Game Of Port-shipping Company Two-echelon Supply Chain Considering Different Emission Abatement Policies

Ships emit a range of contaminants,which have posed serious threats to the environment and public health.This has aroused great concern worldwide.Many policies have been issued by the International Maritime Organization（IMO）and by various countries,such as the global sulphur cap,emission control areas（ECAs）,speed reduction incentive policy and fuel price subsidy.To explore effective incentives to control air pollution from ships,the study established game model of two-echelon supply chains composed of ports and shipping companies with consideration of various abatement policies.The main works and results are as follows:（1）The game model of multi-shipping company considering differential vessel speeds under IMO emission abatement policy is developed,and the effects of IMO emission abatement policy are evaluated and analyzed.By analyzing the game relationship between shipping companies,a multi-shipping company game model aiming at maximizing the shipping companies’profit is developed,in which vessel speed inside ECAs,vessel speed outside ECAs and freight volume are the decision variables.The effects of IMO’s global sulphur cap and ECA policy on SO₂ and CO₂emissions are evaluated.The results show that optimal vessel speed is determined by fuel prices.Moreover,the shipping companies will always reduce their speeds inside ECAs,regardless of the fuel price.IMO’s global sulphur cap and ECA policy do not always reduce SO₂ and CO₂ emissions.In some cases,they will increase SO₂ and CO₂emissions.（2）The evolutionary game model of ports and shipping companies under the speed reduction policy is proposed,and the evolutionary game behavior of ports and shipping companies and its influencing factors are studied.Vessel speed reduction policy is proposed,where the ECA is the speed reduction zone.The evolutionary game model between ports and shipping companies is proposed based on the revenue matrix,and the stability of evolutionary game strategy of port,shipping company,and port-shipping company system are analysed,respectively.It is found that there exists four and five evolutionary stability strategies for ports and shipping companies,respectively.Under any conditions,（non-subsidy,non-speed reduction）is not an evolutionary stability strategy for the port-shipping company system.Under certain conditions,（non-subsidy,speed reduction）,（subsidy,non-speed reduction）,and（subsidy,speed reduction）are the evolutionary stability strategies for the port-shipping company system.The simulation results show that fuel price has little influence on the evolution results.But port subsidy price,opportunity cost,and operation cost play important roles in whether the shipping companies choose speed reduction strategy.（3）The dynamic game models between ports and shipping companies under the speed reduction fuel subsidy policy are developed,and the effects of the policy under different game structures on the operations of ports and shipping companies,and the environment are analyzed.To motivate shipping companies to abate emissions by reducing vessel speed,an incentive policy providing fuel price subsidy to vessels sailing at reduced speed in ECA is proposed.According to the vertical game relations between ports and shipping companies,and the horizontal game relations inside the two group stakeholders,two Stackelberg game models（N-N model and N-S model）are developed considering whether the port-shipping company supply chain implements the speed reduction fuel subsidy policy.In both game models,the ports are leaders and the shipping companies are followers.In N-N model,both the ports and shipping companies play Nash game.In N-S model,the ports play Nash game,while inside the shipping companies there is a leader-follower relationship.The effects of speed reduction fuel subsidy policy on the operations of ports and shipping companies,and the SO₂ and CO₂ emissions are evaluated.The results show that whether there is a leader-follower relationship between shipping companies or not,the subsidy price only affects the service price of ports implementing the speed reduction fuel subsidy policy,and has no effect on shipping companies’freight rate and freight volume.The speed reduction fuel subsidy policy does not always reduce emissions of ports where it is implemented.When fuel price is high,N-N game is unfavorable to the port implementing the speed reduction fuel subsidy policy,and N-S game is unfavorable to the port without taking measures.（4）The dynamic game models of government,ports,and shipping companies under government intervention and speed reduction fuel subsidy policy are developed,and the effects of government subsidy policy and tax policy on ports’and shipping companies’decision-making and environment are analyzed.The government adopts sharing subsidy policy and tax policy to encourage ports to abate emission,and the port-shipping company supply chain can decide whether to implement speed reduction fuel subsidy or not.According to the game relations between government,ports and shipping companies,two three-stage dynamic game models for the government,ports and shipping companies are developed under the sharing subsidy policy and the tax policy,respectively.The effects of sharing subsidy policy and tax policy on the operations of ports and shipping companies,and regional environment are analyzed.The results show that compared to sharing subsidy policy,tax policy is more favorable to port-shipping company supply chain implementing speed reduction fuel subsidy policy.Both government policies contribute to regional environment improvements,but which policy is more effective in reducing emissions depends on optimal tax rate,congest cost,etc.