The Capacity And Operation Optimization Of Integrated Energy Systems Including Photovoltaic And Energy Storage

Excessive consumption of fossil energy has exacerbated the global energy crisis and environmental pollution.Accelerating the development of green,efficient and sustainable energy has become a global consensus.An integrated energy system(IESS)with renewable energy and energy storage can effectively reduce the fossil energy consumption and carbon emissions,which has a great potential to solve the energy crisis and environmental pollution.However,the introduction of renewable energy and energy storage system makes the optimization of energy system more complex,especially when the renewable energy and energy storage system exist at the same time,which brings great difficulties to the capacity allocation and operation optimization of the integrated energy system.How to determine the reasonable operation strategy and capacity matching of the integrated energy system to realize the optimal utilization of the integrated energy system has been widely concerned by researchers.The existing optimization research of the integrated energy system mainly focuses on the capacity optimization and operation optimization of partial equipments on a typical day.There are relatively few researches on the optimization of the system including renewable energy and energy storage,and most of the researches fail to fully consider the influence of photovoltaic and energy storage equipment on the output of other coordinated operation equipment under the hourly load of the user side throughout the year.Therefore,this paper takes an energy station as an example and puts forward an optimization method for equipment capacity and operation in the integrated energy system including photovoltaic and energy storage based on the hourly cooling,heating and electricity load of the user side throughout the year.The main research contents and results of this paper are as follows:(1)The mathematical model of the equipment in the integrated energy system is built.The hourly load of the user side throughout the year of the energy station is taken as the constraint of the model.By taking into account TOU electricity price,quarterly gas price,photovoltaic subsidy and surplus generation feed-in grid,The objective function is to minimize the annual total cost(Annual operating expenses,Total initial investment in equipment,Maintenance costs of equipment,Depreciation expense of equipment,).By using Mathematica software,the sensitivity analysis and capacity optimization of the integrated energy system under the two working conditions of not including photovoltaic and energy storage equipment,and containing photovoltaic and energy storage equipment are comparatively analyzed.The results show that: The total annual cost of operating of the first condition after capacity optimization is reduced by4.43% compared with the original system.The total annual cost of operating of the second condition after capacity optimization is reduced by 7.9% compared with the original system Therefore,this optimization method can effectively reduce the total annual cost of the system,and the photovoltaic and energy storage equipment can effectively enhance the collaborative operation performance of the energy supply equipment,and improve the operation economy of the integrated energy system.(2)By taking the minimum operating cost of the typical days of the energy station system in winter and summer as the objective function,Mathematica is used to analyze and compare the operating costs of the energy station under typical days of partial load(100%,75%,50%,25%)of five working conditions which includes the original system,the original system with the heat storage,the original system with the cold storage,the original system with the cold and the heat equipment,the original system with the photovoltaic and the cold and the heat storage equipment.The results show that:Compared with first operating conditions,the annual operating costs of the second to the fifth operating conditions are respectively reduced by 1.44%,0.35%,1.79% and4.75%.It can be seen that photovoltaic and the energy storage equipment can effectively use the renewable energy,reduce the power consumption and the power purchased from the grid of equipment,and it also verifies the accuracy of capacity optimization.(3)This paper fully considers the influence of different loads and special weather factors on the output status of the energy supply equipment.The equipment optimization scheduling analysis was carried out for the integrated energy system including photovoltaic and energy storage equipment on typical days(100%,75%,50%,25%)under different load conditions in winter/summer and typical days with very low illumination,and output of each energy supply equipment is obtained which provides reference opinions for the operation and energy supply equipment regulation of the actual integrated energy system.When the electricity price is at a higher stage,the output of the gas turbine increases within the capacity range with the reduction of the output of photovoltaic power generation system on typical days with very low illumination.The insufficient supply of electrical load is met by the power purchased from the grid,while the output of other equipment is basically unchanged.The insufficient supply of electrical load is met by the power purchased from the grid,while the output of other equipment is basically unchanged due to the unchanged load of the typical days.