Research On Low-carbon Economic Dispatch Of Integrated Electricity-gas Energy System Considering Carbon Capture,Utilization And Storage

In order to implement the goal of achieving carbon peak by 2030 and carbon neutrality by 2060 proposed by China,promoting the transformation of fossil energy to renewable energy and energy conservation and emission reduction are important trends in the future development of energy systems.Integrated electricity-gas system(IEGS)is an integrated system that takes fossil energy such as coal,oil and natural gas as the core and includes renewable energy such as wind energy and solar energy.It realizes the deep coupling between different heterogeneous sub-energy systems and has a great potential to reduce emissions.In this context,this paper conducts a study on the low carbon economic dispatch strategy of an integrated electricity-gas system considering carbon capture,utilization and storage(CCUS)technology,with the main research contents as follows:(1)The infrastructure of an integrated electricity-gas system is constructed and the mathematical models of the energy subsystems and coupled equipment are modeled and analyzed.Firstly,the operation mode of an integrated electricity-gas energy system considering CCUS is analyzed.According to the Newton-Raphson method(N-L method)and Weymouth equation,the power flow model of power network and the power flow model of natural gas network are established respectively.Then,the mathematical models of power to gas(P2G)device and gas turbine are established and their operation mechanism in IEGS is analyzed.Secondly,the principle of three carbon capture methods and the operation characteristics of carbon capture power plants are analyzed.Finally,the carbon trading cost models and function images under the two carbon trading mechanisms are constructed respectively,laying a theoretical foundation for the subsequent research on low carbon economic dispatch.(2)Aiming at the problem of large amounts of carbon emissions caused by fuel combustion in thermal power units,a CCPP-P2G system coupled with carbon capture power plant(CCPP)and P2G device is constructed.The carbon capture device can transport the captured CO2 to the P2G device to produce synthetic natural gas,which not only reduces carbon emissions but also injects SNG into the natural gas network as an input to reduce gas purchase costs;P2G installations are driven by excess wind power and can effectively reduce wind abandonment.On the basis of this,a low-carbon economic dispatch model of IEGS with the sum of system operation cost and carbon trading cost minimized as the objective function is established.The simulation results show that the CCPP-P2G system can effectively reduce the operating costs and carbon emissions of IEGS and improve the capacity to consume renewable energy.(3)Considering that it is difficult to take into account the economics of both energy networks in a unified modeling,a bi-level dispatching model of an integrated electricity-gas energy system based on CCUS technology has been developed.Firstly,an upper-level natural gas system optimal allocation model and a lower-level power system low-carbon economic dispatch model are developed,and then the lower-level model is transformed and added to the upper-level model based on the KKT conditions of the lower-level model.The non-linear terms are then linearized so that the difficult to solve bi-level model is transformed into a mixed integer linear programming problem.Secondly,a ladder carbon trading mechanism is also introduced to transform the system carbon emissions into economic benefits.Finally,the low-carbon and economical characteristics of the proposed IEGS bilevel model are demonstrated through simulation calculations.