Economic And Environmental Benefits Research And System Optimization Design Of Micro Energy Grid

In recent years,with the continuous expansion of the scale of the power grid,the disadvantages of traditional power system are becoming more and more prominent.The increasingly exhausted fuel resources,the aging of the power system structure and the bottleneck of the efficiency of energy utilization are difficult to adapt to the higher security and reliability requirements of the users.More and more energy problems became a critic challenge in the world.Many scholars focus on distributed energy,but distributed energy is widely distributed compared to the centralized power supply mode,and it is difficult to break energy barriers between different kinds of energy sources.As a terminal type micro integrated energy system,MEG(micro energy grid)meets the significance and purpose of developing integrated energy system.It is of small scale and easy to realize,with great popularization value.,Due to the provision of electricity,cold and heat services at the same time,MEG has a higher rate of return on investment than micro-grid.In addition,its construction has great benefit to society,energy supply side,energy consumption side,energy transmission side and so on.Therefore,the research on simulation optimization and sensitivity analysis of MEG is particularly important.Through the field investigation of a MEG industrial park in Ji'nan,the data of each capacity element,energy storage element,energy use data and energy management system in the structure of the Industrial Park MEG was collected.The key factors that restrict the economic benefits and environmental benefits were identified by the combination with HOMER 3.7.6 software and artificial thermodynamic calculation.In view of the constraints of the existing MEG system,the optimization design of the MEG system was designed,the specific installation scheme is formulated.Scenario analysis method was used to obtain the economic and environmental benefits of the MEG optimization system under different situations,and the sensitivity analysis of the optimization structure of the MEG under each situation was carried out.The impact of sensitive variables on the economic benefits of the park was researched.Finally,the prediction indicators of the optimal design structure of the MEG were obtained.Compared to the ordinary grid users without MEG structure,the existing MEG structure mainly produced economic benefit of 408.5 thousand RMB per year by peeling peak and filling valley through water storage.The estimated value of the existing MEG structure pollutant emission reduction was 14.63%.However,there were some factors to be optimized,such as the lack of reliability(small power equipment installed capacity,unstable output power),economic optimization(non-optimal economic installed capacity,low water storage utilization),and the single power generation situation.Therefore,the structure of the MEG system was optimized,with the gas supply structure added.By using scenario analysis method,the results of the annual economic benefits of three scenarios were 1.817 million per year for planning scenario,1.876 million per year for intermediate scenatio and 1.921 million per year for the optimal scenario,and the reduction of SO2 was increased significantly in the three scenarios,which are 3-4 tons per year.With the natural gas price as a sensitive variable,the sensitivity analysis of three systems optimization design scenarios was carried out,and the economic benefits of all natural gas prices are ranked as the optimal scenario>intermediate scenario>planning scenario.When the price of natural gas goes to 3 RMB/m3,the average energy efficiency of the MEG in the three scenarios was the highest.In the comparison and analysis of the optimization design results of the micro energy network system,it is found that the micro gas triple supply MEG structure can improve the comprehensive utilization efficiency of the primary energy,and make up the shortage of the low efficiency of power generation and the heat transmission loss of the heating network.Using natural gas as primary energy for cascade utilization,its SO2 emission reduction effect is remarkable,as the difference of the composition of natural gas and coal.As for the structure of the micro energy network,natural gas is reliable as a primary energy use,and it can make up the shortage of the current single energy form of micro-grid.It is very important to improve the economic benefits and environmental benefits of the operation of the MEG park.