Research On Low-carbon Operation Optimization Of Integrated Energy System Cousidering Life Cycle Carbon Footprint

Facing the serious shortage of energy reserves and environmental pollution problems,how to improve energy efficiency and achieve green development has become one of the important issues in the world.The integrated energy system has been widely studied and used by many countries for its advantages of flexible energy supply,low pollution,high energy efficiency and low cost.In order to give full play to the advantages of energy conservation and carbon reduction of the integrated energy system and accelerate the formation of a collaborative and complementary,comprehensive utilization,intensive and efficient energy supply mode of various energy sources,this paper carries out research from the following two aspects.On the one hand,from the perspective of carbon emission accounting of the integrated energy system,with the help of the life cycle assessment method,the key units of carbon emission in the system are identified to provide reference for the formulation of reasonable and effective carbon emission reduction program.On the other hand,from the perspective of operation optimization of the integrated energy system,the energy supply scheme of the integrated energy system including carbon emission cost is optimized to form a stable and reliable system operation strategy,to achieve the optimal system efficiency and minimum cost in a real sense,and provide technical support to realize the efficient allocation of energy and energy saving and emission reduction.The details are as follows:(1)Taking the accurate assessment of carbon emissions of the integrated energy system as the research objective,this paper takes the life cycle assessment method as the core,combines the measuring method,material balance algorithm,emission coefficient method and asset estimation method,completes the analysis of the full life cycle list of gas turbine,waste heat boiler,lithium bromide refrigerator,photovoltaic module,gas boiler and electric compression refrigeration unit,the life cycle carbon emission of each equipment was calculated.The results show that the total life cycle carbon emission of the integrated energy system is about 1.141,500 tons,and the natural gas consumption during the operation stage is the main carbon emission unit.Without considering the power consumption of natural gas combustion and electric compression refrigeration unit,the total carbon emission of the system is 872.99 tons during the life cycle.Among them,the gas turbines produced the most carbon emissions(504.93 tons),followed by waste heat boilers(110.30 tons),lithium bromide refrigeration units(91.41 tons),electric compression refrigeration units(75.22 tons),photovoltaic units(69.23 tons)and gas boilers(21.90 tons).On this basis,combined with the energy output of each device,the carbon emission coefficient of each device’s unit energy supply is calculated,providing data support for the construction of low-carbon operation optimization model of the integrated energy system.(2)To investigate the influence of carbon emission cost on the operation strategy of the integrated energy system,for the integrated energy system of a park covering an area of 130,000 square meters in Beijing,with the minimum total cost of the system as the objective function,the balance of cold,heat and electricity supply and demand and the equipment output limit as the main constraint conditions,combined with the unit carbon emission coefficient of the energy supply equipment determined above,two sets of integrated energy system operation optimization models without considering carbon emission cost and with considering carbon emission cost were constructed respectively,and genetic algorithm was used to solve the two optimization models respectively.The results show that when carbon emission cost is considered,the energy supply proportion of equipment with lower unit carbon emission coefficient is increased.Among them,the energy supply ratio of gas turbine,lithium bromide refrigerator and waste heat boiler increased from 83.51%,54.11%and 79.53%to 91.05%,56.02%and 91.04%,respectively.The comparison of the economic costs of the two energy supply schemes shows that the energy supply scheme generated by scenario 2 considering carbon emission cost has smaller carbon emissions and lower cost,which well verifies the feasibility of improving the optimal configuration scheme of the system by expanding the capacity of equipment with high energy efficiency.Based on the above research,on the one hand,key carbon emission units can be identified according to the carbon emission accounting results of the whole life cycle of the integrated energy system,so as to lock carbon reduction objects and formulate more targeted low-carbon equipment transformation measures.On the other hand,based on the optimization results generated by solving the low-carbon model,the optimal energy supply mode with energy-saving and carbon reduction characteristics is generated.Both of them provide reference for the smooth realization of the goal of"carbon peak and carbon neutrality".