Joint Optimal Operation of Multi-Regional Integrated Energy System Considering the Supply and Demand of Carbon Emission Rights

With the opening of the national carbon emission trading market, carbon trading cost has become an important factor affecting low-carbon economic operation of the multi-regional integrated energy system (MRIES). The existing carbon trading cost calculation is based on the premise that the supply of carbon emission rights exceeds the demand. However, the supply of carbon emission rights in the carbon emission trading market may not meet the purchase demand of carbon emission rights in a regional integrated energy system (RIES), resulting in the shortage of carbon emission rights. Therefore, there should be a numerical upper limit on the amount of carbon emission rights purchased by the RIES in the process of carbon emission trading, which in turn is affected by the amount of carbon emission rights sold by other RIESs in the MRIES. In view of the above situation, a joint calculation model of carbon trading cost considering the relationship between supply and demand of carbon emission rights and the constraint of the amount of carbon emission rights purchased was proposed, which can study the carbon emission trading within the MRIES and the carbon emission trading between the MRIES and the external system. The model also has nonlinear constraints, and it needs to be linearized by introducing new decision variables to reduce the computational difficulty. In addition, in order to make use of the characteristic of multi-region interconnection of MRIES, a cooperative game model of the MRIES based on Nash bargaining considering the electric power and thermal power interaction between different RIESs was proposed, which can strengthen the connection between different RIESs, reduce the overall economic cost of MRIES and realize the function that the price of power interaction can be set flexibly among different RIESs. But the cooperative game model is a nonconvex nonlinear model, which needs to be transformed into two subproblems to be solved step by step. The lowest economic cost of the MRIES was calculated in the first subproblem to improve the overall economic benefits of the system, and the optimal power interaction plan was solved in the second subproblem to improve the individual economic benefits of RIESs. In the case study, the optimization results of the joint calculation model of carbon trading cost and the calculation model of reward and punishment ladder-type carbon trading cost were compared, the influence of power interaction between different RIESs on system operation was studied, and the relationship between carbon trading price and carbon emission trading plan was also analyzed. The following conclusions can be drawn: (1) Compared with the calculation model of reward and punishment ladder-type carbon trading cost, the joint calculation model of carbon trading cost can further reduce carbon emission, avoid the occurrence of carbon emission exceeding the standard, and is more conducive to macro-control. (2) The power interaction between different RIESs can make full use of the operation characteristics of each RIES, realize the reasonable distribution of economic cost, and obtain a significant increase in economic benefits by appropriately increasing carbon emission. (3) The quantity of carbon emission rights purchased is negatively correlated with the carbon trading price, while the quantity of carbon emission rights sold is positively correlated with the carbon trading price. When the calculated total amount sold is higher than the total amount purchased, there are redundant carbon emission rights in the carbon trading market, in this case, the regulatory department needs to adjust the distribution coefficient of free carbon emission to further promote the system to reduce carbon emission. © 2023 Chinese Machine Press. All rights reserved.