The Two-echelon Open Location Routing Problem Considering The Carbon Emission

At present,urban environmental pollution is severe,especially the air pollution,and the air pollution is dominated by CO₂ emissions.Cities are densely populated,and the frequency of transportation and distribution activities is high.In this process,CO₂ emissions from fuel vehicles have become one of the main sources of urban air pollution.Electric vehicles are driven by electricity,and thermal power generation is the main power generation method in China,and this power generation method still generates a lot of CO₂.In summary,how to reduce energy consumption and CO₂ emissions on the basis of existing facilities has a significant impact on reducing environmental pollution.When distributing activities within the city,due to the complicated road network and uneven distribution of traffic volume,the speed differences between road sections will be large.In summary,when distributing in cities,the impact of speed on energy consumption and CO₂ emissions should be considered.For distribution in cities with sufficient supply of goods,as long as the ability to organize and manage goods is improved,the open mode of transportation and distribution will be one of the most effective ways to reduce the empty load rate and transportation cost of vehicles in cities.Logistics enterprises take profit as the first goal,and reducing environmental pollution is an inescapable social responsibility;so,in order to reduce the overall distribution cost and CO₂ emissions,this paper addresses the traditional two-stage open location-routing problem（2E-OLRP）,considering the impact of speed and load on energy consumption and CO₂emissions,the 2E-OLRP models considering CO₂ emission for fuel and electric vehicles were established based on the driving and emission characteristics of fuel and electric vehicles respectively.An simulated annealing algorithm is proposed to solve the models.In order to verify the advantages of the models proposed in this paper in terms of energy saving and emission reduction,the models proposed in this paper is compared with the traditional2E-OLRP model（without considering the carbon emission model）.The results show that the model proposed in this paper has obvious advantages in energy saving and emission reduction compared with the traditional 2E-OLRP model;in terms of transportation activities,electric vehicles can save 3.44%of the total cost and reduce 74.03%of CO₂ emissions compared with fuel vehicles indicate that in transportation activities,enterprises should give priority to matching electric vehicles for distribution services.In order to verify the effectiveness and practicability of the models and algorithms in this paper,the models proposed in this paper were solved using the accurate solver CPLEX and simulated annealing algorithm,and the algorithm results of the two models were compared with the exact solutions.The average difference 3.79%and 4.55%,and the average time of 262.70 and 336.84 seconds show that the proposed algorithm can quickly and efficiently solve such models;the performance of the algorithm in this paper when solving model P2 is better than that of model P3;the above research results can provide decision support for energy saving and emission reduction in distribution.