation analysis.Note that,in view of the renewable energy power generation characteristics,the IESP can get its revenue by selling the green certificates in the green certificate market,which takes renewable energy generation as the benchmark.The simulation results show that after the optimization process with game,the users’ cost decreased.For IESP,its cost increased slightly through game process,but the energy supply pressure was relieved significantly.Compared to the case without green certificates,the profits of IESP increased when considering green certificate transactions,and promoted the utilization of renewable energy remarkably.